Chimpanzees prefer African and Indian music over silence.

PubMed

Mingle, Morgan E; Eppley, Timothy M; Campbell, Matthew W; Hall, Katie; Horner, Victoria; de Waal, Frans B M

2014-10-01

[Correction Notice: An Erratum for this article was reported in Vol 40(4) of Journal of Experimental Psychology: Animal Learning and Cognition (see record 2014-35305-001). For the article, the below files were used to create the audio used in this study. The original West African akan and North Indian raga pieces were used in their entirety and the Japanese taiko piece was used from the 0:19 second mark through the end. The tempo of each piece was adjusted so that they maintained an identical base tempo of 90 beats per minute, then looped to create 40 minutes of continuous music. Additionally, the volume of the music was standardized at 50 dB so that the all music maintained the same average amplitude. All audio manipulations were completed using GarageBand © (Apple Inc.).] All primates have an ability to distinguish between temporal and melodic features of music, but unlike humans, in previous studies, nonhuman primates have not demonstrated a preference for music. However, previous research has not tested the wide range of acoustic parameters present in many different types of world music. The purpose of the present study is to determine the spontaneous preference of common chimpanzees (Pan troglodytes) for 3 acoustically contrasting types of world music: West African akan, North Indian raga, and Japanese taiko. Sixteen chimpanzees housed in 2 groups were exposed to 40 min of music from a speaker placed 1.5 m outside the fence of their outdoor enclosure; the proximity of each subject to the acoustic stimulus was recorded every 2 min. When compared with controls, subjects spent significantly more time in areas where the acoustic stimulus was loudest in African and Indian music conditions. This preference for African and Indian music could indicate homologies in acoustic preferences between nonhuman and human primates. .

No evidence for transmission of SIVwrc from western red colobus monkeys (piliocolobus badius badius) to wild west african chimpanzees (pan troglodytes verus) despite high exposure through hunting

PubMed Central

2011-01-01

Background Simian Immunodeficiency Viruses (SIVs) are the precursors of Human Immunodeficiency Viruses (HIVs) which have lead to the worldwide HIV/AIDS pandemic. By studying SIVs in wild primates we can better understand the circulation of these viruses in their natural hosts and habitat, and perhaps identify factors that influence susceptibility and transmission within and between various host species. We investigated the SIV status of wild West African chimpanzees (Pan troglodytes verus) which frequently hunt and consume the western red colobus monkey (Piliocolobus badius badius), a species known to be infected to a high percentage with its specific SIV strain (SIVwrc). Results Blood and plasma samples from 32 wild chimpanzees were tested with INNO-LIA HIV I/II Score kit to detect cross-reactive antibodies to HIV antigens. Twenty-three of the samples were also tested for antibodies to 43 specific SIV and HIV lineages, including SIVwrc. Tissue samples from all but two chimpanzees were tested for SIV by PCRs using generic SIV primers that detect all known primate lentiviruses as well as primers designed to specifically detect SIVwrc. Seventeen of the chimpanzees showed varying degrees of cross-reactivity to the HIV specific antigens in the INNO-LIA test; however no sample had antibodies to SIV or HIV strain - and lineage specific antigens in the Luminex test. No SIV DNA was found in any of the samples. Conclusions We could not detect any conclusive trace of SIV infection from the red colobus monkeys in the chimpanzees, despite high exposure to this virus through frequent hunting. The results of our study raise interesting questions regarding the host-parasite relationship of SIVwrc and wild chimpanzees in their natural habitat. PMID:21284842

Chimpanzees (Pan troglodytes) Are Predominantly Right-Handed: Replication in Three Populations of Apes

PubMed Central

Hopkins, William D.; Wesley, Michael J.; Izard, M. Kay; Hook, Michelle; Schapiro, Steven J.

2007-01-01

Population-level right-handedness has historically been considered a hallmark of human evolution. Even though recent studies in chimpanzees (Pan troglodytes) have demonstrated population-level right-handedness for certain behaviors, some have questioned the validity and consistency of these findings by arguing that reported laterality effects are specific to certain colonies of apes and to those chimpanzees reared by humans. The authors report evidence of population-level right-handedness in 3 separate colonies of chimpanzees. Moreover, handedness in the 3 colonies was unrelated to the proportion of subjects that were raised by humans. This is the strongest evidence to date that population-level handedness is evident in chimpanzees and is not an artifact of human rearing. PMID:15174946

Stone tool production and utilization by bonobo-chimpanzees (Pan paniscus).

PubMed

Roffman, Itai; Savage-Rumbaugh, Sue; Rubert-Pugh, Elizabeth; Ronen, Avraham; Nevo, Eviatar

2012-09-04

Using direct percussion, language-competent bonobo-chimpanzees Kanzi and Pan-Banisha produced a significantly wider variety of flint tool types than hitherto reported, and used them task-specifically to break wooden logs or to dig underground for food retrieval. For log breaking, small flakes were rotated drill-like or used as scrapers, whereas thick cortical flakes were used as axes or wedges, leaving consistent wear patterns along the glued slits, the weakest areas of the log. For digging underground, a variety of modified stone tools, as well as unmodified flint nodules, were used as shovels. Such tool production and utilization competencies reported here in Pan indicate that present-day Pan exhibits Homo-like technological competencies.

Electrocardiogram reference intervals for clinically normal wild-born chimpanzees (Pan troglodytes).

PubMed

Atencia, Rebeca; Revuelta, Luis; Somauroo, John D; Shave, Robert E

2015-08-01

To generate reference intervals for ECG variables in clinically normal chimpanzees (Pan troglodytes). 100 clinically normal (51 young [< 10 years old] and 49 adult [≥ 10 years old]) wild-born chimpanzees. Electrocardiograms collected between 2009 and 2013 at the Tchimpounga Chimpanzee Rehabilitation Centre were assessed to determine heart rate, PR interval, QRS duration, QT interval, QRS axis, P axis, and T axis. Electrocardiographic characteristics for left ventricular hypertrophy (LVH) and morphology of the ST segment, T wave, and QRS complex were identified. Reference intervals for young and old animals were calculated as mean ± 1.96•SD for normally distributed data and as 5th to 95th percentiles for data not normally distributed. Differences between age groups were assessed by use of unpaired Student t tests. RESULTS Reference intervals were generated for young and adult wild-born chimpanzees. Most animals had sinus rhythm with small or normal P wave morphology; 24 of 51 (47%) young chimpanzees and 30 of 49 (61%) adult chimpanzees had evidence of LVH as determined on the basis of criteria for humans. Cardiac disease has been implicated as the major cause of death in captive chimpanzees. Species-specific ECG reference intervals for chimpanzees may aid in the diagnosis and treatment of animals with, or at risk of developing, heart disease. Chimpanzees with ECG characteristics outside of these intervals should be considered for follow-up assessment and regular cardiac monitoring.

Placentophagy in wild chimpanzees (Pan troglodytes verus) at Bossou, Guinea.

PubMed

Fujisawa, Michiko; Hockings, Kimberley J; Soumah, Aly Gaspard; Matsuzawa, Tetsuro

2016-04-01

Despite intensive observation of nonhuman great apes during long-term field studies, observations of great ape births in the wild are rare. Research on wild chimpanzees (Pan troglodytes verus) at Bossou in the Republic of Guinea has been ongoing for 35 years, yet chimpanzee parturitions have been observed on only two occasions. Here we provide information regarding both chimpanzee births, with detailed information from the close observation of one. During this birth, the mother built a day nest in a tree before parturition. After giving birth, the mother consumed the placenta, and the other chimpanzees in her party gathered near her and her neonate. However, she did not share the placenta, and consumed it all herself. In the second observation, the mother also built a nest in a tree and subsequently gave birth. Thereafter, she shared the placenta with some individuals and consumed part of the placenta herself. Although maternal placentophagy is a ubiquitous behavior among the majority of non-human primates, observations of placenta sharing by wild primates are infrequent, and the proximate and ultimate explanations for the behavior remain unclear.

Echocardiography parameters of clinically normal adult captive chimpanzees (Pan troglodytes).

PubMed

Sleeper, Meg M; Drobatz, Ken; Lee, D Richard; Lammey, Michael L

2014-04-15

To generate reference ranges for echocardiographic variables in clinically normal adult chimpanzees (Pan troglodytes). Retrospective cohort study. 88 clinically normal adult chimpanzees. Echocardiographic data obtained between 2002 and 2011 from chimpanzees at the Alamogordo Primate Facility were reviewed (263 echocardiograms obtained from 158 individuals). Data from clinically normal individuals (33 females and 55 males) were analyzed. Basic cardiac parameters measured in all individuals included aortic root diameter and left atrial diameter in the short and long axis during diastole. Left ventricular measurements included left ventricular internal diameter in systole and diastole and diastolic septal and posterior wall thickness. The E point to septal separation was also measured. Spectral Doppler measurements included the peak flow velocity of the pulmonary artery and aorta and diastolic transmitral flow. The presence of arrhythmias was also noted. Standard echocardiographic findings for a large group of adult female and male chimpanzees were obtained. Female and male chimpanzees were grouped by age in 10-year blocks, and echocardiographic findings were analyzed statistically by 10-year block. In male chimpanzees, cardiac arrhythmias were noted to increase with age. Cardiovascular disease is an important cause of morbidity and death in captive chimpanzees; however, basic echocardiographic measurements from a large cohort of clinically normal animals have not previously been reported. The number of animals in the present study was insufficient to generate reference ranges; however, data from a large cohort of clinically normal animals are presented. This information will be useful for veterinarians working in clinical and research settings with this species.

Chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) quantify split solid objects.

PubMed

Cacchione, Trix; Hrubesch, Christine; Call, Josep

2013-01-01

Recent research suggests that gorillas' and orangutans' object representations survive cohesion violations (e.g., a split of a solid object into two halves), but that their processing of quantities may be affected by them. We assessed chimpanzees' (Pan troglodytes) and bonobos' (Pan paniscus) reactions to various fission events in the same series of action tasks modelled after infant studies previously run on gorillas and orangutans (Cacchione and Call in Cognition 116:193-203, 2010b). Results showed that all four non-human great ape species managed to quantify split objects but that their performance varied as a function of the non-cohesiveness produced in the splitting event. Spatial ambiguity and shape invariance had the greatest impact on apes' ability to represent and quantify objects. Further, we observed species differences with gorillas performing lower than other species. Finally, we detected a substantial age effect, with ape infants below 6 years of age being outperformed by both juvenile/adolescent and adult apes.

Exploring the Relationship Between Cerebellar Asymmetry and Handedness in Chimpanzees (Pan troglodytes) and Capuchins (Cebus apella)

PubMed Central

Phillips, Kimberley A.; Hopkins, William D.

2007-01-01

A comparative study of chimpanzee (Pan troglodytes) and capuchin monkey (Cebus apella) cerebellar asymmetry and its relationship to handedness was conducted. Magnetic resonance images of the brain and behavioral data on a coordinated bimanual task were obtained from 16 chimpanzees and 11 capuchins. Chimpanzees displayed a greater rightward bias of the posterior cerebellum and capuchins displayed a greater leftward bias of the anterior cerebellum. Cerebellar asymmetries were significantly associated with handedness in capuchins but not chimpanzees, and this effect was most pronounced in right-handed capuchins. PMID:17382360

An evaluation of the efficacy of video displays for use with chimpanzees (Pan troglodytes).

PubMed

Hopper, Lydia M; Lambeth, Susan P; Schapiro, Steven J

2012-05-01

Video displays for behavioral research lend themselves particularly well to studies with chimpanzees (Pan troglodytes), as their vision is comparable to humans', yet there has been no formal test of the efficacy of video displays as a form of social information for chimpanzees. To address this, we compared the learning success of chimpanzees shown video footage of a conspecific compared to chimpanzees shown a live conspecific performing the same novel task. Footage of an unfamiliar chimpanzee operating a bidirectional apparatus was presented to 24 chimpanzees (12 males, 12 females), and their responses were compared to those of a further 12 chimpanzees given the same task but with no form of information. Secondly, we also compared the responses of the chimpanzees in the video display condition to responses of eight chimpanzees from a previously published study of ours, in which chimpanzees observed live models. Chimpanzees shown a video display were more successful than those in the control condition and showed comparable success to those that saw a live model. Regarding fine-grained copying (i.e. the direction that the door was pushed), only chimpanzees that observed a live model showed significant matching to the model's methods with their first response. Yet, when all the responses made by the chimpanzees were considered, comparable levels of matching were shown by chimpanzees in both the live and video conditions. © 2012 Wiley Periodicals, Inc.

An Evaluation of the Efficacy of Video Displays for Use With Chimpanzees (Pan troglodytes)

PubMed Central

HOPPER, LYDIA M.; LAMBETH, SUSAN P.; SCHAPIRO, STEVEN J.

2013-01-01

Video displays for behavioral research lend themselves particularly well to studies with chimpanzees (Pan troglodytes), as their vision is comparable to humans’, yet there has been no formal test of the efficacy of video displays as a form of social information for chimpanzees. To address this, we compared the learning success of chimpanzees shown video footage of a conspecific compared to chimpanzees shown a live conspecific performing the same novel task. Footage of an unfamiliar chimpanzee operating a bidirectional apparatus was presented to 24 chimpanzees (12 males, 12 females), and their responses were compared to those of a further 12 chimpanzees given the same task but with no form of information. Secondly, we also compared the responses of the chimpanzees in the video display condition to responses of eight chimpanzees from a previously published study of ours, in which chimpanzees observed live models. Chimpanzees shown a video display were more successful than those in the control condition and showed comparable success to those that saw a live model. Regarding fine-grained copying (i.e. the direction that the door was pushed), only chimpanzees that observed a live model showed significant matching to the model’s methods with their first response. Yet, when all the responses made by the chimpanzees were considered, comparable levels of matching were shown by chimpanzees in both the live and video conditions. PMID:22318867

Is music enriching for group-housed captive chimpanzees (Pan troglodytes)?

PubMed

Wallace, Emma K; Altschul, Drew; Körfer, Karoline; Benti, Benjamin; Kaeser, Amanda; Lambeth, Susan; Waller, Bridget M; Slocombe, Katie E

2017-01-01

Many facilities that house captive primates play music for animal enrichment or for caregiver enjoyment. However, the impact on primates is unknown as previous studies have been inconclusive. We conducted three studies with zoo-housed chimpanzees (Pan troglodytes) and one with group-housed chimpanzees at the National Centre for Chimpanzee Care to investigate the effects of classical and pop/rock music on various variables that may be indicative of increased welfare. Study one compared the behaviour and use of space of 18 animals when silence, classical or pop/rock music was played into one of several indoor areas. Overall, chimpanzees did not actively avoid the area when music was playing but were more likely to exit the area when songs with higher beats per minute were broadcast. Chimpanzees showed significantly fewer active social behaviours when music, rather than silence, was playing. They also tended to be more active and engage in less abnormal behaviour during the music but there was no change to either self-grooming or aggression between music and silent conditions. The genre of music had no differential effects on the chimpanzees' use of space and behaviour. In the second study, continuous focal observations were carried out on three individuals with relatively high levels of abnormal behaviour. No differences in behaviour between music and silence periods were found in any of the individuals. The final two studies used devices that allowed chimpanzees to choose if they wanted to listen to music of various types or silence. Both studies showed that there were no persistent preferences for any type of music or silence. When taken together, our results do not suggest music is enriching for group-housed captive chimpanzees, but they also do not suggest that music has a negative effect on welfare.

The influence of ecology on chimpanzee (Pan troglodytes) cultural behavior: a case study of five Ugandan chimpanzee communities.

PubMed

Gruber, Thibaud; Potts, Kevin B; Krupenye, Christopher; Byrne, Maisie-Rose; Mackworth-Young, Constance; McGrew, William C; Reynolds, Vernon; Zuberbühler, Klaus

2012-11-01

The influence of ecology on the development of behavioral traditions in animals is controversial, particularly for chimpanzees (Pan troglodytes), for which it is difficult to rule out environmental influences as a cause of widely observed community-specific behavioral differences. Here, we investigated 3 potential scenarios that could explain the natural variation in a key extractive tool behavior, "fluid-dip," among several communities of chimpanzees of the Pan troglodytes schweinfurthii subspecies in Uganda. We compared data from previous behavioral ecological studies, field experiments, and long-term records of chimpanzee tool-using behavior. We focused on the quality of the available food, dietary preferences, and tool sets of 5 different communities, and carried out a standardized field experiment to test systematically for the presence of fluid-dip in 4 of these communities. Our results revealed major differences in habitat, available diet, and tool use behavior between geographically close communities. However, these differences in ecology and feeding behavior failed to explain the differences in tool use across communities. We conclude that ecological variables may lead both to innovation and loss of behavioral traditions, while contributing little to their transmission within the community. Instead, as soon as a behavioral tradition is established, sociocognitive factors likely play a key maintenance role as long as the ecological conditions do not change sufficiently for the tradition to be abandoned.

Chimpanzee Malaria Parasites Related to Plasmodium ovale in Africa

PubMed Central

Duval, Linda; Nerrienet, Eric; Rousset, Dominique; Sadeuh Mba, Serge Alain; Houze, Sandrine; Fourment, Mathieu; Le Bras, Jacques; Robert, Vincent; Ariey, Frederic

2009-01-01

Since the 1970's, the diversity of Plasmodium parasites in African great apes has been neglected. Surprisingly, P. reichenowi, a chimpanzee parasite, is the only such parasite to have been molecularly characterized. This parasite is closely phylogenetically related to P. falciparum, the principal cause of the greatest malaria burden in humans. Studies of malaria parasites from anthropoid primates may provide relevant phylogenetic information, improving our understanding of the origin and evolutionary history of human malaria species. In this study, we screened 130 DNA samples from chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) from Cameroon for Plasmodium infection, using cytochrome b molecular tools. Two chimpanzees from the subspecies Pan t. troglodytes presented single infections with Plasmodium strains molecularly related to the human malaria parasite P. ovale. These chimpanzee parasites and 13 human strains of P. ovale originated from a various sites in Africa and Asia were characterized using cytochrome b and cytochrome c oxidase 1 mitochondrial partial genes and nuclear ldh partial gene. Consistent with previous findings, two genetically distinct types of P. ovale, classical and variant, were observed in the human population from a variety of geographical locations. One chimpanzee Plasmodium strain was genetically identical, on all three markers tested, to variant P. ovale type. The other chimpanzee Plasmodium strain was different from P. ovale strains isolated from humans. This study provides the first evidence of possibility of natural cross-species exchange of P. ovale between humans and chimpanzees of the subspecies Pan t. troglodytes. PMID:19436742

Moving shadows contribute to the corridor illusion in a chimpanzee (Pan troglodytes).

PubMed

Imura, Tomoko; Tomonaga, Masaki

2009-08-01

Previous studies have reported that backgrounds depicting linear perspective and texture gradients influence relative size discrimination in nonhuman animals (known as the "corridor illusion"), but research has not yet identified the other kinds of depth cues contributing to the corridor illusion. This study examined the effects of linear perspective and shadows on the responses of a chimpanzee (Pan troglodytes) to the corridor illusion. The performance of the chimpanzee was worse when a smaller object was presented at the farther position on a background reflecting a linear perspective, implying that the corridor illusion was replicated in the chimpanzee (Imura, Tomonaga, & Yagi, 2008). The extent of the illusion changed as a function of the position of the shadows cast by the objects only when the shadows were moving in synchrony with the objects. These findings suggest that moving shadows and linear perspective contributed to the corridor illusion in a chimpanzee. Copyright 2009 APA, all rights reserved.

Spontaneous triadic engagement in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes).

PubMed

MacLean, Evan; Hare, Brian

2013-08-01

Humans are believed to have evolved a unique motivation to participate in joint activities that first develops during infancy and supports the development of shared intentionality. We conducted five experiments with bonobos (Pan paniscus) and chimpanzees (Pan troglodytes) (Total n = 119) to assess their motivation to spontaneously participate in joint activities with a conspecific or a human. We found that even the youngest subjects preferred to interact together with a human and a toy rather than engaging in an identical game alone. In addition, we found that subjects could spontaneously interact with a human in a turn-taking game involving passing a ball back and forth and used behaviors to elicit additional interaction when the game was disrupted. However, when paired with a conspecific, subjects preferred to interact with an object individually rather than together. Our results indicate that nonhuman apes are motivated to engage in triadic activities if they occur spontaneously with humans and require a minimum amount of coordination. These findings leave open the question of whether these activities are coordinated through shared intentions.

Is music enriching for group-housed captive chimpanzees (Pan troglodytes)?

PubMed Central

Wallace, Emma K.; Altschul, Drew; Körfer, Karoline; Benti, Benjamin; Kaeser, Amanda; Lambeth, Susan; Waller, Bridget M.; Slocombe, Katie E.

2017-01-01

Many facilities that house captive primates play music for animal enrichment or for caregiver enjoyment. However, the impact on primates is unknown as previous studies have been inconclusive. We conducted three studies with zoo-housed chimpanzees (Pan troglodytes) and one with group-housed chimpanzees at the National Centre for Chimpanzee Care to investigate the effects of classical and pop/rock music on various variables that may be indicative of increased welfare. Study one compared the behaviour and use of space of 18 animals when silence, classical or pop/rock music was played into one of several indoor areas. Overall, chimpanzees did not actively avoid the area when music was playing but were more likely to exit the area when songs with higher beats per minute were broadcast. Chimpanzees showed significantly fewer active social behaviours when music, rather than silence, was playing. They also tended to be more active and engage in less abnormal behaviour during the music but there was no change to either self-grooming or aggression between music and silent conditions. The genre of music had no differential effects on the chimpanzees’ use of space and behaviour. In the second study, continuous focal observations were carried out on three individuals with relatively high levels of abnormal behaviour. No differences in behaviour between music and silence periods were found in any of the individuals. The final two studies used devices that allowed chimpanzees to choose if they wanted to listen to music of various types or silence. Both studies showed that there were no persistent preferences for any type of music or silence. When taken together, our results do not suggest music is enriching for group-housed captive chimpanzees, but they also do not suggest that music has a negative effect on welfare. PMID:28355212

A Longitudinal Assessment of Vocabulary Retention in Symbol-Competent Chimpanzees (Pan troglodytes)

PubMed Central

Beran, Michael J.; Heimbauer, Lisa A.

2015-01-01

A number of studies from the 1960s to 1990s assessed the symbolic competence of great apes and other animals. These studies provided varying forms of evidence that some species were capable of symbolically representing their worlds, both through productive symbol use and comprehension of symbolic stimuli. One such project at the Language Research Center involved training chimpanzees (Pan troglodytes) to use lexigram symbols (geometric visual stimuli that represented objects, actions, locations, and individuals). Those studies now are more than 40 years old, and only a few of the apes involved in those studies are still alive. Three of these chimpanzees (and a fourth, control chimpanzee) were assessed across a 10-year period from 1999 to 2008 for their continued knowledge of lexigram symbols and, in the case of one chimpanzee, the continued ability to comprehend human speech. This article describes that longitudinal assessment and outlines the degree to which symbol competence was retained by these chimpanzees across that decade-long period. All chimpanzees showed retention of lexigram vocabularies, although there were differences in the number of words that were retained across the individuals. One chimpanzee also showed continual retention of human speech perception. These retained vocabularies largely consisted of food item names, but also names of inedible objects, locations, individuals, and some actions. Many of these retained words were for things that are not common in the daily lives of the chimpanzees and for things that are rarely requested by the chimpanzees. Thus, the early experiences of these chimpanzees in symbol-rich environments have produced long-lasting memories for symbol meaning, and those competencies have benefited research in a variety of topics in comparative cognition. PMID:25706561

A longitudinal assessment of vocabulary retention in symbol-competent chimpanzees (Pan troglodytes).

PubMed

Beran, Michael J; Heimbauer, Lisa A

2015-01-01

A number of studies from the 1960s to 1990s assessed the symbolic competence of great apes and other animals. These studies provided varying forms of evidence that some species were capable of symbolically representing their worlds, both through productive symbol use and comprehension of symbolic stimuli. One such project at the Language Research Center involved training chimpanzees (Pan troglodytes) to use lexigram symbols (geometric visual stimuli that represented objects, actions, locations, and individuals). Those studies now are more than 40 years old, and only a few of the apes involved in those studies are still alive. Three of these chimpanzees (and a fourth, control chimpanzee) were assessed across a 10-year period from 1999 to 2008 for their continued knowledge of lexigram symbols and, in the case of one chimpanzee, the continued ability to comprehend human speech. This article describes that longitudinal assessment and outlines the degree to which symbol competence was retained by these chimpanzees across that decade-long period. All chimpanzees showed retention of lexigram vocabularies, although there were differences in the number of words that were retained across the individuals. One chimpanzee also showed continual retention of human speech perception. These retained vocabularies largely consisted of food item names, but also names of inedible objects, locations, individuals, and some actions. Many of these retained words were for things that are not common in the daily lives of the chimpanzees and for things that are rarely requested by the chimpanzees. Thus, the early experiences of these chimpanzees in symbol-rich environments have produced long-lasting memories for symbol meaning, and those competencies have benefited research in a variety of topics in comparative cognition.

Responses to a simple barter task in chimpanzees, Pan troglodytes.

PubMed

Brosnan, Sarah F; de Waal, Frans B M

2005-07-01

Chimpanzees (Pan troglodytes) frequently participate in social exchange involving multiple goods and services of variable value, yet they have not been tested in a formalized situation to see whether they can barter using multiple tokens and rewards. We set up a simple barter economy with two tokens and two associated rewards and tested chimpanzees on their ability to obtain rewards by returning the matching token in situations in which their access to tokens was unlimited or limited. Chimpanzees easily learned to associate value with the tokens, as expected, and did barter, but followed a simple strategy of favoring the higher-value token, regardless of the reward proffered, instead of a more complex but more effective strategy of returning the token that matched the reward. This response is similar to that shown by capuchin monkeys in our previous study. We speculate that this response, while not ideal, may be sufficient to allow for stability of the social exchange system in these primates, and that the importance of social barter to both species may have led to this convergence of strategies.

Age-related decline in ovarian follicle stocks differ between chimpanzees (Pan troglodytes) and humans.

PubMed

Cloutier, Christina T; Coxworth, James E; Hawkes, Kristen

2015-02-01

Similarity in oldest parturitions in humans and great apes suggests that we maintain ancestral rates of ovarian aging. Consistent with that hypothesis, previous counts of primordial follicles in postmortem ovarian sections from chimpanzees (Pan troglodytes) showed follicle stock decline at the same rate that human stocks decline across the same ages. Here, we correct that finding with a chimpanzee sample more than three times larger than the previous one, which also allows comparison into older ages. Analyses show depletion rates similar until about age 35, but after 35, the human counts continue to fall with age, while the change is much less steep in chimpanzees. This difference implicates likely effects on ovarian dynamics from other physiological systems that are senescing at different rates, and, potentially, different perimenopausal experience for chimpanzees and humans.

The bonobo genome compared with the chimpanzee and human genomes

PubMed Central

Prüfer, Kay; Munch, Kasper; Hellmann, Ines; Akagi, Keiko; Miller, Jason R.; Walenz, Brian; Koren, Sergey; Sutton, Granger; Kodira, Chinnappa; Winer, Roger; Knight, James R.; Mullikin, James C.; Meader, Stephen J.; Ponting, Chris P.; Lunter, Gerton; Higashino, Saneyuki; Hobolth, Asger; Dutheil, Julien; Karakoç, Emre; Alkan, Can; Sajjadian, Saba; Catacchio, Claudia Rita; Ventura, Mario; Marques-Bonet, Tomas; Eichler, Evan E.; André, Claudine; Atencia, Rebeca; Mugisha, Lawrence; Junhold, Jörg; Patterson, Nick; Siebauer, Michael; Good, Jeffrey M.; Fischer, Anne; Ptak, Susan E.; Lachmann, Michael; Symer, David E.; Mailund, Thomas; Schierup, Mikkel H.; Andrés, Aida M.; Kelso, Janet; Pääbo, Svante

2012-01-01

Two African apes are the closest living relatives of humans: the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). Although they are similar in many respects, bonobos and chimpanzees differ strikingly in key social and sexual behaviours1–4, and for some of these traits they show more similarity with humans than with each other. Here we report the sequencing and assembly of the bonobo genome to study its evolutionary relationship with the chimpanzee and human genomes. We find that more than three per cent of the human genome is more closely related to either the bonobo or the chimpanzee genome than these are to each other. These regions allow various aspects of the ancestry of the two ape species to be reconstructed. In addition, many of the regions that overlap genes may eventually help us understand the genetic basis of phenotypes that humans share with one of the two apes to the exclusion of the other. PMID:22722832

A Chimpanzee (Pan troglodytes) Model of Triarchic Psychopathy Constructs: Development and Initial Validation

PubMed Central

Latzman, Robert D.; Drislane, Laura E.; Hecht, Lisa K.; Brislin, Sarah J.; Patrick, Christopher J.; Lilienfeld, Scott O.; Freeman, Hani J.; Schapiro, Steven J.; Hopkins, William D.

2015-01-01

The current work sought to operationalize constructs of the triarchic model of psychopathy in chimpanzees (Pan troglodytes), a species well-suited for investigations of basic biobehavioral dispositions relevant to psychopathology. Across three studies, we generated validity evidence for scale measures of the triarchic model constructs in a large sample (N=238) of socially-housed chimpanzees. Using a consensus-based rating approach, we first identified candidate items for the chimpanzee triarchic (CHMP-Tri) scales from an existing primate personality instrument and refined these into scales. In Study 2, we collected data for these scales from human informants (N=301), and examined their convergent and divergent relations with scales from another triarchic inventory developed for human use. In Study 3, we undertook validation work examining associations between CHMP-Tri scales and task measures of approach-avoidance behavior (N=73) and ability to delay gratification (N=55). Current findings provide support for a chimpanzee model of core dispositions relevant to psychopathy and other forms of psychopathology. PMID:26779396

Public Information Use in Chimpanzees (Pan troglodytes) and Children (Homo sapiens)

PubMed Central

Vale, Gill L.; Flynn, Emma G.; Lambeth, Susan P.; Schapiro, Steven J.; Kendal, Rachel L.

2014-01-01

The discernment of resource quality is pertinent to many daily decisions faced by animals. Public information is a critical information source that promotes quality assessments, attained by monitoring others’ performance. Here we provide the first evidence, to our knowledge, that chimpanzees (Pan troglodytes) use public information to guide resource selection. Thirty-two chimpanzees were presented with two simultaneous video demonstrations depicting a conspecific acquiring resources at a fast (resource-rich) or slow (resource-poor) rate. Subsequently, subjects selected the resource-rich site above chance expectation. As a comparison, we report evidence of public information use in young children. Investigation of public information use in primates is pertinent, as it can enhance foraging success and potentially facilitate payoff-biased social learning. PMID:24060244

Fatal arrhythmogenic right ventricular cardiomyopathy in 2 related subadult chimpanzees (Pan troglodytes).

PubMed

Tong, L J; Flach, E J; Sheppard, M N; Pocknell, A; Banerjee, A A; Boswood, A; Bouts, T; Routh, A; Feltrer, Y

2014-07-01

Cardiovascular disease is increasingly recognized as an important cause of morbidity and mortality in captive chimpanzees (Pan troglodytes). This report records 2 cases of sudden cardiac death in closely related subadult captive chimpanzees with marked replacement fibrosis and adipocyte infiltration of the myocardium, which resemble specific atypical forms of the familial human disease arrhythmogenic right ventricular cardiomyopathy. Changes were consistent with left-dominant and biventricular subtypes, which are both phenotypic variants found within human families with familial arrhythmogenic right ventricular cardiomyopathy. Previously reported fibrosing cardiomyopathies in chimpanzees were characterized by nonspecific interstitial fibrosis, in contrast to the replacement fibrofatty infiltration with predilection for the outer myocardium seen in these 2 cases. To the authors' knowledge, this case report is the first to describe cardiomyopathy resembling arrhythmogenic right ventricular cardiomyopathy in nonhuman primates and the first to describe left-dominant arrhythmogenic cardiomyopathy-type lesions in an animal. © The Author(s) 2013.

Morphology of chimpanzee pinworms, Enterobius (Enterobius) anthropopitheci (Gedoelst, 1916) (Nematoda: Oxyuridae), collected from chimpanzees, Pan troglodytes, on Rubondo Island, Tanzania.

PubMed

Hasegawa, Hideo; Ikeda, Yatsukaho; Fujisaki, Akiko; Moscovice, Liza R; Petrzelkova, Klara J; Kaur, Taranjit; Huffman, Michael A

2005-12-01

The chimpanzee pinworm, Enterobius (Enterobius) anthropopitheci (Gedoelst, 1916) (Nematoda: Oxyuridae), is redescribed based on light and scanning electron microscopy of both sexes collected from the feces of chimpanzees, Pan troglodytes, of an introduced population on Rubondo Island, Tanzania. Enterobius (E.) anthropopitheci is characterized by having a small body (males 1.13-1.83 mm long, females 3.33-4.73 mm long), a rather straight spicule with a ventral membranous formation in males, double-crested lateral alae in females, small eggs (53-58 by 24-28 microm), and a smooth eggshell with 3 longitudinal thickenings. Morphological comparison is made between the present and previous descriptions.

Permanent tooth mineralization in bonobos (Pan paniscus) and chimpanzees (P. troglodytes).

PubMed

Boughner, Julia C; Dean, M Christopher; Wilgenbusch, Chelsea S

2012-12-01

The timing of tooth mineralization in bonobos (Pan paniscus) is virtually uncharacterized. Analysis of these developmental features in bonobos and the possible differences with its sister species, the chimpanzee (P. troglodytes), is important to properly quantify the normal ranges of dental growth variation in closely related primate species. Understanding this variation among bonobo, chimpanzee and modern human dental development is necessary to better contextualize the life histories of extinct hominins. This study tests whether bonobos and chimpanzees are distinguished from each other by covariance among the relative timing and sequences of tooth crown initiation, mineralization, root extension, and completion. Using multivariate statistical analyses, we compared the relative timing of permanent tooth crypt formation, crown mineralization, and root extension between 34 P. paniscus and 80 P. troglodytes mandibles radiographed in lateral and occlusal views. Covariance among our 12 assigned dental scores failed to statistically distinguish between bonobos and chimpanzees. Rather than clustering by species, individuals clustered by age group (infant, younger or older juvenile, and adult). Dental scores covaried similarly between the incisors, as well as between both premolars. Conversely, covariance among dental scores distinguished the canine and each of the three molars not only from each other, but also from the rest of the anterior teeth. Our study showed no significant differences in the relative timing of permanent tooth crown and root formation between bonobos and chimpanzees. Copyright © 2012 Wiley Periodicals, Inc.

The default mode network in chimpanzees (Pan troglodytes) is similar to that of humans.

PubMed

Barks, Sarah K; Parr, Lisa A; Rilling, James K

2015-02-01

The human default mode network (DMN), comprising medial prefrontal cortex, precuneus, posterior cingulate cortex, lateral parietal cortex, and medial temporal cortex, is highly metabolically active at rest but deactivates during most focused cognitive tasks. The DMN and social cognitive networks overlap significantly in humans. We previously demonstrated that chimpanzees (Pan troglodytes) show highest resting metabolic brain activity in the cortical midline areas of the human DMN. Human DMN is defined by task-induced deactivations, not absolute resting metabolic levels; ergo, resting activity is insufficient to define a DMN in chimpanzees. Here, we assessed the chimpanzee DMN's deactivations relative to rest during cognitive tasks and the effect of social content on these areas' activity. Chimpanzees performed a match-to-sample task with conspecific behavioral stimuli of varying sociality. Using [(18)F]-FDG PET, brain activity during these tasks was compared with activity during a nonsocial task and at rest. Cortical midline areas in chimpanzees deactivated in these tasks relative to rest, suggesting a chimpanzee DMN anatomically and functionally similar to humans. Furthermore, when chimpanzees make social discriminations, these same areas (particularly precuneus) are highly active relative to nonsocial tasks, suggesting that, as in humans, the chimpanzee DMN may play a role in social cognition. © The Author 2013. Published by Oxford University Press. All rights reserved. For Permissions, please e-mail: journals.permissions@oup.com.

Video-task acquisition in rhesus monkeys (Macaca mulatta) and chimpanzees (Pan troglodytes): a comparative analysis

NASA Technical Reports Server (NTRS)

Hopkins, W. D.; Washburn, D. A.; Hyatt, C. W.; Rumbaugh, D. M. (Principal Investigator)

1996-01-01

This study describes video-task acquisition in two nonhuman primate species. The subjects were seven rhesus monkeys (Macaca mulatta) and seven chimpanzees (Pan troglodytes). All subjects were trained to manipulate a joystick which controlled a cursor displayed on a computer monitor. Two criterion levels were used: one based on conceptual knowledge of the task and one based on motor performance. Chimpanzees and rhesus monkeys attained criterion in a comparable number of trials using a conceptually based criterion. However, using a criterion based on motor performance, chimpanzees reached criterion significantly faster than rhesus monkeys. Analysis of error patterns and latency indicated that the rhesus monkeys had a larger asymmetry in response bias and were significantly slower in responding than the chimpanzees. The results are discussed in terms of the relation between object manipulation skills and video-task acquisition.

Social play in bonobos (Pan paniscus) and chimpanzees (Pan troglodytes): Implications for natural social systems and interindividual relationships.

PubMed

Palagi, Elisabetta

2006-03-01

This study compares adult play behavior in the two Pan species in order to test the effects of phylogenetic closeness and the nature of social systems on play distribution. The social play (both with fertile and immature subjects) performed by adults did not differ between the two species. In contrast, in bonobos, play levels among fertile subjects were higher than in chimpanzees. Findings regarding levels of undecided conflicts (more frequent in bonobos) and formal submission displays (lacking in bonobos) confirm, in the two colonies under study, that bonobos exhibit "egalitarianism" more than chimpanzees. Some authors emphasized the importance of play-fighting for social assessment when relationships among individuals are not codified and structured according to rank-rules. Indeed, adult bonobos played more roughly than chimpanzees. Moreover, adult bonobos displayed the full play-face at a high frequency especially during rough play sessions, whereas in chimpanzees, the frequency of play signals was not affected by roughness of play. The frequency of social play among bonobo females was higher than in any other sex combinations, whereas no difference was found for chimpanzees. As a matter of fact, social play can be viewed as a balance between cooperation and competition. Among bonobo females, characterized by social competence and affiliation, social play might enhance their behavioral flexibility and increase their socially symmetrical relationships which, after all, are the basis for their egalitarian society. (c) 2005 Wiley-Liss, Inc.

Intentionality as Measured in the Persistence and Elaboration of Communication by Chimpanzees (Pan troglodytes)

ERIC Educational Resources Information Center

Leavens, David A.; Russell, Jamie L.; Hopkins, William D.

2005-01-01

In human infancy, 2 criteria for intentional communication are (a) persistence in and (b) elaboration of communication when initial attempts to communicate fail. Twenty-nine chimpanzees (Pan troglodytes) were presented with both desirable (a banana) and undesirable food (commercial primate chow). Three conditions were administered: (a) the banana…

Student-Centered Designs of Pan-African Literature Courses

ERIC Educational Resources Information Center

M'Baye, Babacar

2010-01-01

A student-centered teaching methodology is an essential ingredient of a successful Pan-African literary course. In this article, the author defines Pan-Africanism and how to go about designing a Pan-African literature course. The author combines reading assignments with journals, film presentations, and lectures in a productive learning…

The diet of open-habitat chimpanzees (Pan troglodytes schweinfurthii) in the Issa valley, western Tanzania.

PubMed

Piel, Alex K; Strampelli, Paolo; Greathead, Emily; Hernandez-Aguilar, R Adriana; Moore, Jim; Stewart, Fiona A

2017-11-01

Comparative data on the diets of extant primates inform hypotheses about hominin resource use. Historically, data describing chimpanzee diets stem primarily from forest-dwelling communities, and we lack comparative data from chimpanzees that live in mosaic habitats that more closely resemble those reconstructed for Plio-Pleistocene hominins. We present data on the diet of a partially-habituated community of open habitat chimpanzees (Pan troglodytes schweinfurthii) from the Issa valley, western Tanzania, collected over a four-year period. Based mostly on macroscopic faecal analysis, Issa chimpanzees consumed a minimum of 69 plant species. There was no relationship between plant consumption and either fruit availability or feeding tree density; the most frequently consumed plant species were found in riverine forests, with woodland species consumed more frequently during the late dry season. We conclude by contextualising these findings with those of other open-habitat chimpanzee sites, and also by discussing how our results contribute towards reconstructions of early hominin exploitation of mosaic landscapes. Copyright © 2017 Elsevier Ltd. All rights reserved.

Trading Up: Chimpanzees (Pan troglodytes) Show Self-Control Through Their Exchange Behavior

PubMed Central

Beran, Michael J.; Rossettie, Mattea S.; Parrish, Audrey E.

2015-01-01

Self-control is defined as the ability or capacity to obtain an objectively more valuable outcome rather than an objectively less valuable outcome though tolerating a longer delay or a greater effort requirement (or both) in obtaining that more valuable outcome. A number of tests have been devised to assess self-control in nonhuman animals, including exchange tasks. In this study, three chimpanzees (Pan troglodytes) participated in a delay of gratification task that required food exchange as the behavioral response that reflected self-control. The chimpanzees were offered opportunities to inhibit eating and instead exchange a currently possessed food item for a different (and sometimes better) item, often needing to exchange several food items before obtaining the highest-valued reward. We manipulated reward type, reward size, reward visibility, delay to exchange, and location of the highest-valued reward in the sequence of exchange events to compare performance within the same individuals. The chimpanzees successfully traded until obtaining the best item in most cases, although there were individual differences among participants in some variations of the test. These results support the idea that self-control is robust in chimpanzees even in contexts in which they perhaps anticipate future rewards and sustain delay of gratification until they can obtain the ultimately most-valuable item. PMID:26325355

Trading up: chimpanzees (Pan troglodytes) show self-control through their exchange behavior.

PubMed

Beran, Michael J; Rossettie, Mattea S; Parrish, Audrey E

2016-01-01

Self-control is defined as the ability or capacity to obtain an objectively more valuable outcome rather than an objectively less valuable outcome though tolerating a longer delay or a greater effort requirement (or both) in obtaining that more valuable outcome. A number of tests have been devised to assess self-control in non-human animals, including exchange tasks. In this study, three chimpanzees (Pan troglodytes) participated in a delay of gratification task that required food exchange as the behavioral response that reflected self-control. The chimpanzees were offered opportunities to inhibit eating and instead exchange a currently possessed food item for a different (and sometimes better) item, often needing to exchange several food items before obtaining the highest valued reward. We manipulated reward type, reward size, reward visibility, delay to exchange, and location of the highest valued reward in the sequence of exchange events to compare performance within the same individuals. The chimpanzees successfully traded until obtaining the best item in most cases, although there were individual differences among participants in some variations of the test. These results support the idea that self-control is robust in chimpanzees even in contexts in which they perhaps anticipate future rewards and sustain delay of gratification until they can obtain the ultimately most valuable item.

Cladistic analyses of behavioural variation in wild Pan troglodytes: exploring the chimpanzee culture hypothesis.

PubMed

Lycett, Stephen J; Collard, Mark; McGrew, William C

2009-10-01

chimpanzee cultural data are not only comparable to a series of modern human cultural data sets in terms of how tree-like they are, but are also comparable to a series of genetic, anatomical, and behavioural data sets that can be assumed to have been produced by a branching process. Again, this is what would be expected if vertical inter-group transmission has been the dominant process in chimpanzee cultural evolution. Human culture has long been considered to be adaptive, but recent studies have suggested that this needs to be demonstrated rather than assumed. With this in mind, in the third set of analyses we investigated whether chimpanzee culture is adaptive. We found the hypothesis that chimpanzee culture is adaptive was supported by an analysis of data from the Eastern African subspecies, but not by an analysis of data from the eastern and western subspecies. The results of our analyses have implications for the number of subspecies in Pan troglodytes, the relationship between hominin taxa and Palaeolithic industries, and the evolution of hominin cognition and behaviour.

Chimpanzees (Pan troglodytes) use markers to monitor the movement of a hidden item.

PubMed

Beran, Michael J; Beran, Mary M; Menzel, Charles R

2005-10-01

Four chimpanzees (Pan troglodytes) monitored the movement of hidden items in arrays of opaque cups. A chocolate candy was hidden in an array of four cups and temporarily presented paper markers indicated the location of the candy (which otherwise was not visible). These markers were either non-symbolic or symbolic (lexigram) stimuli that in other contexts acted as a label for the hidden candy, and the array was either rotated 180 degrees after the marker was removed or the array remained in the same location. For three of four chimpanzees, performance was better than chance in all conditions and there was no effect of the type of marker. These experiments indicate that chimpanzees can track the movement of a hidden item in an array of identical cups even when they never see the item itself, but only see a temporarily presented marker for the location of that item. However, there was no benefit to the use of symbolic as opposed to non-symbolic stimuli in this performance.

Stable nitrogen isotope analysis of dentine serial sections elucidate sex differences in weaning patterns of wild chimpanzees (Pan troglodytes).

PubMed

Fahy, Geraldine E; Richards, Michael P; Fuller, Benjamin T; Deschner, Tobias; Hublin, Jean-Jacques; Boesch, Christophe

2014-04-01

Offspring provisioning is one of the most energetically demanding aspects of reproduction for female mammals. Variation in lactation length and weaning strategies between chimpanzees (Pan troglodytes), our closest living relative, and modern human societies have been reported. When and why these changes occurred is frequently debated. Our study used stable nitrogen isotope data of tooth root dentine from wild Western chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire, to quantify weaning in these chimpanzees and explore if infant sex plays a role in maternal investment. We analyzed serial sections of deciduous lateral incisor root dentine from four Taï chimpanzees to establish the δ(15) N signal of nursing infants; we then analyzed serial sections of first permanent mandibular molar root dentine from 12 Taï chimpanzees to provide quantitative δ(15) N data on weaning in this population. Up to 2 years of age both sexes exhibited dentine δ(15) N values ≈2-3‰ higher than adult female Taï chimpanzees, consistent with a nursing signal. Thereafter a steady decrease in δ(15) N values consistent with the onset, and progression, of weaning, was visible. Sex differences were also evident, where male δ(15) N values decreased at a significantly slower rate compared to females. Confirmation of sex differences in maternal investment among Taï chimpanzees, demonstrates the viability of using isotope analysis to investigate weaning in non-human primates. Additionally, assuming that behaviors observed in the Taï chimpanzees are illustrative of the ancestral pattern, our results provide a platform to enable the trajectory of weaning in human evolution to be further explored. Copyright © 2013 Wiley Periodicals, Inc.

Genetic Factors and Orofacial Motor Learning Selectively Influence Variability in Central Sulcus Morphology in Chimpanzees (Pan troglodytes)

PubMed Central

Autrey, Michelle; Mahovetz, Lindsay; Pope, Sarah; Mareno, Mary Catherine; Schapiro, Steven J.

2017-01-01

Captive chimpanzees (Pan troglodytes) have been shown to learn the use of novel attention-getting (AG) sounds to capture the attention of humans as a means of requesting or drawing their attention to a desired object or food. There are significant individual differences in the use of AG sounds by chimpanzees and, here, we examined whether changes in cortical organization of the central sulcus (CS) were associated with AG sound production. MRI scans were collected from 240 chimpanzees, including 122 that reliably produced AG sounds and 118 that did not. For each subject, the depth of CS was quantified along the superior–inferior plane with specific interest in the inferior portion corresponding to the region of the motor cortex where the mouth and orofacial movements are controlled. Results indicated that CS depth in the inferior, but not superior, portion was significantly greater in chimpanzees that reliably produced AG sounds compared with those who did not. Quantitative genetic analyses indicated that overall CS surface area and depth were significantly heritable, particularly in the superior regions, but less so in the inferior and central portions. Further, heritability in CS depth was altered as a function of acquisition of AG sounds. The collective results suggest that learning to produce AG sounds resulted in region-specific cortical reorganization within the inferior portion of the CS, a finding previously undocumented in chimpanzees or any nonhuman primate. SIGNIFICANCE STATEMENT Recent studies in chimpanzees (Pan troglodytes) have shown that some can learn to produce novel sounds by configuring different orofacial movement patterns and these sounds are used in communicatively relevant contexts. Here, we examined the neuromorphological correlates in the production of these sounds in chimpanzees. We show that chimpanzees that have learned to produce these sounds show significant differences in central sulcus (CS) morphology, particularly in the inferior

Genetic Factors and Orofacial Motor Learning Selectively Influence Variability in Central Sulcus Morphology in Chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Coulon, Oliver; Meguerditchian, Adrien; Autrey, Michelle; Davidek, Kendall; Mahovetz, Lindsay; Pope, Sarah; Mareno, Mary Catherine; Schapiro, Steven J

2017-05-31

Captive chimpanzees ( Pan troglodytes ) have been shown to learn the use of novel attention-getting (AG) sounds to capture the attention of humans as a means of requesting or drawing their attention to a desired object or food. There are significant individual differences in the use of AG sounds by chimpanzees and, here, we examined whether changes in cortical organization of the central sulcus (CS) were associated with AG sound production. MRI scans were collected from 240 chimpanzees, including 122 that reliably produced AG sounds and 118 that did not. For each subject, the depth of CS was quantified along the superior-inferior plane with specific interest in the inferior portion corresponding to the region of the motor cortex where the mouth and orofacial movements are controlled. Results indicated that CS depth in the inferior, but not superior, portion was significantly greater in chimpanzees that reliably produced AG sounds compared with those who did not. Quantitative genetic analyses indicated that overall CS surface area and depth were significantly heritable, particularly in the superior regions, but less so in the inferior and central portions. Further, heritability in CS depth was altered as a function of acquisition of AG sounds. The collective results suggest that learning to produce AG sounds resulted in region-specific cortical reorganization within the inferior portion of the CS, a finding previously undocumented in chimpanzees or any nonhuman primate. SIGNIFICANCE STATEMENT Recent studies in chimpanzees ( Pan troglodytes ) have shown that some can learn to produce novel sounds by configuring different orofacial movement patterns and these sounds are used in communicatively relevant contexts. Here, we examined the neuromorphological correlates in the production of these sounds in chimpanzees. We show that chimpanzees that have learned to produce these sounds show significant differences in central sulcus (CS) morphology, particularly in the

Genomic Tools for Evolution and Conservation in the Chimpanzee: Pan troglodytes ellioti Is a Genetically Distinct Population

PubMed Central

Myers, Simon; Hellenthal, Garrett; Nerrienet, Eric; Bontrop, Ronald E.; Freeman, Colin; Donnelly, Peter; Mundy, Nicholas I.

2012-01-01

In spite of its evolutionary significance and conservation importance, the population structure of the common chimpanzee, Pan troglodytes, is still poorly understood. An issue of particular controversy is whether the proposed fourth subspecies of chimpanzee, Pan troglodytes ellioti, from parts of Nigeria and Cameroon, is genetically distinct. Although modern high-throughput SNP genotyping has had a major impact on our understanding of human population structure and demographic history, its application to ecological, demographic, or conservation questions in non-human species has been extremely limited. Here we apply these tools to chimpanzee population structure, using ∼700 autosomal SNPs derived from chimpanzee genomic data and a further ∼100 SNPs from targeted re-sequencing. We demonstrate conclusively the existence of P. t. ellioti as a genetically distinct subgroup. We show that there is clear differentiation between the verus, troglodytes, and ellioti populations at the SNP and haplotype level, on a scale that is greater than that separating continental human populations. Further, we show that only a small set of SNPs (10–20) is needed to successfully assign individuals to these populations. Tellingly, use of only mitochondrial DNA variation to classify individuals is erroneous in 4 of 54 cases, reinforcing the dangers of basing demographic inference on a single locus and implying that the demographic history of the species is more complicated than that suggested analyses based solely on mtDNA. In this study we demonstrate the feasibility of developing economical and robust tests of individual chimpanzee origin as well as in-depth studies of population structure. These findings have important implications for conservation strategies and our understanding of the evolution of chimpanzees. They also act as a proof-of-principle for the use of cheap high-throughput genomic methods for ecological questions. PMID:22396655

Genomic tools for evolution and conservation in the chimpanzee: Pan troglodytes ellioti is a genetically distinct population.

PubMed

Bowden, Rory; MacFie, Tammie S; Myers, Simon; Hellenthal, Garrett; Nerrienet, Eric; Bontrop, Ronald E; Freeman, Colin; Donnelly, Peter; Mundy, Nicholas I

2012-01-01

In spite of its evolutionary significance and conservation importance, the population structure of the common chimpanzee, Pan troglodytes, is still poorly understood. An issue of particular controversy is whether the proposed fourth subspecies of chimpanzee, Pan troglodytes ellioti, from parts of Nigeria and Cameroon, is genetically distinct. Although modern high-throughput SNP genotyping has had a major impact on our understanding of human population structure and demographic history, its application to ecological, demographic, or conservation questions in non-human species has been extremely limited. Here we apply these tools to chimpanzee population structure, using ∼700 autosomal SNPs derived from chimpanzee genomic data and a further ∼100 SNPs from targeted re-sequencing. We demonstrate conclusively the existence of P. t. ellioti as a genetically distinct subgroup. We show that there is clear differentiation between the verus, troglodytes, and ellioti populations at the SNP and haplotype level, on a scale that is greater than that separating continental human populations. Further, we show that only a small set of SNPs (10-20) is needed to successfully assign individuals to these populations. Tellingly, use of only mitochondrial DNA variation to classify individuals is erroneous in 4 of 54 cases, reinforcing the dangers of basing demographic inference on a single locus and implying that the demographic history of the species is more complicated than that suggested analyses based solely on mtDNA. In this study we demonstrate the feasibility of developing economical and robust tests of individual chimpanzee origin as well as in-depth studies of population structure. These findings have important implications for conservation strategies and our understanding of the evolution of chimpanzees. They also act as a proof-of-principle for the use of cheap high-throughput genomic methods for ecological questions.

The complete mitochondrial genome of the central chimpanzee, Pan troglodytes troglodytes.

PubMed

Liu, Bang; Hu, Xiao-di; Gao, Li-Zhi

2016-07-01

This study first report the complete mitochondrial genome sequence of the central chimpanzee, Pan troglodytes troglodytes. The genome was a total of 16 556 bp in length and had a base composition of A (31.05%), G (12.95%), C (30.84%), and T (25.16%), indicating that the percentage of A + T (56.21%) is higher than G + C (43.79%). Similar to other primates, it possessed a typically conserved structure, including 13 protein-coding genes, 22 transfer RNA genes, 2 ribosomal RNA genes and 1 control region (D-loop). Most of these genes were found to locate on the H-strand except for the ND6 gene and 8 tRNA genes. The phylogenetic analysis showed that the P. t. troglodytes mitochondrial genome formed a cluster with the other three Pan troglodytes genomes and that the genus Pan is closely related to the genus Homo. This mitochondrial genome sequence would supply useful genetic resources to help the conservation management of primate germplasm and uncover hominoid evolution.

Geometric distortions affect face recognition in chimpanzees (Pan troglodytes) and monkeys (Macaca mulatta).

PubMed

Taubert, Jessica; Parr, Lisa A

2011-01-01

All primates can recognize faces and do so by analyzing the subtle variation that exists between faces. Through a series of three experiments, we attempted to clarify the nature of second-order information processing in nonhuman primates. Experiment one showed that both chimpanzees (Pan troglodytes) and rhesus monkeys (Macaca mulatta) tolerate geometric distortions along the vertical axis, suggesting that information about absolute position of features does not contribute to accurate face recognition. Chimpanzees differed from monkeys, however, in that they were more sensitive to distortions along the horizontal axis, suggesting that when building a global representation of facial identity, horizontal relations between features are more diagnostic of identity than vertical relations. Two further experiments were performed to determine whether the monkeys were simply less sensitive to horizontal relations compared to chimpanzees or were instead relying on local features. The results of these experiments confirm that monkeys can utilize a holistic strategy when discriminating between faces regardless of familiarity. In contrast, our data show that chimpanzees, like humans, use a combination of holistic and local features when the faces are unfamiliar, but primarily holistic information when the faces become familiar. We argue that our comparative approach to the study of face recognition reveals the impact that individual experience and social organization has on visual cognition.

Do chimpanzees (Pan troglodytes) and 2-year-old children (Homo sapiens) understand double invisible displacement?

PubMed

Collier-Baker, Emma; Suddendorf, Thomas

2006-05-01

Chimpanzees (Pan troglodytes) and young children (Homo sapiens) have difficulty with double invisible displacements in which an object is hidden in two nonadjacent boxes in a linear array. Experiment 1 eliminated the possibility that chimpanzees' previous poor performance was due to the hiding direction of the displacement device. As in Call (2001), subjects failed double nonadjacent displacements, showing a tendency to select adjacent boxes. In Experiments 2 and 3, chimpanzees and 24-month-old children were tested on a new adaptation of the task in which four hiding boxes were presented in a diamond-shaped array on a vertical plane. Both species performed above chance on double invisible displacements using this format, suggesting that previous poor performance was due to a response bias or inhibition problem rather than a fundamental limitation in representational capacity. Copyright 2006 APA, all rights reserved.

Intentionality as Measured in the Persistence and Elaboration of Communication by Chimpanzees (Pan troglodytes)

PubMed Central

Leavens, David A.; Russell, Jamie L.; Hopkins, William D.

2007-01-01

In human infancy, 2 criteria for intentional communication are (a) persistence in and (b) elaboration of communication when initial attempts to communicate fail. Twenty-nine chimpanzees (Pan troglodytes) were presented with both desirable (a banana) and undesirable food (commercial primate chow). Three conditions were administered: (a) the banana was delivered (successful communication), (b) half of the banana was delivered (partially successful communication), and (c) the chow was delivered (failed communication). The chimpanzees exhibited persistence in and elaboration of their communication in every condition except when the banana was delivered. Thus, their communication was about a specific item, demonstrating that both intentionality and nonverbal reference are capacities shared by humans with our nearest living relatives, the great apes. PMID:15693773

Arboreal nesting as anti-predator adaptation by savanna chimpanzees (Pan troglodytes verus) in southeastern Senegal.

PubMed

Pruetz, J D; Fulton, S J; Marchant, L F; McGrew, W C; Schiel, M; Waller, M

2008-04-01

Chimpanzees (Pan troglodytes) make nests for resting and sleeping, which is unusual for anthropoid primates but common to all great apes. Arboreal nesting has been linked to predation pressure, but few studies have tested the adaptive nature of this behavior. We collected data at two chimpanzee study sites in southeastern Senegal that differed in predator presence to test the hypothesis that elevated sleeping platforms are adaptations for predator defense. At Assirik in the Parc National du Niokolo-Koba, chimpanzees face four species of large carnivore, whereas at Fongoli, outside national park boundaries, humans have exterminated almost all natural predators. We quantified the availability of vegetation at the two sites to test the alternative hypothesis that differences in nesting reflect differences in habitat structure. We also examined possible sex differences in nesting behavior, community demographic differences, seasonality and nest age differences as variables also potentially affecting nest characteristics and nesting behavior between the two sites. Chimpanzees at Fongoli nested at lower heights and farther apart than did chimpanzees at Assirik and sometimes made nests on the ground. The absence of predators outside of the national park may account for the differences in nest characteristics at the two sites, given the similarities in habitat structure between Fongoli and Assirik. However, Fongoli chimpanzees regularly build arboreal nests for sleeping, even under minimal predation pressure, and this requires explanation.

Referential understanding of videos in chimpanzees (Pan troglodytes), orangutans (Pongo pygmaeus), and children (Homo sapiens).

PubMed

Poss, Sarah R; Rochat, Philippe

2003-12-01

Performance on identical search tasks based on cues directly perceived or indirectly perceived through video were compared among a group of 4 adult chimpanzees (Pan troglodytes), a group of 2 adult orangutans (Pongo pygmaeus), and a group of 36 children (between 2 and 3 years of age). Children comprehended directly perceived cues but had difficulty with video cues. In contrast, chimpanzees and 1 orangutan were successful in using video to guide their search for a hidden object. Two follow-up studies with 3-year-old children demonstrated the importance of more distinct perceptual and verbal cues in aiding children's understanding of video as referring to real-world events.

Inference of purifying and positive selection in three subspecies of chimpanzees (Pan troglodytes) from exome sequencing.

PubMed

Bataillon, Thomas; Duan, Jinjie; Hvilsom, Christina; Jin, Xin; Li, Yingrui; Skov, Laurits; Glemin, Sylvain; Munch, Kasper; Jiang, Tao; Qian, Yu; Hobolth, Asger; Wang, Jun; Mailund, Thomas; Siegismund, Hans R; Schierup, Mikkel H

2015-03-30

We study genome-wide nucleotide diversity in three subspecies of extant chimpanzees using exome capture. After strict filtering, Single Nucleotide Polymorphisms and indels were called and genotyped for greater than 50% of exons at a mean coverage of 35× per individual. Central chimpanzees (Pan troglodytes troglodytes) are the most polymorphic (nucleotide diversity, θw = 0.0023 per site) followed by Eastern (P. t. schweinfurthii) chimpanzees (θw = 0.0016) and Western (P. t. verus) chimpanzees (θw = 0.0008). A demographic scenario of divergence without gene flow fits the patterns of autosomal synonymous nucleotide diversity well except for a signal of recent gene flow from Western into Eastern chimpanzees. The striking contrast in X-linked versus autosomal polymorphism and divergence previously reported in Central chimpanzees is also found in Eastern and Western chimpanzees. We show that the direction of selection statistic exhibits a strong nonmonotonic relationship with the strength of purifying selection S, making it inappropriate for estimating S. We instead use counts in synonymous versus nonsynonymous frequency classes to infer the distribution of S coefficients acting on nonsynonymous mutations in each subspecies. The strength of purifying selection we infer is congruent with the differences in effective sizes of each subspecies: Central chimpanzees are undergoing the strongest purifying selection followed by Eastern and Western chimpanzees. Coding indels show stronger selection against indels changing the reading frame than observed in human populations. © The Author(s) 2015. Published by Oxford University Press on behalf of the Society for Molecular Biology and Evolution.

Chimpanzees (Pan troglodytes) Flexibly Use Introduced Species for Nesting and Bark Feeding in a Human-Dominated Habitat.

PubMed

McCarthy, Maureen S; Lester, Jack D; Stanford, Craig B

2017-01-01

As habitat loss and fragmentation place growing pressure on endangered nonhuman primate populations, researchers find increasing evidence for novel responses in behavior. In western Uganda between the Budongo and Bugoma Forests, chimpanzees ( Pan troglodytes schweinfurthii ) inhabit a mosaic landscape comprising forest fragments, human settlements, and agricultural land. We recorded nests and feeding evidence of unhabituated chimpanzees in this region over a 12-mo period. We found extensive evidence of nesting in introduced tree species, including eucalyptus ( Eucalyptus grandis ), guava ( Psidium guajava ), cocoa ( Theobroma cacao ), and Caribbean pine ( Pinus caribaea ). In addition, we found instances of ground nesting, nest reuse, and composite nests constructed from branches of multiple trees. This evidence may indicate a lack of suitable nesting trees or attempts by chimpanzees to nest in areas of riparian forest that allow them to avoid human detection. We also found new evidence for eucalyptus bark feeding by chimpanzees. Such evidence suggests chimpanzees respond flexibly to mitigate anthropogenic pressures in human-dominated landscapes. The limits of such flexibility remain unknown. Further research is needed to examine systematically the factors influencing the use of such resources and to understand better the extent to which chimpanzees can persist while relying on them.

Three-dimensional moment arms and architecture of chimpanzee (Pan troglodytes) leg musculature

PubMed Central

Holowka, Nicholas B; O'Neill, Matthew C

2013-01-01

The muscular and skeletal morphology of the chimpanzee ankle and foot differs from that of humans in many important respects. However, little information is available on the moment arms and architecture of the muscles that function around chimpanzee ankle and foot joints. The main goals of this study were to determine the influence of changes in leg and foot position on the moment arms of these muscle–tendon units (MTUs), and provide new measurements of their architecture. Three-dimensional moment arm data were collected from two adult, cadaveric Pan troglodytes specimens for 11 MTUs that cross the ankle and foot joints. Tendon-excursion measurements were made throughout the full range of plantarflexion–dorsiflexion (PF–DF) and eversion–inversion (EV–IN), including repeated measurements for mm. gastrocnemius at 0 °, 45 °, 90 ° and 135 ° of knee flexion. The total range of motion was calculated from three-dimensional joint motion data while ensuring that foot movement was restricted to a single plane. Measurements of muscle mass, fascicle length, pennation angle and physiological cross-sectional area were then collected for each MTU. Our results demonstrate that joint position has a significant effect on moment arm lengths, and that in some cases this effect is counterintuitive. These new data contribute to filling a significant gap in previously published chimpanzee moment arm data, providing a comprehensive characterization of the MTUs that move the chimpanzee ankle and foot joints. They also provide empirical support to the notion that chimpanzees have larger ranges of motion at these joints than humans. Comparison of osteometric estimates of moment arm lengths to direct tendon-excursion measures provides some guidance for the use of skeletal features in estimations of PF–DF moment arms. Finally, muscle architecture data are consistent with the findings of previous studies, and increase the sample size of the chimpanzee data that are currently

A previously undiscovered group of chimpanzees (Pan troglodytes verus) is observed living in the Tonkolili district of Sierra Leone.

PubMed

Halloran, Andrew R; Cloutier, Christina T; Sesay, Papanie Bai

2013-06-01

A previously undocumented group of wild chimpanzees (Pan troglodytes verus) was recently discovered along the Pampana River in the Tonkolili District of Sierra Leone. Based on interviews from local residents (N = 6), we estimate the group size to be approximately 30 individuals. Though this population does not show up in the most recent census of chimpanzees in Sierra Leone, it concurs with findings that indicate most of the chimpanzees in Sierra Leone live scattered throughout the country alongside villages, rather than in protected areas. During a three-week observation in the area, two chimpanzees were hunted and killed. The reason for these deaths, along with other reported instances of hunting in the area, are primarily due to crop-raiding and competition for resources between chimpanzees and humans. We conclude that this is a heavily imperiled population. Based on the ecology of the area and composition of local villages, we propose a number of conservation strategies that will promote a symbiotic relationship between the chimpanzees and human populations residing in the area. © 2013 Wiley Periodicals, Inc.

Can Chimpanzee Biology Highlight Human Origin and Evolution?

PubMed Central

Roffman, Itai; Nevo, Eviatar

2010-01-01

The closest living relatives of humans are their chimpanzee/bonobo (Pan) sister species, members of the same subfamily “Homininae”. This classification is supported by over 50 years of research in the fields of chimpanzee cultural diversity, language competency, genomics, anatomy, high cognition, psychology, society, self-consciousness and relation to others, tool use/production, as well as Homo level emotions, symbolic competency, memory recollection, complex multifaceted problem-solving capabilities, and interspecies communication. Language competence and symbolism can be continuously bridged from chimpanzee to man. Emotions, intercommunity aggression, body language, gestures, facial expressions, and vocalization of intonations seem to parallel between the sister taxa Homo and Pan. The shared suite of traits between Pan and Homo genus demonstrated in this article integrates old and new information on human–chimpanzee evolution, bilateral informational and cross-cultural exchange, promoting the urgent need for Pan cultures in the wild to be protected, as they are part of the cultural heritage of mankind. Also, we suggest that bonobos, Pan paniscus, based on shared traits with Australopithecus, need to be included in Australopithecine’s subgenus, and may even represent living-fossil Australopithecines. Unfolding bonobo and chimpanzee biology highlights our common genetic and cultural evolutionary origins. PMID:23908781

On the Diversity of Malaria Parasites in African Apes and the Origin of Plasmodium falciparum from Bonobos

PubMed Central

Pacheco, M. Andreina; Mugisha, Lawrence; André, Claudine; Halbwax, Michel; Fischer, Anne; Krief, Jean-Michel; Kasenene, John M.; Crandfield, Mike; Cornejo, Omar E.; Chavatte, Jean-Marc; Lin, Clara; Letourneur, Franck; Grüner, Anne Charlotte; McCutchan, Thomas F.; Rénia, Laurent; Snounou, Georges

2010-01-01

The origin of Plasmodium falciparum, the etiological agent of the most dangerous forms of human malaria, remains controversial. Although investigations of homologous parasites in African Apes are crucial to resolve this issue, studies have been restricted to a chimpanzee parasite related to P. falciparum, P. reichenowi, for which a single isolate was available until very recently. Using PCR amplification, we detected Plasmodium parasites in blood samples from 18 of 91 individuals of the genus Pan, including six chimpanzees (three Pan troglodytes troglodytes, three Pan t. schweinfurthii) and twelve bonobos (Pan paniscus). We obtained sequences of the parasites' mitochondrial genomes and/or from two nuclear genes from 14 samples. In addition to P. reichenowi, three other hitherto unknown lineages were found in the chimpanzees. One is related to P. vivax and two to P. falciparum that are likely to belong to distinct species. In the bonobos we found P. falciparum parasites whose mitochondrial genomes indicated that they were distinct from those present in humans, and another parasite lineage related to P. malariae. Phylogenetic analyses based on this diverse set of Plasmodium parasites in African Apes shed new light on the evolutionary history of P. falciparum. The data suggested that P. falciparum did not originate from P. reichenowi of chimpanzees (Pan troglodytes), but rather evolved in bonobos (Pan paniscus), from which it subsequently colonized humans by a host-switch. Finally, our data and that of others indicated that chimpanzees and bonobos maintain malaria parasites, to which humans are susceptible, a factor of some relevance to the renewed efforts to eradicate malaria. PMID:20169187

Three-dimensional kinematics of the pelvis and hind limbs in chimpanzee (Pan troglodytes) and human bipedal walking.

PubMed

O'Neill, Matthew C; Lee, Leng-Feng; Demes, Brigitte; Thompson, Nathan E; Larson, Susan G; Stern, Jack T; Umberger, Brian R

2015-09-01

The common chimpanzee (Pan troglodytes) is a facultative biped and our closest living relative. As such, the musculoskeletal anatomies of their pelvis and hind limbs have long provided a comparative context for studies of human and fossil hominin locomotion. Yet, how the chimpanzee pelvis and hind limb actually move during bipedal walking is still not well defined. Here, we describe the three-dimensional (3-D) kinematics of the pelvis, hip, knee and ankle during bipedal walking and compare those values to humans walking at the same dimensionless and dimensional velocities. The stride-to-stride and intraspecific variations in 3-D kinematics were calculated using the adjusted coefficient of multiple correlation. Our results indicate that humans walk with a more stable pelvis than chimpanzees, especially in tilt and rotation. Both species exhibit similar magnitudes of pelvis list, but with segment motion that is opposite in phasing. In the hind limb, chimpanzees walk with a more flexed and abducted limb posture, and substantially exceed humans in the magnitude of hip rotation during a stride. The average stride-to-stride variation in joint and segment motion was greater in chimpanzees than humans, while the intraspecific variation was similar on average. These results demonstrate substantial differences between human and chimpanzee bipedal walking, in both the sagittal and non-sagittal planes. These new 3-D kinematic data are fundamental to a comprehensive understanding of the mechanics, energetics and control of chimpanzee bipedalism. Copyright © 2015 Elsevier Ltd. All rights reserved.

Morphometrics and inertial properties in the body segments of chimpanzees (Pan troglodytes)

PubMed Central

Schoonaert, Kirsten; D’Août, Kristiaan; Aerts, Peter

2007-01-01

Inertial characteristics and dimensions of the body and body segments form an integral part of a biomechanical analysis of motion. In primate studies, however, segment inertial parameters of non-human hominoids are scarce and often obtained using varying techniques. Therefore, the principal aim of this study was to expand the existing chimpanzee inertial property data set using a non-invasive measuring technique. We also considered age- and sex-related differences within our sample. By means of a geometric model based on Crompton et al. (1996); Am J Phys Anthropol 99, 547–570) we generated inertial properties using external segment length and diameter measurements of 53 anaesthetized chimpanzees (Pan troglodytes). We report absolute inertial parameters for immature and mature subjects and for males and females separately. Proportional data were computed to allow the comparison between age classes and sex classes. In addition, we calculated whole limb inertial properties and we discuss their potential biomechanical consequences. We found no significant differences between the age classes in the proportional data except for hand and foot measures where juveniles exhibit relatively longer and heavier distal segments than adults. Furthermore, most sex-related differences can be directly attributed to the higher absolute segment masses in male chimpanzees resulting in higher moments of inertia. Additionally, males tend to have longer upper limbs than females. However, regarding proportional data we discuss the general inertial properties of the chimpanzee. The described segment inertial parameters of males and females, and of the two age classes, represent a valuable data set ready for use in a range of biomechanical locomotor models. These models offer great potential for improving our understanding of early hominin locomotor patterns. PMID:17451529

Environmental variables across Pan troglodytes study sites correspond with the carbon, but not the nitrogen, stable isotope ratios of chimpanzee hair.

PubMed

Schoeninger, Margaret J; Most, Corinna A; Moore, Jim J; Somerville, Andrew D

2016-10-01

Diet influences the stable isotope ratios of carbon and nitrogen (δ(13) C and δ(15) N values) in animal tissue; but here we explore the influences of particular aspects of the local environment on those values in chimpanzees (Pan troglodytes). In this article we present new δ(13) C and δ(15) N values in Gombe chimpanzees using hairs collected from night nests in 1989. Then, we explore the influence of environmental factors by comparing our Gombe data to those from eight additional Pan study sites with previously published stable isotope data. We compare chimpanzee δ(13) Chair and δ(15) Nhar values to specific characteristics of local site ecology (biome and ecoregion) and to local Mean Annual Precipitation (MAP) to test hypotheses based on known effects of these variables on the δ(13) C and δ(15) N values in plant tissues. The comparison shows that hair from chimpanzees living in savanna sites with lower MAP have higher δ(13) Chair values than do chimpanzees living in woodland and forested sites with higher MAP. These results demonstrate the potential of using δ(13) C values in primate tissue to indicate aspects of their local ecology in cases where the ecology is uncertain, such as samples collected early in the last century and in fossil hominins. In contrast to expectations, however, chimpanzee δ(15) Nhair values from some savanna sites with lower MAP are lower, not higher, than those living in more forested areas with higher MAP. It is likely that diet selectivity by chimpanzees affects δ(15) Nhair values to a greater extent than does the influence of precipitation on plants. Am. J. Primatol. 78:1055-1069, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

Differential Use of Vocal and Gestural Communication by Chimpanzees (Pan troglodytes) in Response to the Attentional Status of a Human (Homo sapiens)

PubMed Central

Hostetter, Autumn B.; Cantero, Monica; Hopkins, William D.

2007-01-01

This study examined the communicative behavior of 49 captive chimpanzees (Pan troglodytes), particularly their use of vocalizations, manual gestures, and other auditory- or tactile-based behaviors as a means of gaining an inattentive audience’s attention. A human (Homo sapiens) experimenter held a banana while oriented either toward or away from the chimpanzee. The chimpanzees’ behavior was recorded for 60 s. Chimpanzees emitted vocalizations faster and were more likely to produce vocalizations as their 1st communicative behavior when a human was oriented away from them. Chimpanzees used manual gestures more frequently and faster when the human was oriented toward them. These results replicate the findings of earlier studies on chimpanzee gestural communication and provide new information about the intentional and functional use of their vocalizations. PMID:11824896

Object-based attention in chimpanzees (Pan troglodytes).

PubMed

Ushitani, Tomokazu; Imura, Tomoko; Tomonaga, Masaki

2010-03-17

We conducted three experiments to investigate how object-based components contribute to the attentional processes of chimpanzees and to examine how such processes operate with regard to perceptually structured objects. In Experiment 1, chimpanzees responded to a spatial cueing task that required them to touch a target appearing at either end of two parallel rectangles. We compared the time involved in shifting attention (cost of attentional shift) when the locations of targets were cued and non cued. Results showed that the cost of the attentional shift within one rectangle was smaller than that beyond the object's boundary, demonstrating object-based attention in chimpanzees. The results of Experiment 2, conducted with different stimulus configurations, replicated the results of Experiment 1, supporting that object-based attention operates in chimpanzees. In Experiment 3, the cost of attentional shift within a cued but partly occluded rectangle was shorter than that within a rectangle that was cued but divided in the middle. The results suggest that the attention of chimpanzees is activated not only by an explicit object but also by fragmented patches represented as an object at a higher-order perceptual level. Chimpanzees' object-based attention may be similar to that of humans. Copyright 2010 Elsevier Ltd. All rights reserved.

Brief communication: Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal: Conceptualization of "fire behavior" and the case for a chimpanzee model.

PubMed

Pruetz, Jill D; LaDuke, Thomas C

2010-04-01

The use and control of fire are uniquely human traits thought to have come about fairly late in the evolution of our lineage, and they are hypothesized to correlate with an increase in intellectual complexity. Given the relatively sophisticated cognitive abilities yet small brain size of living apes compared to humans and even early hominins, observations of wild chimpanzees' reactions to naturally occurring fire can help inform hypotheses about the likely responses of early hominins to fire. We use data on the behavior of savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal during two encounters with wildfires to illuminate the similarities between great apes and humans regarding their reaction to fire. Chimpanzees' close relatedness to our lineage makes them phylogenetically relevant to the study of hominid evolution, and the open, hot and dry environment at Fongoli, similar to the savanna mosaic thought to characterize much of hominid evolution, makes these apes ecologically important as a living primate model as well. Chimpanzees at Fongoli calmly monitor wildfires and change their behavior in anticipation of the fire's movement. The ability to conceptualize the "behavior" of fire may be a synapomorphic trait characterizing the human-chimpanzee clade. If the cognitive underpinnings of fire conceptualization are a primitive hominid trait, hypotheses concerning the origins of the control and use of fire may need revision. We argue that our findings exemplify the importance of using living chimpanzees as models for better understanding human evolution despite recently published suggestions to the contrary. (c) 2009 Wiley-Liss, Inc.

Processes of social learning in the tool use of chimpanzees (Pan troglodytes) and human children (Homo sapiens).

PubMed

Nagell, K; Olguin, R S; Tomasello, M

1993-06-01

Common chimpanzees (Pan troglodytes) and 2-year-old human children (Homo sapiens) were presented with a rakelike tool and a desirable but out-of-reach object. One group of subjects observed a human demonstrator use the tool in one way, and another group observed a demonstrator use the tool in another way. Children in both cases did what the model did. Chimpanzee subjects, however, behaved identically in the 2 model conditions. Both groups performed better than subjects who saw no demonstration. This pattern of results suggest that the chimpanzees were paying attention to the general functional relations in the task and to the results obtained by the demonstrator but not to the actual methods of tool use demonstrated. Human children were focused on the demonstrator's actual methods of tool use (her behavior). The different social learning processes used by the 2 species have implications for their different forms of social organization.

Feeding ecology of chimpanzees (Pan troglodytes verus) inhabiting a forest-mangrove-savanna-agricultural matrix at Caiquene-Cadique, Cantanhez National Park, Guinea-Bissau.

PubMed

Bessa, Joana; Sousa, Cláudia; Hockings, Kimberley J

2015-06-01

With rising conversion of "natural" habitat to other land use such as agriculture, nonhuman primates are increasingly exploiting areas influenced by people and their activities. Despite the conservation importance of understanding the ways in which primates modify their behavior to human pressures, data are lacking, even for well-studied species. Using systematically collected data (fecal samples, feeding traces, and direct observations), we examined the diet and feeding strategies of an unhabituated chimpanzee community (Pan troglodytes verus) at Caiquene-Cadique in Guinea-Bissau that inhabit a forest-savanna-mangrove-agricultural mosaic. The chimpanzees experienced marked seasonal variations in the availability of plant foods, but maintained a high proportion of ripe fruit in the diet across months. Certain wild species were identified as important to this community including oil-palm (Elaeis guineensis) fruit and flower. Honey was frequently consumed but no other insects or vertebrates were confirmed to be eaten by this community. However, we provide indirect evidence of possible smashing and consumption of giant African snails (Achatina sp.) by chimpanzees at this site. Caiquene-Cadique chimpanzees were confirmed to feed on nine different agricultural crops, which represented 13.6% of all plant species consumed. Consumption of fruit and nonfruit crops was regular, but did not increase during periods of wild fruit scarcity. Crop consumption is an increasing and potentially problematic behavior, which can impact local people's tolerance toward wildlife. To maximize the potential success of any human-wildlife coexistence strategy (e.g., to reduce primate crop feeding), knowledge of primate behavior, as well as multifaceted social dimensions of interactions, is critical. © 2015 Wiley Periodicals, Inc.

Eco-geographical diversification of bitter taste receptor genes (TAS2Rs) among subspecies of chimpanzees (Pan troglodytes).

PubMed

Hayakawa, Takashi; Sugawara, Tohru; Go, Yasuhiro; Udono, Toshifumi; Hirai, Hirohisa; Imai, Hiroo

2012-01-01

Chimpanzees (Pan troglodytes) have region-specific difference in dietary repertoires from East to West across tropical Africa. Such differences may result from different genetic backgrounds in addition to cultural variations. We analyzed the sequences of all bitter taste receptor genes (cTAS2Rs) in a total of 59 chimpanzees, including 4 putative subspecies. We identified genetic variations including single-nucleotide variations (SNVs), insertions and deletions (indels), gene-conversion variations, and copy-number variations (CNVs) in cTAS2Rs. Approximately two-thirds of all cTAS2R haplotypes in the amino acid sequence were unique to each subspecies. We analyzed the evolutionary backgrounds of natural selection behind such diversification. Our previous study concluded that diversification of cTAS2Rs in western chimpanzees (P. t. verus) may have resulted from balancing selection. In contrast, the present study found that purifying selection dominates as the evolutionary form of diversification of the so-called human cluster of cTAS2Rs in eastern chimpanzees (P. t. schweinfurthii) and that the other cTAS2Rs were under no obvious selection as a whole. Such marked diversification of cTAS2Rs with different evolutionary backgrounds among subspecies of chimpanzees probably reflects their subspecies-specific dietary repertoires.

Eco-Geographical Diversification of Bitter Taste Receptor Genes (TAS2Rs) among Subspecies of Chimpanzees (Pan troglodytes)

PubMed Central

Hayakawa, Takashi; Sugawara, Tohru; Go, Yasuhiro; Udono, Toshifumi; Hirai, Hirohisa; Imai, Hiroo

2012-01-01

Chimpanzees (Pan troglodytes) have region-specific difference in dietary repertoires from East to West across tropical Africa. Such differences may result from different genetic backgrounds in addition to cultural variations. We analyzed the sequences of all bitter taste receptor genes (cTAS2Rs) in a total of 59 chimpanzees, including 4 putative subspecies. We identified genetic variations including single-nucleotide variations (SNVs), insertions and deletions (indels), gene-conversion variations, and copy-number variations (CNVs) in cTAS2Rs. Approximately two-thirds of all cTAS2R haplotypes in the amino acid sequence were unique to each subspecies. We analyzed the evolutionary backgrounds of natural selection behind such diversification. Our previous study concluded that diversification of cTAS2Rs in western chimpanzees (P. t. verus) may have resulted from balancing selection. In contrast, the present study found that purifying selection dominates as the evolutionary form of diversification of the so-called human cluster of cTAS2Rs in eastern chimpanzees (P. t. schweinfurthii) and that the other cTAS2Rs were under no obvious selection as a whole. Such marked diversification of cTAS2Rs with different evolutionary backgrounds among subspecies of chimpanzees probably reflects their subspecies-specific dietary repertoires. PMID:22916235

Adenovirus infection in savanna chimpanzees (Pan troglodytes schweinfurthii) in the Issa Valley, Tanzania.

PubMed

Dadáková, Eva; Brožová, Kristýna; Piel, Alex K; Stewart, Fiona A; Modrý, David; Celer, Vladimír; Hrazdilová, Kristýna

2018-01-01

Adenoviruses are a widespread cause of diverse human infections with recently confirmed zoonotic roots in African great apes. We focused on savanna-dwelling chimpanzees in the Issa Valley (Tanzania), which differ from those from forested sites in many aspects of behavior and ecology. PCR targeting the DNA polymerase gene detected AdV in 36.7% (69/188) of fecal samples. We detected five groups of strains belonging to the species Human mastadenovirus E and two distinct groups within the species Human mastadenovirus C based on partial hexon sequence. All detected AdVs from the Issa Valley are related to those from nearby Mahale and Gombe National Parks, suggesting chimpanzee movements and pathogen transmission.

Different early rearing experiences have long term effects on cortical organization in captive chimpanzees (Pan troglodytes)

PubMed Central

Bogart, Stephanie L.; Bennett, Allyson J.; Schapiro, Steven J.; Reamer, Lisa A.; Hopkins, William D.

2014-01-01

Consequences of rearing history in chimpanzees (Pan troglodytes) have been explored in relation to behavioral abnormalities and cognition, however, little is known about the effects of rearing conditions on anatomical brain development. Human studies have revealed that experiences of maltreatment and neglect during infancy and childhood can have detrimental effects on brain development and cognition. In this study, we evaluated the effects of early rearing experience on brain morphology in 92 captive chimpanzees (ages 11-43) who were either reared by their mothers (n = 46) or in a nursery (n = 46) with age-group peers. Magnetic resonance brain images were analyzed with a processing program (BrainVISA) that extracts cortical sulci. We obtained various measurements from 11 sulci located throughout the brain, as well as whole brain gyrification and white and grey matter volumes. We found that mother-reared chimpanzees have greater global white-to-grey matter volume, more cortical folding and thinner grey matter within the cortical folds than nursery-reared animals. The findings reported here are the first to demonstrate that differences in early rearing conditions have significant consequences on brain morphology in chimpanzees and suggests potential differences in the development of white matter expansion and myelination. PMID:24206013

Different early rearing experiences have long-term effects on cortical organization in captive chimpanzees (Pan troglodytes).

PubMed

Bogart, Stephanie L; Bennett, Allyson J; Schapiro, Steven J; Reamer, Lisa A; Hopkins, William D

2014-03-01

Consequences of rearing history in chimpanzees (Pan troglodytes) have been explored in relation to behavioral abnormalities and cognition; however, little is known about the effects of rearing conditions on anatomical brain development. Human studies have revealed that experiences of maltreatment and neglect during infancy and childhood can have detrimental effects on brain development and cognition. In this study, we evaluated the effects of early rearing experience on brain morphology in 92 captive chimpanzees (ages 11-43) who were either reared by their mothers (n = 46) or in a nursery (n = 46) with age-group peers. Magnetic resonance brain images were analyzed with a processing program (BrainVISA) that extracts cortical sulci. We obtained various measurements from 11 sulci located throughout the brain, as well as whole brain gyrification and white and grey matter volumes. We found that mother-reared chimpanzees have greater global white-to-grey matter volume, more cortical folding and thinner grey matter within the cortical folds than nursery-reared animals. The findings reported here are the first to demonstrate that differences in early rearing conditions have significant consequences on brain morphology in chimpanzees and suggests potential differences in the development of white matter expansion and myelination. © 2013 John Wiley & Sons Ltd.

Patterns of mandibular variation in Pan and Gorilla and implications for African ape taxonomy.

PubMed

Taylor, Andrea B; Groves, Colin P

2003-05-01

Pan and Gorilla taxonomy is currently in a state of flux, with the number of existing species and subspecies of common chimpanzee and gorilla having been recently challenged. While Pan and Gorilla systematics have been evaluated on the basis of craniometric and odontometric data, only a handful of studies have evaluated multivariate craniometric variation within P. troglodytes, and none have evaluated in detail mandibular variation in either P. troglodytes or Gorilla gorilla. In this paper, we examine ontogenetic and adult mandibular variation in Pan and Gorilla. We test the hypothesis that patterns and degrees of mandibular variation in Pan and Gorilla closely correspond to those derived from previous analyses of craniometric variation. We then use these data to address some current issues surrounding Pan and Gorilla taxonomy. Specifically, we evaluate the purported distinctiveness of P.t. verus from the other two subspecies of Pan troglodytes, and the recent proposals to recognize Nigerian gorillas as a distinct subspecies, Gorilla gorilla diehli, and to acknowledge mountain and lowland gorillas as two separate species. Overall, patterns and degrees of multivariate mandibular differentiation parallel those obtained previously for the cranium and dentition. Thus, differences among the three conventionally recognized gorilla subspecies are somewhat greater than among subspecies of common chimpanzees, but differences between P. paniscus and P. troglodytes are greater than those observed between any gorilla subspecies. In this regard, the mandible does not appear to be more variable, or of less taxonomic value, than the face and other parts of the cranium. There are, however, some finer differences in the pattern and degree of morphological differentiation in Pan and Gorilla, both with respect to cranial and dental morphology, and in terms of the application and manner of size adjustment. Mandibular differentiation supports the conventional separation of bonobos from

Causal knowledge and imitation/emulation switching in chimpanzees (Pan troglodytes) and children (Homo sapiens).

PubMed

Horner, Victoria; Whiten, Andrew

2005-07-01

This study explored whether the tendency of chimpanzees and children to use emulation or imitation to solve a tool-using task was a response to the availability of causal information. Young wild-born chimpanzees from an African sanctuary and 3- to 4-year-old children observed a human demonstrator use a tool to retrieve a reward from a puzzle-box. The demonstration involved both causally relevant and irrelevant actions, and the box was presented in each of two conditions: opaque and clear. In the opaque condition, causal information about the effect of the tool inside the box was not available, and hence it was impossible to differentiate between the relevant and irrelevant parts of the demonstration. However, in the clear condition causal information was available, and subjects could potentially determine which actions were necessary. When chimpanzees were presented with the opaque box, they reproduced both the relevant and irrelevant actions, thus imitating the overall structure of the task. When the box was presented in the clear condition they instead ignored the irrelevant actions in favour of a more efficient, emulative technique. These results suggest that emulation is the favoured strategy of chimpanzees when sufficient causal information is available. However, if such information is not available, chimpanzees are prone to employ a more comprehensive copy of an observed action. In contrast to the chimpanzees, children employed imitation to solve the task in both conditions, at the expense of efficiency. We suggest that the difference in performance of chimpanzees and children may be due to a greater susceptibility of children to cultural conventions, perhaps combined with a differential focus on the results, actions and goals of the demonstrator.

Assessment of gastrointestinal parasites in wild chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon

PubMed Central

Bertout, Sébastien; Locatelli, Sabrina; Butel, Christelle; Pion, Sébastien; Mpoudi-Ngole, Eitel; Delaporte, Eric; Peeters, Martine; Mallié, Michèle

2014-01-01

We tested 114 faecal samples from wild simian immunodeficiency virus (SIV)-positive (n=43) and SIV-negative (n=71) chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon for the presence of gastrointestinal parasites by direct smear. We observed cysts from different protozoa (Entamoeba coli and Entamoeba histolytica/Entamoeba dispar, Endolimax nana, Iodamoeba butschlii, Chilomastix mesnili, Balantidium coli and Blastocystis cells) and trophozoites from Troglodytella abrassarti and Balantidium coli. Eggs from different helminths (strongylids, Ascaris lumbricoides, Abbreviata caucasica, Trichuris sp., Capillaria sp., Enterobius anthropopeci, Bertiella sp., Hymenolepis diminuta and an undetermined fluke) were also observed. Finally, we observed eggs that could not be properly identified and classified. We did not observe any differences between the SIV+ and SIV− samples except for the unidentified eggs. The studied chimpanzees were highly parasitised by strongylid (85.1 % of prevalence), Troglodytella (43.8 %) and Blastocystis (2.9 %), and the frequency of the other parasites ranged from 0.9 to 8.8 %. These high levels of parasite infections could represent an additional burden in a population where there is a high rate of the SIV virus in circulation. PMID:24781023

Assessment of gastrointestinal parasites in wild chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon.

PubMed

Drakulovski, Pascal; Bertout, Sébastien; Locatelli, Sabrina; Butel, Christelle; Pion, Sébastien; Mpoudi-Ngole, Eitel; Delaporte, Eric; Peeters, Martine; Mallié, Michèle

2014-07-01

We tested 114 faecal samples from wild simian immunodeficiency virus (SIV)-positive (n = 43) and SIV-negative (n = 71) chimpanzees (Pan troglodytes troglodytes) in southeast Cameroon for the presence of gastrointestinal parasites by direct smear. We observed cysts from different protozoa (Entamoeba coli and Entamoeba histolytica / Entamoeba dispar, Endolimax nana, Iodamoeba butschlii, Chilomastix mesnili, Balantidium coli and Blastocystis cells) and trophozoites from Troglodytella abrassarti and Balantidium coli. Eggs from different helminths (strongylids, Ascaris lumbricoides, Abbreviata caucasica, Trichuris sp., Capillaria sp., Enterobius anthropopeci, Bertiella sp., Hymenolepis diminuta and an undetermined fluke) were also observed. Finally, we observed eggs that could not be properly identified and classified. We did not observe any differences between the SIV+ and SIV- samples except for the unidentified eggs. The studied chimpanzees were highly parasitised by strongylid (85.1% of prevalence), Troglodytella (43.8%) and Blastocystis (2.9%), and the frequency of the other parasites ranged from 0.9 to 8.8%. These high levels of parasite infections could represent an additional burden in a population where there is a high rate of the SIV virus in circulation.

Etiology of Triarchic Psychopathy Dimensions in Chimpanzees (Pan troglodytes)

PubMed Central

Latzman, Robert D.; Patrick, Christopher J.; Freeman, Hani J.; Schapiro, Steven J.; Hopkins, William D.

2016-01-01

The current study undertook analyses of genealogical data from a sample of 178 socially-housed chimpanzees (Pan troglodytes) with well-documented pedigrees, to clarify the etiologic bases of triarchic psychopathy dimensions and the influence of early social rearing experiences. Whereas biometric analyses for the full sample indicated significant heritability for the boldness dimension of psychopathy only, heritability estimates varied by early rearing, with all three triarchic dimensions showing significant heritabilities among mother-reared but not nursery-reared apes. For mother-reared apes, both genes and environment contributed to covariance between meanness and disinhibition, whereas environment contributed mainly to covariation between these dimensions and boldness. Results indicate contributions of both genes and environment to psychopathic tendencies, with an important role for early-rearing in their relative contributions to distinct phenotypic subdimensions. In conjunction with findings from human studies, results provide valuable insights into core biobehavioral processes relevant to psychological illness and health. PMID:28503367

Learning from others' mistakes? limits on understanding a trap-tube task by young chimpanzees (Pan troglodytes) and children (Homo sapiens).

PubMed

Horner, Victoria; Whiten, Andrew

2007-02-01

A trap-tube task was used to determine whether chimpanzees (Pan troglodytes) and children (Homo sapiens) who observed a model's errors and successes could master the task in fewer trials than those who saw only successes. Two- to 7-year-old chimpanzees and 3- to 4-year-old children did not benefit from observing errors and found the task difficult. Two of the 6 chimpanzees developed a successful anticipatory strategy but showed no evidence of representing the core causal relations involved in trapping. Three- to 4-year-old children showed a similar limitation and tended to copy the actions of the demonstrator, irrespective of their causal relevance. Five- to 6-year-old children were able to master the task but did not appear to be influenced by social learning or benefit from observing errors.

Hyperprogesteronemia in response to Vitex fischeri consumption in wild chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Emery Thompson, Melissa; Wilson, Michael L; Gobbo, Grace; Muller, Martin N; Pusey, Anne E

2008-11-01

Chimpanzees in Gombe National Park consume fruits of Vitex fischeri during a short annual fruiting season. This fruit species is a member of a genus widely studied for phytoestrogen composition and varied physiological effects. One particularly well-studied species, V. agnus-castus, is noted for its documented effects on female reproductive function, evidenced in increased progesterone levels and consequent regulation of luteal function. We examined reproductive hormone levels in both male and female chimpanzees during a 6-week period of intense V. fischeri consumption. V. fischeri consumption was associated with an abrupt and dramatic increase in urinary progesterone levels of female chimpanzees to levels far exceeding the normal range of variation. Female estrogen levels were not significantly impacted, nor were male testosterone levels. These are some of the first data indicating that phytochemicals in the natural diet of a primate can have significant impacts on the endocrine system, though the fluctuating nature of chimpanzee diet and reproductive function does not allow us to determine whether the effects observed during this short period had a broader positive or negative impact on female fertility. Given the widespread use of various Vitex species by African primates and the as-yet-undescribed phytochemical properties of these species, we predict that our observations may be indicative of a broader phenomenon. Copyright 2008 Wiley-Liss, Inc.

Limited evidence for third-party affiliation during development in wild chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Miller, Jordan A; Stanton, Margaret A; Lonsdorf, Elizabeth V; Wellens, Kaitlin R; Markham, A Catherine; Murray, Carson M

2017-09-01

Examining the ontogeny of conflict-mitigating behaviours in our closest living relatives is an important component of understanding the evolutionary origins of cooperation in our species. In this study, we used 26 years of data to investigate the emergence of third-party affiliation (TPA), defined as affiliative contact given to recipients of aggression by uninvolved bystanders (regardless of initiation), in wild immature eastern chimpanzees ( Pan troglodytes schweinfurthii ) of Gombe National Park, Tanzania. We also characterized TPA by mothers in the same dataset as an adult benchmark for interpreting immature TPA patterns. In summary, we found that immatures did not express TPA as measured by grooming between the ages of 1.5 and 12.0 years, and that there was limited evidence that immatures expressed TPA via play. We also found that mothers did express TPA to offspring, although mothers did not show TPA towards non-offspring. Cases of TPA by mothers to other adults were too few to analyse separately. These results contrast with findings from captive studies which found that chimpanzees as young as 6 years of age demonstrated TPA. We argue that within-species variation in the expression of TPA, both in immatures and adulthood, provides evidence that the conflict management behaviours of young chimpanzees may be heavily influenced by social, ecological and demographic factors.

Limited evidence for third-party affiliation during development in wild chimpanzees (Pan troglodytes schweinfurthii)

PubMed Central

Stanton, Margaret A.; Lonsdorf, Elizabeth V.; Wellens, Kaitlin R.

2017-01-01

Examining the ontogeny of conflict-mitigating behaviours in our closest living relatives is an important component of understanding the evolutionary origins of cooperation in our species. In this study, we used 26 years of data to investigate the emergence of third-party affiliation (TPA), defined as affiliative contact given to recipients of aggression by uninvolved bystanders (regardless of initiation), in wild immature eastern chimpanzees (Pan troglodytes schweinfurthii) of Gombe National Park, Tanzania. We also characterized TPA by mothers in the same dataset as an adult benchmark for interpreting immature TPA patterns. In summary, we found that immatures did not express TPA as measured by grooming between the ages of 1.5 and 12.0 years, and that there was limited evidence that immatures expressed TPA via play. We also found that mothers did express TPA to offspring, although mothers did not show TPA towards non-offspring. Cases of TPA by mothers to other adults were too few to analyse separately. These results contrast with findings from captive studies which found that chimpanzees as young as 6 years of age demonstrated TPA. We argue that within-species variation in the expression of TPA, both in immatures and adulthood, provides evidence that the conflict management behaviours of young chimpanzees may be heavily influenced by social, ecological and demographic factors. PMID:28989757

The contribution of genetics and early rearing experiences to hierarchical personality dimensions in chimpanzees (Pan troglodytes).

PubMed

Latzman, Robert D; Freeman, Hani D; Schapiro, Steven J; Hopkins, William D

2015-11-01

A reliable literature finds that traits are related to each other in an organized hierarchy encompassing various conceptualizations of personality (e.g., Big Three, five-factor model). Recent work suggests the potential of a similar organization among our closest nonhuman relative, chimpanzees (Pan troglodytes), with significant links to neurobiology suggesting an evolutionarily and neurobiologically based hierarchical structure of personality. The current study investigated this hierarchical structure, the heritability of the various personality dimensions across levels of the hierarchy, and associations with early social rearing experience in a large sample (N = 238) of socially housed, captive chimpanzees residing in 2 independent colonies of apes. Results provide support for a hierarchical structure of personality in chimpanzees with significant associations with early rearing experiences. Further, heritabilities of the various dimensions varied by early rearing, with affective dimensions found to be significantly heritable among mother-reared apes, whereas personality dimensions were largely independent of relatedness among the nursery-reared apes. Taken together, these findings provide evidence for the influence of both genetic and environmental factors on personality profiles across levels of the hierarchy, supporting the importance of considering environmental variation in models of quantitative trait evolution. (c) 2015 APA, all rights reserved).

The contribution of genetics and early rearing experiences to hierarchical personality dimensions in chimpanzees (Pan troglodytes)

PubMed Central

Latzman, Robert D.; Freeman, Hani D.; Schapiro, Steven J.; Hopkins, William D.

2015-01-01

A reliable literature finds that traits are related to each other in an organized hierarchy encompassing various conceptualizations of personality (e.g., Big Three, Five Factor Model). Recent work suggests the potential of a similar organization among our closest nonhuman relative, chimpanzees (Pan troglodytes), with significant links to neurobiology suggesting an evolutionarily- and neurobiologically-based hierarchical structure of personality. The current study investigated this hierarchical structure, the heritability of the various personality dimensions across levels of the hierarchy, and associations with early social rearing experience in a large sample (N = 238) of socially-housed, captive chimpanzees residing in two independent colonies of apes. Results provide support for a hierarchical structure of personality in chimpanzees with significant associations with early rearing experiences. Further, heritabilities of the various dimensions varied by early rearing, with affective dimensions found to be significantly heritable among mother-reared apes, while personality dimensions were largely independent of relatedness among the nursery-reared apes. Taken together, these findings provide evidence for the influence of both genetic and environmental factors on personality profiles across levels of the hierarchy, supporting the importance of considering environmental variation in models of quantitative trait evolution. PMID:25915132

Nut Cracking Tools Used by Captive Chimpanzees (Pan troglodytes) and Their Comparison with Early Stone Age Percussive Artefacts from Olduvai Gorge.

PubMed

Arroyo, Adrián; Hirata, Satoshi; Matsuzawa, Tetsuro; de la Torre, Ignacio

2016-01-01

We present the results of a series of experiments at the Kumamoto Sanctuary in Japan, in which captive chimpanzees (Pan troglodytes) performed several nut cracking sessions using raw materials from Olduvai Gorge, Tanzania. We examined captive chimpanzee pounding tools using a combination of technological analysis, use-wear distribution, and micro-wear analysis. Our results show specific patterns of use-wear distribution across the active surfaces of pounding tools, which reveal some similarities with traces on archaeological percussive objects from the Early Stone Age, and are consistent with traces on other experimental pounding tools used by modern humans. The approach used in this study may help to stablish a framework with which to interpret archaeological assemblages and improve understanding of use-wear formation processes on pounding tools used by chimpanzees. This study represents the first direct comparison of chimpanzee pounding tools and archaeological material, and thus may contribute to a better understanding of hominin percussive activities.

Nut Cracking Tools Used by Captive Chimpanzees (Pan troglodytes) and Their Comparison with Early Stone Age Percussive Artefacts from Olduvai Gorge

PubMed Central

Arroyo, Adrián; Hirata, Satoshi; Matsuzawa, Tetsuro; de la Torre, Ignacio

2016-01-01

We present the results of a series of experiments at the Kumamoto Sanctuary in Japan, in which captive chimpanzees (Pan troglodytes) performed several nut cracking sessions using raw materials from Olduvai Gorge, Tanzania. We examined captive chimpanzee pounding tools using a combination of technological analysis, use-wear distribution, and micro-wear analysis. Our results show specific patterns of use-wear distribution across the active surfaces of pounding tools, which reveal some similarities with traces on archaeological percussive objects from the Early Stone Age, and are consistent with traces on other experimental pounding tools used by modern humans. The approach used in this study may help to stablish a framework with which to interpret archaeological assemblages and improve understanding of use-wear formation processes on pounding tools used by chimpanzees. This study represents the first direct comparison of chimpanzee pounding tools and archaeological material, and thus may contribute to a better understanding of hominin percussive activities. PMID:27870877

A group-specific arbitrary tradition in chimpanzees (Pan troglodytes).

PubMed

van Leeuwen, Edwin J C; Cronin, Katherine A; Haun, Daniel B M

2014-11-01

Social learning in chimpanzees has been studied extensively and it is now widely accepted that chimpanzees have the capacity to learn from conspecifics through a multitude of mechanisms. Very few studies, however, have documented the existence of spontaneously emerged traditions in chimpanzee communities. While the rigour of experimental studies is helpful to investigate social learning mechanisms, documentation of naturally occurring traditions is necessary to understand the relevance of social learning in the real lives of animals. In this study, we report on chimpanzees spontaneously copying a seemingly non-adaptive behaviour ("grass-in-ear behaviour"). The behaviour entailed chimpanzees selecting a stiff, straw-like blade of grass, inserting the grass into one of their own ears, adjusting the position, and then leaving it in their ear during subsequent activities. Using a daily focal follow procedure, over the course of 1 year, we observed 8 (out of 12) group members engaging in this peculiar behaviour. Importantly, in the three neighbouring groups of chimpanzees (n = 82), this behaviour was only observed once, indicating that ecological factors were not determiners of the prevalence of this behaviour. These observations show that chimpanzees have a tendency to copy each other's behaviour, even when the adaptive value of the behaviour is presumably absent.

Pneumatic processes in the temporal bone of chimpanzee (Pan troglodytes) and gorilla (Gorilla gorilla).

PubMed

Sherwood, R J

1999-08-01

The ontogeny of human temporal bone pneumatization has been well studied from both comparative and clinical perspectives. While a difference in the extent of air cell distribution has been noted in our closest living relatives, chimpanzees and gorillas, the processes responsible have been relatively unexplored. To examine these processes, a large, age-graded series of hominoid skulls was radiographed and the progress of pneumatization recorded. Additionally, a subsample of 30 chimpanzees and 12 gorillas was subjected to high-resolution CT scanning. Neonatal specimens show a well-developed mastoid antrum, as well as a capacious hypotympanum extending into the petrous apex. In African apes, as in humans, the mastoid antrum serves as the focus for air cell expansion into the mastoid and immediately adjacent areas. In chimpanzees and gorillas, however, a pronounced lateral structure, described as the squamous antrum, serves as the focus of pneumatization for anterior structures such as the squamous and zygomatic. The diminution of this structure in Homo sapiens explains the difference in air cell distribution in these regions. Copyright 1999 Wiley-Liss, Inc.

Chimpanzees (Pan troglodytes) Produce the Same Types of 'Laugh Faces' when They Emit Laughter and when They Are Silent.

PubMed

Davila-Ross, Marina; Jesus, Goncalo; Osborne, Jade; Bard, Kim A

2015-01-01

The ability to flexibly produce facial expressions and vocalizations has a strong impact on the way humans communicate, as it promotes more explicit and versatile forms of communication. Whereas facial expressions and vocalizations are unarguably closely linked in primates, the extent to which these expressions can be produced independently in nonhuman primates is unknown. The present work, thus, examined if chimpanzees produce the same types of facial expressions with and without accompanying vocalizations, as do humans. Forty-six chimpanzees (Pan troglodytes) were video-recorded during spontaneous play with conspecifics at the Chimfunshi Wildlife Orphanage. ChimpFACS was applied, a standardized coding system to measure chimpanzee facial movements, based on FACS developed for humans. Data showed that the chimpanzees produced the same 14 configurations of open-mouth faces when laugh sounds were present and when they were absent. Chimpanzees, thus, produce these facial expressions flexibly without being morphologically constrained by the accompanying vocalizations. Furthermore, the data indicated that the facial expression plus vocalization and the facial expression alone were used differently in social play, i.e., when in physical contact with the playmates and when matching the playmates' open-mouth faces. These findings provide empirical evidence that chimpanzees produce distinctive facial expressions independently from a vocalization, and that their multimodal use affects communicative meaning, important traits for a more explicit and versatile way of communication. As it is still uncertain how human laugh faces evolved, the ChimpFACS data were also used to empirically examine the evolutionary relation between open-mouth faces with laugh sounds of chimpanzees and laugh faces of humans. The ChimpFACS results revealed that laugh faces of humans must have gradually emerged from laughing open-mouth faces of ancestral apes. This work examines the main evolutionary

How Young Children and Chimpanzees ("Pan Troglodytes") Perceive Objects in a 2D Display: Putting an Assumption to the Test

ERIC Educational Resources Information Center

Leighty, Katherine A.; Menzel, Charles R.; Fragaszy, Dorothy M.

2008-01-01

Object recognition research is typically conducted using 2D stimuli in lieu of 3D objects. This study investigated the amount and complexity of knowledge gained from 2D stimuli in adult chimpanzees ("Pan troglodytes") and young children (aged 3 and 4 years) using a titrated series of cross-dimensional search tasks. Results indicate that 3-year-old…

Significant differentiation in the apolipoprotein(a)/lipoprotein(a) trait between chimpanzees from Western and Central Africa.

PubMed

Noureen, Asma; Ronke, Claudius; Khalifa, Mahmoud; Halbwax, Michel; Fischer, Anne; André, Claudine; Atencia, Rebeca; Garriga, Rosa; Mugisha, Lawrence; Ceglarek, Uta; Thiery, Joachim; Utermann, Gerd; Schmidt, Konrad

2017-09-01

Elevated Lipoprotein(a) (Lp(a)) plasma concentrations are a risk factor for cardiovascular disease in humans, largely controlled by the LPA gene encoding apolipoprotein(a) (apo(a)). Lp(a) is composed of low-density lipoprotein (LDL) and apo(a) and restricted to Catarrhini. A variable number of kringle IV (KIV) domains in LPA lead to a size polymorphism of apo(a) that is inversely correlated with Lp(a) concentrations. Smaller apo(a) isoforms and higher Lp(a) levels in central chimpanzees (Pan troglodytes troglodytes [PTT]) compared to humans from Europe had been reported. We studied apo(a) isoforms and Lp(a) concentrations in 75 western (Pan troglodytes verus [PTV]) and 112 central chimpanzees, and 12 bonobos (Pan paniscus [PPA]), all wild born and living in sanctuaries in Sierra Leone, Republic of the Congo, and DR Congo, respectively, and 116 humans from Gabon. Lp(a) levels were severalfold higher in western than in central chimpanzees (181.0 ± 6.7 mg/dl vs. 56.5 ± 4.3 mg/dl), whereas bonobos showed intermediate levels (134.8 ± 33.4 mg/dl). Apo(a) isoform sizes differed significantly between subspecies (means 20.9 ± 2.2, 22.9 ± 4.4, and 23.8 ± 3.8 KIV repeats in PTV, PTT, and PPA, respectively). However, far higher isoform-associated Lp(a) concentrations for all isoform sizes in western chimpanzees offered the main explanation for the higher overall Lp(a) levels in this subspecies. Human Lp(a) concentrations (mean 47.9 ± 2.8 mg/dl) were similar to those in central chimpanzees despite larger isoforms (mean 27.1 ± 4.9 KIV). Lp(a) and LDL, apoB-100, and total cholesterol levels only correlated in PTV. This remarkable differentiation between chimpanzees from different African habitats and the trait's similarity in humans and chimpanzees from Central Africa poses the question of a possible impact of an environmental factor that has shaped the genetic architecture of LPA. Overall, studies on the cholesterol

When Less is More: Like Humans, Chimpanzees (Pan troglodytes) Misperceive Food Amounts Based on Plate Size

PubMed Central

Parrish, Audrey E.; Beran, Michael J.

2013-01-01

We investigated whether chimpanzees (Pan troglodytes) misperceived food portion sizes depending upon the context in which they were presented, something that often affects how much humans serve themselves and subsequently consume. Chimpanzees judged same-sized and smaller food portions to be larger in amount when presented on a small plate compared to an equal or larger food portion presented on a large plate, and did so despite clearly being able to tell the difference in portions when plate size was identical. These results are consistent with data from the human literature in which people misperceive food portion sizes as a function of plate size. This misperception is attributed to the Delboeuf illusion which occurs when the size of a central item is misperceived on the basis of its surrounding context. These results demonstrate a cross-species shared visual misperception of portion size that affects choice behavior, here in a nonhuman species for which there is little experience with tests that involve choosing between food amounts on dinnerware. The biases resulting in this form of misperception of food portions appear to have a deep-rooted evolutionary history which we share with, at minimum, our closest living nonhuman relative, the chimpanzee. PMID:23949698

Chimpanzee pinworm, Enterobius anthropopitheci (Nematoda: Oxyuridae), maintained for more than twenty years in captive chimpanzees in Japan.

PubMed

Hasegawa, Hideo; Udono, Toshifumi

2007-08-01

The chimpanzee pinworm, Enterobius anthropopitheci (Gedoelst, 1916), was found in chimpanzees, Pan troglodytes, reared in Kumamoto Primate Research Park, Sanwa Kagaku Kenkyusho Co., Ltd., Kumamoto, Japan, in 2006. Because the chimpanzees in this institution originated from chimpanzees imported from Africa before 1984, it is considered that E. anthropopitheci infection has persisted for more than 20 yr in the chimpanzees. Analysis of pinworm specimens preserved in the institution revealed that transition of predominant pinworm species occurred, responding to the change of anthelmintics used for pinworm treatment. Present dominance of E. anthropopitheci is surmised to be caused by fenbendazole, which has been adopted from 2002. Scarcity of mixed infection with E. anthropopitheci and Enterobius vermicularis suggests interspecific competition between the pinworms.

Problem solving in the presence of others: how rank and relationship quality impact resource acquisition in chimpanzees (Pan troglodytes).

PubMed

Cronin, Katherine A; Pieper, Bridget A; van Leeuwen, Edwin J C; Mundry, Roger; Haun, Daniel B M

2014-01-01

In the wild, chimpanzees (Pan troglodytes) are often faced with clumped food resources that they may know how to access but abstain from doing so due to social pressures. To better understand how social settings influence resource acquisition, we tested fifteen semi-wild chimpanzees from two social groups alone and in the presence of others. We investigated how resource acquisition was affected by relative social dominance, whether collaborative problem solving or (active or passive) sharing occurred amongst any of the dyads, and whether these outcomes were related to relationship quality as determined from six months of observational data. Results indicated that chimpanzees obtained fewer rewards when tested in the presence of others compared to when they were tested alone, and this loss tended to be greater when paired with a higher ranked individual. Individuals demonstrated behavioral inhibition; chimpanzees who showed proficient skill when alone often abstained from solving the task when in the presence of others. Finally, individuals with close social relationships spent more time together in the problem solving space, but collaboration and sharing were infrequent and sessions in which collaboration or sharing did occur contained more instances of aggression. Group living provides benefits and imposes costs, and these findings highlight that one cost of group living may be diminishing productive individual behaviors.

Chimpanzees (Pan troglodytes) Produce the Same Types of ‘Laugh Faces’ when They Emit Laughter and when They Are Silent

PubMed Central

Davila-Ross, Marina; Jesus, Goncalo; Osborne, Jade; Bard, Kim A.

2015-01-01

The ability to flexibly produce facial expressions and vocalizations has a strong impact on the way humans communicate, as it promotes more explicit and versatile forms of communication. Whereas facial expressions and vocalizations are unarguably closely linked in primates, the extent to which these expressions can be produced independently in nonhuman primates is unknown. The present work, thus, examined if chimpanzees produce the same types of facial expressions with and without accompanying vocalizations, as do humans. Forty-six chimpanzees (Pan troglodytes) were video-recorded during spontaneous play with conspecifics at the Chimfunshi Wildlife Orphanage. ChimpFACS was applied, a standardized coding system to measure chimpanzee facial movements, based on FACS developed for humans. Data showed that the chimpanzees produced the same 14 configurations of open-mouth faces when laugh sounds were present and when they were absent. Chimpanzees, thus, produce these facial expressions flexibly without being morphologically constrained by the accompanying vocalizations. Furthermore, the data indicated that the facial expression plus vocalization and the facial expression alone were used differently in social play, i.e., when in physical contact with the playmates and when matching the playmates’ open-mouth faces. These findings provide empirical evidence that chimpanzees produce distinctive facial expressions independently from a vocalization, and that their multimodal use affects communicative meaning, important traits for a more explicit and versatile way of communication. As it is still uncertain how human laugh faces evolved, the ChimpFACS data were also used to empirically examine the evolutionary relation between open-mouth faces with laugh sounds of chimpanzees and laugh faces of humans. The ChimpFACS results revealed that laugh faces of humans must have gradually emerged from laughing open-mouth faces of ancestral apes. This work examines the main evolutionary

Cars kill chimpanzees: case report of a wild chimpanzee killed on a road at Bulindi, Uganda.

PubMed

McLennan, Matthew R; Asiimwe, Caroline

2016-07-01

Roads have broadly adverse impacts on wildlife, including nonhuman primates. One direct effect is mortality from collisions with vehicles. While highly undesirable, roadkills provide valuable information on the health and condition of endangered species. We present a case report of a wild chimpanzee (Pan troglodytes schweinfurthii) killed crossing a road in Bulindi, Uganda, where chimpanzees inhabit forest fragments amid farmland. Details of the collision are constructed from eyewitness accounts of pedestrians. Physical examination of the cadaver indicated good overall body condition; at 40 kg, the deceased female was heavier than usual for an adult female East African chimpanzee. No external wounds or fractures were noted. Coprological assessment demonstrated infection by several gastrointestinal parasites commonly reported in living wild chimpanzees. Histopathology revealed eosinophilic enteritis and biliary hyperplasia potentially caused by parasite infection. However, eosinophilia was not widely spread into the submucosa, while egg/cyst counts suggested low-intensity parasite infections compared to healthy female chimpanzees of similar age in nearby Budongo Forest. No behavioral indicators of ill health were noted in the deceased female in the month prior to the accident. We conclude that cause of death was acute, i.e., shock from the collision, and was probably unrelated to parasite infection or any other underlying health condition. Notably, this female had asymmetrical polythelia, and, while nursing at the time of her death, had one functioning mammary gland only. In Uganda, where primates often inhabit human-dominated landscapes, human population growth and economic development has given rise to increasing motor traffic, while road development is enabling motorists to travel at greater speeds. Thus, the danger of roads to apes and other wildlife is rising, necessitating urgent strategies to reduce risks. Installation of simple speed-bumps-common on Ugandan

Age-related alterations of plasma glutathione and oxidation of redox potentials in chimpanzee (Pan troglodytes) and rhesus monkey (Macaca mulatta).

PubMed

Paredes, Jamespaul; Jones, Dean P; Wilson, Mark E; Herndon, James G

2014-04-01

Chimpanzee (Pan troglodytes) and rhesus macaque (Macaca mulatta) and humans (Homo sapiens) share physiological and genetic characteristics, but have remarkably different life spans, with chimpanzees living 50-60 % and the rhesus living 35-40 % of maximum human survival. Since oxidative processes are associated with aging and longevity, we might expect to see species differences in age-related oxidative processes. Blood and extracellular fluid contain two major thiol redox nodes, glutathione (GSH)/glutathione-disulfide (GSSG) and cysteine (Cys)/cystine (CySS), which are subject to reversible oxidation-reduction reactions and are maintained in a dynamic non-equilibrium state. Disruption of these thiol redox nodes leads to oxidation of their redox potentials (EhGSSG and EhCySS) which affects cellular physiology and is associated with aging and the development of chronic diseases in humans. The purpose of this study was to measure age-related changes in these redox thiols and their corresponding redox potentials (Eh) in chimpanzees and rhesus monkeys. Our results show similar age-related decreases in the concentration of plasma GSH and Total GSH as well as oxidation of the EhGSSG in male and female chimpanzees. Female chimpanzees and female rhesus monkeys also were similar in several outcome measures. For example, similar age-related decreases in the concentration of plasma GSH and Total GSH, as well as age-related oxidation of the EhGSSG were observed. The data collected from chimpanzees and rhesus monkeys corroborates previous reports on oxidative changes in humans and confirms their value as a comparative reference for primate aging.

How chimpanzees (Pan troglodytes) perform in a modified emotional Stroop task.

PubMed

Allritz, Matthias; Call, Josep; Borkenau, Peter

2016-05-01

The emotional Stroop task is an experimental paradigm developed to study the relationship between emotion and cognition. Human participants required to identify the color of words typically respond more slowly to negative than to neutral words (emotional Stroop effect). Here we investigated whether chimpanzees (Pan troglodytes) would show a comparable effect. Using a touch screen, eight chimpanzees were trained to choose between two simultaneously presented stimuli based on color (two identical images with differently colored frames). In Experiment 1, the images within the color frames were shapes that were either of the same color as the surrounding frame or of the alternative color. Subjects made fewer errors and responded faster when shapes were of the same color as the frame surrounding them than when they were not, evidencing that embedded images affected target selection. Experiment 2, a modified version of the emotional Stroop task, presented subjects with four different categories of novel images: three categories of pictures of humans (veterinarian, caretaker, and stranger), and control stimuli showing a white square. Because visits by the veterinarian that include anaesthetization can be stressful for subjects, we expected impaired performance in trials presenting images of the veterinarian. For the first session, we found correct responses to be indeed slower in trials of this category. This effect was more pronounced for subjects whose last anaesthetization experience was more recent, indicating that emotional valence caused the slowdown. We propose our modified emotional Stroop task as a simple method to explore which emotional stimuli affect cognitive performance in nonhuman primates.

Comparative Assessment of Handedness for a Coordinated Bimanual Task in Chimpanzees (Pan troglodytes), Gorillas (Gorilla gorilla), and Orangutans (Pongo pygmaeus)

PubMed Central

Hopkins, William D.; Stoinski, Tara S.; Lukas, Kristen E.; Ross, Stephen R.; Wesley, Michael J.

2007-01-01

Hand preferences for a coordinated bimanual task were assessed in a sample of 31 captive gorillas (Gorilla gorilla) and 19 captive orangutans (Pongo pygmaeus) and were compared with chimpanzee (Pan troglodytes) hand preferences in subjects that were matched on the basis of age, sex, and rearing history. The task required that the apes remove food from the inside edges of a symmetrical polyvinyl chloride pipe presented to them in their home cages. The results indicate significant species differences with chimpanzees showing population-level right-handedness and orangutans showing population-level left-handedness. The gorillas showed a nonsignificant trend toward right-handedness. The results are discussed in terms of possible ecological or biomechanical factors that may influence hand preferences in different ape species. PMID:14498806

Terrestrial nest-building by wild chimpanzees (Pan troglodytes): implications for the tree-to-ground sleep transition in early hominins.

PubMed

Koops, Kathelijne; McGrew, William C; Matsuzawa, Tetsuro; Knapp, Leslie A

2012-07-01

Nest-building is a great ape universal and arboreal nesting in chimpanzees and bonobos suggests that the common ancestor of Pan and Homo also nested in trees. It has been proposed that arboreal nest-building remained the prevailing pattern until Homo erectus, a fully terrestrial biped, emerged. We investigated the unusual occurrence of ground-nesting in chimpanzees (Pan troglodytes), which may inform on factors influencing the tree-to-ground sleep transition in the hominin lineage. We used a novel genetic approach to examine ground-nesting in unhabituated chimpanzees at Seringbara in the Nimba Mountains, Guinea. Previous research showed that ground-nesting at Seringbara was not ecologically determined. Here, we tested a possible mate-guarding function of ground-nesting by analyzing DNA from shed hairs collected from ground nests and tree nests found in close proximity. We examined whether or not ground-nesting was a group-level behavioral pattern and whether or not it occurred in more than one community. We used multiple genetic markers to identify sex and to examine variation in mitochondrial DNA control region (HV1, HV2) sequences. Ground-nesting was a male-biased behavior and males constructed more elaborate ("night") nests than simple ("day") nests on the ground. The mate-guarding hypothesis was not supported, as ground and associated tree nests were built either by maternally-related males or possibly by the same individuals. Ground-nesting was widespread and likely habitual in two communities. We suggest that terrestrial nest-building may have already occurred in arboreally-adapted early hominins before the emergence of H. erectus. Copyright © 2012 Wiley Periodicals, Inc.

Feeding in fear? How adult male western chimpanzees (Pan troglodytes verus) adjust to predation and savanna habitat pressures.

PubMed

Lindshield, Stacy; Danielson, Brent J; Rothman, Jessica M; Pruetz, Jill D

2017-07-01

We evaluated risk-sensitive foraging in adult male western chimpanzees (Pan troglodytes verus) occupying a savanna environment at Fongoli, Senegal. The aim of this study was to determine how the risks of predation and heat stress influenced their behavior while feeding on a key food, fruit of the baobab tree (Adansonia digitata). Proximity of fruiting baobab trees to anthropogenic landmarks were compared to food intake, feeding rate, and behavioral indicators of fear in adult males (N = 11) at Fongoli. Additionally, we compared foraging to vegetative habitats, baobab ripe fruit nutritive quality, surface water availability, and foraging party composition. Fruit abundance increased with proximity to anthropogenic landmarks, and chimpanzees exhibited higher frequencies of antipredator behaviors as they approached these risky areas. However, predation risk did not deter adult males from visiting these fruiting trees; instead, risky foraging bouts were associated with higher food intakes and longer feeding times. Additionally, higher feeding rates were observed in open-canopy habitats, and this behavior may have minimized their risk of heat stress. Adaptations that minimize predation risk are widespread in mammalian prey species, but these traits are poorly understood in chimpanzees. Great apes encounter few nonhuman predators capable of successfully capturing and killing them; thus, such events are rarely observed. Although people rarely hunt chimpanzees in Senegal, we found that adult males perceived humans as predators and adjusted their behavior while foraging in risky habitats. From an applied perspective, risk-taking behavior is important for understanding and mitigating the problem of crop-feeding in locations where chimpanzees and humans live in sympatry. © 2017 Wiley Periodicals, Inc.

Problem Solving in the Presence of Others: How Rank and Relationship Quality Impact Resource Acquisition in Chimpanzees (Pan troglodytes)

PubMed Central

Cronin, Katherine A.; Pieper, Bridget A.; van Leeuwen, Edwin J. C.; Mundry, Roger; Haun, Daniel B. M.

2014-01-01

In the wild, chimpanzees (Pan troglodytes) are often faced with clumped food resources that they may know how to access but abstain from doing so due to social pressures. To better understand how social settings influence resource acquisition, we tested fifteen semi-wild chimpanzees from two social groups alone and in the presence of others. We investigated how resource acquisition was affected by relative social dominance, whether collaborative problem solving or (active or passive) sharing occurred amongst any of the dyads, and whether these outcomes were related to relationship quality as determined from six months of observational data. Results indicated that chimpanzees obtained fewer rewards when tested in the presence of others compared to when they were tested alone, and this loss tended to be greater when paired with a higher ranked individual. Individuals demonstrated behavioral inhibition; chimpanzees who showed proficient skill when alone often abstained from solving the task when in the presence of others. Finally, individuals with close social relationships spent more time together in the problem solving space, but collaboration and sharing were infrequent and sessions in which collaboration or sharing did occur contained more instances of aggression. Group living provides benefits and imposes costs, and these findings highlight that one cost of group living may be diminishing productive individual behaviors. PMID:24695486

Why Are Nigeria-Cameroon Chimpanzees (Pan troglodytes ellioti) Free of SIVcpz Infection?

PubMed

Locatelli, Sabrina; Harrigan, Ryan J; Sesink Clee, Paul R; Mitchell, Matthew W; McKean, Kurt A; Smith, Thomas B; Gonder, Mary Katherine

2016-01-01

Simian immunodeficiency virus (SIV) naturally infects two subspecies of chimpanzee: Pan troglodytes troglodytes from Central Africa (SIVcpzPtt) and P. t. schweinfurtii from East Africa (SIVcpzPts), but is absent in P. t. verus from West Africa and appears to be absent in P. t. ellioti inhabiting Nigeria and western Cameroon. One explanation for this pattern is that P. t. troglodytes and P. t schweinfurthii may have acquired SIVcpz after their divergence from P. t. verus and P. t. ellioti. However, all of the subspecies, except P. t. verus, still occasionally exchange migrants making the absence of SIVcpz in P. t. ellioti puzzling. Sampling of P. t. ellioti has been minimal to date, particularly along the banks of the Sanaga River, where its range abuts that of P. t. troglodytes. This study had three objectives. First, we extended the sampling of SIVcpz across the range of chimpanzees north of the Sanaga River to address whether under-sampling might account for the absence of evidence for SIVcpz infection in P. t. ellioti. Second, we investigated how environmental variation is associated with the spread and prevalence of SIVcpz in the two chimpanzee subspecies inhabiting Cameroon since environmental variation has been shown to contribute to their divergence from one another. Finally, we compared the prevalence and distribution of SIVcpz with that of Simian Foamy Virus (SFV) to examine the role of ecology and behavior in shaping the distribution of diseases in wild host populations. The dataset includes previously published results on SIVcpz infection and SFVcpz as well as newly collected data, and represents over 1000 chimpanzee fecal samples from 41 locations across Cameroon. Results revealed that none of the 181 P. t. ellioti fecal samples collected across the range of P. t. ellioti tested positive for SIVcpz. In addition, species distribution models suggest that environmental variation contributes to differences in the distribution and prevalence of SIVcpz and

Why Are Nigeria-Cameroon Chimpanzees (Pan troglodytes ellioti) Free of SIVcpz Infection?

PubMed Central

Locatelli, Sabrina; Harrigan, Ryan J.; Sesink Clee, Paul R.; Mitchell, Matthew W; McKean, Kurt A.; Smith, Thomas B.; Gonder, Mary Katherine

2016-01-01

Simian immunodeficiency virus (SIV) naturally infects two subspecies of chimpanzee: Pan troglodytes troglodytes from Central Africa (SIVcpzPtt) and P. t. schweinfurtii from East Africa (SIVcpzPts), but is absent in P. t. verus from West Africa and appears to be absent in P. t. ellioti inhabiting Nigeria and western Cameroon. One explanation for this pattern is that P. t. troglodytes and P. t schweinfurthii may have acquired SIVcpz after their divergence from P. t. verus and P. t. ellioti. However, all of the subspecies, except P. t. verus, still occasionally exchange migrants making the absence of SIVcpz in P. t. ellioti puzzling. Sampling of P. t. ellioti has been minimal to date, particularly along the banks of the Sanaga River, where its range abuts that of P. t. troglodytes. This study had three objectives. First, we extended the sampling of SIVcpz across the range of chimpanzees north of the Sanaga River to address whether under-sampling might account for the absence of evidence for SIVcpz infection in P. t. ellioti. Second, we investigated how environmental variation is associated with the spread and prevalence of SIVcpz in the two chimpanzee subspecies inhabiting Cameroon since environmental variation has been shown to contribute to their divergence from one another. Finally, we compared the prevalence and distribution of SIVcpz with that of Simian Foamy Virus (SFV) to examine the role of ecology and behavior in shaping the distribution of diseases in wild host populations. The dataset includes previously published results on SIVcpz infection and SFVcpz as well as newly collected data, and represents over 1000 chimpanzee fecal samples from 41 locations across Cameroon. Results revealed that none of the 181 P. t. ellioti fecal samples collected across the range of P. t. ellioti tested positive for SIVcpz. In addition, species distribution models suggest that environmental variation contributes to differences in the distribution and prevalence of SIVcpz and

Numerical judgments by chimpanzees (Pan troglodytes) in a token economy.

PubMed

Beran, Michael J; Evans, Theodore A; Hoyle, Daniel

2011-04-01

We presented four chimpanzees with a series of tasks that involved comparing two token sets or comparing a token set to a quantity of food. Selected tokens could be exchanged for food items on a one-to-one basis. Chimpanzees successfully selected the larger numerical set for comparisons of 1 to 5 items when both sets were visible and when sets were presented through one-by-one addition of tokens into two opaque containers. Two of four chimpanzees used the number of tokens and food items to guide responding in all conditions, rather than relying on token color, size, total amount, or duration of set presentation. These results demonstrate that judgments of simultaneous and sequential sets of stimuli are made by some chimpanzees on the basis of the numerousness of sets rather than other non-numerical dimensions. The tokens were treated as equivalent to food items on the basis of their numerousness, and the chimpanzees maximized reward by choosing the larger number of items in all situations.

Within- and between-task consistency in hand use as a means of characterizing hand preferences in captive chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Gardner, Molly; Mingle, Morgan; Reamer, Lisa; Schapiro, Steven J

2013-11-01

There remain considerable questions regarding the evidence for population-level handedness in nonhuman primates when compared with humans. One challenge in comparing human and nonhuman primate handedness involves the procedures used to characterize individual handedness. Studies of human handedness use consistency in hand use within and between tasks as a basis for hand preference classification. In contrast, studies of handedness in nonhuman primates use statistical criteria for classifying handedness. In this study, we examined within- and between-task consistency in hand use as a means of characterizing individual handedness in a sample of 300 captive chimpanzees (Pan troglodytes). Chimpanzees showed population-level right-handedness for both within- and between-tasks consistency, though the proportion of right-handed chimpanzees was lower than what has typically been reported for humans. We further found that there were small, but significant, associations in hand use between measures. There were no significant sex or colony effects on the distribution of handedness. The results are discussed in the context of theories on the evolution of handedness in nonhuman primates.

Within- and Between-Task Consistency in Hand Use as a Means of Characterizing Hand Preferences in Captive Chimpanzees (Pan troglodytes)

PubMed Central

Hopkins, William D.; Gardner, Molly; Mingle, Morgan; Reamer, Lisa; Schapiro, Steven J.

2013-01-01

There remain considerable questions regarding the evidence for population-level handedness in nonhuman primates when compared with humans. One challenge in comparing human and nonhuman primate handedness involves the procedures used to characterize individual handedness. Studies of human handedness use consistency in hand use within and between tasks as a basis for hand preference classification. In contrast, studies of handedness in nonhuman primates use statistical criteria for classifying handedness. In this study, we examined within- and between-task consistency in hand use as a means of characterizing individual handedness in a sample of 300 captive chimpanzees (Pan troglodytes). Chimpanzees showed population-level right-handedness for both within- and between-tasks consistency, though the proportion of right-handed chimpanzees was lower than what has typically been reported for humans. We further found that there were small, but significant, associations in hand use between measures. There were no significant sex or colony effects on the distribution of handedness. The results are discussed in the context of theories on the evolution of handedness in nonhuman primates. PMID:23356440

Comparison of the anesthetic effects of oral transmucosal versus injectable medetomidine in combination with tiletamine-zolazepam for immobilization of chimpanzees (Pan troglodytes).

PubMed

Naples, Lisa M; Langan, Jennifer N; Kearns, Karen S

2010-03-01

Seventeen adult chimpanzees (Pan troglodytes) with an average age of 37 yr were immobilized with a combination of tiletamine-zolazepam (TZ) and medetomidine (MED) by one of two modes of delivery. Group A animals received the drug combination intramuscularly at 3 mg/kg and 0.05 mg/kg, respectively. Animals in group B received MED by oral transmucosal administration, meaning oral delivery with presumptive transmucosal absorption. MED at 0.1 mg/kg was mixed with marshmallow crème, and delivery was followed by 3 mg/kg of TZ intramuscularly. Chimpanzees from both groups were recovered after administration of atipamezole at 0.3 mg/kg intramuscularly. All chimpanzees were compliant with oral transmucosal drug administration, although two chimpanzees preferred oral MED mixed with applesauce. All animals exhibited some anxiety and excitatory behavior associated with darting, but this was reduced in group B, which was premedicated with oral transmucosal MED. The mean time from TZ administration to sedation sufficient for human contact was 16.4 and 14.7 min with and without oral transmucosal premedication, respectively. The mean time for recovery for those chimpanzees given oral transmucosal premedication was 13.8 min, which was significantly shorter than the time of recovery for the group not given oral premedication (P = 0.02). Oral transmucosal administration of MED provided light sedation in 16 of 17 chimpanzees to the level of arousable recumbency and a heavier sedation in one chimpanzee with no adverse side effects. TZ combined with MED by either oral transmucosal or injectable administration provided safe, heavy, long sedation with rapid, smooth, uneventful recoveries.

Development of Face Recognition in Infant Chimpanzees (Pan Troglodytes)

ERIC Educational Resources Information Center

Myowa-Yamakoshi, M.; Yamaguchi, M.K.; Tomonaga, M.; Tanaka, M.; Matsuzawa, T.

2005-01-01

In this paper, we assessed the developmental changes in face recognition by three infant chimpanzees aged 1-18 weeks, using preferential-looking procedures that measured the infants' eye- and head-tracking of moving stimuli. In Experiment 1, we prepared photographs of the mother of each infant and an ''average'' chimpanzee face using…

Causal capture effects in chimpanzees (Pan troglodytes).

PubMed

Matsuno, Toyomi; Tomonaga, Masaki

2017-01-01

Extracting a cause-and-effect structure from the physical world is an important demand for animals living in dynamically changing environments. Human perceptual and cognitive mechanisms are known to be sensitive and tuned to detect and interpret such causal structures. In contrast to rigorous investigations of human causal perception, the phylogenetic roots of this perception are not well understood. In the present study, we aimed to investigate the susceptibility of nonhuman animals to mechanical causality by testing whether chimpanzees perceived an illusion called causal capture (Scholl & Nakayama, 2002). Causal capture is a phenomenon in which a type of bistable visual motion of objects is perceived as causal collision due to a bias from a co-occurring causal event. In our experiments, we assessed the susceptibility of perception of a bistable stream/bounce motion event to a co-occurring causal event in chimpanzees. The results show that, similar to in humans, causal "bounce" percepts were significantly increased in chimpanzees with the addition of a task-irrelevant causal bounce event that was synchronously presented. These outcomes suggest that the perceptual mechanisms behind the visual interpretation of causal structures in the environment are evolutionarily shared between human and nonhuman animals. Copyright © 2016 Elsevier B.V. All rights reserved.

Masticatory form and function in the African apes.

PubMed

Taylor, Andrea B

2002-02-01

This study examines variability in masticatory morphology as a function of dietary preference among the African apes. The African apes differ in the degree to which they consume leaves and other fibrous vegetation. Gorilla gorilla beringei, the eastern mountain gorilla, consumes the most restricted diet comprised of mechanically resistant foods such as leaves, pith, bark, and bamboo. Gorilla gorilla gorilla, the western lowland gorilla subspecies, consumes leaves and other terrestrial herbaceous vegetation (THV) but also consumes a fair amount of ripe, fleshy fruit. In contrast to gorillas, chimpanzees are frugivores and rely on vegetation primarily as fallback foods. However, there has been a long-standing debate regarding whether Pan paniscus, the pygmy chimpanzee (or bonobo), consumes greater quantities of THV as compared to Pan troglodytes, the common chimpanzee. Because consumption of resistant foods involves more daily chewing cycles and may require larger average bite force, the mechanical demands placed on the masticatory system are expected to be greater in folivores as compared to primates that consume large quantities of fleshy fruit. Therefore, more folivorous taxa are predicted to exhibit features that improve load-resistance capabilities and increase force production. To test this hypothesis, jaw and skull dimensions were compared in ontogenetic series of G. g. beringei, G. g. gorilla, P. t. troglodytes, and P. paniscus. Controlling for the influence of allometry, results show that compared to both chimpanzees and bonobos, gorillas exhibit some features of the jaw complex that are suggestive of improved masticatory efficiency. For example, compared to all other taxa, G. g. beringei has a significantly wider mandibular corpus and symphysis, larger area for the masseter muscle, higher mandibular ramus, and higher mandibular condyle relative to the occlusal plane of the mandible. However, the significantly wider mandibular symphysis may be an

[Comparison of the Latissimus dorsi insertions on the iliac crest in chimpanzee (Pan troglodytes) and in man].

PubMed

Vacher, C; Ben Hadj Yahia, S; Braun, M; Journeau, P

2014-03-01

Comparing to other primates, one of the most important specificities of the human anatomy are consequences of bipedalism. Although bone consequences are well known (lumbar lordosis, horizontal position of the foramen magnum, lengthening of the lower limbs, reduction of the pelvis, specialization of the foot), consequences of our locomotion on the Latissimus dorsi are still unclear. One dissection of a chimpanzee Latissimus dorsi (Pan troglodytes) has been performed and compared to 30 human Latissimus dorsi dissections (10 fresh cadavers and 20 formoled cadavers). In each dissection, the existence of direct muscular insertions on the iliac crest has been investigated and the constitution of the thoracolumbar fascia has been described. In chimpanzee dissection, a muscular direct insertion of the Latissimus dorsi was present on the iliac crest of 9 cm long. The TLF was made of the superficial and the deep fascias of the Latissimus dorsi and the superficial fascia of the erector spinae muscles which was deeper. In man, there was no direct muscular insertion of the Latissimus dorsi in 90 % of cases, the TLF was constituted the same way. This study suggests that the Latissimus dorsi has been separated from the iliac crest in man during the evolution because of the permanent bipedalism and that it stayed inserted on the iliac crest in chimpanzee because of the brachiation. Copyright © 2013 Elsevier Masson SAS. All rights reserved.

Perceived differences between chimpanzee (Pan troglodytes) and human (Homo sapiens) facial expressions are related to emotional interpretation.

PubMed

Waller, Bridget M; Bard, Kim A; Vick, Sarah-Jane; Smith Pasqualini, Marcia C

2007-11-01

Human face perception is a finely tuned, specialized process. When comparing faces between species, therefore, it is essential to consider how people make these observational judgments. Comparing facial expressions may be particularly problematic, given that people tend to consider them categorically as emotional signals, which may affect how accurately specific details are processed. The bared-teeth display (BT), observed in most primates, has been proposed as a homologue of the human smile (J. A. R. A. M. van Hooff, 1972). In this study, judgments of similarity between BT displays of chimpanzees (Pan troglodytes) and human smiles varied in relation to perceived emotional valence. When a chimpanzee BT was interpreted as fearful, observers tended to underestimate the magnitude of the relationship between certain features (the extent of lip corner raise) and human smiles. These judgments may reflect the combined effects of categorical emotional perception, configural face processing, and perceptual organization in mental imagery and may demonstrate the advantages of using standardized observational methods in comparative facial expression research. Copyright 2007 APA.

Cortisol analysis of hair of captive chimpanzees (Pan troglodytes).

PubMed

Yamanashi, Yumi; Morimura, Naruki; Mori, Yusuke; Hayashi, Misato; Suzuki, Juri

2013-12-01

In addition to behavioral evaluations, stress assessments are also important for measuring animal welfare. Assessments of long-term stress are particularly important given that prolonged stress can affect physical health and reproduction. The use of hair cortisol as a marker of long-term stress has been increasing, but there has not yet been any report on the use of such methods with chimpanzees. Therefore, the purpose of this study was to establish and validate a methodology for analyzing hair cortisol in captive chimpanzees. In the first experiment, hair was removed from the arms of nine chimpanzees living in the Kumamoto Sanctuary (KS) and the regrown hair was sampled 3 months later. Fecal samples were collected periodically during the hair-growth period. The results showed that hair cortisol level was positively correlated with the rate of receiving aggression. Although the correlation between hair and fecal cortisol levels was not significant, the individual with the highest hair cortisol concentration also had the highest fecal cortisol concentration. These results suggest that hair cortisol may reflect long-term stress in chimpanzees. In the second experiment, we investigated the physiological factors affecting hair cortisol concentrations. We cut hair from the arms, sides, and backs of 25 chimpanzees living at the KS and the Primate Research Institute. The results revealed that cortisol varied based on source body part and hair whiteness. Therefore, we recommend that hair should always be collected from the same body part and that white hair should be avoided as much as possible. Copyright © 2013 Elsevier Inc. All rights reserved.

High levels of Y-chromosome nucleotide diversity in the genus Pan

PubMed Central

Stone, Anne C.; Griffiths, Robert C.; Zegura, Stephen L.; Hammer, Michael F.

2002-01-01

Although some mitochondrial, X chromosome, and autosomal sequence diversity data are available for our closest relatives, Pan troglodytes and Pan paniscus, data from the nonrecombining portion of the Y chromosome (NRY) are more limited. We examined ≈3 kb of NRY DNA from 101 chimpanzees, seven bonobos, and 42 humans to investigate: (i) relative levels of intraspecific diversity; (ii) the degree of paternal lineage sorting among species and subspecies of the genus Pan; and (iii) the date of the chimpanzee/bonobo divergence. We identified 10 informative sequence-tagged sites associated with 23 polymorphisms on the NRY from the genus Pan. Nucleotide diversity was significantly higher on the NRY of chimpanzees and bonobos than on the human NRY. Similar to mtDNA, but unlike X-linked and autosomal loci, lineages defined by mutations on the NRY were not shared among subspecies of P. troglodytes. Comparisons with mtDNA ND2 sequences from some of the same individuals revealed a larger female versus male effective population size for chimpanzees. The NRY-based divergence time between chimpanzees and bonobos was estimated at ≈1.8 million years ago. In contrast to human populations who appear to have had a low effective size and a recent origin with subsequent population growth, some taxa within the genus Pan may be characterized by large populations of relatively constant size, more ancient origins, and high levels of subdivision. PMID:11756656

Maternal Behavior by Birth Order in Wild Chimpanzees (Pan troglodytes): Increased Investment by First-Time Mothers.

PubMed

Stanton, Margaret A; Lonsdorf, Elizabeth V; Pusey, Anne E; Goodall, Jane; Murray, Carson M

2014-08-01

Parental investment theory predicts that maternal resources are finite and allocated among offspring based on factors including maternal age and condition, and offspring sex and parity. Among humans, firstborn children are often considered to have an advantage and receive greater investment than their younger siblings. However, conflicting evidence for this "firstborn advantage" between modern and hunter-gatherer societies raises questions about the evolutionary history of differential parental investment and birth order. In contrast to humans, most non-human primate firstborns belong to young, inexperienced mothers and exhibit higher mortality than laterborns. In this study, we investigated differences in maternal investment and offspring outcomes based on birth order (firstborn vs. later-born) among wild chimpanzees ( Pan troglodyte schweinfurthii ). During the critical first year of life, primiparous mothers nursed, groomed, and played with their infants more than did multiparous mothers. Furthermore, this pattern of increased investment in firstborns appeared to be compensatory, as probability of survival did not differ by birth order. Our study did not find evidence for a firstborn advantage as observed in modern humans but does suggest that unlike many other primates, differences in maternal behavior help afford chimpanzee first-borns an equal chance of survival.

New evidence on the tool-assisted hunting exhibited by chimpanzees (Pan troglodytes verus) in a savannah habitat at Fongoli, Sénégal.

PubMed

Pruetz, J D; Bertolani, P; Ontl, K Boyer; Lindshield, S; Shelley, M; Wessling, E G

2015-04-01

For anthropologists, meat eating by primates like chimpanzees (Pan troglodytes) warrants examination given the emphasis on hunting in human evolutionary history. As referential models, apes provide insight into the evolution of hominin hunting, given their phylogenetic relatedness and challenges reconstructing extinct hominin behaviour from palaeoanthropological evidence. Among chimpanzees, adult males are usually the main hunters, capturing vertebrate prey by hand. Savannah chimpanzees (P. t. verus) at Fongoli, Sénégal are the only known non-human population that systematically hunts vertebrate prey with tools, making them an important source for hypotheses of early hominin behaviour based on analogy. Here, we test the hypothesis that sex and age patterns in tool-assisted hunting (n=308 cases) at Fongoli occur and differ from chimpanzees elsewhere, and we compare tool-assisted hunting to the overall hunting pattern. Males accounted for 70% of all captures but hunted with tools less than expected based on their representation on hunting days. Females accounted for most tool-assisted hunting. We propose that social tolerance at Fongoli, along with the tool-assisted hunting method, permits individuals other than adult males to capture and retain control of prey, which is uncommon for chimpanzees. We assert that tool-assisted hunting could have similarly been important for early hominins.

Morphological Identification of Hair Recovered from Feces for Detection of Cannibalism in Eastern Chimpanzees.

PubMed

Walker, Christopher S; Walker, Kara K; Paulo, Gabo; Pusey, Anne E

2018-01-01

Chimpanzees (Pan troglodytes) are primarily frugivorous but consume a variable amount of meat from a variety of organisms, including other chimpanzees. Cannibalism is rare, usually follows lethal aggression, and does not occur following natural deaths. While chimpanzee cannibalism has been documented at multiple sites, many instances of this behavior go unrecorded. Identification of chimpanzee remains in feces, however, can provide indirect evidence of cannibalism. Hair, in particular, typically passes through the gastrointestinal tract undamaged and is commonly used for purposes of identification in wildlife forensics. Here we test the hypothesis that eastern chimpanzee (Pan troglodytes schweinfurthii) guard hair morphology can be reliably distinguished from the hairs of their most common prey species. Methods and results are presented in the context of a case study involving a suspected chimpanzee infanticide from Gombe, Tanzania. We find that chimpanzee guard hair morphology is unique among tested mammals and that the presence of abundant chimpanzee hair in feces is likely the result of cannibalism and not incidental ingestion from grooming or other means. Accordingly, morphological analysis of guard hairs from feces is a promising, cost-effective tool for the determination of cannibalistic acts in chimpanzees. © 2018 S. Karger AG, Basel.

Changes in Frontoparietotemporal Connectivity following Do-As-I-Do Imitation Training in Chimpanzees ( Pan troglodytes).

PubMed

Pope, Sarah M; Taglialatela, Jared P; Skiba, Sara A; Hopkins, William D

2018-03-01

Human imitation is supported by an underlying "mirror system" principally composed of inferior frontal, inferior parietal, and superior temporal cortical regions. Across primate species, differences in frontoparietotemporal connectivity have been hypothesized to explain phylogenetic variation in imitative abilities. However, if and to what extent these regions are involved in imitation in nonhuman primates is unknown. We hypothesized that "Do As I Do" (DAID) imitation training would enhance white matter integrity within and between frontoparietotemporal regions. To this end, four captive chimpanzees ( Pan troglodytes) were trained to reproduce 23 demonstrated actions, and four age-/sex-matched controls were trained to produce basic husbandry behaviors in response to manual cues. Diffusion tensor images were acquired before and after 600 min of training over an average of 112 days. Bilateral and asymmetrical changes in frontoparietotemporal white matter integrity were compared between DAID trained subjects and controls. We found that imitation trained subjects exhibited leftward shifts in both mean fractional anisotropy and tract strength asymmetry measures in brain regions within the mirror system. This is the first report of training-induced changes in white matter integrity in chimpanzees and suggests that frontoparietotemporal connectivity, particularly in the left hemisphere, may have facilitated the emergence of increasingly complex imitation learning abilities.

Delay of Gratification by Chimpanzees (Pan troglodytes) in Working and Waiting Situations

PubMed Central

Beran, Michael J.; Evans, Theodore A.

2009-01-01

We tested four chimpanzees in a self-control task in which food rewards accumulated as long as they were not eaten. In one condition, the chimpanzees had to perform a computer task that directly led to the delivery of the food rewards. In another condition, working on the computerized task was not required and any such work was not linked to the delivery of rewards. The third condition offered no computerized task (chimpanzees simply waited for food rewards to be delivered). Three of four chimpanzees showed no effect of the work scenario on delay of gratification. The one chimpanzee that showed an influence of work scenario on self-control was the overall poorest performing animal. This animal delayed gratification the longest, however, when work was required and reward delivery was directly linked to that work. Therefore, although there is little evidence linking delay of gratification to work requirements in chimpanzees, chimpanzees with lower overall self-control might benefit from having some work available if reward accumulation is contingent on performing that work. PMID:19084581

Enculturated Chimpanzees Imitate Rationally

ERIC Educational Resources Information Center

Buttelmann, David; Carpenter, Malinda; Call, Josep; Tomasello, Michael

2007-01-01

Human infants imitate others' actions "rationally": they copy a demonstrator's action when that action is freely chosen, but less when it is forced by some constraint (Gergely, Bekkering & Kiraly, 2002). We investigated whether enculturated chimpanzees (Pan troglodytes) also imitate rationally. Using Gergely and colleagues' (2002) basic procedure,…

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections

PubMed Central

Greenwood, Edward J. D.; Schmidt, Fabian; Kondova, Ivanela; Niphuis, Henk; Hodara, Vida L.; Clissold, Leah; McLay, Kirsten; Guerra, Bernadette; Redrobe, Sharon; Giavedoni, Luis D.; Lanford, Robert E.; Murthy, Krishna K.; Rouet, François; Heeney, Jonathan L.

2015-01-01

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in ‘natural host’ species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections. PMID:26360709

Simian Immunodeficiency Virus Infection of Chimpanzees (Pan troglodytes) Shares Features of Both Pathogenic and Non-pathogenic Lentiviral Infections.

PubMed

Greenwood, Edward J D; Schmidt, Fabian; Kondova, Ivanela; Niphuis, Henk; Hodara, Vida L; Clissold, Leah; McLay, Kirsten; Guerra, Bernadette; Redrobe, Sharon; Giavedoni, Luis D; Lanford, Robert E; Murthy, Krishna K; Rouet, François; Heeney, Jonathan L

2015-09-01

The virus-host relationship in simian immunodeficiency virus (SIV) infected chimpanzees is thought to be different from that found in other SIV infected African primates. However, studies of captive SIVcpz infected chimpanzees are limited. Previously, the natural SIVcpz infection of one chimpanzee, and the experimental infection of six chimpanzees was reported, with limited follow-up. Here, we present a long-term study of these seven animals, with a retrospective re-examination of the early stages of infection. The only clinical signs consistent with AIDS or AIDS associated disease was thrombocytopenia in two cases, associated with the development of anti-platelet antibodies. However, compared to uninfected and HIV-1 infected animals, SIVcpz infected animals had significantly lower levels of peripheral blood CD4+ T-cells. Despite this, levels of T-cell activation in chronic infection were not significantly elevated. In addition, while plasma levels of β2 microglobulin, neopterin and soluble TNF-related apoptosis inducing ligand (sTRAIL) were elevated in acute infection, these markers returned to near-normal levels in chronic infection, reminiscent of immune activation patterns in 'natural host' species. Furthermore, plasma soluble CD14 was not elevated in chronic infection. However, examination of the secondary lymphoid environment revealed persistent changes to the lymphoid structure, including follicular hyperplasia in SIVcpz infected animals. In addition, both SIV and HIV-1 infected chimpanzees showed increased levels of deposition of collagen and increased levels of Mx1 expression in the T-cell zones of the lymph node. The outcome of SIVcpz infection of captive chimpanzees therefore shares features of both non-pathogenic and pathogenic lentivirus infections.

Efficient search for a face by chimpanzees (Pan troglodytes).

PubMed

Tomonaga, Masaki; Imura, Tomoko

2015-07-16

The face is quite an important stimulus category for human and nonhuman primates in their social lives. Recent advances in comparative-cognitive research clearly indicate that chimpanzees and humans process faces in a special manner; that is, using holistic or configural processing. Both species exhibit the face-inversion effect in which the inverted presentation of a face deteriorates their perception and recognition. Furthermore, recent studies have shown that humans detect human faces among non-facial objects rapidly. We report that chimpanzees detected chimpanzee faces among non-facial objects quite efficiently. This efficient search was not limited to own-species faces. They also found human adult and baby faces--but not monkey faces--efficiently. Additional testing showed that a front-view face was more readily detected than a profile, suggesting the important role of eye-to-eye contact. Chimpanzees also detected a photograph of a banana as efficiently as a face, but a further examination clearly indicated that the banana was detected mainly due to a low-level feature (i.e., color). Efficient face detection was hampered by an inverted presentation, suggesting that configural processing of faces is a critical element of efficient face detection in both species. This conclusion was supported by a simple simulation experiment using the saliency model.

Efficient search for a face by chimpanzees (Pan troglodytes)

PubMed Central

Tomonaga, Masaki; Imura, Tomoko

2015-01-01

The face is quite an important stimulus category for human and nonhuman primates in their social lives. Recent advances in comparative-cognitive research clearly indicate that chimpanzees and humans process faces in a special manner; that is, using holistic or configural processing. Both species exhibit the face-inversion effect in which the inverted presentation of a face deteriorates their perception and recognition. Furthermore, recent studies have shown that humans detect human faces among non-facial objects rapidly. We report that chimpanzees detected chimpanzee faces among non-facial objects quite efficiently. This efficient search was not limited to own-species faces. They also found human adult and baby faces-but not monkey faces-efficiently. Additional testing showed that a front-view face was more readily detected than a profile, suggesting the important role of eye-to-eye contact. Chimpanzees also detected a photograph of a banana as efficiently as a face, but a further examination clearly indicated that the banana was detected mainly due to a low-level feature (i.e., color). Efficient face detection was hampered by an inverted presentation, suggesting that configural processing of faces is a critical element of efficient face detection in both species. This conclusion was supported by a simple simulation experiment using the saliency model. PMID:26180944

Differential serotonergic innervation of the amygdala in bonobos and chimpanzees

PubMed Central

Barger, Nicole; Taglialatela, Jared P.; Gendron-Fitzpatrick, Annette; Hof, Patrick R.; Hopkins, William D.; Sherwood, Chet C.

2016-01-01

Humans’ closest living relatives are bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), yet these great ape species differ considerably from each other in terms of social behavior. Bonobos are more tolerant of conspecifics in competitive contexts and often use sexual behavior to mediate social interactions. Chimpanzees more frequently employ aggression during conflicts and actively patrol territories between communities. Regulation of emotional responses is facilitated by the amygdala, which also modulates social decision-making, memory and attention. Amygdala responsiveness is further regulated by the neurotransmitter serotonin. We hypothesized that the amygdala of bonobos and chimpanzees would differ in its neuroanatomical organization and serotonergic innervation. We measured volumes of regions and the length density of serotonin transporter-containing axons in the whole amygdala and its lateral, basal, accessory basal and central nuclei. Results showed that accessory basal nucleus volume was larger in chimpanzees than in bonobos. Of particular note, the amygdala of bonobos had more than twice the density of serotonergic axons than chimpanzees, with the most pronounced differences in the basal and central nuclei. These findings suggest that variation in serotonergic innervation of the amygdala may contribute to mediating the remarkable differences in social behavior exhibited by bonobos and chimpanzees. PMID:26475872

Gestural Communication and Mating Tactics in Wild Chimpanzees

PubMed Central

Roberts, Anna Ilona; Roberts, Sam George Bradley

2015-01-01

The extent to which primates can flexibly adjust the production of gestural communication according to the presence and visual attention of the audience provides key insights into the social cognition underpinning gestural communication, such as an understanding of third party relationships. Gestures given in a mating context provide an ideal area for examining this flexibility, as frequently the interests of a male signaller, a female recipient and a rival male bystander conflict. Dominant chimpanzee males seek to monopolize matings, but subordinate males may use gestural communication flexibly to achieve matings despite their low rank. Here we show that the production of mating gestures in wild male East African chimpanzees (Pan troglodytes schweunfurthii) was influenced by a conflict of interest with females, which in turn was influenced by the presence and visual attention of rival males. When the conflict of interest was low (the rival male was present and looking away), chimpanzees used visual/ tactile gestures over auditory gestures. However, when the conflict of interest was high (the rival male was absent, or was present and looking at the signaller) chimpanzees used auditory gestures over visual/ tactile gestures. Further, the production of mating gestures was more common when the number of oestrous and non-oestrus females in the party increased, when the female was visually perceptive and when there was no wind. Females played an active role in mating behaviour, approaching for copulations more often when the number of oestrus females in the party increased and when the rival male was absent, or was present and looking away. Examining how social and ecological factors affect mating tactics in primates may thus contribute to understanding the previously unexplained reproductive success of subordinate male chimpanzees. PMID:26536467

The energetic and nutritional yields from insectivory for Kasekela chimpanzees.

PubMed

O'Malley, Robert C; Power, Michael L

2014-06-01

Insectivory is hypothesized to be an important source of macronutrients, minerals, and vitamins for chimpanzees (Pan troglodytes), yet nutritional data based on actual intake are lacking. Drawing on observations from 2008 to 2010 and recently published nutritional assays, we determined the energy, macronutrient and mineral yields for termite-fishing (Macrotermes), ant-dipping (Dorylus), and ant-fishing (Camponotus) by the Kasekela chimpanzees of Gombe National Park, Tanzania. We also estimated the yields from consumption of weaver ants (Oecophylla) and termite alates (Macrotermes and Pseudacanthotermes). On days when chimpanzees were observed to prey on insects, the time spent in insectivorous behavior ranged from <1 min to over 4 h. After excluding partial bouts and those of <1 min duration, ant-dipping bouts were of significantly shorter duration than the other two forms of tool-assisted insectivory but provided the highest mass intake rate. Termite-fishing bouts were of significantly longer duration than ant-dipping and had a lower mass intake rate, but provided higher mean and maximum mass yields. Ant-fishing bouts were comparable to termite-fishing bouts in duration but had significantly lower mass intake rates. Mean and maximum all-day yields from termite-fishing and ant-dipping contributed to or met estimated recommended intake (ERI) values for a broad array of minerals. The mean and maximum all-day yields of other insects consistently contributed to the ERI only for manganese. All forms of insectivory provided small but probably non-trivial amounts of fat and protein. We conclude that different forms of insectivory have the potential to address different nutritional needs for Kasekela chimpanzees. Other than honeybees, insects have received little attention as potential foods for hominins. Our results suggest that ants and (on a seasonal basis) termites would have been viable sources of fat, high-quality protein and minerals for extinct hominins employing

Phylogenetic relations of humans and African apes from DNA sequences in the Psi eta-globin region

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyamoto, M.M.; Slightom, J.L.; Goodman, M.

Sequences from the upstream and downstream flanking DNA regions of the Psi eta-globin locus in Pan troglodytes (common chimpanzee), Gorilla gorilla (gorilla), and Pongo pygmaeus (orangutan, the closest living relative to Homo, Pan, and Gorilla) provided further data for evaluating the phylogenetic relations of humans and African apes. These newly sequenced orthologs (an additional 4.9 kilobase pairs (kbp) for each species) were combined with published Psi eta-gene sequences and then compared to the same orthologous stretch (a continuous 7.1-kbp region) available for humans. Phylogenetic analysis of these nucleotide sequences by the parsimony method indicated (i) that human and chimpanzee aremore » more closely related to each other than either is to gorilla and (ii) that the slowdown in the rate of sequence evolution evident in higher primates is especially pronounced in humans. These results indicate that features unique to African apes (but not to humans) are primitive and that even local molecular clocks should be applied with caution.« less

Comparison of hand use and forelimb posture during vertical climbing in mountain gorillas (Gorilla beringei beringei) and chimpanzees (Pan troglodytes).

PubMed

Neufuss, Johanna; Robbins, Martha M; Baeumer, Jana; Humle, Tatyana; Kivell, Tracy L

2017-12-01

Studies on grasping and limb posture during arboreal locomotion in great apes in their natural environment are scarce and thus, attempts to correlate behavioral and habitat differences with variation in morphology are limited. The aim of this study is to compare hand use and forelimb posture during vertical climbing in wild, habituated mountain gorillas (Gorilla beringei beringei) and semi-free-ranging chimpanzees (Pan troglodytes) to assess differences in the climbing styles that may relate to variation in hand or forelimb morphology and body size. We investigated hand use and forelimb posture during both ascent and descent vertical climbing in 15 wild mountain gorillas and eight semi-free-ranging chimpanzees, using video records obtained ad libitum. In both apes, forelimb posture was correlated with substrate size during both ascent and descent climbing. While climbing, both apes used power grips and diagonal power grips, including three different thumb postures. Mountain gorillas showed greater ulnar deviation of the wrist during vertical descent than chimpanzees, and the thumb played an important supportive role when gorillas vertically descended lianas. We found that both apes generally had the same grip preferences and used similar forelimb postures on supports of a similar size, which is consistent with their overall similarity in hard and soft tissue morphology of the hand and forelimb. However, some species-specific differences in morphology appear to elicit slightly different grasping strategies during vertical climbing between mountain gorillas and chimpanzees. © 2017 Wiley Periodicals, Inc.

Group Differences in the Mutual Gaze of Chimpanzees (Pan Troglodytes)

ERIC Educational Resources Information Center

Bard, Kim A.; Myowa-Yamakoshi, Masako; Tomonaga, Masaki; Tanaka, Masayuki; Costall, Alan; Matsuzawa, Tetsuro

2005-01-01

A comparative developmental framework was used to determine whether mutual gaze is unique to humans and, if not, whether common mechanisms support the development of mutual gaze in chimpanzees and humans. Mother-infant chimpanzees engaged in approximately 17 instances of mutual gaze per hour. Mutual gaze occurred in positive, nonagonistic…

Demographic and Ecological Effects on Patterns of Parasitism in Eastern Chimpanzees (Pan troglodytes schweinfurthii) in Gombe National Park, Tanzania

PubMed Central

Gillespie, Thomas R.; Lonsdorf, Elizabeth V.; Canfield, Elizabeth P.; Meyer, Derek J.; Nadler, Yvonne; Raphael, Jane; Pusey, Anne E.; Pond, Joel; Pauley, John; Mlengeya, Titus; Travis, Dominic A.

2014-01-01

From January 2006 to January 2008, we collected 1,045 fecal samples from 90 individually-recognized, free-ranging, eastern chimpanzees (Pan troglodytes schweinfurthii) inhabiting Gombe National Park, Tanzania to determine how patterns of parasitism are affected by demographic and ecological covariates. Seventeen parasite species were recovered, including eight nematodes (Oesophagostomum sp., Necator sp., Probstmayria gombensis, Strongyloides fulleborni, Ascaris sp., Trichuris sp., Abbreviata caucasica, and an unidentified strongyle), 1 cestode (Bertiella sp.), 1 trematode (Dicrocoeliidae), and 7 protozoa (Entamoeba coli, Entamoeba histolytica/dispar, Iodamoeba bütschlii, Troglodytella abrassarti, Troglocorys cava, Balantidium coli, and an unidentified protozoa). Significant differences were observed in interannual infection prevalence and parasite richness between 2006 and 2007. Intercommunity comparisons demonstrated higher prevalence of parasites for the Mitumba compared with Kasekela chimpanzee community. Prevalence of several parasites was strongly correlated with monthly rainfall patterns for both 2006 and 2007. Subadult chimpanzees had lower prevalence for most parasite species compared with adults in both years and also yielded a lower average parasite species richness. No significant differences were observed between males and females in prevalence in 2006. However, in 2007 the prevalence of S. fulleborni and I. bütschlii were higher in males than in females. Parasite prevalence and richness were substantially higher in this multiyear study compared with previous short-term studies of the gastrointestinal parasites of Gombe chimpanzees. This coupled with the significant interannual and interseasonal variation, demonstrated in this study, emphasizes the importance of multiyear monitoring with adequate sample size to effectively determine patterns of parasitism in wild primate populations. PMID:20623606

The effectiveness of using carbonate isotope measurements of body tissues to infer diet in human evolution: Evidence from wild western chimpanzees (Pan troglodytes verus).

PubMed

Fahy, Geraldine E; Boesch, Christophe; Hublin, Jean-Jacques; Richards, Michael P

2015-11-01

Changes in diet throughout hominin evolution have been linked with important evolutionary changes. Stable carbon isotope analysis of inorganic apatite carbonate is the main isotopic method used to reconstruct fossil hominin diets; to test its effectiveness as a paleodietary indicator we present bone and enamel carbonate carbon isotope data from a well-studied population of modern wild western chimpanzees (Pan troglodytes verus) of known sex and age from Taï, Cote d'Ivoire. We found a significant effect of age class on bone carbonate values, with adult chimpanzees being more (13)C- and (18)O-depleted compared to juveniles. Further, to investigate habitat effects, we compared our data to existing apatite data on eastern chimpanzees (P. troglodytes schweinfurthii) and found that the Taï chimpanzees are significantly more depleted in enamel δ(13)Cap and δ(18)Oap compared to their eastern counterparts. Our data are the first to present a range of tissue-specific isotope data from the same group of wild western chimpanzees and, as such, add new data to the growing number of modern non-human primate comparative isotope datasets providing valuable information for the interpretation of diet throughout hominin evolution. By comparing our data to published isotope data on fossil hominins we found that our modern chimpanzee bone and enamel data support hypotheses that the trend towards increased consumption of C4 foods after 4 Ma (millions of years ago) is unique to hominins. Copyright © 2015 Elsevier Ltd. All rights reserved.

Factors influencing young chimpanzees' (Pan troglodytes) recognition of attention.

PubMed

Povinelli, D J; Eddy, T J

1996-12-01

By 2 1/2 years of age, human infants appear to understand how others are connected to the external world through the mental state of attention and also appear to understand the specific role that the eyes play in deploying this attention. Previous research with chimpanzees suggests that, although they track the gaze of others, they may simultaneously be unaware of the underlying state of attention behind gaze. In a series of 3 experiments, the investigators systematically explored how the presence of eyes, direct eye contact, and head orientation and movement affected young chimpanzees' choice of 2 experimenters from whom to request food. The results indicate that young chimpanzees may be selectively attached to other organisms making direct eye contact with them or engaged in postures or movements that indicate attention, even though they may not appreciate the underlying mentalistic significance of these behaviors.

Demographic History of the Genus Pan Inferred from Whole Mitochondrial Genome Reconstructions

PubMed Central

Tucci, Serena; de Manuel, Marc; Ghirotto, Silvia; Benazzo, Andrea; Prado-Martinez, Javier; Lorente-Galdos, Belen; Nam, Kiwoong; Dabad, Marc; Hernandez-Rodriguez, Jessica; Comas, David; Navarro, Arcadi; Schierup, Mikkel H.; Andres, Aida M.; Barbujani, Guido; Hvilsom, Christina; Marques-Bonet, Tomas

2016-01-01

The genus Pan is the closest genus to our own and it includes two species, Pan paniscus (bonobos) and Pan troglodytes (chimpanzees). The later is constituted by four subspecies, all highly endangered. The study of the Pan genera has been incessantly complicated by the intricate relationship among subspecies and the statistical limitations imposed by the reduced number of samples or genomic markers analyzed. Here, we present a new method to reconstruct complete mitochondrial genomes (mitogenomes) from whole genome shotgun (WGS) datasets, mtArchitect, showing that its reconstructions are highly accurate and consistent with long-range PCR mitogenomes. We used this approach to build the mitochondrial genomes of 20 newly sequenced samples which, together with available genomes, allowed us to analyze the hitherto most complete Pan mitochondrial genome dataset including 156 chimpanzee and 44 bonobo individuals, with a proportional contribution from all chimpanzee subspecies. We estimated the separation time between chimpanzees and bonobos around 1.15 million years ago (Mya) [0.81–1.49]. Further, we found that under the most probable genealogical model the two clades of chimpanzees, Western + Nigeria-Cameroon and Central + Eastern, separated at 0.59 Mya [0.41–0.78] with further internal separations at 0.32 Mya [0.22–0.43] and 0.16 Mya [0.17–0.34], respectively. Finally, for a subset of our samples, we compared nuclear versus mitochondrial genomes and we found that chimpanzee subspecies have different patterns of nuclear and mitochondrial diversity, which could be a result of either processes affecting the mitochondrial genome, such as hitchhiking or background selection, or a result of population dynamics. PMID:27345955

Reproductive state and rank influence patterns of meat consumption in wild female chimpanzees (Pan troglodytes schweinfurthii).

PubMed

O'Malley, Robert C; Stanton, Margaret A; Gilby, Ian C; Lonsdorf, Elizabeth V; Pusey, Anne; Markham, A Catherine; Murray, Carson M

2016-01-01

An increase in faunivory is a consistent component of human evolutionary models. Animal matter is energy- and nutrient-dense and can provide macronutrients, minerals, and vitamins that are limited or absent in plant foods. For female humans and other omnivorous primates, faunivory may be of particular importance during the costly periods of pregnancy and early lactation. Yet, because animal prey is often monopolizable, access to fauna among group-living primates may be mediated by social factors such as rank. Wild chimpanzees (Pan troglodytes) across Africa habitually consume insects and/or vertebrates. However, no published studies have examined patterns of female chimpanzee faunivory during pregnancy and early lactation relative to non-reproductive periods, or by females of different rank. In this study, we assessed the influence of reproductive state and dominance rank on the consumption of fauna (meat and insects) by female chimpanzees of Gombe National Park, Tanzania. Using observational data collected over 38 years, we tested (a) whether faunivory varied by reproductive state, and (b) if high-ranking females spent more time consuming fauna than lower-ranking females. In single-factor models, pregnant females consumed more meat than lactating and baseline (meaning not pregnant and not in early lactation) females, and high-ranking females consumed more meat than lower-ranking females. A two-factor analysis of a subset of well-sampled females identified an interaction between rank and reproductive state: lower-ranking females consumed more meat during pregnancy than lower-ranking lactating and baseline females did. High-ranking females did not significantly differ in meat consumption between reproductive states. We found no relationships between rank or reproductive state with insectivory. We conclude that, unlike insectivory, meat consumption by female chimpanzees is mediated by both reproductive state and social rank. We outline possible mechanisms for these

Reproductive State and Rank Influence Patterns of Meat Consumption in Wild Female Chimpanzees (Pan troglodytes schweinfurthii)

PubMed Central

Stanton, Margaret A.; Gilby, Ian C.; Lonsdorf, Elizabeth V.; Pusey, Anne; Markham, A. Catherine; Murray, Carson M.

2015-01-01

An increase in faunivory is a consistent component of human evolutionary models. Animal matter is energy- and nutrient-dense and can provide macronutrients, minerals, and vitamins that are limited or absent in plant foods. For female humans and other omnivorous primates, faunivory may be of particular importance during the costly periods of pregnancy and early lactation. Yet, because animal prey is often monopolizable, access to fauna among group-living primates may be mediated by social factors such as rank. Wild chimpanzees (Pan troglodytes) across Africa habitually consume insects and/or vertebrates. However, no published studies have examined patterns of female chimpanzee faunivory during pregnancy and early lactation relative to non-reproductive periods, or by females of different rank. In this study, we assessed the influence of reproductive state and dominance rank on the consumption of fauna (meat and insects) by female chimpanzees of Gombe National Park, Tanzania. Using observational data collected over 38 years, we tested (a) whether faunivory varied by reproductive state, and (b) if high-ranking females spent more time consuming fauna than lower-ranking females. In single-factor models, pregnant females consumed more meat than lactating and baseline (meaning not pregnant and not in early lactation) females, and high-ranking females consumed more meat than lower-ranking females. A two-factor analysis of a subset of well-sampled females identified an interaction between rank and reproductive state: lower-ranking females consumed more meat during pregnancy than lower-ranking lactating and baseline females did. High-ranking females did not significantly differ in meat consumption between reproductive states. We found no relationships between rank or reproductive state with insectivory. We conclude that, unlike insectivory, meat consumption by female chimpanzees is mediated by both reproductive state and social rank. We outline several possible mechanisms for

Wild chimpanzees plan their breakfast time, type, and location

PubMed Central

Janmaat, Karline R. L.; Polansky, Leo; Ban, Simone Dagui; Boesch, Christophe

2014-01-01

Not all tropical fruits are equally desired by rainforest foragers and some fruit trees get depleted more quickly and carry fruit for shorter periods than others. We investigated whether a ripe-fruit specialist, the chimpanzee (Pan troglodytes verus), arrived earlier at breakfast sites with very ephemeral and highly sought-after fruit, like figs, than sites with less ephemeral fruit that can be more predictably obtained throughout the entire day. We recorded when and where five adult female chimpanzees spent the night and acquired food for a total of 275 full days during three fruit-scarce periods in a West African tropical rainforest. We found that chimpanzees left their sleeping nests earlier (often before sunrise when the forest is still dark) when breakfasting on very ephemeral fruits, especially when they were farther away. Moreover, the females positioned their sleeping nests more in the direction of the next day’s breakfast sites with ephemeral fruit compared with breakfast sites with other fruit. By analyzing departure times and nest positioning as a function of fruit type and location, while controlling for more parsimonious explanations, such as temperature, we found evidence that wild chimpanzees flexibly plan their breakfast time, type, and location after weighing multiple disparate pieces of information. Our study reveals a cognitive mechanism by which large-brained primates can buffer the effects of seasonal declines in food availability and increased interspecific competition to facilitate first access to nutritious food. We discuss the implications for theories on hominoid brain-size evolution. PMID:25349399

Untrained Chimpanzees (Pan troglodytes schweinfurthii) Fail to Imitate Novel Actions

PubMed Central

Tennie, Claudio; Call, Josep; Tomasello, Michael

2012-01-01

Background Social learning research in apes has focused on social learning in the technical (problem solving) domain - an approach that confounds action and physical information. Successful subjects in such studies may have been able to perform target actions not as a result of imitation learning but because they had learnt some technical aspect, for example, copying the movements of an apparatus (i.e., different forms of emulation learning). Methods Here we present data on action copying by non-enculturated and untrained chimpanzees when physical information is removed from demonstrations. To date, only one such study (on gesture copying in a begging context) has been conducted – with negative results. Here we have improved this methodology and have also added non-begging test situations (a possible confound of the earlier study). Both familiar and novel actions were used as targets. Prior to testing, a trained conspecific demonstrator was rewarded for performing target actions in view of observers. All but one of the tested chimpanzees already failed to copy familiar actions. When retested with a novel target action, also the previously successful subject failed to copy – and he did so across several contexts. Conclusion Chimpanzees do not seem to copy novel actions, and only some ever copy familiar ones. Due to our having tested only non-enculturated and untrained chimpanzees, the performance of our test subjects speak more than most other studies of the general (dis-)ability of chimpanzees to copy actions, and especially novel actions. PMID:22905102

Chimpanzees (Pan troglodytes) display limited behavioural flexibility when faced with a changing foraging task requiring tool use

PubMed Central

Harrison, Rachel A.

2018-01-01

Behavioural flexibility, the ability to alter behaviour in response to environmental feedback, and to relinquish previously successful solutions to problems, is a crucial ability in allowing organisms to adapt to novel environments and environmental change; it is essential to cumulative cultural change. To explore this ability in chimpanzees, 18 individuals (Pan troglodytes) were presented with an artificial foraging task consisting of a tube partially filled with juice that could be reached by hand or retrieved using tool materials to hand. Effective solutions were then restricted in the second phase of the study by narrowing the diameter of the tube, necessitating the abandonment of previously successful solutions. Chimpanzees showed limited behavioural flexibility in comparison to some previous studies, increasing their use of effective techniques, but also continuing to attempt solutions that had been rendered ineffective. This adds to a literature reporting divergent evidence for flexibility (the ability to alter behaviour in response to environmental feedback, and to relinquish previously successful solutions to problems) versus conservatism (a reluctance or inability to explore or adopt novel solutions to problems when a solution is already known) in apes. PMID:29479495

The vertebral formula of the last common ancestor of African apes and humans.

PubMed

McCollum, Melanie A; Rosenman, Burt A; Suwa, Gen; Meindl, Richard S; Lovejoy, C Owen

2010-03-15

The modal number of lumbar vertebrae in modern humans is five. It varies between three and four in extant African apes (mean=3.5). Because both chimpanzees (Pan troglodytes) and gorillas (Gorilla gorilla) possess the same distributions of thoracic, lumbar, and sacral vertebrae, it has been assumed from parsimony that the last common ancestor (LCA) of African apes and humans possessed a similarly short lower back. This "short-backed LCA" scenario has recently been viewed favorably in an analysis of the intra- and interspecific variation in axial formulas observed among African apes and humans (Pilbeam, 2004. J Exp Zool 302B:241-267). However, the number of bonobo (Pan paniscus) specimens in that study was small (N=17). Here we reconsider vertebral type and number in the LCA in light of an expanded P. paniscus sample as well as evidence provided by the human fossil record. The precaudal (pre-coccygeal) axial column of bonobos differs from those of chimpanzees and gorillas in displaying one additional vertebra as well as significantly different combinations of sacral, lumbar, and thoracic vertebrae. These findings, along with the six-segmented lumbar column of early Australopithecus and early Homo, suggest that the LCA possessed a long axial column and long lumbar spine and that reduction in the lumbar column occurred independently in humans and in each ape clade, and continued after separation of the two species of Pan as well. Such an explanation is strongly congruent with additional details of lumbar column reduction and lower back stabilization in African apes.

Robust representations of individual faces in chimpanzees (Pan troglodytes) but not monkeys (Macaca mulatta).

PubMed

Taubert, Jessica; Weldon, Kimberly B; Parr, Lisa A

2017-03-01

Being able to recognize the faces of our friends and family members no matter where we see them represents a substantial challenge for the visual system because the retinal image of a face can be degraded by both changes in the person (age, expression, pose, hairstyle, etc.) and changes in the viewing conditions (direction and degree of illumination). Yet most of us are able to recognize familiar people effortlessly. A popular theory for how face recognition is achieved has argued that the brain stabilizes facial appearance by building average representations that enhance diagnostic features that reliably vary between people while diluting features that vary between instances of the same person. This explains why people find it easier to recognize average images of people, created by averaging multiple images of the same person together, than single instances (i.e. photographs). Although this theory is gathering momentum in the psychological and computer sciences, there is no evidence of whether this mechanism represents a unique specialization for individual recognition in humans. Here we tested two species, chimpanzees (Pan troglodytes) and rhesus monkeys (Macaca mulatta), to determine whether average images of different familiar individuals were easier to discriminate than photographs of familiar individuals. Using a two-alternative forced-choice, match-to-sample procedure, we report a behaviour response profile that suggests chimpanzees encode the faces of conspecifics differently than rhesus monkeys and in a manner similar to humans.

Female reproductive strategies, paternity and community structure in wild West African chimpanzees.

PubMed

Gagneux; Boesch; Woodruff

1999-01-01

Although the variability and complexity of chimpanzee behaviour frustrates generalization, it is widely believed that social evolution in this species occurs in the context of the recognizable social group or community. We used a combination of field observations and noninvasive genotyping to study the genetic structure of a habituated community of 55 wild chimpanzees, Pan troglodytes verus, in the Taï Forest, Côte d'Ivoire. Pedigree relationships in that community show that female mate choice strategies are more variable than previously supposed and that the observed social groups are not the exclusive reproductive units. Genetic evidence based on nuclear microsatellite markers and behavioural obser-vations reveal that females in the Taï forest actively seek mating partners outside their social unit; noncommunity males accounted for half the paternities over 5 years. This female mating strategy increases male gene flow between communities despite male philopatry, and negates the predicted higher relatedness among community males. Kin selection seems unlikely to explain the frequent cooperation and sharing observed among group males in this population. Similarly, inbreeding avoidance is probably not the sole cause of permanent adolescent female dispersal as a combination of extragroup mating and avoidance of incest with home group males would allow females to avoid inbreeding without the hazards associated with immigration into a new community. Extragroup mating as part of chimpanzee females' reproductive strategy may allow them to choose from a wider variety and number of males, without losing the resources and support provided by their male social group partners. Copyright 1999 The Association for the Study of Animal Behaviour.

Differential serotonergic innervation of the amygdala in bonobos and chimpanzees.

PubMed

Stimpson, Cheryl D; Barger, Nicole; Taglialatela, Jared P; Gendron-Fitzpatrick, Annette; Hof, Patrick R; Hopkins, William D; Sherwood, Chet C

2016-03-01

Humans' closest living relatives are bonobos (Pan paniscus) and chimpanzees (Pan troglodytes), yet these great ape species differ considerably from each other in terms of social behavior. Bonobos are more tolerant of conspecifics in competitive contexts and often use sexual behavior to mediate social interactions. Chimpanzees more frequently employ aggression during conflicts and actively patrol territories between communities. Regulation of emotional responses is facilitated by the amygdala, which also modulates social decision-making, memory and attention. Amygdala responsiveness is further regulated by the neurotransmitter serotonin. We hypothesized that the amygdala of bonobos and chimpanzees would differ in its neuroanatomical organization and serotonergic innervation. We measured volumes of regions and the length density of serotonin transporter-containing axons in the whole amygdala and its lateral, basal, accessory basal and central nuclei. Results showed that accessory basal nucleus volume was larger in chimpanzees than in bonobos. Of particular note, the amygdala of bonobos had more than twice the density of serotonergic axons than chimpanzees, with the most pronounced differences in the basal and central nuclei. These findings suggest that variation in serotonergic innervation of the amygdala may contribute to mediating the remarkable differences in social behavior exhibited by bonobos and chimpanzees. © The Author (2015). Published by Oxford University Press. For Permissions, please email: journals.permissions@oup.com.

Distal Communication by Chimpanzees (Pan troglodytes): Evidence for Common Ground?

PubMed Central

Leavens, David A.; Reamer, Lisa A.; Mareno, Mary Catherine; Russell, Jamie L.; Wilson, Daniel; Schapiro, Steven J.; Hopkins, William D.

2015-01-01

van der Goot et al. (2014) proposed that distal, deictic communication indexed the appreciation of the psychological state of a common ground between a signaler and a receiver. In their study, great apes did not signal distally, which they construed as evidence for the human uniqueness of a sense of common ground. This study exposed 166 chimpanzees to food and an experimenter, at an angular displacement, to ask, “Do chimpanzees display distal communication?” Apes were categorized as (a) proximal or (b) distal signalers on each of four trials. The number of chimpanzees who communicated proximally did not statistically differ from the number who signaled distally. Therefore, contrary to the claim by van der Goot et al., apes do communicate distally. PMID:26292996

Object permanence in orangutans (Pongo pygmaeus), chimpanzees (Pan troglodytes), and children (Homo sapiens).

PubMed

Call, J

2001-06-01

Juvenile and adult orangutans (n = 5; Pongo pygmaeus), chimpanzees (n = 7; Pan troglodytes), and 19- and 26-month-old children (n = 24; Homo sapiens) received visible and invisible displacements. Three containers were presented forming a straight line, and a small box was used to displace a reward under them. Subjects received 3 types of displacement: single (the box visited 1 container), double adjacent (the box visited 2 contiguous containers), and double nonadjacent (the box visited 2 noncontiguous containers). All species performed at comparable levels, solving all problems except the invisible nonadjacent displacements. Visible displacements were easier than invisible, and single were easier than double displacements. In a 2nd experiment, subjects saw the baiting of either 2 adjacent or 2 nonadjacent containers with no displacements. All species selected the empty container more often when the baited containers were nonadjacent than when they were adjacent. It is hypothesized that a response bias and inhibition problem were responsible for the poor performance in nonadjacent displacements.

Relative quantity judgments between discrete spatial arrays by chimpanzees (Pan troglodytes) and New Zealand robins (Petroica longipes).

PubMed

Garland, Alexis; Beran, Michael J; McIntyre, Joseph; Low, Jason

2014-08-01

Quantity discrimination for items spread across spatial arrays was investigated in chimpanzees (Pan troglodytes) and North Island New Zealand robins (Petroica longipes), with the aim of examining the role of spatial separation on the ability of these 2 species to sum and compare nonvisible quantities which are both temporally and spatially separated, and to assess the likely mechanism supporting such summation performance. Birds and chimpanzees compared 2 sets of discrete quantities of items that differed in number. Six quantity comparisons were presented to both species: 1v2, 1v3, 1v5, 2v3, 2v4, and 2v5. Each was distributed 1 at a time across 2 7-location arrays. Every individual item was viewed 1 at a time and hidden, with no more than a single item in each location of an array, in contrast to a format where all items were placed together into 2 single locations. Subjects responded by selecting 1 of the 2 arrays and received the entire quantity of food items hidden within that array. Both species performed better than chance levels. The ratio of items between sets was a significant predictor of performance in the chimpanzees, but it was not significant for robins. Instead, the absolute value of the smaller quantity of items presented was the significant factor in robin responses. These results suggest a species difference for this task when considering various dimensions such as ratio or total number of items in quantity comparisons distributed across discrete 7-location arrays.

Mapping the groundwater vulnerability for pollution at the pan African scale.

PubMed

Ouedraogo, Issoufou; Defourny, Pierre; Vanclooster, Marnik

2016-02-15

We estimated vulnerability and pollution risk of groundwater at the pan-African scale. We therefore compiled the most recent continental scale information on soil, land use, geology, hydrogeology and climate in a Geographical Information System (GIS) at a resolution of 15 km × 15 km and at the scale of 1:60,000,000. The groundwater vulnerability map was constructed by means of the DRASTIC method. The map reveals that groundwater is highly vulnerable in Central and West Africa, where the watertable is very low. In addition, very low vulnerability is found in the large sedimentary basins of the African deserts where groundwater is situated in very deep aquifers. The groundwater pollution risk map is obtained by overlaying the DRASTIC vulnerability map with land use. The northern, central and western part of the African continent is dominated by high pollution risk classes and this is very strongly related to shallow groundwater systems and the development of agricultural activities. Subsequently, we performed a sensitivity analysis to evaluate the relative importance of each parameter on groundwater vulnerability and pollution risk. The sensitivity analysis indicated that the removal of the impact of vadose zone, the depth of the groundwater, the hydraulic conductivity and the net recharge causes a large variation in the mapped vulnerability and pollution risk. The mapping model was validated using nitrate concentration data of groundwater as a proxy of pollution risk. Pan-African concentration data were inferred from a meta-analysis of literature data. Results shows a good match between nitrate concentration and the groundwater pollution risk classes. The pan African assessment of groundwater vulnerability and pollution risk is expected to be of particular value for water policy and for designing groundwater resources management programs. We expect, however, that this assessment can be strongly improved when better pan African monitoring data related to groundwater

Comparative rates of violence in chimpanzees and humans.

PubMed

Wrangham, Richard W; Wilson, Michael L; Muller, Martin N

2006-01-01

This paper tests the proposal that chimpanzees (Pan troglodytes) and humans have similar rates of death from intraspecific aggression, whereas chimpanzees have higher rates of non-lethal physical attack (Boehm 1999, Hierarchy in the forest: the evolution of egalitarian behavior. Harvard University Press). First, we assembled data on lethal aggression from long-term studies of nine communities of chimpanzees living in five populations. We calculated rates of death from intraspecific aggression both within and between communities. Variation among communities in mortality rates from aggression was high, and rates of death from intercommunity and intracommunity aggression were not correlated. Estimates for average rates of lethal violence for chimpanzees proved to be similar to average rates for subsistence societies of hunter-gatherers and farmers. Second, we compared rates of non-lethal physical aggression for two populations of chimpanzees and one population of recently settled hunter-gatherers. Chimpanzees had rates of aggression between two and three orders of magnitude higher than humans. These preliminary data support Boehm's hypothesis.

The development of feeding behavior in wild chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Bray, Joel; Emery Thompson, Melissa; Muller, Martin N; Wrangham, Richard W; Machanda, Zarin P

2018-01-01

Primates have an extended period of juvenility before adulthood. Although dietary complexity plays a prominent role in hypotheses regarding the evolution of extended juvenility, the development of feeding behavior is still poorly understood. Indeed, few studies have investigated the timing and nature of feeding transitions in apes, including chimpanzees. We describe general patterns of feeding development in wild chimpanzees and evaluate predictions of the needing-to-learn hypothesis. We analyzed 4 years of behavioral data (2010-2013) from 26 immature chimpanzees and 31 adult chimpanzees of the Kanyawara community in Kibale National Park, Uganda. Specifically, we examined milestones of nutritional independence (first consumption of solid food and cessation of suckling) as well as developmental changes in feeding time, diet composition, diet breadth, and ingestion rates. Chimpanzees first fed on solid food at 5.1 months and, on average, suckled until 4.8 years. Daily feeding time of immature individuals reached adult levels between 4 and 6 years, while diet composition showed minor changes with age. By juvenility (5-10 years), individuals had a complete adult diet breadth. Ingestion rates for five ripe fruit species remained below adult levels until juvenility but continued to show absolute increases into adolescence. Chimpanzees acquired adult-like patterns on all feeding measures by infancy or juvenility. These data are inconsistent with the needing-to-learn hypothesis; moreover, where delays exist, alternatives hypotheses make similar predictions but implicate physical constraints rather than learning as causal factors. We outline predictions for how future studies might distinguish between hypotheses for the evolution of extended juvenility. © 2017 Wiley Periodicals, Inc.

Distal Communication by Chimpanzees (Pan troglodytes): Evidence for Common Ground?

PubMed

Leavens, David A; Reamer, Lisa A; Mareno, Mary Catherine; Russell, Jamie L; Wilson, Daniel; Schapiro, Steven J; Hopkins, William D

2015-01-01

van der Goot et al. (2014) proposed that distal, deictic communication indexed the appreciation of the psychological state of a common ground between a signaler and a receiver. In their study, great apes did not signal distally, which they construed as evidence for the human uniqueness of a sense of common ground. This study exposed 166 chimpanzees to food and an experimenter, at an angular displacement, to ask, "Do chimpanzees display distal communication?" Apes were categorized as (a) proximal or (b) distal signalers on each of four trials. The number of chimpanzees who communicated proximally did not statistically differ from the number who signaled distally. Therefore, contrary to the claim by van der Goot et al., apes do communicate distally. © 2015 The Authors. Child Development © 2015 Society for Research in Child Development, Inc.

Chimpanzees create and modify probe tools functionally: A study with zoo-housed chimpanzees.

PubMed

Hopper, Lydia M; Tennie, Claudio; Ross, Stephen R; Lonsdorf, Elizabeth V

2015-02-01

Chimpanzees (Pan troglodytes) use tools to probe for out-of-reach food, both in the wild and in captivity. Beyond gathering appropriately-sized materials to create tools, chimpanzees also perform secondary modifications in order to create an optimized tool. In this study, we recorded the behavior of a group of zoo-housed chimpanzees when presented with opportunities to use tools to probe for liquid foods in an artificial termite mound within their enclosure. Previous research with this group of chimpanzees has shown that they are proficient at gathering materials from within their environment in order to create tools to probe for the liquid food within the artificial mound. Extending beyond this basic question, we first asked whether they only made and modified probe tools when it was appropriate to do so (i.e. when the mound was baited with food). Second, by collecting continuous data on their behavior, we also asked whether the chimpanzees first (intentionally) modified their tools prior to probing for food or whether such modifications occurred after tool use, possibly as a by-product of chewing and eating the food from the tools. Following our predictions, we found that tool modification predicted tool use; the chimpanzees began using their tools within a short delay of creating and modifying them, and the chimpanzees performed more tool modifying behaviors when food was available than when they could not gain food through the use of probe tools. We also discuss our results in terms of the chimpanzees' acquisition of the skills, and their flexibility of tool use and learning. © 2014 Wiley Periodicals, Inc.

Task design influences prosociality in captive chimpanzees (Pan troglodytes).

PubMed

House, Bailey R; Silk, Joan B; Lambeth, Susan P; Schapiro, Steven J

2014-01-01

Chimpanzees confer benefits on group members, both in the wild and in captive populations. Experimental studies of how animals allocate resources can provide useful insights about the motivations underlying prosocial behavior, and understanding the relationship between task design and prosocial behavior provides an important foundation for future research exploring these animals' social preferences. A number of studies have been designed to assess chimpanzees' preferences for outcomes that benefit others (prosocial preferences), but these studies vary greatly in both the results obtained and the methods used, and in most cases employ procedures that reduce critical features of naturalistic social interactions, such as partner choice. The focus of the current study is on understanding the link between experimental methodology and prosocial behavior in captive chimpanzees, rather than on describing these animals' social motivations themselves. We introduce a task design that avoids isolating subjects and allows them to freely decide whether to participate in the experiment. We explore key elements of the methods utilized in previous experiments in an effort to evaluate two possibilities that have been offered to explain why different experimental designs produce different results: (a) chimpanzees are less likely to deliver food to others when they obtain food for themselves, and (b) evidence of prosociality may be obscured by more "complex" experimental apparatuses (e.g., those including more components or alternative choices). Our results suggest that the complexity of laboratory tasks may generate observed variation in prosocial behavior in laboratory experiments, and highlights the need for more naturalistic research designs while also providing one example of such a paradigm.

Task Design Influences Prosociality in Captive Chimpanzees (Pan troglodytes)

PubMed Central

House, Bailey R.; Silk, Joan B.; Lambeth, Susan P.; Schapiro, Steven J.

2014-01-01

Chimpanzees confer benefits on group members, both in the wild and in captive populations. Experimental studies of how animals allocate resources can provide useful insights about the motivations underlying prosocial behavior, and understanding the relationship between task design and prosocial behavior provides an important foundation for future research exploring these animals' social preferences. A number of studies have been designed to assess chimpanzees' preferences for outcomes that benefit others (prosocial preferences), but these studies vary greatly in both the results obtained and the methods used, and in most cases employ procedures that reduce critical features of naturalistic social interactions, such as partner choice. The focus of the current study is on understanding the link between experimental methodology and prosocial behavior in captive chimpanzees, rather than on describing these animals' social motivations themselves. We introduce a task design that avoids isolating subjects and allows them to freely decide whether to participate in the experiment. We explore key elements of the methods utilized in previous experiments in an effort to evaluate two possibilities that have been offered to explain why different experimental designs produce different results: (a) chimpanzees are less likely to deliver food to others when they obtain food for themselves, and (b) evidence of prosociality may be obscured by more “complex” experimental apparatuses (e.g., those including more components or alternative choices). Our results suggest that the complexity of laboratory tasks may generate observed variation in prosocial behavior in laboratory experiments, and highlights the need for more naturalistic research designs while also providing one example of such a paradigm. PMID:25191860

Pan-African granulites of central Dronning Maud Land and Mozambique: A comparison within the East-African-Antarctic orogen

USGS Publications Warehouse

Engvik, A.K.; Elevevold, S.; Jacobs, J.; Tveten, E.; de Azevedo, S.; Njange, F.

2007-01-01

Granulite-facies metamorphism is extensively reported in Late Neoproterozoic/Early Palaeozoic time during formation of the East-African-Antarctic orogen (EAAO). Metamorphic data acquired from the Pan-African orogen of central Dronning Maud Land (cDML) are compared with data from northern Mozambique. The metamorphic rocks of cDML are characterised by Opx±Grt-bearing gneisses and Sil+Kfs-bearing metapelites which indicate medium-P granulite-facies metamorphism. Peak conditions, which are estimated to 800-900ºC at pressures up to 1.0 GPa, were followed by near-isothermal decompression during late Pan-African extension and exhumation. Granulite-facies lithologies are widespread in northern Mozambique, and Grt+Cpx-bearing assemblages show that high-P granulite-facies conditions with PT reaching 1.55 GPa and 900ºC were reached during the Pan-African orogeny. Garnet is replaced by symplectites of Pl+Opx+Mag indicating isothermal decompression, and the subsequent formation of Pl+amphibole-coronas suggests cooling into amphibolite facies. It is concluded that high-T metamorphism was pervasive in EAAO in Late Neoproterozoic/Early Paleozoic time, strongly overprinting evidences of earlier metamorphic assemblages.

Production of grooming-associated sounds by chimpanzees (Pan troglodytes) at Ngogo: variation, social learning, and possible functions.

PubMed

Watts, David P

2016-01-01

Chimpanzees (Pan troglodytes) use some communicative signals flexibly and voluntarily, with use influenced by learning. These signals include some vocalizations and also sounds made using the lips, oral cavity, and/or teeth, but not the vocal tract, such as "attention-getting" sounds directed at humans by captive chimpanzees and lip smacking during social grooming. Chimpanzees at Ngogo, in Kibale National Park, Uganda, make four distinct sounds while grooming others. Here, I present data on two of these ("splutters" and "teeth chomps") and consider whether social learning contributes to variation in their production and whether they serve social functions. Higher congruence in the use of these two sounds between dyads of maternal relatives than dyads of non-relatives implies that social learning occurs and mostly involves vertical transmission, but the results are not conclusive and it is unclear which learning mechanisms may be involved. In grooming between adult males, tooth chomps and splutters were more likely in long than in short bouts; in bouts that were bidirectional rather than unidirectional; in grooming directed toward high-ranking males than toward low-ranking males; and in bouts between allies than in those between non-allies. Males were also more likely to make these sounds while they were grooming other males than while they were grooming females. These results are expected if the sounds promote social bonds and induce tolerance of proximity and of grooming by high-ranking males. However, the alternative hypothesis that the sounds are merely associated with motivation to groom, with no additional social function, cannot be ruled out. Limited data showing that bouts accompanied by teeth chomping or spluttering at their initiation were longer than bouts for which this was not the case point toward a social function, but more data are needed for a definitive test. Comparison to other research sites shows that the possible existence of grooming

Intranasal Oxytocin Failed to Affect Chimpanzee (Pan troglodytes) Social Behavior

PubMed Central

Calcutt, Sarah E.; Burke, Kimberly; de Waal, Frans B. M.

2017-01-01

Oxytocin has been suggested as a treatment to promote positive social interactions in people with Autism Spectrum Disorders (ASD). However, it is difficult to test this effect outside of the laboratory in realistic social situations. One way to resolve this issue is to study behavioral changes in closely related species with complex social relationships, such as chimpanzees. Here, we use captive, socially housed chimpanzees to evaluate the effects of oxytocin in a socially complex environment. After administering intranasal oxytocin or a placebo to an individual chimpanzee (total n = 8), she was returned to her social group. An experimenter blind to the condition measured the subject's social behavior. We failed to find a behavioral difference between conditions. As one of the goals for oxytocin administration as a treatment for ASD is increasing prosocial behaviors during ‘real world’ encounters, it is problematic that we failed to detect behavioral changes in our closest living relatives. However, our null findings may be related to methodological challenges such as determining an effective dose of oxytocin for chimpanzees and how long oxytocin takes to cross the blood-brain barrier. Thus, more research on intranasal oxytocin dosing and uptake are needed to continue exploring whether oxytocin changes social behavior in naturalistic settings and as a treatment for ASD. PMID:28845444

Skeletal development in Pan paniscus with comparisons to Pan troglodytes.

PubMed

Bolter, Debra R; Zihlman, Adrienne L

2012-04-01

Fusion of skeletal elements provides markers for timing of growth and is one component of a chimpanzee's physical development. Epiphyseal closure defines bone growth and signals a mature skeleton. Most of what we know about timing of development in chimpanzees derives from dental studies on Pan troglodytes. Much less is known about the sister species, Pan paniscus, with few in captivity and a wild range restricted to central Africa. Here, we report on the timing of skeletal fusion for female captive P. paniscus (n = 5) whose known ages range from 0.83 to age 11.68 years. Observations on the skeletons were made after the individuals were dissected and bones cleaned. Comparisons with 10 female captive P. troglodytes confirm a generally uniform pattern in the sequence of skeletal fusion in the two captive species. We also compared the P. paniscus to a sample of three unknown-aged female wild P. paniscus, and 10 female wild P. troglodytes of known age from the Taï National Park, Côte d'Ivoire. The sequence of teeth emergence to bone fusion is generally consistent between the two species, with slight variations in late juvenile and subadult stages. The direct-age comparisons show that skeletal growth in captive P. paniscus is accelerated compared with both captive and wild P. troglodytes populations. The skeletal data combined with dental stages have implications for estimating the life stage of immature skeletal materials of wild P. paniscus and for more broadly comparing the skeletal growth rates among captive and wild chimpanzees (Pan), Homo sapiens, and fossil hominins. Copyright © 2012 Wiley Periodicals, Inc.

Chimpanzees (Pan troglodytes) and human children (Homo sapiens) know when they are ignorant about the location of food.

PubMed

Neldner, Karri; Collier-Baker, Emma; Nielsen, Mark

2015-05-01

Over the last decade, the metacognitive abilities of nonhuman primates and the developmental emergence of metacognition in children have become topics of increasing research interest. In the current study, the performance of three adult chimpanzees (Pan troglodytes; Experiment 1) and forty-four 3.5- and 5.5-year-old human children (Experiment 2) was assessed on a behavioral search paradigm designed to assess metacognition. Subjects either directly observed the baiting of a large reward into one cup among an array of four, or had the baiting occluded from their view. In half of the trials, subjects were also presented with an additional distinctive cup that was always visibly baited with a small reward. This cup allowed subjects the opportunity to escape from making a guess about the location of the bigger reward. All three chimpanzees and both age groups of children selected the escape cup more often when the baiting of the large reward was concealed, compared to when it was visible. This demonstrates that both species can selectively choose a guaranteed smaller reward when they do not know the location of a larger reward and provides insight into the development of metacognition.

Social environment elicits lateralized behaviors in gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes).

PubMed

Quaresmini, Caterina; Forrester, Gillian S; Spiezio, Caterina; Vallortigara, Giorgio

2014-08-01

The influence of the social environment on lateralized behaviors has now been investigated across a wide variety of animal species. New evidence suggests that the social environment can modulate behavior. Currently, there is a paucity of data relating to how primates navigate their environmental space, and investigations that consider the naturalistic context of the individual are few and fragmented. Moreover, there are competing theories about whether only the right or rather both cerebral hemispheres are involved in the processing of social stimuli, especially in emotion processing. Here we provide the first report of lateralized social behaviors elicited by great apes. We employed a continuous focal animal sampling method to record the spontaneous interactions of a captive zoo-living colony of chimpanzees (Pan troglodytes) and a biological family group of peer-reared western lowland gorillas (Gorilla gorilla gorilla). We specifically focused on which side of the body (i.e., front, rear, left, right) the focal individual preferred to keep conspecifics. Utilizing a newly developed quantitative corpus-coding scheme, analysis revealed both chimpanzees and gorillas demonstrated a significant group-level preference for focal individuals to keep conspecifics positioned to the front of them compared with behind them. More interestingly, both groups also manifested a population-level bias to keep conspecifics on their left side compared with their right side. Our findings suggest a social processing dominance of the right hemisphere for context-specific social environments. Results are discussed in light of the evolutionary adaptive value of social stimulus as a triggering factor for the manifestation of group-level lateralized behaviors.

Conservatism and "copy-if-better" in chimpanzees (Pan troglodytes).

PubMed

van Leeuwen, Edwin J C; Call, Josep

2017-05-01

Social learning is predicted to evolve in socially living animals provided the learning process is not random but biased by certain socio-ecological factors. One bias of particular interest for the emergence of (cumulative) culture is the tendency to forgo personal behaviour in favour of relatively better variants observed in others, also known as the "copy-if-better" strategy. We investigated whether chimpanzees employ copy-if-better in a simple token-exchange paradigm controlling for individual and random social learning. After being trained on one token-type, subjects were confronted with a conspecific demonstrator who either received the same food reward as the subject (control condition) or a higher value food reward than the subject (test condition) for exchanging another token-type. In general, the chimpanzees persisted in exchanging the token-type they were trained on individually, indicating a form of conservatism consistent with previous studies. However, the chimpanzees were more inclined to copy the demonstrator in the test compared to the control condition, indicating a tendency to employ a copy-if-better strategy. We discuss the validity of our results by considering alternative explanations and relate our findings to the emergence of cumulative culture.

Forest chimpanzees (Pan troglodytes verus) remember the location of numerous fruit trees.

PubMed

Normand, Emmanuelle; Ban, Simone Dagui; Boesch, Christophe

2009-11-01

It is assumed that spatial memory contributes crucially to animal cognition since animals' habitats entail a large number of dispersed and unpredictable food sources. Spatial memory has been investigated under controlled conditions, with different species showing and different conditions leading to varying performance levels. However, the number of food sources investigated is very low compared to what exists under natural conditions, where food resources are so abundant that it is difficult to precisely identify what is available. By using a detailed botanical map containing over 12,499 trees known to be used by the Taï chimpanzees, we created virtual maps of all productive fruit trees to simulate potential strategies used by wild chimpanzees to reach resources without spatial memory. First, we simulated different assumptions concerning the chimpanzees' preference for a particular tree species, and, second, we varied the detection field to control for the possible use of smell to detect fruiting trees. For all these assumptions, we compared simulated distance travelled, frequencies of trees visited, and revisit rates with what we actually observed in wild chimpanzees. Our results show that chimpanzees visit rare tree species more frequently, travel shorter distances to reach them, and revisit the same trees more often than if they had no spatial memory. In addition, we demonstrate that chimpanzees travel longer distances to reach resources where they will eat for longer periods of time, and revisit resources more frequently where they ate for a long period of time during their first visit. Therefore, this study shows that forest chimpanzees possess a precise spatial memory which allows them to remember the location of numerous resources and use this information to select the most attractive resources.

What is the role of mothers in the acquisition of termite-fishing behaviors in wild chimpanzees (Pan troglodytes schweinfurthii)?

PubMed

Lonsdorf, Elizabeth V

2006-01-01

This paper explores the role of maternal influences on the acquisition of a tool-using task in wild chimpanzees (Pan troglodytes schweinfurthii) in order to build on and complement previous work done in captivity. Young chimpanzees show a long period of offspring dependency on mothers and it is during this period that offspring learn several important skills, especially how to and on what to forage. At Gombe National Park, one skill that is acquired during dependency is termite-fishing, a complex behavior that involves inserting a tool made from the surrounding vegetation into a termite mound and extracting the termites that attack and cling to the tool. All chimpanzees observed at Gombe have acquired the termite-fishing skill by the age of 5.5 years. Since the mother is the primary source of information throughout this time period, I investigated the influence of mothers' individual termite-fishing characteristics on their offsprings' speed of acquisition and proficiency at the skill once acquired. Mother's time spent alone or with maternal family members, which is highly correlated to time spent termite-fishing, was positively correlated to offspring's acquisition of critical elements of the skill. I also investigated the specific types of social interactions that occur between mothers and offspring at the termite mound and found that mothers are highly tolerant to offspring, even when the behavior of the offspring may disrupt the termite-fishing attempt. However, no active facilitation by mothers of offsprings' attempts were observed.

Sex Differences in Object Manipulation in Wild Immature Chimpanzees (Pan troglodytes schweinfurthii) and Bonobos (Pan paniscus): Preparation for Tool Use?

PubMed

Koops, Kathelijne; Furuichi, Takeshi; Hashimoto, Chie; van Schaik, Carel P

2015-01-01

Sex differences in immatures predict behavioural differences in adulthood in many mammal species. Because most studies have focused on sex differences in social interactions, little is known about possible sex differences in 'preparation' for adult life with regards to tool use skills. We investigated sex and age differences in object manipulation in immature apes. Chimpanzees use a variety of tools across numerous contexts, whereas bonobos use few tools and none in foraging. In both species, a female bias in adult tool use has been reported. We studied object manipulation in immature chimpanzees at Kalinzu (Uganda) and bonobos at Wamba (Democratic Republic of Congo). We tested predictions of the 'preparation for tool use' hypothesis. We confirmed that chimpanzees showed higher rates and more diverse types of object manipulation than bonobos. Against expectation, male chimpanzees showed higher object manipulation rates than females, whereas in bonobos no sex difference was found. However, object manipulation by male chimpanzees was play-dominated, whereas manipulation types of female chimpanzees were more diverse (e.g., bite, break, carry). Manipulation by young immatures of both species was similarly dominated by play, but only in chimpanzees did it become more diverse with age. Moreover, in chimpanzees, object types became more tool-like (i.e., sticks) with age, further suggesting preparation for tool use in adulthood. The male bias in object manipulation in immature chimpanzees, along with the late onset of tool-like object manipulation, indicates that not all (early) object manipulation (i.e., object play) in immatures prepares for subsistence tool use. Instead, given the similarity with gender differences in human children, object play may also function in motor skill practice for male-specific behaviours (e.g., dominance displays). In conclusion, even though immature behaviours almost certainly reflect preparation for adult roles, more detailed future work is

Androgen and androgen metabolite levels in serum and urine of East African chimpanzees (Pan troglodytes schweinfurthii): comparison of EIA and LC-MS analyses.

PubMed

Preis, Anna; Mugisha, Lawrence; Hauser, Barbara; Weltring, Anja; Deschner, Tobias

2011-12-01

The primary male androgen testosterone (T) is often used as an endocrinological marker to investigate androgen-behaviour interactions in males. In chimpanzees and bonobos, studies investigating the relationship between T levels and dominance rank or aggressive behaviour have revealed contradictory results. The immunoassays used in these studies were originally developed for the measurement of steroids in serum. Their application to non-invasively collected samples, however, can lead to methodological problems due to cross-reacting metabolites, which might occur in urine or faeces but not in blood. The overall aim of this study, therefore, is to clarify whether a T enzyme immunoassay (EIA) is an applicable method to monitor testicular function in adult male chimpanzees. To estimate the impact of cross-reacting androgens on the used T EIA, we compared the results of an EIA measurement with a set of androgen metabolite levels measured by LC-MS. In urine from male chimpanzees, cross-reactivities appear to exist mainly with T and its exclusive metabolites, 5α-dihydrotestosterone (5α-DHT) and 5α-androstanediol (androstanediol). Both urinary and serum T levels of male chimpanzees were significantly higher than female T levels when measured with the T EIA, indicating a reliable measurement of testicular androgens and their exclusive metabolites with the used EIA. In urine from female chimpanzees, the comparison between LC-MS and T EIA results indicated a higher impact of cross-reactions with adrenal androgen metabolites. Therefore, the investigation of urinary T levels in female chimpanzees with a T EIA seems to be problematic. Overall our results show that a T EIA can be a reliable method to monitor testicular function in male chimpanzee urine and that LC-MS is a valuable tool for the validation of immunoassays. Copyright © 2011 Elsevier Inc. All rights reserved.

Resolution of the African hominoid trichotomy by use of a mitochondrial gene sequence

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ruvolo, M.; Disotell, T.R.; Allard, M.W.

1991-02-15

Mitochondrial DNA sequences encoding the cytochrome oxidase subunit II gene have been determined for five primate species, siamang (Hylobates syndactylus), lowland gorilla (Gorilla gorilla), pygmy chimpanzee (Pan paniscus), crab-eating macaque (Macaca fascicularis), and green monkey (Cercopithecus aethiops), and compared with published sequences of other primate and nonprimate species. Comparisons of cytochrome oxidase subunit II gene sequences provide clear-cut evidence from the mitochondrial genome for the separation of the African ape trichotomy into two evolutionary lineages, one leading to gorillas and the other to humans and chimpanzees. Several different tree-building methods support this same phylogenetic tree topology. The comparisons also yieldmore » trees in which a substantial length separates the divergence point of gorillas from that of humans and chimpanzees, suggesting that the lineage most immediately ancestral to humans and chimpanzees may have been in existence for a relatively long time.« less

Maternal Behavior and Physiological Stress Levels in Wild Chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Stanton, Margaret A; Heintz, Matthew R; Lonsdorf, Elizabeth V; Santymire, Rachel M; Lipende, Iddi; Murray, Carson M

2015-06-01

Individual differences in maternal behavior toward, and investment in, offspring can have lasting consequences, particularly among primate taxa characterized by prolonged periods of development over which mothers can exert substantial influence. Given the role of the neuroendocrine system in the expression of behavior, researchers are increasingly interested in understanding the hormonal correlates of maternal behavior. Here, we examined the relationship between maternal behavior and physiological stress levels, as quantified by fecal glucocorticoid metabolite (FGM) concentrations, in lactating chimpanzees, Pan troglodytes schweinfurthii , at Gombe National Park, Tanzania. After accounting for temporal variation in FGM concentrations, we found that mothers interacted socially (groomed and played) with and nursed their infants more on days when FGM concentrations were elevated compared to days when FGM concentrations were within the range expected given the time of year. However, the proportion of time mothers and infants spent in contact did not differ based on FGM concentrations. These results generally agree with the suggestion that elevated GC concentrations are related to maternal motivation and responsivity to infant cues and are the first evidence of a hormonal correlate of maternal behavior in a wild great ape.

Grip preference, dermatoglyphics, and hand use in captive chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Russell, Jamie L; Hostetter, Autumn; Pilcher, Dawn; Dahl, Jeremy F

2005-09-01

This paper examined the association between grip type, hand use, and fingerprint patterns in a sample of captive chimpanzees. Grip type for simple reaching was assessed for the left and right hand and classified as thumb-index, middle-index, or single-digit responses. Fingerprint patterns were characterized as whorls, loops, or arches on each finger. The results indicated that chimpanzees exhibit significantly more thumb-index responses for the right compared to the left hand. In addition, thumb-index responses were more prevalent for subjects that had a whorl compared to a loop or arch on their thumb. The results suggest that fingerprint patterns are associated with individual differences in grasping type in chimpanzees as well as some variation in hand use. (c) 2005 Wiley-Liss, Inc.

Grip Preference, Dermatoglyphics, and Hand Use in Captive Chimpanzees (Pan troglodytes)

PubMed Central

Hopkins, William D.; Russell, Jamie L.; Hostetter, Autumn; Pilcher, Dawn; Dahl, Jeremy F.

2007-01-01

This paper examined the association between grip type, hand use, and fingerprint patterns in a sample of captive chimpanzees. Grip type for simple reaching was assessed for the left and right hand and classified as thumb-index, middle-index, or single-digit responses. Fingerprint patterns were characterized as whorls, loops, or arches on each finger. The results indicated that chimpanzees exhibit significantly more thumb-index responses for the right compared to the left hand. In addition, thumb-index responses were more prevalent for subjects that had a whorl compared to a loop or arch on their thumb. The results suggest that fingerprint patterns are associated with individual differences in grasping type in chimpanzees as well as some variation in hand use. PMID:15761856

Brain size growth in wild and captive chimpanzees (Pan troglodytes).

PubMed

Cofran, Zachary

2018-05-24

Despite many studies of chimpanzee brain size growth, intraspecific variation is under-explored. Brain size data from chimpanzees of the Taï Forest and the Yerkes Primate Research Center enable a unique glimpse into brain growth variation as age at death is known for individuals, allowing cross-sectional growth curves to be estimated. Because Taï chimpanzees are from the wild but Yerkes apes are captive, potential environmental effects on neural development can also be explored. Previous research has revealed differences in growth and health between wild and captive primates, but such habitat effects have yet to be investigated for brain growth. Here, I use an iterative curve fitting procedure to estimate brain growth and regression parameters for each population, statistically comparing growth models using bootstrapped confidence intervals. Yerkes and Taï brain sizes overlap at all ages, although the sole Taï newborn is at the low end of captive neonatal variation. Growth rate and duration are statistically indistinguishable between the two populations. Resampling the Yerkes sample to match the Taï sample size and age group composition shows that ontogenetic variation in the two groups are remarkably similar despite the latter's limited size. Best fit growth curves for each sample indicate cessation of brain size growth at around 2 years, earlier than has previously been reported. The overall similarity between wild and captive chimpanzees points to the canalization of brain growth in this species. © 2018 Wiley Periodicals, Inc.

Spatial cohesion of adult male chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d'Ivoire.

PubMed

Eckhardt, Nadin; Polansky, Leo; Boesch, Christophe

2015-02-01

Group living animals can exhibit fission-fusion behavior whereby individuals temporarily separate to reduce the costs of living in large groups. Primates living in groups with fission-fusion dynamics face numerous challenges in maintaining spatial cohesion, especially in environments with limited visibility. Here we investigated the spatial cohesion of adult male chimpanzees (Pan troglodytes verus) living in Taï National Park, Côte d'Ivoire, to better understand the mechanisms by which individuals maintain group cohesion during fission-fusion events. Over a 3-year period, we simultaneously tracked the movements of 2-4 males for 4-12 hr on up to 12 consecutive days using handheld GPS devices that recorded locations at one-minute intervals. Analyses of the male's inter-individual distance (IID) showed that the maximum, median, and mean IID values across all observations were 7.2 km, 73 m, and 483 m, respectively. These males (a) had maximum daily IID values below the limits of auditory communication (<1 km) for 63% of the observation time, (b) remained out of visual range (≥100 m) for 46% of observation time, and (c) remained within auditory range for 70% of the time when they were in different parties. We compared the observed distribution of IIDs with a random distribution obtained from permutations of the individuals' travel paths using Kolmogorov-Smirnov tests. Observation IID values were significantly smaller than those generated by the permutation procedure. We conclude that these male chimpanzees actively maintain cohesion when out of sight, and that auditory communication is one likely mechanism by which they do so. We discuss mechanisms by which chimpanzees may maintain the level of cohesion observed. This study provides a first analysis of spatial group cohesion over large distances in forest chimpanzees using high-resolution tracking, and illustrates the utility of such data for quantifying socio-ecological processes in primate ecology. �

Sex Differences in Object Manipulation in Wild Immature Chimpanzees (Pan troglodytes schweinfurthii) and Bonobos (Pan paniscus): Preparation for Tool Use?

PubMed Central

Koops, Kathelijne; Furuichi, Takeshi; Hashimoto, Chie; van Schaik, Carel P.

2015-01-01

Sex differences in immatures predict behavioural differences in adulthood in many mammal species. Because most studies have focused on sex differences in social interactions, little is known about possible sex differences in ‘preparation’ for adult life with regards to tool use skills. We investigated sex and age differences in object manipulation in immature apes. Chimpanzees use a variety of tools across numerous contexts, whereas bonobos use few tools and none in foraging. In both species, a female bias in adult tool use has been reported. We studied object manipulation in immature chimpanzees at Kalinzu (Uganda) and bonobos at Wamba (Democratic Republic of Congo). We tested predictions of the ‘preparation for tool use’ hypothesis. We confirmed that chimpanzees showed higher rates and more diverse types of object manipulation than bonobos. Against expectation, male chimpanzees showed higher object manipulation rates than females, whereas in bonobos no sex difference was found. However, object manipulation by male chimpanzees was play-dominated, whereas manipulation types of female chimpanzees were more diverse (e.g., bite, break, carry). Manipulation by young immatures of both species was similarly dominated by play, but only in chimpanzees did it become more diverse with age. Moreover, in chimpanzees, object types became more tool-like (i.e., sticks) with age, further suggesting preparation for tool use in adulthood. The male bias in object manipulation in immature chimpanzees, along with the late onset of tool-like object manipulation, indicates that not all (early) object manipulation (i.e., object play) in immatures prepares for subsistence tool use. Instead, given the similarity with gender differences in human children, object play may also function in motor skill practice for male-specific behaviours (e.g., dominance displays). In conclusion, even though immature behaviours almost certainly reflect preparation for adult roles, more detailed future

The higher the farther: distance-specific referential gestures in chimpanzees (Pan troglodytes).

PubMed

Gonseth, Chloe; Kawakami, Fumito; Ichino, Etsuko; Tomonaga, Masaki

2017-11-01

Referential signals, such as manual pointing or deictic words, allow individuals to efficiently locate a specific entity in the environment, using distance-specific linguistic and/or gestural units. To explore the evolutionary prerequisites of such deictic ability, the present study investigates the ability of chimpanzees to adjust their communicative signals to the distance of a referent. A food-request paradigm in which the chimpanzees had to request a close or distant piece of food on a table in the presence/absence of an experimenter was employed. Our main finding concerns the chimpanzees adjusting their requesting behaviours to the distance of the food such that higher manual gestures and larger mouth openings were used to request the distant piece of food. To the best of our knowledge, this is the first study to demonstrate that chimpanzees are able to use distance-specific gestures. © 2017 The Authors.

Chimpanzees create and modify probe tools functionally: A study with zoo-housed chimpanzees

PubMed Central

Hopper, Lydia M; Tennie, Claudio; Ross, Stephen R; Lonsdorf, Elizabeth V

2015-01-01

Chimpanzees (Pan troglodytes) use tools to probe for out-of-reach food, both in the wild and in captivity. Beyond gathering appropriately-sized materials to create tools, chimpanzees also perform secondary modifications in order to create an optimized tool. In this study, we recorded the behavior of a group of zoo-housed chimpanzees when presented with opportunities to use tools to probe for liquid foods in an artificial termite mound within their enclosure. Previous research with this group of chimpanzees has shown that they are proficient at gathering materials from within their environment in order to create tools to probe for the liquid food within the artificial mound. Extending beyond this basic question, we first asked whether they only made and modified probe tools when it was appropriate to do so (i.e. when the mound was baited with food). Second, by collecting continuous data on their behavior, we also asked whether the chimpanzees first (intentionally) modified their tools prior to probing for food or whether such modifications occurred after tool use, possibly as a by-product of chewing and eating the food from the tools. Following our predictions, we found that tool modification predicted tool use; the chimpanzees began using their tools within a short delay of creating and modifying them, and the chimpanzees performed more tool modifying behaviors when food was available than when they could not gain food through the use of probe tools. We also discuss our results in terms of the chimpanzees’ acquisition of the skills, and their flexibility of tool use and learning. Am. J. Primatol. 77:162–170, 2015. © 2014 The Authors. American Journal of Primatology Published by Wiley Periodicals Inc. PMID:25220050

Nocturnal behavior by a diurnal ape, the West African chimpanzee (Pan troglodytes verus), in a savanna environment at Fongoli, Senegal.

PubMed

Pruetz, Jill D

2018-02-08

I report on the nocturnal behavior of Fongoli chimpanzees in a savanna mosaic during different seasons and lunar phases and test the hypothesis that hot daytime temperatures influence activity at night. I predicted that apes would be more active at night during periods of greater lunar illuminosity given diurnal primates' lack of visual specializations for low-light conditions and in dry season months when water scarcity exacerbated heat stress. I observed chimpanzees for 403 hrs on 40 nights between 2007 and 2013 and categorized their activity as social, movement, or vocalization. I scored their activity as occurring after moonrise or before moonset and considered the influence of moon phase (fuller versus darker phases) as well as season on chimpanzee nocturnal behavior in the analyses. Results indicate that apes were more active after moonrise or before moonset during fuller moon phases in the dry season but not the wet season. Most night-time activity involved movement (travel or forage), followed by social behavior, and long-distance vocal communication. Animals in highly seasonal habitats often exhibit thermoregulatory adaptations but, like other primates, chimpanzees lack physiological mechanisms to combat thermal stress. This study provides evidence that they may exhibit behaviors that allow them to avoid high temperatures in a savanna environment, such as feeding and socializing at night during the hottest time of year and in the brightest moon phases. The results support theories invoking thermal stress as a selective pressure for hominins in open environments where heat would constrain temporal foraging niches, and suggest an adaptability of sleeping patterns in response to external factors. © 2018 Wiley Periodicals, Inc.

Acupuncture as an Adjunct Therapy for Osteoarthritis in Chimpanzees (Pan troglodytes)

PubMed Central

Magden, Elizabeth R; Haller, Rachel L; Thiele, Erica J; Buchl, Stephanie J; Lambeth, Susan P; Schapiro, Steven J

2013-01-01

Acupuncture is an ancient practice that is currently used to treat disorders ranging from osteoarthritis to cardiomyopathy. Acupuncture involves the insertion of thin, sterile needles into defined acupuncture points that stimulate physiologic processes through neural signaling. Numerous scientific studies have proven the benefits of acupuncture, and given this scientific support, we hypothesized that acupuncture could benefit the nonhuman primates at our facility. As our chimpanzee colony ages, we are observing an increase in osteoarthritis and have focused our initial acupuncture treatments on this condition. We successfully trained 3 chimpanzees, by using positive-reinforcement training techniques, to voluntarily participate in acupuncture treatments for stifle osteoarthritis. We used 3 acupuncture points that correlate with alleviation of stifle pain and inflammation in humans. A mobility scoring system was used to assess improvements in mobility as a function of the acupuncture treatments. The 2 chimpanzees with the most severe osteoarthritis showed significant improvement in mobility after acupuncture treatments. Acupuncture therapy not only resulted in improved mobility, but the training sessions also served as enrichment for the animals, as demonstrated by their voluntary participation in the training and treatment sessions. Acupuncture is an innovative treatment technique that our data show to be safe, inexpensive, and, most importantly, effective for chimpanzees. PMID:23849446

Displacement behaviors in chimpanzees (Pan troglodytes): A neurogenomics investigation of the RDoC Negative Valence Systems domain.

PubMed

Latzman, Robert D; Young, Larry J; Hopkins, William D

2016-03-01

The current study aimed to systematically investigate genetic and neuroanatomical correlates of individual variation in scratching behaviors, a well-validated animal-behavioral indicator of negative emotional states with clear links to the NIMH Research Domain Criteria (RDoC) response to potential harm ("anxiety") construct within the Negative Valence Systems domain. Utilizing data from a sample of 76 captive chimpanzees (Pan troglodytes), we (a) examined the association between scratching and presence or absence of the RS3-containing DupB element in the AVPR1A 5' flanking region, (b) utilized voxel-based morphometry (VBM) to identify gray matter (GM) voxel clusters that differentiated AVPR1A genotype, and (c) conducted a VBM-guided voxel-of-interest analysis to examine the association between GM intensity and scratching. AVPR1A evidenced sexually dimorphic associations with scratching. VBM analyses revealed significant differences in GM by genotype across twelve clusters largely in the frontal cortex. Regions differentiating AVPR1A genotype showed sex-specific associations with scratching. Results suggest that sexually dimorphic associations between AVPR1A and scratching may be explained by genotype-specific neuroanatomical variation. The current study provides an example of the way in which chimpanzee research is uniquely poised for multilevel, systematic investigations of psychopathology-relevant constructs within the context of the RDoC framework. © 2016 Society for Psychophysiological Research.

Chimpanzees are vengeful but not spiteful

PubMed Central

Jensen, Keith; Call, Josep; Tomasello, Michael

2007-01-01

People are willing to punish others at a personal cost, and this apparently antisocial tendency can stabilize cooperation. What motivates humans to punish noncooperators is likely a combination of aversion to both unfair outcomes and unfair intentions. Here we report a pair of studies in which captive chimpanzees (Pan troglodytes) did not inflict costs on conspecifics by knocking food away if the outcome alone was personally disadvantageous but did retaliate against conspecifics who actually stole the food from them. Like humans, chimpanzees retaliate against personally harmful actions, but unlike humans, they are indifferent to simply personally disadvantageous outcomes and are therefore not spiteful. PMID:17644612

Brief communication: Adrenal androgens and aging: Female chimpanzees (Pan troglodytes) compared with women.

PubMed

Blevins, James K; Coxworth, James E; Herndon, James G; Hawkes, Kristen

2013-08-01

Ovarian cycling continues to similar ages in women and chimpanzees yet our nearest living cousins become decrepit during their fertile years and rarely outlive them. Given the importance of estrogen in maintaining physiological systems aside from fertility, similar ovarian aging in humans and chimpanzees combined with somatic aging differences indicates an important role for nonovarian estrogen. Consistent with this framework, researchers have nominated the adrenal androgen dehydroepiandrosterone (DHEA) and its sulfate (DHEAS), which can be peripherally converted to estrogen, as a biomarker of aging in humans and other primates. Faster decline in production of this steroid with age in chimpanzees could help explain somatic aging differences. Here, we report circulating levels of DHEAS in captive female chimpanzees and compare them with published levels in women. Instead of faster, the decline is slower in chimpanzees, but from a much lower peak. Levels reported for other great apes are lower still. These results point away from slowed decline but toward increased DHEAS production as one of the mechanisms underlying the evolution of human longevity. Copyright © 2013 Wiley Periodicals, Inc.

Aping humans: age and sex effects in chimpanzee (Pan troglodytes) and human (Homo sapiens) personality.

PubMed

King, James E; Weiss, Alexander; Sisco, Melissa M

2008-11-01

Ratings of 202 chimpanzees on 43 personality descriptor adjectives were used to calculate scores on five domains analogous to the human Five-Factor Model and a chimpanzee-specific Dominance domain. Male and female chimpanzees were divided into five age groups ranging from juvenile to old adult. Internal consistencies and interrater reliabilities of factors were stable across age groups and approximately 6.8 year retest reliabilities were high. Age-related declines in Extraversion and Openness and increases in Agreeableness and Conscientiousness paralleled human age differences. The mean change in absolute standardized units for all five factors was virtually identical in humans and chimpanzees after adjustment for different developmental rates. Consistent with their aggressive behavior in the wild, male chimpanzees were rated as more aggressive, emotional, and impulsive than females. Chimpanzee sex differences in personality were greater than comparable human gender differences. These findings suggest that chimpanzee and human personality develop via an unfolding maturational process. (PsycINFO Database Record (c) 2008 APA, all rights reserved).

What Meaning Means for Same and Different: Analogical Reasoning in Humans (Homo sapiens), Chimpanzees (Pan troglodytes), and Rhesus Monkeys (Macaca mulatta)

PubMed Central

Flemming, Timothy M.; Beran, Michael J.; Thompson, Roger K. R.; Kleider, Heather M.; Washburn, David A.

2013-01-01

Thus far, language- and token-trained apes (e.g., D. Premack, 1976; R. K. R. Thompson, D. L. Oden, & S. T. Boysen, 1997) have provided the best evidence that nonhuman animals can solve, complete, and construct analogies, thus implicating symbolic representation as the mechanism enabling the phenomenon. In this study, the authors examined the role of stimulus meaning in the analogical reasoning abilities of three different primate species. Humans (Homo sapiens), chimpanzees (Pan troglodytes), and rhesus monkeys (Macaca mulatta) completed the same relational matching-to-sample (RMTS) tasks with both meaningful and nonmeaningful stimuli. This discrimination of relations-between-relations serves as the basis for analogical reasoning. Meaningfulness facilitated the acquisition of analogical matching for human participants, whereas individual differences among the chimpanzees suggest that meaning can either enable or hinder their ability to complete analogies. Rhesus monkeys did not succeed in the RMTS task regardless of stimulus meaning, suggesting that their ability to reason analogically, if present at all, may be dependent on a dimension other than the representational value of stimuli. PMID:18489233

Token transfers among great apes (Gorilla gorilla, Pongo pygmaeus, Pan paniscus, and Pan troglodytes): species differences, gestural requests, and reciprocal exchange.

PubMed

Pelé, Marie; Dufour, Valérie; Thierry, Bernard; Call, Josep

2009-11-01

Great apes appear to be the nonhuman primates most capable of recognizing trading opportunities and engaging in transfers of commodities with conspecifics. Spontaneous exchange of goods between them has not yet been reported. We tested gorillas (Gorilla gorilla), orangutans (Pongo pygmaeus), bonobos (Pan paniscus), and chimpanzees (Pan troglodytes) in a token-exchange task involving two conspecifics and a human experimenter. Tested in pairs, subjects had to exchange tokens with a partner to obtain food from the experimenter. We observed 4, 5, 264, and 328 transfers of tokens in gorillas, chimpanzees, orangutans, and bonobos, respectively. Most gifts were indirect in gorillas, chimpanzees, and bonobos, whereas most were direct in orangutans. The analysis showed no evidence of calculated reciprocity in interactions. A main finding of the study was the high rate of repeated gifts and begging gestures recorded in orangutans. This raises the question of the meaning of pointing in great apes and their ability to understand the communicative intent of others.

Personality in the chimpanzees of Gombe National Park

PubMed Central

Weiss, Alexander; Wilson, Michael L.; Collins, D. Anthony; Mjungu, Deus; Kamenya, Shadrack; Foerster, Steffen; Pusey, Anne E.

2017-01-01

Researchers increasingly view animal personality traits as products of natural selection. We present data that describe the personalities of 128 eastern chimpanzees (Pan troglodytes schweinfurthii) currently living in or who lived their lives in the Kasekela and Mitumba communities of Gombe National Park, Tanzania. We obtained ratings on 24 items from an established, reliable, well-validated questionnaire used to study personality in captive chimpanzee populations. Ratings were made by former and present Tanzanian field assistants who followed individual chimpanzees for years and collected detailed behavioral observations. Interrater reliabilities across items ranged from acceptable to good, but the personality dimensions they formed were not as interpretable as those from captive samples. However, the personality dimensions corresponded to ratings of 24 Kasekela chimpanzees on a different questionnaire in 1973 that assessed some similar traits. These correlations established the repeatability and construct validity of the present ratings, indicating that the present data can facilitate historical and prospective studies that will lead to better understanding of the evolution of personality in chimpanzees and other primates. PMID:29064463

Chimpanzees (Pan troglodytes) instrumentally help but do not communicate in a mutualistic cooperative task.

PubMed

Bullinger, Anke F; Melis, Alicia P; Tomasello, Michael

2014-08-01

Chimpanzees cooperate in a variety of contexts, but communicating to influence and regulate cooperative activities is rare. It is unclear whether this reflects chimpanzees' general inability or whether they have found other means to coordinate cooperative activities. In the present study chimpanzees could help a partner play her role in a mutually beneficial food-retrieval task either by transferring a needed tool (transfer condition) or by visually or acoustically communicating the hiding-location of the needed tool (communication condition). Overall, chimpanzees readily helped their partner by delivering the needed tool, but none of them communicated the hiding location of the tool to their partner reliably across trials. These results demonstrate that although chimpanzees can coordinate their cooperative activities by instrumentally helping their partner in her role, they do not readily use communication with their partner for this same end.

Social Attention in the Two Species of Pan: Bonobos Make More Eye Contact than Chimpanzees.

PubMed

Kano, Fumihiro; Hirata, Satoshi; Call, Josep

2015-01-01

Humans' two closest primate living relatives, bonobos and chimpanzees, differ behaviorally, cognitively, and emotionally in several ways despite their general similarities. While bonobos show more affiliative behaviors towards conspecifics, chimpanzees display more overt and severe aggression against conspecifics. From a cognitive standpoint, bonobos perform better in social coordination, gaze-following and food-related cooperation, while chimpanzees excel in tasks requiring extractive foraging skills. We hypothesized that attention and motivation play an important role in shaping the species differences in behavior, cognition, and emotion. Thus, we predicted that bonobos would pay more attention to the other individuals' face and eyes, as those are related to social affiliation and social coordination, while chimpanzees would pay more attention to the action target objects, as they are related to foraging. Using eye-tracking we examined the bonobos' and chimpanzees' spontaneous scanning of pictures that included eyes, mouth, face, genitals, and action target objects of conspecifics. Although bonobos and chimpanzees viewed those elements overall similarly, bonobos viewed the face and eyes longer than chimpanzees, whereas chimpanzees viewed the other elements, the mouth, action target objects and genitals, longer than bonobos. In a discriminant analysis, the individual variation in viewing patterns robustly predicted the species of individuals, thus clearly demonstrating species-specific viewing patterns. We suggest that such attentional and motivational differences between bonobos and chimpanzees could have partly contributed to shaping the species-specific behaviors, cognition, and emotion of these species, even in a relatively short period of evolutionary time.

A thermodynamic comparison of arboreal and terrestrial sleeping sites for dry-habitat chimpanzees (Pan troglodytes schweinfurthii) at the Toro-Semliki Wildlife Reserve, Uganda.

PubMed

Samson, David R; Hunt, Kevin D

2012-09-01

The nightly construction of an arboreal sleeping platform (SP) has been observed among every chimpanzee's population studied to date. Here, we report on bioclimatic aspects of SP site choice among dry-habitat chimpanzees (Pan troglodytes schweinfurthii) at the Toro-Semliki Wildlife Reserve, Uganda. We placed a portable weather monitor within 1 m of chimpanzee SPs and compared the microenvironment of this site with terrestrial monitors placed 10 cm above the ground directly underneath the simultaneously studied SP. We calculated physical "comfort levels" of monitored sites using the RayMan thermophysiological model that we modified to take ape body proportions into account. The RayMan tool gauges energy balance using wind speed, temperature, relative humidity, and heat index in conjunction with the study subject's mass and stature to determine whether the individual is in energy balance or homeostasis. We found that (1) terrestrial microclimates have greater homeostatic potential than arboreal microclimates, and (2) there is a significant positive linear relationship between wind speed and height of SP in the forest canopy. Advantages of terrestrial sites are that they require lesser energetic expenditure to stabilize the body when the SP is under construction and perhaps during use as well. We found that terrestrial sites also had better homeostatic potentials. This combination of advantages explains why SPs are so often sited terrestrially in habitats where predation risk is low. Early hominins must have had technological or social measures to avoid or deter predators that were significantly advanced over those found among chimpanzees before they began sleeping on the ground. © 2012 Wiley Periodicals, Inc.

Foot use during vertical climbing in chimpanzees (Pan troglodytes).

PubMed

Wunderlich, R E; Ischinger, S B

2017-08-01

Upright bipedalism is a hallmark of hominin locomotion, however debates continue regarding the extent of arboreal locomotion and the nature of bipedalism practiced by early hominins. Pedal form and function play a prominent role in these debates, as the foot is the element that directly interacts with the locomotor substrate. Recent finds have substantially increased the availability of associated foot remains of early hominins and emphasized the enigmatic nature of the early evolution of human bipedalism. New discoveries of associated forefoot remains have afforded the opportunity to assess relative proportions across the forefoot of fossil hominins and illuminated the need for data on relative loading across the forefoot in extant hominoids. In order to provide functional data with which to examine the relationship between bony features and load distribution across the forefoot during climbing, we present the first analysis of plantar pressure distribution across the forefoot of chimpanzees climbing a vertical support. Chimpanzees load the medial metatarsals and first toe disproportionately during vertical climbing. Peak pressures on these elements occur at the end of stance phase during climbing and are higher than on any other elements of the foot. Toe pressures are considerably higher during vertical climbing than during knuckle-walking or movement on horizontal poles, supporting the notion that the plantarly-broad and dorsally-narrow metatarsal heads in chimpanzees and some early hominins are associated with close-packing of the metatarsophalangeal joint during climbing. Copyright © 2017 Elsevier Ltd. All rights reserved.

Mating behavior of adolescent male chimpanzees (Pan troglodytes) at Ngogo, Kibale National Park, Uganda.

PubMed

Watts, David P

2015-04-01

Male mating tactics vary extensively in many primates. Some variation occurs because adolescent males often are sexually active but cannot invest heavily in mating effort because of their limited ability to compete directly with adults and because they are still investing in growth; consequently, most of their mating attempts may be surreptitious and/or with females whose fecundity is low. Chimpanzees (Pan troglodytes) have a complex mating system: most copulations occur between estrous females with full sexual swelling and multiple males in group settings where the potential for sperm competition is high, but males sometimes mate-guard females, and sometimes male-female pairs mate exclusively with each other while avoiding other males during "consortships." Among other factors, dominance ranks, coalition formation, and variation in male-female association influence male mating and reproductive success. Mating effort increases from adolescence into prime adulthood. At Gombe and Mahale, adolescent males copulated more with nulliparous than with parous females, and mostly when females were unlikely to be ovulating, partly because of low adult male interest in nulliparous females and partly because of aggression from or avoidance of adult males. Adolescents thus had low probabilities of siring infants. However, adolescents are known to have gained some paternity at Gombe and in other populations, and their mating behavior deserves more study. I present data on mating by adolescent males in an unusually large chimpanzee community at Ngogo, Kibale National Park, Uganda. Adolescents at Ngogo also copulated more with nulliparous than parous females and mostly copulated outside of periovulatory periods. Also, they directed less aggression at estrous females than did adult males. However, they gained lower shares of copulations than reported for Gombe and Mahale, regardless of female parity, and received more aggression from adult males. These differences might partly

Captive chimpanzee (Pan troglodytes) behavior as a function of space per animal and enclosure type.

PubMed

Neal Webb, Sarah J; Hau, Jann; Schapiro, Steven J

2018-03-01

Space per animal, or animal density, and enclosure type are important elements of functionally appropriate captive environments (FACEs) for chimpanzees. The National Institutes of Health (NIH) recommends that captive chimpanzees be maintained in areas of >250 ft 2 /animal. Several studies have investigated chimpanzee behavior in relation to space per animal, but only two studies have examined these variables while attempting to hold environmental complexity constant. Both have found few, if any, significant differences in behavior associated with increased space per animal. The NIH does not provide recommendations pertaining to enclosure type. Although Primadomes™ and corrals are considered acceptable FACE housing, no studies have investigated chimpanzee behavior in relation to these two common types of enclosures. We examined the NIH space per animal recommendation, and the effects of enclosure type, while maintaining similar levels of environmental complexity. We used focal animal observations to record the behavior of 22 chimpanzees in three social groups following within-facility housing transfers. Chimpanzees that were moved from an area with space below the NIH recommendation to the same type of enclosure with space above the recommendation (dome to double dome) exhibited significantly more locomotion and behavioral diversity post-transfer. Chimpanzees that were moved from an area with space below the recommendation to a different type of enclosure with space above the recommendation (dome to corral) exhibited significant increases in foraging and behavioral diversity, and a decrease in rough scratching. Lastly, chimpanzees that were moved from an area above the recommendation to a different enclosure type with space equal to the recommendation (corral to double dome) exhibited an increase in behavioral diversity. These results add to the body of literature that addresses the concept of specific minimum space requirements per chimpanzee, and highlight the

Chimpanzees and the mathematics of battle.

PubMed

Wilson, Michael L; Britton, Nicholas F; Franks, Nigel R

2002-06-07

Recent experiments have demonstrated the importance of numerical assessment in animal contests. Nevertheless, few attempts have been made to model explicitly the relationship between the relative number of combatants on each side and the costs and benefits of entering a contest. One framework that may be especially suitable for making such explicit predictions is Lanchester's theory of combat, which has proved useful for understanding combat strategies in humans and several species of ants. We show, with data from a recent series of playback experiments, that a model derived from Lanchester's 'square law' predicts willingness to enter intergroup contests in wild chimpanzees (Pan troglodytes). Furthermore, the model predicts that, in contests with multiple individuals on each side, chimpanzees in this population should be willing to enter a contest only if they outnumber the opposing side by a factor of 1.5. We evaluate these results for intergroup encounters in chimpanzees and also discuss potential applications of Lanchester's square and linear laws for understanding combat strategies in other species.

The Critically Endangered western chimpanzee declines by 80.

PubMed

Kühl, Hjalmar S; Sop, Tenekwetche; Williamson, Elizabeth A; Mundry, Roger; Brugière, David; Campbell, Genevieve; Cohen, Heather; Danquah, Emmanuel; Ginn, Laura; Herbinger, Ilka; Jones, Sorrel; Junker, Jessica; Kormos, Rebecca; Kouakou, Celestin Y; N'Goran, Paul K; Normand, Emma; Shutt-Phillips, Kathryn; Tickle, Alexander; Vendras, Elleni; Welsh, Adam; Wessling, Erin G; Boesch, Christophe

2017-09-01

African large mammals are under extreme pressure from unsustainable hunting and habitat loss. Certain traits make large mammals particularly vulnerable. These include late age at first reproduction, long inter-birth intervals, and low population density. Great apes are a prime example of such vulnerability, exhibiting all of these traits. Here we assess the rate of population change for the western chimpanzee, Pan troglodytes verus, over a 24-year period. As a proxy for change in abundance, we used transect nest count data from 20 different sites archived in the IUCN SSC A.P.E.S. database, representing 25,000 of the estimated remaining 35,000 western chimpanzees. For each of the 20 sites, datasets for 2 different years were available. We estimated site-specific and global population change using Generalized Linear Models. At 12 of these sites, we detected a significant negative trend. The estimated change in the subspecies abundance, as approximated by nest encounter rate, yielded a 6% annual decline and a total decline of 80.2% over the study period from 1990 to 2014. This also resulted in a reduced geographic range of 20% (657,600 vs. 524,100 km 2 ). Poverty, civil conflict, disease pandemics, agriculture, extractive industries, infrastructure development, and lack of law enforcement, are some of the many reasons for the magnitude of threat. Our status update triggered the uplisting of the western chimpanzee to "Critically Endangered" on the IUCN Red List. In 2017, IUCN will start updating the 2003 Action Plan for western chimpanzees and will provide a consensus blueprint for what is needed to save this subspecies. We make a plea for greater commitment to conservation in West Africa across sectors. Needed especially is more robust engagement by national governments, integration of conservation priorities into the private sector and development planning across the region and sustained financial support from donors. © 2017 Wiley Periodicals, Inc.

Visual search by chimpanzees (Pan): assessment of controlling relations.

PubMed Central

Tomonaga, M

1995-01-01

Three experimentally sophisticated chimpanzees (Pan), Akira, Chloe, and Ai, were trained on visual search performance using a modified multiple-alternative matching-to-sample task in which a sample stimulus was followed by the search display containing one target identical to the sample and several uniform distractors (i.e., negative comparison stimuli were identical to each other). After they acquired this task, they were tested for transfer of visual search performance to trials in which the sample was not followed by the uniform search display (odd-item search). Akira showed positive transfer of visual search performance to odd-item search even when the display size (the number of stimulus items in the search display) was small, whereas Chloe and Ai showed a transfer only when the display size was large. Chloe and Ai used some nonrelational cues such as perceptual isolation of the target among uniform distractors (so-called pop-out). In addition to the odd-item search test, various types of probe trials were presented to clarify the controlling relations in multiple-alternative matching to sample. Akira showed a decrement of accuracy as a function of the display size when the search display was nonuniform (i.e., each "distractor" stimulus was not the same), whereas Chloe and Ai showed perfect performance. Furthermore, when the sample was identical to the uniform distractors in the search display, Chloe and Ai never selected an odd-item target, but Akira selected it when the display size was large. These results indicated that Akira's behavior was controlled mainly by relational cues of target-distractor oddity, whereas an identity relation between the sample and the target strongly controlled the performance of Chloe and Ai. PMID:7714449

Behavioural Development in Chimpanzee (Pan troglodytes) and Human Newborns across the First Month of Life.

ERIC Educational Resources Information Center

Hallock, Martha B.; And Others

1989-01-01

Reports comparisons of behaviors of nine chimpanzee and nine human newborns on a standardized human neonatal assessment scale at the ages of three days and one month. Human infants scored higher than chimpanzee infants on the orientation cluster at both ages, but were lower than chimpanzee infants in motoric maturity. (RJC)

Social Attention in the Two Species of Pan: Bonobos Make More Eye Contact than Chimpanzees

PubMed Central

Kano, Fumihiro; Hirata, Satoshi; Call, Josep

2015-01-01

Humans’ two closest primate living relatives, bonobos and chimpanzees, differ behaviorally, cognitively, and emotionally in several ways despite their general similarities. While bonobos show more affiliative behaviors towards conspecifics, chimpanzees display more overt and severe aggression against conspecifics. From a cognitive standpoint, bonobos perform better in social coordination, gaze-following and food-related cooperation, while chimpanzees excel in tasks requiring extractive foraging skills. We hypothesized that attention and motivation play an important role in shaping the species differences in behavior, cognition, and emotion. Thus, we predicted that bonobos would pay more attention to the other individuals’ face and eyes, as those are related to social affiliation and social coordination, while chimpanzees would pay more attention to the action target objects, as they are related to foraging. Using eye-tracking we examined the bonobos’ and chimpanzees’ spontaneous scanning of pictures that included eyes, mouth, face, genitals, and action target objects of conspecifics. Although bonobos and chimpanzees viewed those elements overall similarly, bonobos viewed the face and eyes longer than chimpanzees, whereas chimpanzees viewed the other elements, the mouth, action target objects and genitals, longer than bonobos. In a discriminant analysis, the individual variation in viewing patterns robustly predicted the species of individuals, thus clearly demonstrating species-specific viewing patterns. We suggest that such attentional and motivational differences between bonobos and chimpanzees could have partly contributed to shaping the species-specific behaviors, cognition, and emotion of these species, even in a relatively short period of evolutionary time. PMID:26075710

Microsatellites evolve more rapidly in humans than in chimpanzees

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rubinsztein, D.C.; Leggo, J.; Amos, W.

1995-12-10

Microsatellites are highly polymorphic markers consisting of varying numbers of tandem repeats. At different loci, these repeats can consist of one to five nucleotides. Microsatellites have been used in many fields of genetics, including genetic mapping, linkage disequilibrium analyses, forensic studies, and population genetics. It is important that we understand their mutational processes better so that they can be exploited optimally for studies of human diversity and evolutionary genetics. We have analyzed 24 microsatellite loci in chimpanzees, East Anglians, and Sub-Saharan Africans. The stepwise-weighted genetic distances between the humans and the chimpanzees and between the two human populations were calculatedmore » according to the method described by Deka et al. The ratio of the genetic distances between the chimpanzees and the humans relative to that between the Africans and the East Anglians was more than 10 times smaller than expected. This suggests that microsatellites have evolved more rapidly in humans than in chimpanzees. 12 refs., 1 tab.« less

The Human Semicircular Canals Orientation Is More Similar to the Bonobos than to the Chimpanzees

PubMed Central

El Khoury, Marwan; Braga, José; Dumoncel, Jean; Nancy, Javotte; Esclassan, Remi; Vaysse, Frederic

2014-01-01

For some traits, the human genome is more closely related to either the bonobo or the chimpanzee genome than they are to each other. Therefore, it becomes crucial to understand whether and how morphostructural differences between humans, chimpanzees and bonobos reflect the well known phylogeny. Here we comparatively investigated intra and extra labyrinthine semicircular canals orientation using 260 computed tomography scans of extant humans (Homo sapiens), bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). Humans and bonobos proved more similarities between themselves than with chimpanzees. This finding did not fit with the well established chimpanzee – bonobo monophyly. One hypothesis was convergent evolution in which bonobos and humans produce independently similar phenotypes possibly in response to similar selective pressures that may be associated with postural adaptations. Another possibility was convergence following a “random walk” (Brownian motion) evolutionary model. A more parsimonious explanation was that the bonobo-human labyrinthine shared morphology more closely retained the ancestral condition with chimpanzees being subsequently derived. Finally, these results might be a consequence of genetic diversity and incomplete lineage sorting. The remarkable symmetry of the Semicircular Canals was the second major finding of this article with possible applications in taphonomy. It has the potential to investigate altered fossils, inferring the probability of post-mortem deformation which can lead to difficulties in understanding taxonomic variation, phylogenetic relationships, and functional morphology. PMID:24710502

Stable isotope evidence of meat eating and hunting specialization in adult male chimpanzees

PubMed Central

Fahy, Geraldine E.; Richards, Michael; Riedel, Julia; Hublin, Jean-Jacques; Boesch, Christophe

2013-01-01

Observations of hunting and meat eating in our closest living relatives, chimpanzees (Pan troglodytes), suggest that among primates, regular inclusion of meat in the diet is not a characteristic unique to Homo. Wild chimpanzees are known to consume vertebrate meat, but its actual dietary contribution is, depending on the study population, often either unknown or minimal. Constraints on continual direct observation throughout the entire hunting season mean that behavioral observations are limited in their ability to accurately quantify meat consumption. Here we present direct stable isotope evidence supporting behavioral observations of frequent meat eating among wild adult male chimpanzees (Pan troglodytes verus) in Taï National Park, Côte d’Ivoire. Meat eating among some of the male chimpanzees is significant enough to result in a marked isotope signal detectable on a short-term basis in their hair keratin and long-term in their bone collagen. Although both adult males and females and juveniles derive their dietary protein largely from daily fruit and seasonal nut consumption, our data indicate that some adult males also derive a large amount of dietary protein from hunted meat. Our results reinforce behavioral observations of male-dominated hunting and meat eating in adult Taï chimpanzees, suggesting that sex differences in food acquisition and consumption may have persisted throughout hominin evolution, rather than being a recent development in the human lineage. PMID:23530185

Cognitive and motor aging in female chimpanzees.

PubMed

Lacreuse, Agnès; Russell, Jamie L; Hopkins, William D; Herndon, James G

2014-03-01

We present the first longitudinal data on cognitive and motor aging in the chimpanzee (Pan troglodytes). Thirty-eight adult female chimpanzees (10-54 years old) were studied. The apes were tested longitudinally for 3 years in a modified Primate Cognition Test Battery, which comprised 12 tests of physical and social cognition. The chimpanzees were also administered a fine motor task requiring them to remove a steel nut from rods of various complexity. There was little evidence for an age-related decline in tasks of Physical Cognition: for most tasks, performance was either stable or improved with repeated testing across age groups. An exception was Spatial Memory, for which 4 individuals more than 50 years old experienced a significant performance decline across the 3 years of testing. Poorer performance with age was found in 2 tasks of Social Cognition, an attention-getting task and a gaze-following task. A slight motor impairment was also observed, with old chimpanzees improving less than younger animals with repeated testing on the simplest rod. Hormonal status effects were restricted to spatial memory, with non-cycling females outperforming cycling females independently of age. Unexpectedly, older chimpanzees were better than younger individuals in understanding causality relationships based on sound. Copyright © 2014 Elsevier Inc. All rights reserved.

Molecular identification of Entamoeba species in savanna woodland chimpanzees (Pan troglodytes schweinfurthii).

PubMed

Jirků-Pomajbíková, Kateřina; Čepička, Ivan; Kalousová, Barbora; Jirků, Milan; Stewart, Fiona; Levecke, Bruno; Modrý, David; Piel, Alex K; Petrželková, Klára J

2016-05-01

To address the molecular diversity and occurrence of pathogenic species of the genus Entamoeba spp. in wild non-human primates (NHP) we conducted molecular-phylogenetic analyses on Entamoeba from wild chimpanzees living in the Issa Valley, Tanzania. We compared the sensitivity of molecular [using a genus-specific polymerase chain reaction (PCR)] and coproscopic detection (merthiolate-iodine-formaldehyde concentration) of Entamoeba spp. We identified Entamoeba spp. in 72 chimpanzee fecal samples (79%) subjected to species-specific PCRs for six Entamoeba species/groups (Entamoeba histolytica, Entamoeba nuttalli, Entamoeba dispar, Entamoeba moshkovskii, Entamoeba coli and Entamoeba polecki ST2). We recorded three Entamoeba species: E. coli (47%), E. dispar (16%), Entamoeba hartmanni (51%). Coproscopically, we could only distinguish the cysts of complex E. histolytica/dispar/moshkovskii/nuttalli and E. coli. Molecular prevalence of entamoebas was higher than the prevalence based on the coproscopic examination. Our molecular phylogenies showed that sequences of E. dispar and E. coli from Issa chimpanzees are closely related to sequences from humans and other NHP from GenBank. The results showed that wild chimpanzees harbour Entamoeba species similar to those occurring in humans; however, no pathogenic species were detected. Molecular-phylogenetic methods are critical to improve diagnostics of entamoebas in wild NHP and for determining an accurate prevalence of Entamoeba species.

Perception of the average size of multiple objects in chimpanzees (Pan troglodytes)

PubMed Central

Kawakami, Fumito; Shirai, Nobu; Tomonaga, Masaki

2017-01-01

Humans can extract statistical information, such as the average size of a group of objects or the general emotion of faces in a crowd without paying attention to any individual object or face. To determine whether summary perception is unique to humans, we investigated the evolutional origins of this ability by assessing whether chimpanzees, which are closely related to humans, can also determine the average size of multiple visual objects. Five chimpanzees and 18 humans were able to choose the array in which the average size was larger, when presented with a pair of arrays, each containing 12 circles of different or the same sizes. Furthermore, both species were more accurate in judging the average size of arrays consisting of 12 circles of different or the same sizes than they were in judging the average size of arrays consisting of a single circle. Our findings could not be explained by the use of a strategy in which the chimpanzee detected the largest or smallest circle among those in the array. Our study provides the first evidence that chimpanzees can perceive the average size of multiple visual objects. This indicates that the ability to compute the statistical properties of a complex visual scene is not unique to humans, but is shared between both species. PMID:28835550

From colour photographs to black-and-white line drawings: an assessment of chimpanzees' (Pan troglodytes') transfer behaviour.

PubMed

Close, James; Call, Josep

2015-03-01

Over two experiments, we investigated the ability of two adolescent and two adult chimpanzees to generalise a learnt, pictorial categorisation to increasingly degraded and abstract stimuli. In Experiment 2, we further assessed the ability of the adolescent chimpanzees to engage in open-ended categorisation of black-and-white line drawings. The current results confirmed and extended previous findings, showing that sub-adult chimpanzees outperform adult chimpanzees in the categorisation of pictorial stimuli, particularly when the stimuli are more degraded and abstract in nature. However, none of the four chimpanzees showed positive transfer of their category learning to a set of black-and-white line drawings, and neither of the adolescent chimpanzees evidenced reliable open-ended categorisation of the black-and-white line drawings. The latter findings suggest that both sub-adult and adult chimpanzees find it difficult to recognise black-and-white line drawings, and that open-ended categorisation of black-and-white line drawings is challenging for chimpanzees.

Natural Choice in Chimpanzees ("Pan troglodytes"): Perceptual and Temporal Effects on Selective Value

ERIC Educational Resources Information Center

Beran, Michael J.; Ratliff, Chasity L.; Evans, Theodore A.

2009-01-01

In three experiments, four chimpanzees made choices between two visible food options to assess the validity of the "selective value effect" (the assignment of value to only the most preferred type of food presented in a comparison). In Experiment 1, we established that all chimpanzees preferred single banana pieces to single apple pieces before…

The Togo-Benin-Nigeria Shield: evidence of crustal aggregation in the Pan-African belt

NASA Astrophysics Data System (ADS)

Ajibade, A. C.; Wright, J. B.

1989-08-01

The importance of "suspect" or "exotic" (i.e. allochthonous) terranes as a major element in collisional orogenic belts is becoming well established. We propose that the southern Pan-African domain in West Africa is an aggregation or " mosaic" of island arcs, interarc (ensimatic) basins and continental fragments. A fracture zone in northwestern Nigeria, already identified as a possible crustal suture, is shown to separate two contrasted basement terranes. Elsewhere in the shield are flat-lying structures characteristic of those associated with crustal convergence, lying within or near to major fractures. Many small ultramafic/mafic bodies occur in the shield and some of them may be remnants of ophiolites caught up in suture zones. An aggregation of allochthonous terranes (island arcs, sedimentary basins and continental blocks) would help to explain: (a) the great width of the Pan-African belt; (b) the spread of ages within the "Pan-African" range (c. 750-450 Ma), also the relict Liberian and Eburnian ages (c. 2700 and 2000 Ma respectively); and the enigmatic Kibaran "event" (c. 1100 Ma); (c) the contrasted volcano-sedimentary characteristics of the different supracrustal belts.

Distinguishing intentional from accidental actions in orangutans (Pongo pygmaeus), chimpanzees (Pan troglodytes), and human children (Homo sapiens).

PubMed

Call, J; Tomasello, M

1998-06-01

This study investigates the understanding of others' intentions in 2- and 3-year-old children, chimpanzees (Pan troglodytes), and orangutans (Pongo pygmaeus). During training, subjects learned to use a discriminative cue to select a baited box. During testing, the experimenter placed a marker on top of the baited box to inform the subject of the reward's location. However, the experimenter also accidentally dropped the marker on top of an unbaited box, so that during any given trial the experimenter marked 2 boxes, 1 intentionally and 1 accidentally. All 3 species preferentially selected the box the experimenter had marked intentionally (especially during the initial trials), with 3-year-old children presenting the most robust results. These findings suggest that subjects understood something about the experimenter's intentions. The authors speculate that understanding of others' intentions may precede the understanding of others' beliefs both at the ontogenetic and phylogenetic levels.

Prospective Memory in a Language-Trained Chimpanzee ("Pan Troglodytes")

ERIC Educational Resources Information Center

Beran, Michael J.; Perdue, Bonnie M.; Bramlett, Jessica L.; Menzel, Charles R.; Evans, Theodore A.

2012-01-01

Prospective memory involves the encoding, retention, and implementation of an intended future action. Although humans show many forms of prospective memory, less is known about the future oriented processes of nonhuman animals, or their ability to use prospective memory. In this experiment, a chimpanzee named Panzee, who had learned to associate…

Delay of gratification is associated with white matter connectivity in the dorsal prefrontal cortex: a diffusion tensor imaging study in chimpanzees (Pan troglodytes).

PubMed

Latzman, Robert D; Taglialatela, Jared P; Hopkins, William D

2015-06-22

Individual variability in delay of gratification (DG) is associated with a number of important outcomes in both non-human and human primates. Using diffusion tensor imaging (DTI), this study describes the relationship between probabilistic estimates of white matter tracts projecting from the caudate to the prefrontal cortex (PFC) and DG abilities in a sample of 49 captive chimpanzees (Pan troglodytes). After accounting for time between collection of DTI scans and DG measurement, age and sex, higher white matter connectivity between the caudate and right dorsal PFC was found to be significantly associated with the acquisition (i.e. training phase) but not the maintenance of DG abilities. No other associations were found to be significant. The integrity of white matter connectivity between regions of the striatum and the PFC appear to be associated with inhibitory control in chimpanzees, with perturbations on this circuit potentially leading to a variety of maladaptive outcomes. Additionally, results have potential translational implications for understanding the pathophysiology of a number of psychiatric and clinical outcomes in humans. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Delay of gratification is associated with white matter connectivity in the dorsal prefrontal cortex: a diffusion tensor imaging study in chimpanzees (Pan troglodytes)

PubMed Central

Latzman, Robert D.; Taglialatela, Jared P.; Hopkins, William D.

2015-01-01

Individual variability in delay of gratification (DG) is associated with a number of important outcomes in both non-human and human primates. Using diffusion tensor imaging (DTI), this study describes the relationship between probabilistic estimates of white matter tracts projecting from the caudate to the prefrontal cortex (PFC) and DG abilities in a sample of 49 captive chimpanzees (Pan troglodytes). After accounting for time between collection of DTI scans and DG measurement, age and sex, higher white matter connectivity between the caudate and right dorsal PFC was found to be significantly associated with the acquisition (i.e. training phase) but not the maintenance of DG abilities. No other associations were found to be significant. The integrity of white matter connectivity between regions of the striatum and the PFC appear to be associated with inhibitory control in chimpanzees, with perturbations on this circuit potentially leading to a variety of maladaptive outcomes. Additionally, results have potential translational implications for understanding the pathophysiology of a number of psychiatric and clinical outcomes in humans. PMID:26041344

The Development of Representational Play in Chimpanzees and Bonobos: Evolutionary Implications, Pretense, and the Role of Interspecies Communication

ERIC Educational Resources Information Center

Lyn, Heidi; Greenfield, Patricia; Savage-Rumbaugh, Sue

2006-01-01

This research investigates the development of symbolic or representational play in two species of the genus "Pan", bonobos ("Pan paniscus") and chimpanzees ("Pan troglodytes"). The participants varied not only by species, but also as to whether they had become proficient in communicating with humans via a set of arbitrary visual symbols, called…

Defining value through quantity and quality-Chimpanzees (Pan troglodytes) undervalue food quantities when items are broken.

PubMed

Parrish, Audrey E; Evans, Theodore A; Beran, Michael J

2015-02-01

Decision-making largely is influenced by the relative value of choice options, and the value of such options can be determined by a combination of different factors (e.g., the quantity, size, or quality of a stimulus). In this study, we examined the competing influences of quantity (i.e., the number of food items in a set) and quality (i.e., the original state of a food item) of choice items on chimpanzees' food preferences in a two-option natural choice paradigm. In Experiment 1, chimpanzees chose between sets of food items that were either entirely whole or included items that were broken into pieces before being shown to the chimpanzees. Chimpanzees exhibited a bias for whole food items even when such choice options consisted of a smaller overall quantity of food than the sets containing broken items. In Experiment 2, chimpanzees chose between sets of entirely whole food items and sets of initially whole items that were subsequently broken in view of the chimpanzees just before choice time. Chimpanzees continued to exhibit a bias for sets of whole items. In Experiment 3, chimpanzees chose between sets of new food items that were initially discrete but were subsequently transformed into a larger cohesive unit. Here, chimpanzees were biased to choose the discrete sets that retained their original qualitative state rather than toward the cohesive or clumped sets. These results demonstrate that beyond a food set's quantity (i.e., the value dimension that accounts for maximization in terms of caloric intake), other seemingly non-relevant features (i.e., quality in terms of a set's original state) affect how chimpanzees assign value to their choice options. Copyright © 2014 Elsevier B.V. All rights reserved.

Perception of the average size of multiple objects in chimpanzees (Pan troglodytes).

PubMed

Imura, Tomoko; Kawakami, Fumito; Shirai, Nobu; Tomonaga, Masaki

2017-08-30

Humans can extract statistical information, such as the average size of a group of objects or the general emotion of faces in a crowd without paying attention to any individual object or face. To determine whether summary perception is unique to humans, we investigated the evolutional origins of this ability by assessing whether chimpanzees, which are closely related to humans, can also determine the average size of multiple visual objects. Five chimpanzees and 18 humans were able to choose the array in which the average size was larger, when presented with a pair of arrays, each containing 12 circles of different or the same sizes. Furthermore, both species were more accurate in judging the average size of arrays consisting of 12 circles of different or the same sizes than they were in judging the average size of arrays consisting of a single circle. Our findings could not be explained by the use of a strategy in which the chimpanzee detected the largest or smallest circle among those in the array. Our study provides the first evidence that chimpanzees can perceive the average size of multiple visual objects. This indicates that the ability to compute the statistical properties of a complex visual scene is not unique to humans, but is shared between both species. © 2017 The Authors.

Responses of chimpanzees to cues of conspecific observation☆

PubMed Central

Nettle, Daniel; Cronin, Katherine A.; Bateson, Melissa

2013-01-01

Recent evidence has shown that humans are remarkably sensitive to artificial cues of conspecific observation when making decisions with potential social consequences. Whether similar effects are found in other great apes has not yet been investigated. We carried out two experiments in which individual chimpanzees, Pan troglodytes, took items of food from an array in the presence of either an image of a large conspecific face or a scrambled control image. In experiment 1 we compared three versions of the face image varying in size and the amount of the face displayed. In experiment 2 we compared a fourth variant of the image with more prominent coloured eyes displayed closer to the focal chimpanzee. The chimpanzees did not look at the face images significantly more than at the control images in either experiment. Although there were trends for some individuals in each experiment to be slower to take high-value food items in the face conditions, these were not consistent or robust. We suggest that the extreme human sensitivity to cues of potential conspecific observation may not be shared with chimpanzees. PMID:24027343

Eastern Chimpanzees, but Not Bonobos, Represent a Simian Immunodeficiency Virus Reservoir

PubMed Central

Li, Yingying; Ndjango, Jean-Bosco; Learn, Gerald H.; Ramirez, Miguel A.; Keele, Brandon F.; Bibollet-Ruche, Frederic; Liu, Weimin; Easlick, Juliet L.; Decker, Julie M.; Rudicell, Rebecca S.; Inogwabini, Bila-Isia; Ahuka-Mundeke, Steve; Leendertz, Fabian H.; Reynolds, Vernon; Muller, Martin N.; Chancellor, Rebecca L.; Rundus, Aaron S.; Simmons, Nicole; Worobey, Michael; Shaw, George M.; Peeters, Martine; Sharp, Paul M.

2012-01-01

Chimpanzees in west central Africa (Pan troglodytes troglodytes) are endemically infected with simian immunodeficiency viruses (SIVcpzPtt) that have crossed the species barrier to humans and gorillas on at least five occasions, generating pandemic and nonpandemic forms of human immunodeficiency virus type 1 (HIV-1) as well as gorilla SIV (SIVgor). Chimpanzees in east Africa (Pan troglodytes schweinfurthii) are also infected with SIVcpz; however, their viruses (SIVcpzPts) have never been found in humans. To examine whether this is due to a paucity of natural infections, we used noninvasive methods to screen wild-living eastern chimpanzees in the Democratic Republic of the Congo (DRC), Uganda, and Rwanda. We also screened bonobos (Pan paniscus) in the DRC, a species not previously tested for SIV in the wild. Fecal samples (n = 3,108) were collected at 50 field sites, tested for species and subspecies origin, and screened for SIVcpz antibodies and nucleic acids. Of 2,565 samples from eastern chimpanzees, 323 were antibody positive and 92 contained viral RNA. The antibody-positive samples represented 76 individuals from 19 field sites, all sampled north of the Congo River in an area spanning 250,000 km2. In this region, SIVcpzPts was common and widespread, with seven field sites exhibiting infection rates of 30% or greater. The overall prevalence of SIVcpzPts infection was 13.4% (95% confidence interval, 10.7% to 16.5%). In contrast, none of the 543 bonobo samples from six sites was antibody positive. All newly identified SIVcpzPts strains clustered in strict accordance to their subspecies origin; however, they exhibited considerable genetic diversity, especially in protein domains known to be under strong host selection pressure. Thus, the absence of SIVcpzPts zoonoses cannot be explained by an insufficient primate reservoir. Instead, greater adaptive hurdles may have prevented the successful colonization of humans by P. t. schweinfurthii viruses. PMID:22837215

The extent of cultural variation between adjacent chimpanzee (Pan troglodytes verus) communities; a microecological approach.

PubMed

Luncz, Lydia V; Boesch, Christophe

2015-01-01

Chimpanzees show cultural differences among populations across Africa but also between neighboring communities. The extent of these differences among neighbors, however, remains largely unknown. Comparing three neighboring chimpanzee community in the Taï National Park, Côte d'Ivoire, we found 27 putative cultural traits, including tool use, foraging, social interaction, communication and hunting behavior, exceeding by far previously known diversity. As foraging behavior is predominantly influenced by the environment, we further compared in detail ecological circumstances underlying insectivore feeding behavior to analyze whether foraging differences on Dorylus ants and Thoracotermes termites seen between neighboring chimpanzee communities were caused by environmental factors. Differences in the prey characteristics of Dorylus ants (aggression level, running speed, and nest structure) that could influence the behavior of chimpanzees were excluded, suggesting that the observed group-specific variation is not ecologically driven. Only one community preyed on Thoracotermes termites despite a similar abundance of termite mounds in all three territories, supporting the idea that this difference is also not shaped by the environment. Therefore, our study suggests that transmission of cultural knowledge plays a role in determining insectivory prey behavior. This behavioral plasticity, independent of ecological conditions, can lead to large numbers of cultural diversification between neighboring chimpanzee communities. These findings not only deepen our understanding of the cultural abilities of chimpanzees in the wild but also open up possible future comparisons of the origin of cultural diversification among humans and chimpanzees. © 2014 Wiley Periodicals, Inc.

Malignant Neoplasia of the Sex Skin in 2 Chimpanzees (Pan troglodytes).

PubMed

Beck, Amanda P; Magden, Elizabeth R; Buchl, Stephanie J; Baze, Wallace B

2016-04-01

This report describes 2 cases of spontaneous malignant neoplasia within the sex skin of aged female chimpanzees. In both cases, the initial presentation resembled nonhealing traumatic wounds to the sex skin, with different degrees of infection, ulceration, and tissue necrosis. Histopathology of the lesions confirmed the diagnosis of squamous cell carcinoma in one case and of adenocarcinoma with metastasis in the other. Advanced age and previous trauma likely contributed to the development of the neoplasias in both cases; long-term sun exposure may also have contributed to the development of the squamous cell carcinoma. To our knowledge, these 2 cases represent the first reports of sex skin neoplasia in chimpanzees.

Social, contextual, and individual factors affecting the occurrence and acoustic structure of drumming bouts in wild chimpanzees (Pan troglodytes).

PubMed

Babiszewska, Magdalena; Schel, Anne Marijke; Wilke, Claudia; Slocombe, Katie E

2015-01-01

The production of structured and repetitive sounds by striking objects is a behavior found not only in humans, but also in a variety of animal species, including chimpanzees (Pan troglodytes). In this study we examined individual and social factors that may influence the frequency with which individuals engage in drumming behavior when producing long distance pant hoot vocalizations, and analyzed the temporal structure of those drumming bouts. Male chimpanzees from Budongo Forest, Uganda, drummed significantly more frequently during travel than feeding or resting and older individuals were significantly more likely to produce drumming bouts than younger ones. In contrast, we found no evidence that the presence of estrus females, high ranking males and preferred social partners in the caller's vicinty had an effect on the frequency with which an individual accompanied their pant hoot vocalization with drumming. Through acoustic analyses, we demonstrated that drumming sequences produced with pant hoots may have contained information on individual identity and that qualitatively, there was individual variation in the complexity of the temporal patterns produced. We conclude that drumming patterns may act as individually distinctive long-distance signals that, together with pant hoot vocalizations, function to coordinate the movement and spacing of dispersed individuals within a community, rather than as signals to group members in the immediate audience. © 2014 Wiley Periodicals, Inc.

Robust retention and transfer of tool construction techniques in chimpanzees (Pan troglodytes).

PubMed

Vale, Gill L; Flynn, Emma G; Pender, Lydia; Price, Elizabeth; Whiten, Andrew; Lambeth, Susan P; Schapiro, Steven J; Kendal, Rachel L

2016-02-01

Long-term memory can be critical to a species' survival in environments with seasonal and even longer-term cycles of resource availability. The present, longitudinal study investigated whether complex tool behaviors used to gain an out-of-reach reward, following a hiatus of about 3 years and 7 months since initial experiences with a tool use task, were retained and subsequently executed more quickly by experienced than by naïve chimpanzees. Ten of the 11 retested chimpanzees displayed impressive long-term procedural memory, creating elongated tools using the same methods employed years previously, either combining 2 tools or extending a single tool. The complex tool behaviors were also transferred to a different task context, showing behavioral flexibility. This represents some of the first evidence for appreciable long-term procedural memory, and improvements in the utility of complex tool manufacture in chimpanzees. Such long-term procedural memory and behavioral flexibility have important implications for the longevity and transmission of behavioral traditions. (c) 2016 APA, all rights reserved).

Robust Retention and Transfer of Tool Construction Techniques in Chimpanzees (Pan troglodytes)

PubMed Central

Vale, Gill L.; Flynn, Emma G.; Pender, Lydia; Price, Elizabeth; Whiten, Andrew; Lambeth, Susan P.; Schapiro, Steven J.; Kendal, Rachel L.

2016-01-01

Long-term memory can be critical to a species’ survival in environments with seasonal and even longer-term cycles of resource availability. The present, longitudinal study investigated whether complex tool behaviors used to gain an out-of-reach reward, following a hiatus of about 3 years and 7 months since initial experiences with a tool use task, were retained and subsequently executed more quickly by experienced than by naïve chimpanzees. Ten of the 11 retested chimpanzees displayed impressive long-term procedural memory, creating elongated tools using the same methods employed years previously, either combining 2 tools or extending a single tool. The complex tool behaviors were also transferred to a different task context, showing behavioral flexibility. This represents some of the first evidence for appreciable long-term procedural memory, and improvements in the utility of complex tool manufacture in chimpanzees. Such long-term procedural memory and behavioral flexibility have important implications for the longevity and transmission of behavioral traditions. PMID:26881941

Expression of myosin heavy chain isoforms mRNA transcripts in the temporalis muscle of common chimpanzees (Pan troglodytes).

PubMed

Ciurana, Neus; Artells, Rosa; Muñoz, Carmen; Arias-Martorell, Júlia; Bello-Hellegouarch, Gaëlle; Casado, Aroa; Cuesta, Elisabeth; Pérez-Pérez, Alejandro; Pastor, Juan Francisco; Potau, Josep Maria

2017-11-01

The common chimpanzee (Pan troglodytes) is the primate that is phylogenetically most closely related to humans (Homo sapiens). In order to shed light on the anatomy and function of the temporalis muscle in the chimpanzee, we have analyzed the expression patterns of the mRNA transcripts of the myosin heavy chain (MyHC) isoforms in different parts of the muscle. We dissected the superficial, deep and sphenomandibularis portions of the temporalis muscle in five adult P. troglodytes and quantified the expression of the mRNA transcripts of the MyHC isoforms in each portion using real-time quantitative polymerase chain reaction. We observed significant differences in the patterns of expression of the mRNA transcripts of the MyHC-IIM isoform between the sphenomandibularis portion and the anterior superficial temporalis (33.6% vs 47.0%; P=0.032) and between the sphenomandibularis portion and the anterior deep temporalis (33.6% vs 43.0; P=0.016). We also observed non-significant differences between the patterns of expression in the anterior and posterior superficial temporalis. The differential expression patterns of the mRNA transcripts of the MyHC isoforms in the temporalis muscle in P. troglodytes may be related to the functional differences that have been observed in electromyographic studies in other species of primates. Our findings can be applicable to the fields of comparative anatomy, evolutionary anatomy, and anthropology. Copyright © 2017 Elsevier GmbH. All rights reserved.

Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: Enlarging genus Homo

PubMed Central

Wildman, Derek E.; Uddin, Monica; Liu, Guozhen; Grossman, Lawrence I.; Goodman, Morris

2003-01-01

What do functionally important DNA sites, those scrutinized and shaped by natural selection, tell us about the place of humans in evolution? Here we compare ≈90 kb of coding DNA nucleotide sequence from 97 human genes to their sequenced chimpanzee counterparts and to available sequenced gorilla, orangutan, and Old World monkey counterparts, and, on a more limited basis, to mouse. The nonsynonymous changes (functionally important), like synonymous changes (functionally much less important), show chimpanzees and humans to be most closely related, sharing 99.4% identity at nonsynonymous sites and 98.4% at synonymous sites. On a time scale, the coding DNA divergencies separate the human–chimpanzee clade from the gorilla clade at between 6 and 7 million years ago and place the most recent common ancestor of humans and chimpanzees at between 5 and 6 million years ago. The evolutionary rate of coding DNA in the catarrhine clade (Old World monkey and ape, including human) is much slower than in the lineage to mouse. Among the genes examined, 30 show evidence of positive selection during descent of catarrhines. Nonsynonymous substitutions by themselves, in this subset of positively selected genes, group humans and chimpanzees closest to each other and have chimpanzees diverge about as much from the common human–chimpanzee ancestor as humans do. This functional DNA evidence supports two previously offered taxonomic proposals: family Hominidae should include all extant apes; and genus Homo should include three extant species and two subgenera, Homo (Homo) sapiens (humankind), Homo (Pan) troglodytes (common chimpanzee), and Homo (Pan) paniscus (bonobo chimpanzee). PMID:12766228

Implications of natural selection in shaping 99.4% nonsynonymous DNA identity between humans and chimpanzees: enlarging genus Homo.

PubMed

Wildman, Derek E; Uddin, Monica; Liu, Guozhen; Grossman, Lawrence I; Goodman, Morris

2003-06-10

What do functionally important DNA sites, those scrutinized and shaped by natural selection, tell us about the place of humans in evolution? Here we compare approximately 90 kb of coding DNA nucleotide sequence from 97 human genes to their sequenced chimpanzee counterparts and to available sequenced gorilla, orangutan, and Old World monkey counterparts, and, on a more limited basis, to mouse. The nonsynonymous changes (functionally important), like synonymous changes (functionally much less important), show chimpanzees and humans to be most closely related, sharing 99.4% identity at nonsynonymous sites and 98.4% at synonymous sites. On a time scale, the coding DNA divergencies separate the human-chimpanzee clade from the gorilla clade at between 6 and 7 million years ago and place the most recent common ancestor of humans and chimpanzees at between 5 and 6 million years ago. The evolutionary rate of coding DNA in the catarrhine clade (Old World monkey and ape, including human) is much slower than in the lineage to mouse. Among the genes examined, 30 show evidence of positive selection during descent of catarrhines. Nonsynonymous substitutions by themselves, in this subset of positively selected genes, group humans and chimpanzees closest to each other and have chimpanzees diverge about as much from the common human-chimpanzee ancestor as humans do. This functional DNA evidence supports two previously offered taxonomic proposals: family Hominidae should include all extant apes; and genus Homo should include three extant species and two subgenera, Homo (Homo) sapiens (humankind), Homo (Pan) troglodytes (common chimpanzee), and Homo (Pan) paniscus (bonobo chimpanzee).

Piagetian conservation of discrete quantities in bonobos (Pan paniscus), chimpanzees (Pan troglodytes), and orangutans (Pongo pygmaeus).

PubMed

Suda, Chikako; Call, Josep

2005-10-01

This study investigated whether physical discreteness helps apes to understand the concept of Piagetian conservation (i.e. the invariance of quantities). Subjects were four bonobos, three chimpanzees, and five orangutans. Apes were tested on their ability to conserve discrete/continuous quantities in an over-conservation procedure in which two unequal quantities of edible rewards underwent various transformations in front of subjects. Subjects were examined to determine whether they could track the larger quantity of reward after the transformation. Comparison between the two types of conservation revealed that tests with bonobos supported the discreteness hypothesis. Bonobos, but neither chimpanzees nor orangutans, performed significantly better with discrete quantities than with continuous ones. The results suggest that at least bonobos could benefit from the discreteness of stimuli in their acquisition of conservation skills.

Factors affecting initial training success of blood glucose testing in captive chimpanzees (Pan troglodytes).

PubMed

Reamer, Lisa A; Haller, Rachel L; Thiele, Erica J; Freeman, Hani D; Lambeth, Susan P; Schapiro, Steven J

2014-01-01

Type 2 diabetes can be a problem for captive chimpanzees. Accurate blood glucose (BG) readings are necessary to monitor and treat this disease. Thus, obtaining voluntary samples from primates through positive reinforcement training (PRT) is critical. The current study assessed the voluntary participation of 123 chimpanzees in BG sampling and investigated factors that may contribute to individual success. All subjects participate in regular PRT sessions as part of a comprehensive behavioral management program. Basic steps involved in obtaining BG values include: voluntarily presenting a finger/toe; allowing digit disinfection; holding for the lancet device; and allowing blood collection onto a glucometer test strip for analysis. We recorded the level of participation (none, partial, or complete) when each chimpanzee was first asked to perform the testing procedure. Nearly 30% of subjects allowed the entire procedure in one session, without any prior specific training for the target behavior. Factors that affected this initial successful BG testing included sex, personality (chimpanzees rated higher on the factor "openness" were more likely to participate with BG testing), and past training performance for "present-for-injection" (chimpanzees that presented for their most recent anesthetic injection were more likely to participate). Neither age, rearing history, time since most recent anesthetic event nor social group size significantly affected initial training success. These results have important implications for captive management and training program success, underlining individual differences in training aptitude and the need for developing individual management plans in order to provide optimal care and treatment for diabetic chimpanzees in captivity. © 2014 Wiley Periodicals, Inc.

Chimpanzees and the mathematics of battle.

PubMed Central

Wilson, Michael L; Britton, Nicholas F; Franks, Nigel R

2002-01-01

Recent experiments have demonstrated the importance of numerical assessment in animal contests. Nevertheless, few attempts have been made to model explicitly the relationship between the relative number of combatants on each side and the costs and benefits of entering a contest. One framework that may be especially suitable for making such explicit predictions is Lanchester's theory of combat, which has proved useful for understanding combat strategies in humans and several species of ants. We show, with data from a recent series of playback experiments, that a model derived from Lanchester's 'square law' predicts willingness to enter intergroup contests in wild chimpanzees (Pan troglodytes). Furthermore, the model predicts that, in contests with multiple individuals on each side, chimpanzees in this population should be willing to enter a contest only if they outnumber the opposing side by a factor of 1.5. We evaluate these results for intergroup encounters in chimpanzees and also discuss potential applications of Lanchester's square and linear laws for understanding combat strategies in other species. PMID:12061952

Using cross correlations to investigate how chimpanzees (Pan troglodytes) use conspecific gaze cues to extract and exploit information in a foraging competition.

PubMed

Hall, Katie; Oram, Mike W; Campbell, Matthew W; Eppley, Timothy M; Byrne, Richard W; De Waal, Frans B M

2014-10-01

In a dyadic informed forager task, chimpanzees (Pan troglodytes) are known to exploit the knowledge of informed subordinates; however, the behavioral mechanisms they employ are unknown. It is tempting to interpret outcome measures, such as which individual obtained the food, in a cognitively richer way than the outcomes may justify. We employed a different approach from prior research, asking how chimpanzees compete by maneuvering around each other, whether they use gaze cues to acquire information from others, and what information they use in moment-to-moment decision-making. We used cross correlations, which plot the correlation between two variables as a function of time, systematically to examine chimpanzee interactions in a series of dyadic informed forager contests. We used cross correlations as a "proof of concept" so as to determine whether the target actions were contingent on, or occurred in a time-locked pattern relative to, the referent actions. A subordinate individual was given privileged knowledge of food location. As expected, an ignorant dominant followed the informed subordinate's movement in the enclosure. The dominant also followed the subordinate's gaze direction: after she looked at the subordinate, she was more likely to gaze toward this same direction within one second. In contrast, the subordinate only occasionally followed the dominant's movement and gaze. The dominant also changed her own direction of movement to converge on the location to which the subordinate directed her gaze and movement. Cross correlation proves an effective technique for charting contingencies in social interactions, an important step in understanding the use of cognition in natural situations. © 2014 Wiley Periodicals, Inc.

Lethal aggression in Pan is better explained by adaptive strategies than human impacts.

PubMed

Wilson, Michael L; Boesch, Christophe; Fruth, Barbara; Furuichi, Takeshi; Gilby, Ian C; Hashimoto, Chie; Hobaiter, Catherine L; Hohmann, Gottfried; Itoh, Noriko; Koops, Kathelijne; Lloyd, Julia N; Matsuzawa, Tetsuro; Mitani, John C; Mjungu, Deus C; Morgan, David; Muller, Martin N; Mundry, Roger; Nakamura, Michio; Pruetz, Jill; Pusey, Anne E; Riedel, Julia; Sanz, Crickette; Schel, Anne M; Simmons, Nicole; Waller, Michel; Watts, David P; White, Frances; Wittig, Roman M; Zuberbühler, Klaus; Wrangham, Richard W

2014-09-18

Observations of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) provide valuable comparative data for understanding the significance of conspecific killing. Two kinds of hypothesis have been proposed. Lethal violence is sometimes concluded to be the result of adaptive strategies, such that killers ultimately gain fitness benefits by increasing their access to resources such as food or mates. Alternatively, it could be a non-adaptive result of human impacts, such as habitat change or food provisioning. To discriminate between these hypotheses we compiled information from 18 chimpanzee communities and 4 bonobo communities studied over five decades. Our data include 152 killings (n = 58 observed, 41 inferred, and 53 suspected killings) by chimpanzees in 15 communities and one suspected killing by bonobos. We found that males were the most frequent attackers (92% of participants) and victims (73%); most killings (66%) involved intercommunity attacks; and attackers greatly outnumbered their victims (median 8:1 ratio). Variation in killing rates was unrelated to measures of human impacts. Our results are compatible with previously proposed adaptive explanations for killing by chimpanzees, whereas the human impact hypothesis is not supported.

HEART RATE AND INDIRECT BLOOD PRESSURE RESPONSES TO FOUR DIFFERENT FIELD ANESTHETIC PROTOCOLS IN WILD-BORN CAPTIVE CHIMPANZEES (PAN TROGLODYTES).

PubMed

Atencia, Rebeca; Stöhr, Eric J; Drane, Aimee L; Stembridge, Mike; Howatson, Glyn; Del Rio, Pablo Rodriguez Lopez; Feltrer, Yedra; Tafon, Babila; Redrobe, Sharon; Peck, Bruce; Eng, Jaclyn; Unwin, Steve; Sanchez, Carlos R; Shave, Rob E

2017-09-01

Limited data are available on hemodynamic responses to anesthetic protocols in wild-born chimpanzees (Pan troglodytes). Accordingly, this study characterized the heart rate (HR) and blood pressure responses to four anesthetic protocols in 176 clinically healthy, wild-born chimpanzees undergoing routine health assessments. Animals were anesthetized with medetomidine-ketamine (MK) (n = 101), tiletamine-zolazepam (TZ) (n = 30), tiletamine-zolazepam-medetomidine (TZM) (n = 24), or medetomidine-ketamine (maintained with isoflurane) (MKI) (n = 21). During each procedure, HR, systolic blood pressure (SBP), and diastolic blood pressure (DBP) were regularly recorded. Data were grouped according to anesthetic protocol, and mean HR, SBP, and DBP were calculated. Differences between mean HR, SBP, and DBP for each anesthetic protocol were assessed using the Kruskall-Wallis test and a Dunn multiple comparisons post hoc analysis. To assess the hemodynamic time course response to each anesthetic protocol, group mean data (±95% confidence interval [CI]) were plotted against time postanesthetic induction. Mean HR (beats/min [CI]) was significantly higher in TZ (86 [80-92]) compared to MKI (69 [61-78]) and MK (62 [60-64]) and in TZM (73 [68-78]) compared to MK. The average SBP and DBP values (mm Hg [CI]) were significantly higher in MK (130 [126-134] and 94 [91-97]) compared to TZ (104 [96-112] and 58 [53-93]) and MKI (113 [103-123] and 78 [69-87]) and in TZM (128 [120-135] and 88 [83-93]) compared to TZ. Time course data were markedly different between protocols, with MKI showing the greatest decline over time. Both the anesthetic protocol adopted and the timing of measurement after injection influence hemodynamic recordings in wild-born chimpanzees and need to be considered when monitoring or assessing cardiovascular health.

Comparison of male conflict behavior in chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), with specific regard to coalition and post-conflict behavior.

PubMed

Surbeck, Martin; Boesch, Christophe; Girard-Buttoz, Cédric; Crockford, Catherine; Hohmann, Gottfried; Wittig, Roman M

2017-06-01

Coalitions among males during within group conflicts have a strong influence on the competitive and social environment within social groups. To evaluate possible variation in the occurrence of such coalitions in our closest relatives, chimpanzees and bonobos, we compared male aggression and coalitionary behavior in two natural communities, one of each species, with a similar size and composition. Furthermore we compared affiliative behavior that might be related to coalition formation among males. We found higher frequencies of aggression and a greater likelihood to form coalitions during within-group conflicts among wild male chimpanzees at Taï compared to wild male bonobos at LuiKotale. The species differed in the predominant sex of the male coalition partners, with male bonobos forming coalitions more often with females, while male chimpanzees formed coalitions more often with other males. Compared to male bonobos, male chimpanzees showed higher rates of grooming and tended to reconcile more conflicts with other males. Overall our results showed lower frequencies of reconciliation among bonobos than those described in captivity and at artificial feeding sites. These findings add to the evidence that male cooperation and conflict resolution are potentially very different in bonobos and chimpanzees, despite the fact that these two species are closely related, live in multi-male, multi-female communities with a high degree of fission-fusion dynamics and have female-biased migration patterns. Given the correlation between aggressive, cooperative and some affiliative patterns within the species in our study, we hypothesize that the fitness benefits of male relationships are greater in chimpanzees compared to bonobos. © 2017 Wiley Periodicals, Inc.

Brief communication: Cineradiographic analysis of the chimpanzee (Pan troglodytes) talonavicular and calcaneocuboid joints.

PubMed

Thompson, Nathan E; Holowka, Nicholas B; O'Neill, Matthew C; Larson, Susan G

2014-08-01

During terrestrial locomotion, chimpanzees exhibit dorsiflexion of the midfoot between midstance and toe-off of stance phase, a phenomenon that has been called the "midtarsal break." This motion is generally absent during human bipedalism, and in chimpanzees is associated with more mobile foot joints than in humans. However, the contribution of individual foot joints to overall foot mobility in chimpanzees is poorly understood, particularly on the medial side of the foot. The talonavicular (TN) and calcaneocuboid (CC) joints have both been suggested to contribute significantly to midfoot mobility and to the midtarsal break in chimpanzees. To evaluate the relative magnitude of motion that can occur at these joints, we tracked skeletal motion of the hindfoot and midfoot during passive plantarflexion and dorsiflexion manipulations using cineradiography. The sagittal plane range of motion was 38 ± 10° at the TN joint and 14 ± 8° at the CC joint. This finding indicates that the TN joint is more mobile than the CC joint during ankle plantarflexion-dorsiflexion. We suggest that the larger range of motion at the TN joint during dorsiflexion is associated with a rotation (inversion-eversion) across the transverse tarsal joint, which may occur in addition to sagittal plane motion. © 2014 Wiley Periodicals, Inc.

Isotopic ecology and dietary profiles of Liberian chimpanzees.

PubMed

Smith, Catherine C; Morgan, Michèle E; Pilbeam, David

2010-01-01

An extensive suite of isotopic data (delta(13)C, delta(15)N, and delta(18)O) from enamel apatite and bone collagen of adult male and female wild chimpanzees establishes baseline values for Pan troglodytes verus in a primary rainforest setting. The Ganta chimpanzee sample derives from a restricted region in northern Liberia. Diet is examined using stable light isotopes at three life stages-infant, young juvenile, and adult-and developmental differences are investigated within and between individual males and females. The isotopic data are very homogeneous with few exceptions. Juvenile females show consistent enrichment in (13)C relative to infants, while juvenile males do not. These data suggest that age at weaning may be more variable for male offspring who survive to adulthood than for female offspring. Alternatively, or additionally, the weaning diet of males and females may differ, with greater consumption of technologically extracted insects and/or nuts by young females. Metabolic differences, including growth and hormone-mediated responses, may also contribute to the observed variation. The Ganta chimpanzee data offer an independent and objective line of evidence to primatologists interested in the dietary strategies of the great apes and to paleoanthropologists seeking comparative models for reconstructing early hominin subsistence patterns. Despite the high diversity of dietary items consumed by chimpanzees, isotopic signatures of chimpanzees from a primary rainforest setting exhibit narrow ranges of variation similar to chimpanzees in more open habitats.

Leaf swallowing behavior in chimpanzees (Pan troglodytes): biased learning and the emergence of group level cultural differences.

PubMed

Huffman, Michael A; Spiezio, Caterina; Sgaravatti, Andrea; Leca, Jean-Baptiste

2010-11-01

Demonstrating the ability to 'copy' the behavior of others is an important aspect in determining whether social learning occurs and whether group level differences in a given behavior represent cultural differences or not. Understanding the occurrence of this process in its natural context is essential, but can be a daunting task in the wild. In order to test the social learning hypothesis for the acquisition of leaf swallowing (LS), a self-medicative behavior associated with the expulsion of parasites, we conducted semi-naturalistic experiments on two captive groups of parasite-free, naïve chimpanzees (Pan troglodytes). Individuals in the group were systematically provided appropriate stimuli (rough hispid leaves) identical to those used by chimpanzees in the wild. Individuals initially responded in a variety of ways, ranging from total aversion to normal chewing and swallowing. Over time, however, the two groups adopted different variants for inserting and folding the leaves in the mouth prior to swallowing them (complete and partial LS), following the specific method spontaneously displayed by the first and primary LS models in their respective groups. These variants were similar to LS displayed by chimpanzees in the wild. Using the option-bias method, we found evidence for social learning leading to group-level biased transmission and group-level stabilization of these two variants. This is the first report on two distinct cultural variants innovated in response to the introduction of natural stimuli that emerged and spread spontaneously and concurrently within two adjacent groups of socially housed primates. These observations support the assertion that LS may reflect a generalized propensity for ingesting rough hispid leaves, which can be socially induced and transmitted within a group. Ingesting an adequate number of these leaves induces increased gut motility, which is responsible for the subsequent expulsion of particular parasite species in the wild

Neuroanatomical correlates of personality in chimpanzees (Pan troglodytes): Associations between personality and frontal cortex.

PubMed

Latzman, Robert D; Hecht, Lisa K; Freeman, Hani D; Schapiro, Steven J; Hopkins, William D

2015-12-01

Converging empirical data suggests that a set of largely consistent personality traits exist in both human and nonhuman primates; despite these similarities, almost nothing is known concerning the neurobiological basis of these traits in nonhuman primates. The current study examined associations between chimpanzee personality traits and the grey matter volume and asymmetry of various frontal cortex regions in 107 captive chimpanzees. Chimpanzees rated as higher on Openness and Extraversion had greater bilateral grey matter volumes in the anterior cingulate cortex. Further, chimpanzee rated as higher on Dominance had larger grey volumes in the left anterior cingulate cortex and right Prefrontal Cortex (PFC). Finally, apes rated higher on Reactivity/Unpredictability had higher grey matter volumes in the right mesial PFC. All associations survived after applying False Discovery Rate (FDR) thresholds. Results are discussed in terms of current neuroscientific models of personality which suggest that the frontal cortex, and asymmetries in this region, play an important role in the neurobiological foundation of broad dispositional traits. Copyright © 2015 Elsevier Inc. All rights reserved.

Planum Temporale Asymmetries Correlate with Corpus Callosum Axon Fiber Density in Chimpanzees (Pan troglodytes)

PubMed Central

Hopkins, William D.; Pilger, John F.; Storz, Rachel; Ambrose, Alex; Hof, Patrick R.; Sherwood, Chet C.

2012-01-01

The corpus callosum (CC) is the major white matter tract that connects the two cerebral hemispheres. Some have theorized that individual differences in behavioral and brain asymmetries are linked to variation in the density of axon fibers that traverse different sections of the CC. In this study, we examined whether variation in axon fiber density in the CC was associated with variation in asymmetries in the planum temporale (PT) in a sample of 20 post-mortem chimpanzee brains. We further tested for sex differences in small and large CC fiber proportions and density in the chimpanzees. We found that the distribution of small and large fibers within the CC of chimpanzees follows a similar pattern to those reported in humans. We also found that chimpanzees with larger asymmetries in the PT had fewer large fibers in the posterior portion of the CC, particularly among females. As has been reported in human brains, the findings reported here indicate that individual differences in brain asymmetries are associated with variation in interhemispheric connectivity as manifest in axon fiber density and size. PMID:22766214

78 FR 35201 - Endangered and Threatened Wildlife and Plants; Listing All Chimpanzees as Endangered

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-12

...We, the U.S. Fish and Wildlife Service, propose to list all chimpanzees (Pan troglodytes) as endangered under the Endangered Species Act of 1973, as amended (Act). We are taking this action in response to a petition to list the entire species, whether in the wild or in captivity, as endangered under the Act. This proposal constitutes our 12-month finding on the petition and announces our finding that listing all chimpanzees as endangered is warranted. This document also serves as our 5-year review of the species. If we finalize this rule as proposed, we would eliminate the separate classification of captive and wild chimpanzees under the Act and extend the Act's protections to captive chimpanzees in the United States. In addition, we propose to amend the special rule for primates to remove chimpanzees from the rule. If the listing of all chimpanzees as endangered is finalized, the provisions of the special rule can no longer be applied to captive chimpanzees. We seek comments from the public on this proposed rule.

Egalitarian despots: hierarchy steepness, reciprocity and the grooming-trade model in wild chimpanzees, Pan troglodytes.

PubMed

Kaburu, Stefano S K; Newton-Fisher, Nicholas E

2015-01-01

Biological market theory models the action of natural selection as a marketplace in which animals are viewed as traders with commodities to offer and exchange. Studies of female Old World monkeys have suggested that grooming might be employed as a commodity to be reciprocated or traded for alternative services, yet previous tests of this grooming-trade model in wild adult male chimpanzees have yielded mixed results. Here we provide the strongest test of the model to date for male chimpanzees: we use data drawn from two social groups (communities) of chimpanzees from different populations and give explicit consideration to variation in dominance hierarchy steepness, as such variation results in differing conditions for biological markets. First, analysis of data from published accounts of other chimpanzee communities, together with our own data, showed that hierarchy steepness varied considerably within and across communities and that the number of adult males in a community aged 20-30 years predicted hierarchy steepness. The two communities in which we tested predictions of the grooming-trade model lay at opposite extremes of this distribution. Second, in accord with the grooming-trade model, we found evidence that male chimpanzees trade grooming for agonistic support where hierarchies are steep (despotic) and consequent effective support is a rank-related commodity, but not where hierarchies are shallow (egalitarian). However, we also found that grooming was reciprocated regardless of hierarchy steepness. Our findings also hint at the possibility of agonistic competition, or at least exclusion, in relation to grooming opportunities compromising the free market envisioned by biological market theory. Our results build on previous findings across chimpanzee communities to emphasize the importance of reciprocal grooming exchanges among adult male chimpanzees, which can be understood in a biological markets framework if grooming by or with particular individuals is a

Egalitarian despots: hierarchy steepness, reciprocity and the grooming-trade model in wild chimpanzees, Pan troglodytes

PubMed Central

Kaburu, Stefano S. K.; Newton-Fisher, Nicholas E.

2014-01-01

Biological market theory models the action of natural selection as a marketplace in which animals are viewed as traders with commodities to offer and exchange. Studies of female Old World monkeys have suggested that grooming might be employed as a commodity to be reciprocated or traded for alternative services, yet previous tests of this grooming-trade model in wild adult male chimpanzees have yielded mixed results. Here we provide the strongest test of the model to date for male chimpanzees: we use data drawn from two social groups (communities) of chimpanzees from different populations and give explicit consideration to variation in dominance hierarchy steepness, as such variation results in differing conditions for biological markets. First, analysis of data from published accounts of other chimpanzee communities, together with our own data, showed that hierarchy steepness varied considerably within and across communities and that the number of adult males in a community aged 20–30 years predicted hierarchy steepness. The two communities in which we tested predictions of the grooming-trade model lay at opposite extremes of this distribution. Second, in accord with the grooming-trade model, we found evidence that male chimpanzees trade grooming for agonistic support where hierarchies are steep (despotic) and consequent effective support is a rank-related commodity, but not where hierarchies are shallow (egalitarian). However, we also found that grooming was reciprocated regardless of hierarchy steepness. Our findings also hint at the possibility of agonistic competition, or at least exclusion, in relation to grooming opportunities compromising the free market envisioned by biological market theory. Our results build on previous findings across chimpanzee communities to emphasize the importance of reciprocal grooming exchanges among adult male chimpanzees, which can be understood in a biological markets framework if grooming by or with particular individuals is

Genetic basis in motor skill and hand preference for tool use in chimpanzees (Pan troglodytes).

PubMed

Hopkins, William D; Reamer, Lisa; Mareno, Mary Catherine; Schapiro, Steven J

2015-02-07

Chimpanzees are well known for their tool using abilities. Numerous studies have documented variability in tool use among chimpanzees and the role that social learning and other factors play in their development. There are also findings on hand use in both captive and wild chimpanzees; however, less understood are the potential roles of genetic and non-genetic mechanisms in determining individual differences in tool use skill and laterality. Here, we examined heritability in tool use skill and handedness for a probing task in a sample of 243 captive chimpanzees. Quantitative genetic analysis, based on the extant pedigrees, showed that overall both tool use skill and handedness were significantly heritable. Significant heritability in motor skill was evident in two genetically distinct populations of apes, and between two cohorts that received different early social rearing experiences. We further found that motor skill decreased with age and that males were more commonly left-handed than females. Collectively, these data suggest that though non-genetic factors do influence tool use performance and handedness in chimpanzees, genetic factors also play a significant role, as has been reported in humans. © 2014 The Author(s) Published by the Royal Society. All rights reserved.

Chimpanzee quiet hoo variants differ according to context.

PubMed

Crockford, Catherine; Gruber, Thibaud; Zuberbühler, Klaus

2018-05-01

In comparative studies of evolution of communication, the function and use of animal quiet calls have typically been understudied, despite that these signals are presumably under selection like other vocalizations, such as alarm calls. Here, we examine vocalization diversification of chimpanzee quiet 'hoos' produced in three contexts-travel, rest and alert-and potential pressures promoting diversification. Previous playback and observational studies have suggested that the overarching function of chimpanzee hoos is to stay in contact with others, particularly bond partners. We conducted an acoustic analysis of hoos using audio recordings from wild chimpanzees ( Pan troglodytes schweinfurthii ) of Budongo Forest, Uganda. We identified three acoustically distinguishable, context-specific hoo variants. Each call variant requires specific responses from receivers to avoid breaking up the social unit. We propose that callers may achieve coordination by using acoustically distinguishable calls, advertising their own behavioural intentions. We conclude that natural selection has acted towards acoustically diversifying an inconspicuous, quiet vocalization, the chimpanzee hoo. This evolutionary process may have been favoured by the fact that signallers and recipients share the same goal, to maintain social cohesion, particularly among those who regularly cooperate, suggesting that call diversification has been favoured by the demands of cooperative activities.

Chemical immobilization of chimpanzees (Pan troglodytes) using a combination of detomidine and ketamine.

PubMed

Melis, Sanne; Schauvliege, Stijn; van Bolhuis, Hester; Hoyer, Mark; Gasthuys, Frank

2012-09-01

To determine if a combination of detomidine and ketamine can be used for effective chemical immobilization of chimpanzees. Observational study. Twenty-one adult captive chimpanzees (12 males, nine females), age 8-46 years, weighing 40.4-68.4 kg. The chimpanzees were immobilized with intramuscular (IM) detomidine and ketamine by a darting system. Based on estimated weights, doses administered were 50 μg kg(-1) detomidine and 4 mg kg(-1) ketamine in groups 1 and 2, and 60 μg kg(-1) and 5 mg kg(-1) respectively in group 3. Eight minutes in group 1 and 15 minutes in groups 2 and 3 were allowed from the time of apparent immobilization before removing the animals from their enclosures. Body temperature, arterial haemoglobin saturation and pulse rate were measured. The time from injection to induction (recumbency and absence of voluntary movement), total anaesthetic and recovery times (with or without atipamezole) were recorded. Immobilization occurred within 5 minutes after darting in most animals. Early handling of the chimpanzees often resulted in arousal and required further doses of ketamine IM. Most animals were hypoxaemic and hypothermic. Occasionally, bradycardia was observed. Atipamezole resulted in an acceptable quality of recovery 10 minutes after IM injection. The duration of immobilization varied widely when no antagonist was administered. The combination detomidine (60 μg kg(-1) ) and ketamine (5-6 mg kg(-1) ) can be used for the immobilization of chimpanzees for non- to minimally invasive procedures. A period of 15 minutes should be allowed before handling to avoid unwanted arousal. Oxygen administration is recommended to reduce hypoxaemia. Administration of atipamezole is justified to hasten recovery. © 2012 The Authors. Veterinary Anaesthesia and Analgesia. © 2012 Association of Veterinary Anaesthetists and the American College of Veterinary Anesthesiologists.

Chimpanzees return favors at a personal cost.

PubMed

Schmelz, Martin; Grueneisen, Sebastian; Kabalak, Alihan; Jost, Jürgen; Tomasello, Michael

2017-07-11

Humans regularly provide others with resources at a personal cost to themselves. Chimpanzees engage in some cooperative behaviors in the wild as well, but their motivational underpinnings are unclear. In three experiments, chimpanzees ( Pan troglodytes ) always chose between an option delivering food both to themselves and a partner and one delivering food only to themselves. In one condition, a conspecific partner had just previously taken a personal risk to make this choice available. In another condition, no assistance from the partner preceded the subject's decision. Chimpanzees made significantly more prosocial choices after receiving their partner's assistance than when no assistance was given (experiment 1) and, crucially, this was the case even when choosing the prosocial option was materially costly for the subject (experiment 2). Moreover, subjects appeared sensitive to the risk of their partner's assistance and chose prosocially more often when their partner risked losing food by helping (experiment 3). These findings demonstrate experimentally that chimpanzees are willing to incur a material cost to deliver rewards to a conspecific, but only if that conspecific previously assisted them, and particularly when this assistance was risky. Some key motivations involved in human cooperation thus may have deeper phylogenetic roots than previously suspected.

Assessment of behavior and space use before and after forelimb amputation in a zoo-housed chimpanzee (Pan troglodytes).

PubMed

Ang, Mabel Y L; Shender, Marisa A; Ross, Stephen R

2017-01-01

Primates possess great manual dexterity, and their limbs are integral to many aspects of normal functioning (e.g., climbing, feeding). As such, the loss of a limb carries the risk of significant disability and potentially harmful impairment of species-typical functioning. Limb loss is known to occur in some wild primate populations due to entanglement in hunting snares, but can also occur in captive settings due to injury that necessitates therapeutic amputation. In this study, we conducted a detailed evaluation of the behavior, travel, and space use expressed by a female zoo-housed chimpanzee (Pan troglodytes) before and following surgical amputation of her right forelimb. Overall, our results suggest that the injury did not substantively affect her daily activities. She showed no change to her vertical space use, spending equivalent proportions of her time on the ground and high in the enclosure. There was a decrease in the frequency of locomotion on the ground (P = 0.006) but also a significant increase in the overall distance travelled (P = 0.0015) following the removal of the limb. This case study provides evidence that individual chimpanzees are able to successfully adjust to significant anatomical changes when provided adequate environments in which to stay active, and highlights the importance of an effective post-surgical monitoring period-a comprehensive recovery evaluation that includes input from both veterinary and behavioral research staff is likely to provide the most holistic assessment of animal health and long-term wellbeing. Zoo Biol. 36:5-10, 2017. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

A legacy of low-impact logging does not elevate prevalence of potentially pathogenic protozoa in free-ranging gorillas and chimpanzees in the Republic of Congo: logging and parasitism in African apes.

PubMed

Gillespie, Thomas R; Morgan, David; Deutsch, J Charlie; Kuhlenschmidt, Mark S; Salzer, Johanna S; Cameron, Kenneth; Reed, Trish; Sanz, Crickette

2009-12-01

Many studies have examined the long-term effects of selective logging on the abundance and diversity of free-ranging primates. Logging is known to reduce the abundance of some primate species through associated hunting and the loss of food trees for frugivores; however, the potential role of pathogens in such primate population declines is largely unexplored. Selective logging results in a suite of alterations in host ecology and forest structure that may alter pathogen dynamics in resident wildlife populations. In addition, environmental pollution with human fecal material may present a risk for wildlife infections with zoonotic protozoa, such as Cryptosporidium and Giardia. To better understand this interplay, we compared patterns of infection with these potentially pathogenic protozoa in sympatric western lowland gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes troglodytes) in the undisturbed Goualougo Triangle of Nouabalé-Ndoki National Park and the adjacent previously logged Kabo Concession in northern Republic of Congo. No Cryptosporidium infections were detected in any of the apes examined and prevalence of infection with Giardia was low (3.73% overall) and did not differ between logged and undisturbed forest for chimpanzees or gorillas. These results provide a baseline for prevalence of these protozoa in forest-dwelling African apes and suggest that low-intensity logging may not result in long-term elevated prevalence of potentially pathogenic protozoa.

A Legacy of Low-Impact Logging does not Elevate Prevalence of Potentially Pathogenic Protozoa in Free-Ranging Gorillas and Chimpanzees in the Republic of Congo: Logging and Parasitism in African Apes

PubMed Central

Morgan, David; Deutsch, J. Charlie; Kuhlenschmidt, Mark S.; Salzer, Johanna S.; Cameron, Kenneth; Reed, Trish; Sanz, Crickette

2010-01-01

Many studies have examined the long-term effects of selective logging on the abundance and diversity of free-ranging primates. Logging is known to reduce the abundance of some primate species through associated hunting and the loss of food trees for frugivores; however, the potential role of pathogens in such primate population declines is largely unexplored. Selective logging results in a suite of alterations in host ecology and forest structure that may alter pathogen dynamics in resident wildlife populations. In addition, environmental pollution with human fecal material may present a risk for wildlife infections with zoonotic protozoa, such as Cryptosporidium and Giardia. To better understand this interplay, we compared patterns of infection with these potentially pathogenic protozoa in sympatric western lowland gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes troglodytes) in the undisturbed Goualougo Triangle of Nouabalé-Ndoki National Park and the adjacent previously logged Kabo Concession in northern Republic of Congo. No Cryptosporidium infections were detected in any of the apes examined and prevalence of infection with Giardia was low (3.73% overall) and did not differ between logged and undisturbed forest for chimpanzees or gorillas. These results provide a baseline for prevalence of these protozoa in forest-dwelling African apes and suggest that low-intensity logging may not result in long-term elevated prevalence of potentially pathogenic protozoa. PMID:20238141

Early social deprivation negatively affects social skill acquisition in chimpanzees (Pan troglodytes).

PubMed

van Leeuwen, Edwin J C; Mulenga, Innocent Chitalu; Chidester, Diana Lisensky

2014-03-01

In a highly social species like chimpanzees, the process by which individuals become attuned to their social environment may be of vital importance to their chances of survival. Typically, this socialization process, defined by all acquisition experiences and fine-tuning efforts of social interaction patterns during ontogeny, occurs in large part through parental investment. In this study, we investigated whether maternal presence enhances the socialization process in chimpanzees by comparing the social interactions of orphaned and mother-reared individuals at the Chimfunshi Wildlife Orphanage Trust in Zambia. As response variables, we selected social interactions during which an elaborate level of fine-tuning is assumed to be necessary for sustaining the interaction and preventing escalation: social play. Comparing orphaned (n = 8) to sex- and age-matched mother-reared juvenile chimpanzees (n = 9), we hypothesized that the orphaned juveniles would play less frequently than the mother-reared and would be less equipped for fine-tuning social play (which we assayed by rates of aggression) because of the lack of a safe and facilitating social environment provided by the mother. First, contrary to our hypothesis, results showed that the orphaned juveniles engaged in social play more frequently than the mother-reared juveniles, although for significantly shorter amounts of time. Second, in support of our hypothesis, results showed that social play of the orphaned juveniles more often resulted in aggression than social play of the mother-reared juveniles. In conjunction, these results may indicate that, just like in humans, chimpanzee mothers provide their offspring with adequate social skills that might be of pivotal importance for future challenges like successful group-living and securing competitive fitness advantages.

Using cross correlations to investigate how chimpanzees (Pan troglodytes) use conspecific gaze cues to extract and exploit information in a foraging competition

PubMed Central

Hall, Katie; Oram, Mike W.; Campbell, Matthew W.; Eppley, Timothy M.; Byrne, Richard W.; de Waal, Frans B.M.

2014-01-01

In a dyadic informed forager task, chimpanzees (Pan troglodytes) are known to exploit the knowledge of informed subordinates; however, the behavioral mechanisms they employ are unknown. It is tempting to interpret outcome measures, such as which individual obtained the food, in a cognitively richer way than the outcomes may justify. We employed a different approach from prior research, asking how chimpanzees compete by maneuvering around each other, whether they use gaze cues to acquire information from others, and what information they use in moment-to-moment decision-making. We used cross correlations, which plot the correlation between two variables as a function of time, systematically to examine chimpanzee interactions in a series of dyadic informed forager contests. We used cross correlations as a “proof of concept” so as to determine whether the target actions were contingent on, or occurred in a time-locked pattern relative to, the referent actions. A subordinate individual was given privileged knowledge of food location. As expected, an ignorant dominant followed the informed subordinate’s movement in the enclosure. The dominant also followed the subordinate’s gaze direction: after she looked at the subordinate, she was more likely to gaze towards this same direction within one second. In contrast, the subordinate only occasionally followed the dominant’s movement and gaze. The dominant also changed her own direction of movement to converge on the location to which the subordinate directed her gaze and movement. Cross correlation proves an effective technique for charting contingencies in social interactions, an important step in understanding the use of cognition in natural situations. PMID:24710756

Age- and Sex-associated Differences in Phenotypic and Functional Characteristics of Peripheral Blood Lymphocytes in Chimpanzees (Pan troglodytes).

PubMed

Nehete, Pramod N; Magden, Elizabeth R; Nehete, Bharti P; Williams, Lawrence E; Abee, Christian R; Sastry, K Jagannadha

2017-09-01

Chimpanzees are the closest phylogenetic relatives to humans, sharing more than 98% genetic sequence identity. These genetic similarities prompted the belief that chimpanzees can serve as an ideal model for human disease conditions and vaccine development. However, in light of the recent NIH decision to phase out biomedical research in chimpanzees and retire NIH-supported chimpanzees, data from the present study will continue to provide value for the care of aged and sick chimpanzees located in zoos, sanctuaries, and primate centers. Surprisingly little information has been published regarding the normal chimpanzee immune system, and most extant studies have been based on small numbers of animals. In the current study, we provide a better understanding of the chimpanzee immune system with regard to age and sex. We examined immune parameters of chimpanzees (n = 94; 51 female, 43 male; age, 6 to 47 y) by using flow cytometry, immune function analysis, and cytokine analysis. Because lymphocytes are key mediators of cellular immune responses, particularly to intracellular pathogens such as viruses, we surveyed the phenotypic and functional attributes of T and B lymphocytes in this healthy and age-stratified population of chimpanzees. We noted a significantly higher percentage of CD16+T cells in male compared with female chimpanzees but no significant changes in percentages of CD3+, CD4+, CD8+, or CD4+CD8+ T cells with age or sex. In addition, aging was associated with decreased proliferative responses to mitogens in both sexes. Sex-specific differences also were present in the percentage of NK cells but not in their cytotoxic activity and in circulating cytokine levels in plasma. Going forward, the data presented here regarding immune cell changes associated with aging in healthy chimpanzees will serve to enhance the care of geriatric and ill animals.

Flexibility and persistence of chimpanzee (Pan troglodytes) foraging behavior in a captive environment.

PubMed

Bonnie, Kristin E; Milstein, Marissa S; Calcutt, Sarah E; Ross, Stephen R; Wagner, Kathy E; Lonsdorf, Elizabeth V

2012-07-01

As a result of environmental variability, animals may be confronted with uncertainty surrounding the presence of, or accessibility to, food resources at a given location or time. While individuals can rely on personal experience to manage this variability, the behavior of members of an individual's social group can also provide information regarding the availability or location of a food resource. The purpose of the present study was to measure how captive chimpanzees individually and collectively adjust their foraging strategies at an artificial termite mound, as the availability of resources provided by the mound varied over a number of weeks. As predicted, fishing activity at the mound was related to resource availability. However, chimpanzees continued to fish at unbaited locations on the days and weeks after a location had last contained food. Consistent with previous studies, our findings show that chimpanzees do not completely abandon previously learned habits despite learning individually and/or socially that the habit is no longer effective. © 2012 Wiley Periodicals, Inc.

Language-Trained Chimpanzees (Pan troglodytes) Delay Gratification by Choosing Token Exchange Over Immediate Reward Consumption

PubMed Central

Beran, Michael J.; Evans, Theodore A.

2012-01-01

Token exchange inherently introduces an element of delay between behavior and reward and so token studies may help us better understand delay of gratification and self-control. To examine this possibility, we presented three language-trained chimpanzees with repeated choices involving different foods that could be eaten immediately or lexigram (graphic symbol) tokens that represented (and could be traded for) foods later. When both options were foods, chimpanzees always chose more preferred foods over less preferred foods. When both options were lexigram tokens representing those same foods, performance remained the same as chimpanzees selected the higher value token and then traded it for food. Then, when faced with choosing a token that could be traded later or choosing a food item that could be eaten immediately, most chimpanzees learned to make whatever response led to the more preferred food. They did this even when that meant selecting a high value lexigram token that could be traded only two to three minutes later instead of a medium value, but immediately available, food item. Thus, chimpanzees flexibly selected tokens even though such selections necessarily delayed gratification and required forgoing immediately available food. This finding illustrates the utility of symbolic token exchange for assessing self-control in nonhuman animals. PMID:22674686

Thermal history of the Pan-African basement under the Jurassic Marib-Shabwa Basin, Yemen

NASA Astrophysics Data System (ADS)

Rice, A. Hugh N.; Schneider, David; Veeningen, Resi; Grasemann, Bernhard; Decker, Kurt

2013-04-01

Pan-African tectonism within the Arabian Nubian Shield in Yemen is very poorly known. New drill-cores from the Marib-Shabwa Basin (Habban oil field) from central Yemen penetrated 600 m into the pre-Jurassic crystalline basement, providing a unique opportunity to extend our understanding of Pan-African events in Yemen. The cores were obtained some 80 km NE of the exposure limit of the Al Bayda Terrane, which lies SE of Sana'a. This terrane, which has no direct correlative in the ANS further north in Saudi Arabia, comprises deformed greenschist facies acid to basic volcanic rocks later witnessing acid to basic magmatism and has been previously interpreted as a Pan-African island arc complex with a basement component. Ophiolite fragments are common, both within the terrane and at its margins (sutures). To the north lies the Abas Gneiss Terrane and to the south the Al Mahfid Gneiss Terrane; both consist of older pre-Pan-African crystalline basement rocks. Geochemistry of a red, undeformed granite from the drill core indicates an A-type composition. LA-ICPMS U-Pb analysis of granite zircons gave two concordant age populations: 628.3 ± 3.1 Ma (large & small zircons) and 604.9 ± 2.0 Ma (intermediate sized zircons). The former age is interpreted as the time of crystallization, within the range of other A-type Younger Granites in the ANS, and the latter age as constraining lower temperature dissolution-reprecipitation of zircon, due to hydrothermal fluids or melt remobilization. Nd Tdm model ages for two granite samples from the drill core both gave ages of 1.24 Ga, within the range of the Al Bayda Terrane (1.2-2.5 Ga) and outside the range of the adjacent Palaeoproterozoic gneissic terranes (1.7-2.3 Ga, Abas Gneiss Terrane; 1.8-3.0 Ga, Al Mahfid Gneiss Terrane). Thus it seems certain that the Al Bayda Terrane extends at least 80 km to the NE of its present surface exposure. Rb-Sr biotite ages from the granite indicate closure through ~300°C at 593 Ma, indicating fast

Handedness influences intermanual transfer in chimpanzees (Pan troglodytes) but not rhesus monkeys (Macaca mulatta).

PubMed

Boeving, Emily R; Lacreuse, Agnès; Hopkins, William D; Phillips, Kimberley A; Novak, Melinda A; Nelson, Eliza L

2015-03-01

Intermanual transfer refers to an effect, whereby training one hand to perform a motor task improves performance in the opposite untrained hand. We tested the hypothesis that handedness facilitates intermanual transfer in two nonhuman primate species: rhesus monkeys (N = 13) and chimpanzees (N = 52). Subjects were grouped into one of four conditions: (1) left-handers trained with the left (dominant) hand; (2) left-handers trained with the right (nondominant) hand; (3) right-handers trained with the left (nondominant) hand; and (4) right-handers trained with the right (dominant) hand. Intermanual transfer was measured using a task where subjects removed a Life Savers(®) candy (monkeys) or a washer (chimpanzees) from metal shapes. Transfer was measured with latency by comparing the average time taken to solve the task in the first session with the trained hand compared to the first session with the untrained hand. Hypotheses and predictions were derived from three models of transfer: access: benefit training with nondominant hand; proficiency: benefit training with dominant hand; and cross-activation: benefit irrespective of trained hand. Intermanual transfer (i.e., shorter latency in untrained hand) occurred regardless of whether monkeys trained with the dominant hand or nondominant hand, supporting the cross-activation model. However, transfer was only observed in chimpanzees that trained with the dominant hand. When handedness groups were examined separately, the transfer effect was only significant for right-handed chimpanzees, partially supporting the proficiency model. Findings may be related to neurophysiological differences in motor control as well as differences in handedness patterning between rhesus monkeys and chimpanzees.

Handedness influences intermanual transfer in chimpanzees (Pan troglodytes) but not rhesus monkeys (Macaca mulatta)

PubMed Central

Boeving, Emily R.; Lacreuse, Agnès; Hopkins, William D.; Phillips, Kimberley A.; Novak, Melinda A.; Nelson, Eliza L.

2015-01-01

Intermanual transfer refers to an effect whereby training one hand to perform a motor task improves performance in the opposite untrained hand. We tested the hypothesis that handedness facilitates intermanual transfer in two nonhuman primate species: rhesus monkeys (N = 13) and chimpanzees (N = 52). Subjects were grouped into one of four conditions: (1) left-handers trained with the left (dominant) hand; (2) left-handers trained with the right (non-dominant) hand; (3) right-handers trained with the left (non-dominant) hand; and (4) right-handers trained with the right (dominant) hand. Intermanual transfer was measured using a task where subjects removed a Life Savers® candy (monkeys) or a washer (chimpanzees) from metal shapes. Transfer was measured with latency by comparing the average time taken to solve the task in the first session with the trained hand compared to the first session with the untrained hand. Hypotheses and predictions were derived from three models of transfer: access: benefit training with non-dominant hand; proficiency: benefit training with dominant hand; and cross-activation: benefit irrespective of trained hand. Intermanual transfer (i.e., shorter latency in untrained hand) occurred regardless of whether monkeys trained with the dominant hand or non-dominant hand, supporting the cross-activation model. However, transfer was only observed in chimpanzees that trained with the dominant hand. When handedness groups were examined separately, the transfer effect was only significant for right-handed chimpanzees, partially supporting the proficiency model. Findings may be related to neurophysiological differences in motor control as well as differences in handedness patterning between rhesus monkeys and chimpanzees. PMID:25466868

Differential changes in steroid hormones before competition in bonobos and chimpanzees

PubMed Central

Wobber, Victoria; Hare, Brian; Maboto, Jean; Lipson, Susan; Wrangham, Richard; Ellison, Peter T.

2010-01-01

A large body of research has demonstrated that variation in competitive behavior across species and individuals is linked to variation in physiology. In particular, rapid changes in testosterone and cortisol during competition differ according to an individual's or species’ psychological and behavioral responses to competition. This suggests that among pairs of species in which there are behavioral differences in competition, there should also be differences in the endocrine shifts surrounding competition. We tested this hypothesis by presenting humans’ closest living relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), with a dyadic food competition and measuring their salivary testosterone and cortisol levels. Given that chimpanzees and bonobos differ markedly in their food-sharing behavior, we predicted that they would differ in their rapid endocrine shifts. We found that in both species, males showed an anticipatory decrease (relative to baseline) in steroids when placed with a partner in a situation in which the two individuals shared food, and an anticipatory increase when placed with a partner in a situation in which the dominant individual obtained more food. The species differed, however, in terms of which hormone was affected; in bonobo males the shifts occurred in cortisol, whereas in chimpanzee males the shifts occurred in testosterone. Thus, in anticipation of an identical competition, bonobo and chimpanzee males showed differential endocrine shifts, perhaps due to differences in perception of the situation, that is, viewing the event either as a stressor or a dominance contest. In turn, common selection pressures in human evolution may have acted on the psychology and the endocrinology of our competitive behavior. PMID:20616027

Co–Residence between Males and Their Mothers and Grandmothers Is More Frequent in Bonobos Than Chimpanzees

PubMed Central

Schubert, Grit; Vigilant, Linda; Boesch, Christophe; Klenke, Reinhard; Langergraber, Kevin; Mundry, Roger; Surbeck, Martin; Hohmann, Gottfried

2013-01-01

In long–lived social mammals such as primates, individuals can benefit from social bonds with close kin, including their mothers. In the patrilocal chimpanzee (Pan troglodytes spp.) and bonobo (Pan paniscus), sexually mature males reside and reproduce in their natal groups and can retain post-dependency bonds with their mothers, while immatures of both sexes might also have their paternal grandmothers available. However, quantitative information on the proportion of males and immatures that co-reside with both types of these close female relatives is limited for both species. Combining genetic parentage determination and group composition data from five communities of wild chimpanzees and three communities of wild bonobos, we estimated the frequency of co-residence between (1) mature males and their mothers, and (2) immature males and females and their paternal grandmothers. We found that adult males resided twice as frequently with their mothers in bonobos than in chimpanzees, and that immature bonobos were three times more likely to possess a living paternal grandmother than were immature chimpanzees. Patterns of female and male survivorship from studbook records of captive individuals of both species suggest that mature bonobo females survive longer than their chimpanzee counterparts, possibly contributing to the differences observed in mother–son and grandmother–immature co-residency levels. Taking into account reports of bonobo mothers supporting their sons' mating efforts and females sharing food with immatures other than their own offspring, our findings suggest that life history traits may facilitate maternal and grandmaternal support more in bonobos than in chimpanzees. PMID:24358316

Vaccination to conserved influenza antigens in mice using a novel Simian adenovirus vector, PanAd3, derived from the bonobo Pan paniscus.

PubMed

Vitelli, Alessandra; Quirion, Mary R; Lo, Chia-Yun; Misplon, Julia A; Grabowska, Agnieszka K; Pierantoni, Angiolo; Ammendola, Virginia; Price, Graeme E; Soboleski, Mark R; Cortese, Riccardo; Colloca, Stefano; Nicosia, Alfredo; Epstein, Suzanne L

2013-01-01

Among approximately 1000 adenoviruses from chimpanzees and bonobos studied recently, the Pan Adenovirus type 3 (PanAd3, isolated from a bonobo, Pan paniscus) has one of the best profiles for a vaccine vector, combining potent transgene immunogenicity with minimal pre-existing immunity in the human population. In this study, we inserted into a replication defective PanAd3 a transgene expressing a fusion protein of conserved influenza antigens nucleoprotein (NP) and matrix 1 (M1). We then studied antibody and T cell responses as well as protection from challenge infection in a mouse model. A single intranasal administration of PanAd3-NPM1 vaccine induced strong antibody and T cell responses, and protected against high dose lethal influenza virus challenge. Thus PanAd3 is a promising candidate vector for vaccines, including universal influenza vaccines.

Chimpanzees (Pan troglodytes) flexibly adjust their behaviour in order to maximize payoffs, not to conform to majorities.

PubMed

Van Leeuwen, Edwin J C; Cronin, Katherine A; Schütte, Sebastian; Call, Josep; Haun, Daniel B M

2013-01-01

Chimpanzees have been shown to be adept learners, both individually and socially. Yet, sometimes their conservative nature seems to hamper the flexible adoption of superior alternatives, even to the extent that they persist in using entirely ineffective strategies. In this study, we investigated chimpanzees' behavioural flexibility in two different conditions under which social animals have been predicted to abandon personal preferences and adopt alternative strategies: i) under influence of majority demonstrations (i.e. conformity), and ii) in the presence of superior reward contingencies (i.e. maximizing payoffs). Unlike previous nonhuman primate studies, this study disentangled the concept of conformity from the tendency to maintain one's first-learned strategy. Studying captive (n=16) and semi-wild (n=12) chimpanzees in two complementary exchange paradigms, we found that chimpanzees did not abandon their behaviour in order to match the majority, but instead remained faithful to their first-learned strategy (Study 1a and 1b). However, the chimpanzees' fidelity to their first-learned strategy was overridden by an experimental upgrade of the profitability of the alternative strategy (Study 2). We interpret our observations in terms of chimpanzees' relative weighing of behavioural options as a function of situation-specific trade-offs. More specifically, contrary to previous findings, chimpanzees in our study abandoned their familiar behaviour to maximize payoffs, but not to conform to a majority.

Patterns of gastro-intestinal parasites and commensals as an index of population and ecosystem health: the case of sympatric western chimpanzees (Pan troglodytes verus) and guinea baboons (Papio hamadryas papio) at Fongoli, Senegal.

PubMed

Howells, Michaela E; Pruetz, Jill; Gillespie, Thomas R

2011-02-01

The exponential decline of great apes over the past 50 years has resulted in an urgent need for data to inform population viability assessment and conservation strategies. Health monitoring of remaining ape populations is an important component of this process. In support of this effort, we examined endoparasitic and commensal prevalence and richness as proxies of population health for western chimpanzees (Pan troglodytes verus) and sympatric guinea baboons (Papio hamadryas papio) at Fongoli, Senegal, a site dominated by woodland-savanna at the northwestern extent of chimpanzees' geographic range. The small population size and extreme environmental pressures experienced by Fongoli chimpanzees make them particularly sensitive to the potential impact of pathogens. One hundred thirty-two chimpanzee and seventeen baboon fecal samples were processed using sodium nitrate floatation and fecal sedimentation to isolate helminth eggs, larvae, and protozoal cysts. Six nematodes (Physaloptera sp., Ascaris sp., Stronglyloides fuelleborni, Trichuris sp., an unidentified hookworm, and an unidentified larvated nematode), one cestode (Bertiella sp.), and five protozoans (Iodamoeba buetschlii, Entamoeba coli, Troglodytella abrassarti, Troglocorys cava, and an unidentified ciliate) were detected in chimpanzee fecal samples. Four nematodes (Necator sp., S. fuelleborni, Trichuris sp., and an unidentified hookworm sp.), two trematodes (Shistosoma mansoni and an unidentified fluke), and six protozoans (Entamoeba histolytica/dispar, E. coli, Chilomastix mesnili, Balantidium coli, T. abrassarti, and T. cava) were detected in baboon fecal samples. The low prevalence of pathogenic parasite species and high prevalence of symbiotic protozoa in Fongoli chimpanzees are indicative of good overall population health. However, the high prevalence of pathogenic parasites in baboons, who may serve as transport hosts, highlight the need for ongoing pathogen surveillance of the Fongoli chimpanzee

Ontogenetic Trajectories of Chimpanzee Social Play: Similarities with Humans

PubMed Central

Cordoni, Giada; Palagi, Elisabetta

2011-01-01

Social play, a widespread phenomenon in mammals, is a multifunctional behavior, which can have many different roles according to species, sex, age, relationship quality between playmates, group membership, context, and habitat. Play joins and cuts across a variety of disciplines leading directly to inquiries relating to individual developmental changes and species adaptation, thus the importance of comparative studies appears evident. Here, we aim at proposing a possible ontogenetic pathway of chimpanzee play (Pan troglodytes) and contrast our data with those of human play. Chimpanzee play shows a number of changes from infancy to juvenility. Particularly, solitary and social play follows different developmental trajectories. While solitary play peaks in infancy, social play does not show any quantitative variation between infancy and juvenility but shows a strong qualitative variation in complexity, asymmetry, and playmate choice. Like laughter in humans, the playful expressions in chimpanzees (at the different age phases) seem to have a role in advertising cooperative dispositions and intentions thus increasing the likelihood of engaging in solid social relationships. In conclusion, in chimpanzees, as in humans, both play behavior and the signals that accompany play serve multiple functions according to the different age phases. PMID:22110630

Ontogenetic trajectories of chimpanzee social play: similarities with humans.

PubMed

Cordoni, Giada; Palagi, Elisabetta

2011-01-01

Social play, a widespread phenomenon in mammals, is a multifunctional behavior, which can have many different roles according to species, sex, age, relationship quality between playmates, group membership, context, and habitat. Play joins and cuts across a variety of disciplines leading directly to inquiries relating to individual developmental changes and species adaptation, thus the importance of comparative studies appears evident. Here, we aim at proposing a possible ontogenetic pathway of chimpanzee play (Pan troglodytes) and contrast our data with those of human play. Chimpanzee play shows a number of changes from infancy to juvenility. Particularly, solitary and social play follows different developmental trajectories. While solitary play peaks in infancy, social play does not show any quantitative variation between infancy and juvenility but shows a strong qualitative variation in complexity, asymmetry, and playmate choice. Like laughter in humans, the playful expressions in chimpanzees (at the different age phases) seem to have a role in advertising cooperative dispositions and intentions thus increasing the likelihood of engaging in solid social relationships. In conclusion, in chimpanzees, as in humans, both play behavior and the signals that accompany play serve multiple functions according to the different age phases.

Use of “Entertainment” Chimpanzees in Commercials Distorts Public Perception Regarding Their Conservation Status

PubMed Central

Schroepfer, Kara K.; Rosati, Alexandra G.; Chartrand, Tanya; Hare, Brian

2011-01-01

Chimpanzees (Pan troglodytes) are often used in movies, commercials and print advertisements with the intention of eliciting a humorous response from audiences. The portrayal of chimpanzees in unnatural, human-like situations may have a negative effect on the public's understanding of their endangered status in the wild while making them appear as suitable pets. Alternatively, media content that elicits a positive emotional response toward chimpanzees may increase the public's commitment to chimpanzee conservation. To test these competing hypotheses, participants (n = 165) watched a series of commercials in an experiment framed as a marketing study. Imbedded within the same series of commercials was one of three chimpanzee videos. Participants either watched 1) a chimpanzee conservation commercial, 2) commercials containing “entertainment” chimpanzees or 3) control footage of the natural behavior of wild chimpanzees. Results from a post-viewing questionnaire reveal that participants who watched the conservation message understood that chimpanzees were endangered and unsuitable as pets at higher levels than those viewing the control footage. Meanwhile participants watching commercials with entertainment chimpanzees showed a decrease in understanding relative to those watching the control footage. In addition, when participants were given the opportunity to donate part of their earnings from the experiment to a conservation charity, donations were least frequent in the group watching commercials with entertainment chimpanzees. Control questions show that participants did not detect the purpose of the study. These results firmly support the hypothesis that use of entertainment chimpanzees in the popular media negatively distorts the public's perception and hinders chimpanzee conservation efforts. PMID:22022503

Rationale and design of the Pan-African Sudden Cardiac Death survey: the Pan-African SCD study.

PubMed

Bonny, Aimé; Ngantcha, Marcus; Amougou, Sylvie Ndongo; Kane, Adama; Marrakchi, Sonia; Okello, Emmy; Taty, Georges; Gehani, Abdulrrazzak; Diakite, Mamadou; Talle, Mohammed A; Lambiase, Pier D; Houenassi, Martin; Chin, Ashley; Otieno, Harun; Temu, Gloria; Owusu, Isaac Koffi; Karaye, Kamilu M; Awad, Abdalla A M; Winkel, Bo Gregers; Priori, Silvia G

2014-01-01

The estimated rate of sudden cardiac death (SCD) in Western countries ranges from 300,000 to 400,000 annually, which represents 0.36 to 1.28 per 1 000 inhabitants in Europe and the United States. The burden of SCD in Africa is unknown. Our aim is to assess the epidemiology of SCD in Africa. The Pan-Africa SCD study is a prospective, multicentre, community-based registry monitoring all cases of cardiac arrest occurring in victims over 15 years old. We will use the definition of SCD as 'witnessed natural death occurring within one hour of the onset of symptoms' or 'unwitnessed natural death within 24 hours of the onset of symptoms'. After approval from institutional boards, we will record demographic, clinical, electrocardiographic and biological variables of SCD victims (including survivors of cardiac arrest) in several African cities. All deaths occurring in residents of districts of interest will be checked for past medical history, circumstances of death, and autopsy report (if possible). We will also analyse the employment of resuscitation attempts during the time frame of sudden cardiac arrest (SCA) in various patient populations throughout African countries. This study will provide comprehensive, contemporary data on the epidemiology of SCD in Africa and will help in the development of strategies to prevent and manage cardiac arrest in this region of the world.

Focusing and shifting attention in human children (Homo sapiens) and chimpanzees (Pan troglodytes).

PubMed

Herrmann, Esther; Tomasello, Michael

2015-08-01

Humans often must coordinate co-occurring activities, and their flexible skills for doing so would seem to be uniquely powerful. In 2 studies, we compared 4- and 5-year-old children and one of humans' nearest relatives, chimpanzees, in their ability to focus and shift their attention when necessary. The results of Study 1 showed that 4-year-old children and chimpanzees were very similar in their ability to monitor two identical devices and to sequentially switch between the two to collect a reward, and that they were less successful at doing so than 5-year-old children. In Study 2, which required subjects to alternate between two different tasks, one of which had rewards continuously available whereas the other one only occasionally released rewards, no species differences were found. These results suggest that chimpanzees and human children share some fundamental attentional control skills, but that such abilities continue to develop during human ontogeny, resulting in the uniquely human capacity to succeed at complex multitasking. (c) 2015 APA, all rights reserved).

Reflections of the social environment in chimpanzee memory: applying rational analysis beyond humans.

PubMed

Stevens, Jeffrey R; Marewski, Julian N; Schooler, Lael J; Gilby, Ian C

2016-08-01

In cognitive science, the rational analysis framework allows modelling of how physical and social environments impose information-processing demands onto cognitive systems. In humans, for example, past social contact among individuals predicts their future contact with linear and power functions. These features of the human environment constrain the optimal way to remember information and probably shape how memory records are retained and retrieved. We offer a primer on how biologists can apply rational analysis to study animal behaviour. Using chimpanzees ( Pan troglodytes ) as a case study, we modelled 19 years of observational data on their social contact patterns. Much like humans, the frequency of past encounters in chimpanzees linearly predicted future encounters, and the recency of past encounters predicted future encounters with a power function. Consistent with the rational analyses carried out for human memory, these findings suggest that chimpanzee memory performance should reflect those environmental regularities. In re-analysing existing chimpanzee memory data, we found that chimpanzee memory patterns mirrored their social contact patterns. Our findings hint that human and chimpanzee memory systems may have evolved to solve similar information-processing problems. Overall, rational analysis offers novel theoretical and methodological avenues for the comparative study of cognition.

Cognitive and physiological markers of emotional awareness in chimpanzees (Pan troglodytes).

PubMed

Parr, L A

2001-11-01

The ability to understand emotion in others is one of the most important factors involved in regulating social interactions in primates. Such emotional awareness functions to coordinate activity among group members, enable the formation of long-lasting individual relationships, and facilitate the pursuit of shared interests. Despite these important evolutionary implications, comparative studies of emotional processing in humans and great apes are practically nonexistent, constituting a major gap in our understanding of the extent to which emotional awareness has played an important role in shaping human behavior and societies. This paper presents the results of two experiments that examine chimpanzees' responses to emotional stimuli. First, changes in peripheral skin temperature were measured while subjects viewed three categories of emotionally negative video scenes; conspecifics being injected with needles (INJ), darts and needles alone (DART), and conspecific directing agonism towards the veterinarians (CHASE). Second, chimpanzees were required to use facial expressions to categorize emotional video scenes, i.e., favorite food and objects and veterinarian procedures, according to their positive and negative valence. With no prior training, subjects spontaneously matched the emotional videos to conspecific facial expressions according to their shared emotional meaning, indicating that chimpanzee facial expressions are processed emotionally, as are human expressions. Decreases in peripheral skin temperature, indicative of negative sympathetic arousal, were significantly lower when subjects viewed the INJ and DART videos, compared to the CHASE videos, indicating greater negative arousal when viewing conspecifics being injected with needles, and needles themselves, than when viewing conspecifics engaged in general agonism.

Male dominance rank and reproductive success in chimpanzees, Pan troglodytes schweinfurthii.

PubMed

Wroblewski, Emily E; Murray, Carson M; Keele, Brandon F; Schumacher-Stankey, Joann C; Hahn, Beatrice H; Pusey, Anne E

2009-01-01

Competition for fertile females determines male reproductive success in many species. The priority of access model predicts that male dominance rank determines access to females, but this model has been difficult to test in wild populations, particularly in promiscuous mating systems. Tests of the model have produced variable results, probably because of the differing socioecological circumstances of individual species and populations. We tested the predictions of the priority of access model in the chimpanzees of Gombe National Park, Tanzania. Chimpanzees are an interesting species in which to test the model because of their fission-fusion grouping patterns, promiscuous mating system and alternative male mating strategies. We determined paternity for 34 offspring over a 22-year period and found that the priority of access model was generally predictive of male reproductive success. However, we found that younger males had higher success per male than older males, and low-ranking males sired more offspring than predicted. Low-ranking males sired offspring with younger, less desirable females and by engaging in consortships more often than high-ranking fathers. Although alpha males never sired offspring with related females, inbreeding avoidance of high-ranking male relatives did not completely explain the success of low-ranking males. While our work confirms that male rank typically predicts male chimpanzee reproductive success, other factors are also important; mate choice and alternative male strategies can give low-ranking males access to females more often than would be predicted by the model. Furthermore, the success of younger males suggests that they are more successful in sperm competition.

A survey of entodiniomorphid ciliates in chimpanzees and bonobos.

PubMed

Pomajbíková, Katerina; Petrzelková, Klára J; Profousová, Ilona; Petrásová, Jana; Kisidayová, Svetlana; Varádyová, Zora; Modrý, David

2010-05-01

Intestinal entodiniomorphid ciliates are commonly diagnosed in the feces of wild apes of the genera Pan and Gorilla. Although some authors previously considered entodiniomorphid ciliates as possible pathogens, a symbiotic function within the intestinal ecosystem and their participation in fiber fermentation has been proposed. Previous studies have suggested that these ciliates gradually disappear under captive conditions. We studied entodiniomorphid ciliates in 23 captive groups of chimpanzees, three groups of captive bonobos and six populations of wild chimpanzees. Fecal samples were examined using Sheather's flotation and Merthiolate-Iodine-Formaldehyde Concentration (MIFC) methods. We quantified the number of ciliates per gram of feces. The MIFC method was more sensitive for ciliate detection than the flotation method. Ciliates of genus Troglodytella were detected in 13 groups of captive chimpanzees, two groups of bonobos and in all wild chimpanzee populations studied. The absence of entodiniomorphids in some captive groups might be because of the extensive administration of chemotherapeutics in the past or a side-effect of the causative or prophylactic administration of antiparasitic or antibiotic drugs. The infection intensities of ciliates in captive chimpanzees were higher than in wild ones. We suppose that the over-supply of starch, typical in captive primate diets, might induce an increase in the number of ciliates. In vitro studies on metabolism and biochemical activities of entodiniomorphids are needed to clarify their role in ape digestion.

Do juveniles help or hinder? Influence of juvenile offspring on maternal behavior and reproductive outcomes in wild chimpanzees (Pan troglodytes).

PubMed

Stanton, Margaret A; Lonsdorf, Elizabeth V; Pusey, Anne E; Murray, Carson M

2017-10-01

Compared to great apes, humans maintain a relatively rapid reproductive pace despite long periods of dependency. This seemingly contradictory set of traits is made possible by weaning offspring before nutritional independence and alloparents who help provide care. In traditional societies, this help may be provided to mothers in part by their juvenile offspring who carry, supervise, or provision younger siblings. In contrast to humans, chimpanzees (Pan troglodytes) are nutritionally independent after weaning, yet juveniles continue to travel with their mother and younger sibling for an additional 4-5 years. This continued association could be costly to the mother if she continues to invest in weaned offspring. Alternately, while juvenile chimpanzees do not typically provision younger siblings, their presence and social interaction with infants may allow mothers to focus on other tasks. In this study, we investigate the costs and benefits to mothers of continued association with juveniles in wild chimpanzees. Using 26 years of long-term behavioral data we examined how maternal activity budgets varied based on the presence of a dependent juvenile offspring. We found that continued social interaction between mothers and juveniles does not influence the mother's time allocated to interacting with the younger infant, her feeding, resting, or travel time, or time socializing with other community members. Instead, mothers may benefit from the additional social interaction and/or relationship with their older offspring. Using 45 years of demographic data we found that those offspring who had an older sibling tended to be more likely to survive each year from birth to 8 years than those without an older sibling. Additionally, interbirth intervals were more likely to end when the female had an older offspring present. A mutually beneficial mother-juvenile dynamic in great apes provides insight into continued association between mothers and offspring after nutritional

How did bonobos come to range south of the congo river? Reconsideration of the divergence of Pan paniscus from other Pan populations.

PubMed

Takemoto, Hiroyuki; Kawamoto, Yoshi; Furuichi, Takeshi

2015-01-01

While investigating the genetic structure in wild bonobos,(1) we realized that the widely accepted scenario positing that the Pleistocene appearance of the Congo River separated the common ancestor of chimpanzees (Pan troglodytes) and bonobos (P. paniscus) into two species is not supported by recent geographical knowledge about the formation of the Congo River. We explored the origin of bonobos using a broader biogeographical perspective by examining local faunas in the central African region. The submarine Congo River sediments and paleotopography of central Africa show that the Congo River has functioned as a geographical barrier for the last 34 million years. This evidence allows us to hypothesize that when the river was first formed, the ancestor of bonobos did not inhabit the current range of the species on the left bank of the Congo River but that, during rare times when the Congo River discharge decreased during the Pleistocene, one or more founder populations of ancestral Pan paniscus crossed the river to its left bank. The proposed scenario for formation of the Congo River and the corridor hypothesis for an ancestral bonobo population is key to understanding the distribution of great apes and their evolution. © 2015 Wiley Periodicals, Inc.

4,300-Year-old chimpanzee sites and the origins of percussive stone technology

PubMed Central

Mercader, Julio; Barton, Huw; Gillespie, Jason; Harris, Jack; Kuhn, Steven; Tyler, Robert; Boesch, Christophe

2007-01-01

Archaeological research in the African rainforest reveals unexpected results in the search for the origins of hominoid technology. The ancient Panin sites from Côte d'Ivoire constitute the only evidence of prehistoric ape behavior known to date anywhere in the world. Recent archaeological work has yielded behaviorally modified stones, dated by chronometric means to 4,300 years of age, lodging starch residue suggestive of prehistoric dietary practices by ancient chimpanzees. The “Chimpanzee Stone Age” pre-dates the advent of settled farming villages in this part of the African rainforest and suggests that percussive material culture could have been inherited from an common human–chimpanzee clade, rather than invented by hominins, or have arisen by imitation, or resulted from independent technological convergence. PMID:17360606

Spontaneous innovation for future deception in a male chimpanzee.

PubMed

Osvath, Mathias; Karvonen, Elin

2012-01-01

The ability to invent means to deceive others, where the deception lies in the perceptually or contextually detached future, appears to require the coordination of sophisticated cognitive skills toward a single goal. Meanwhile innovation for a current situation has been observed in a wide range of species. Planning, on the one hand, and the social cognition required for deception on the other, have been linked to one another, both from a co-evolutionary and a neuroanatomical perspective. Innovation and deception have also been suggested to be connected in their nature of relying on novelty. We report on systematic observations suggesting innovation for future deception by a captive male chimpanzee (Pan troglodytes). As an extension of previously described behaviour--caching projectiles for later throwing at zoo visitors--the chimpanzee, again in advance, manufactured concealments from hay, as well as used naturally occurring concealments. All were placed near the visitors' observation area, allowing the chimpanzee to make throws before the crowd could back off. We observed what was likely the first instance of this innovation. Further observations showed that the creation of future-oriented concealments became the significantly preferred strategy. What is more, the chimpanzee appeared consistently to combine two deceptive strategies: hiding projectiles and inhibiting dominance display behaviour. The findings suggest that chimpanzees can represent the future behaviours of others while those others are not present, as well as take actions in the current situation towards such potential future behaviours. Importantly, the behaviour of the chimpanzee produced a future event, rather than merely prepared for an event that had been reliably re-occurring in the past. These findings might indicate that the chimpanzee recombined episodic memories in perceptual simulations.

Seasonal Effects on Great Ape Health: A Case Study of Wild Chimpanzees and Western Gorillas

PubMed Central

Masi, Shelly; Chauffour, Sophie; Bain, Odile; Todd, Angelique; Guillot, Jacques; Krief, Sabrina

2012-01-01

Among factors affecting animal health, environmental influences may directly or indirectly impact host nutritional condition, fecundity, and their degree of parasitism. Our closest relatives, the great apes, are all endangered and particularly sensitive to infectious diseases. Both chimpanzees and western gorillas experience large seasonal variations in fruit availability but only western gorillas accordingly show large changes in their degree of frugivory. The aim of this study is to investigate and compare factors affecting health (through records of clinical signs, urine, and faecal samples) of habituated wild ape populations: a community (N = 46 individuals) of chimpanzees (Pan troglodytes) in Kanyawara, Kibale National Park (Uganda), and a western gorilla (G. gorilla) group (N = 13) in Bai Hokou in the Dzanga-Ndoki National Park (Central African Republic). Ape health monitoring was carried out in the wet and dry seasons (chimpanzees: July–December 2006; gorillas: April–July 2008 and December 2008–February 2009). Compared to chimpanzees, western gorillas were shown to have marginally greater parasite diversity, higher prevalence and intensity of both parasite and urine infections, and lower occurrence of diarrhea and wounds. Parasite infections (prevalence and load), but not abnormal urine parameters, were significantly higher during the dry season of the study period for western gorillas, who thus appeared more affected by the large temporal changes in the environment in comparison to chimpanzees. Infant gorillas were the most susceptible among all the age/sex classes (of both apes) having much more intense infections and urine blood concentrations, again during the dry season. Long term studies are needed to confirm the influence of seasonal factors on health and parasitism of these great apes. However, this study suggest climate change and forest fragmentation leading to potentially larger seasonal fluctuations of the environment may affect

Brief communication: dental development timing in captive Pan paniscus with comparisons to Pan troglodytes.

PubMed

Bolter, Debra R; Zihlman, Adrienne L

2011-08-01

Dental eruption provides markers of growth and is one component of a chimpanzee's physical development. Dental markers help characterize transitions between life stages, e.g., infant to juvenile. Most of what we know about the timing of development in chimpanzees derives from Pan troglodytes. Much less is known about the sister species, Pan paniscus, with few in captivity and a restricted wild range in central Africa. Here we report on the dental eruption timing for female captive P. paniscus (n = 5) from the Milwaukee and San Diego Zoos whose ages are known and range from birth to age 8.54 years. Some observations were recorded in zoo records on the gingiva during life; others were made at death on the gingiva and on the skeleton. At birth, P. paniscus infants have no teeth emerged. By 0.83 years, all but the deciduous second molars (dm(2) ) (when both upper and lower dentitions are referenced collectively, no super or subscript notation is used) and canines (dc) are emerged. For permanent teeth, results show a sequence polymorphism for an early P4 eruption, not previously described for P. paniscus. Comparisons between P. paniscus and P. troglodytes document absolute timing differences of emergence in upper second incisors (I(2) ), and upper and lower canines (C) and third molars (M3). The genus Pan encompasses variability in growth not previously recognized. These preliminary data suggest that physical growth in captive P. paniscus may be accelerated, a general pattern found in captive P. troglodytes. Copyright © 2011 Wiley-Liss, Inc.

Lack of conformity to new local dietary preferences in migrating captive chimpanzees

PubMed Central

Vale, Gillian L.; Davis, Sarah J.; van de Waal, Erica; Schapiro, Steven J.; Lambeth, Susan P.; Whiten, Andrew

2017-01-01

Conformity to the behavioural preferences of others can have powerful effects on intragroup behavioural homogeneity in humans, but evidence in animals remains minimal. In this study, we took advantage of circumstances in which individuals or pairs of captive chimpanzees, Pan troglodytes, were ‘migrated’ between groups, to investigate whether immigrants would conform to a new dietary population preference experienced in the group they entered, an effect suggested by recent fieldwork. Such ‘migratory-minority’ chimpanzees were trained to avoid one of two differently coloured foods made unpalatable, before ‘migrating’ to, and then observing, a ‘local-majority’ group consume a different food colour. Both migratory-minority and local-majority chimpanzees displayed social learning, spending significantly more time consuming the previously unpalatable, but instead now edible, food, than did control chimpanzees who did not see immigrants eat this food, nor emigrate themselves. However, following the migration of migratory-minority chimpanzees, these control individuals and the local-majority chimpanzees tended to rely primarily upon personal information, consuming first the food they had earlier learned was palatable before sampling the alternative. Thus, chimpanzees did not engage in conformity in the context we tested; instead seeing others eat a previously unpalatable food led to socially learned and adaptive re-exploration of this now-safe option in both minority and majority participants. PMID:29200465

Chimpanzees and Bonobos Exhibit Emotional Responses to Decision Outcomes

PubMed Central

Rosati, Alexandra G.; Hare, Brian

2013-01-01

The interface between cognition, emotion, and motivation is thought to be of central importance in understanding complex cognitive functions such as decision-making and executive control in humans. Although nonhuman apes have complex repertoires of emotional expression, little is known about the role of affective processes in ape decision-making. To illuminate the evolutionary origins of human-like patterns of choice, we investigated decision-making in humans' closest phylogenetic relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus). In two studies, we examined these species' temporal and risk preferences, and assessed whether apes show emotional and motivational responses in decision-making contexts. We find that (1) chimpanzees are more patient and more risk-prone than are bonobos, (2) both species exhibit affective and motivational responses following the outcomes of their decisions, and (3) some emotional and motivational responses map onto species-level and individual-differences in decision-making. These results indicate that apes do exhibit emotional responses to decision-making, like humans. We explore the hypothesis that affective and motivational biases may underlie the psychological mechanisms supporting value-based preferences in these species. PMID:23734175

Effects of body region and time on hair cortisol concentrations in chimpanzees (Pan troglodytes).

PubMed

Carlitz, Esther H D; Kirschbaum, Clemens; Miller, Robert; Rukundo, Joshua; van Schaik, Carel P

2015-11-01

Hair cortisol concentrations (HCC) are increasingly recognized as an integrated measure of the systemic cortisol secretion. Yet, we still know very little about confounding effects on HCC in animals. The present study therefore used hair from semi-wild and zoo living chimpanzees to investigate (1) intra-individual variability of HCC (body-region effect), and (2) the stability of HCC along the hair shaft (traditionally called the washout effect). Our results indicate that absolute HCC varied substantially between certain body regions, but a factor analysis revealed that these HCC differences were mainly attributable to one common source of variance. Thus, hair from all body regions provides similar biological signals and can be mixed, albeit at the cost of a lower signal-to-noise ratio. With regard to potential underlying mechanisms, we studied skin blood flow, as observed through thermal images from one chimpanzee. We found the general HCC pattern was reflected in differences in surface body temperature observed in this individual in three out of four body regions. In a separate set of samples, we found first evidence to suggest that the systematic cortisol decrease along the hair shaft, as observed in humans, is also present in chimpanzee hair. The effect was more pronounced in semi-wild than in zoo chimpanzees presumably due to more exposure to ambient weather conditions. Copyright © 2015 Elsevier Inc. All rights reserved.

Socially transmitted diffusion of a novel behaviour from subordinate chimpanzees

PubMed Central

Watson, Stuart K; Reamer, Lisa A; Mareno, Mary Catherine; Vale, Gillian; Harrison, Rachel A; Lambeth, Susan P; Schapiro, Steven J; Whiten, Andrew

2017-01-01

Chimpanzees (Pan troglodytes) demonstrate much cultural diversity in the wild, yet a majority of novel behaviours do not become group-wide traditions. Since many such novel behaviours are introduced by low-ranking individuals, a bias toward copying dominant individuals (‘rank-bias’) has been proposed as an explanation for their limited diffusion. Previous experimental work showed that chimpanzees (Pan troglodytes) preferentially copy dominant over low-rank models. We investigated whether low ranking individuals may nevertheless successfully seed a beneficial behaviour as a tradition if there are no ‘competing’ models. In each of four captive groups, either a single high-rank (HR, n=2) or a low-rank (LR, n=2) chimpanzee model was trained on one method of opening a two-action puzzle-box, before demonstrating the trained method in a group context. This was followed by eight hours of group-wide, open-access to the puzzle-box. Successful manipulations and observers of each manipulation were recorded. Barnard’s exact tests showed that individuals in the LR groups used the seeded method as their first-choice option at significantly above chance levels, whereas those in the HR groups did not. Furthermore, individuals in the LR condition used the seeded method on their first attempt significantly more often than those in the HR condition. A network-based diffusion analysis revealed that the best supported statistical models were those in which social transmission occurred only in groups with subordinate models. Finally, we report an innovation by a subordinate individual that built cumulatively on existing methods of opening the puzzle-box and was subsequently copied by a dominant observer. These findings illustrate that chimpanzees are motivated to copy rewarding novel behaviours that are demonstrated by subordinate individuals and that, in some cases, social transmission may be constrained by high-rank demonstrators. PMID:28171684

"Missing perikymata"--fact or fiction? A study on chimpanzee (Pan troglodytes verus) canines.

PubMed

Kierdorf, Horst; Witzel, Carsten; Kierdorf, Uwe; Skinner, Matthew M; Skinner, Mark F

2015-06-01

Recently, a lower than expected number of perikymata between repetitive furrow-type hypoplastic defects has been reported in chimpanzee canines from the Fongoli site, Senegal (Skinner and Pruetz: Am J Phys Anthropol 149 (2012) 468-482). Based on an observation in a localized enamel fracture surface of a canine of a chimpanzee from the Taï Forest (Ivory Coast), these authors inferred that a nonemergence of striae of Retzius could be the cause for the "missing perikymata" phenomenon in the Fongoli chimpanzees. To check this inference, we analyzed the structure of outer enamel in three chimpanzee canines. The teeth were studied using light-microscopic and scanning-electron microscopic techniques. Our analysis of the specimen upon which Skinner and Pruetz (Am J Phys Anthropol 149 (2012) 468-482) had made their original observation does not support their hypothesis. We demonstrate that the enamel morphology described by them is not caused by a nonemergence of striae of Retzius but can be attributed to structural variations in outer enamel that result in a differential fracture behavior. Although rejecting the presumed existence of nonemergent striae of Retzius, our study provided evidence that, in furrow-type hypoplastic defects, a pronounced tapering of Retzius increments can occur, with the striae of Retzius forming acute angles with the outer enamel surface. We suggest that in such cases the outcrop of some striae of Retzius is essentially unobservable at the enamel surface, causing too low perikymata counts. The pronounced tapering of Retzius increments in outer enamel presumably reflects a mild to moderate disturbance of the function of late secretory ameloblasts. © 2015 Wiley Periodicals, Inc.

Antimicrobial potential of 27 plants consumed by chimpanzees (Pan troglodytes verus Blumenbach) in Ivory Coast.

PubMed

Ahoua, Angora Rémi Constant; Konan, Amoin Georgette; Bonfoh, Bassirou; Koné, Mamidou Witabouna

2015-10-23

Due to their genetic proximity, chimpanzees share with human several diseases including bacterial, fungal and viral infections, such as candidiasis, acquired immune deficiency syndrome (AIDS), Ebola virus disease. However, in its natural environment, chimpanzees are tolerant to several pathogens including simian immunodeficiency virus (SIV), virus related to human immunodeficiency virus (HIV) that contribute to the emergence of opportunistic diseases such as microbial infections. Twenty seven species of plants consumed by chimpanzees were evaluated for their antimicrobial potential against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Candida albicans, Candida tropicalis and Candida glabrata using the agar diffusion technique and micro-dilution in 96-well plates. In total 132 extracts (33 dichloromethane, 33 methanol, 33 ethyl acetate and 33 aqueous) were tested. The results showed that 24 extracts (18 %) showed activity against bacteria and 6 extracts (5 %) were active against yeasts. The minimal inhibitory concentrations (MICs) values of active extracts ranged between 23 and 750 μg/ml for bacteria and between 188 and 1500 μg/ml for yeasts. Tristemma coronatum was the most promising on the studied microorganisms followed by Beilschmiedia mannii. The extracts of the two plants indicated by chimpanzees have potential for antimicrobial use in human.

An 8-year longitudinal study of mirror self-recognition in chimpanzees (Pan troglodytes).

PubMed

de Veer, Monique W; Gallup, Gordon G; Theall, Laura A; van den Bos, Ruud; Povinelli, Daniel J

2003-01-01

In a previous cross-sectional study of mirror self-recognition involving 92 chimpanzees, Povinelli et al. [Journal of Comparative Psychology 107 (1993) 347] reported a peak in the proportion of animals exhibiting self-recognition in the adolescent/young adult sample (8-15 years), with 75% being classified as positive. In contrast, only 26% of the older animals (16-39 years) were classified as positive, suggesting a marked decline in self-recognition in middle to late adulthood. In the present study, all of the chimpanzees from the 8-15-year-old group in the Povinelli et al. study (n=12) were again tested for self-recognition, 8 years later. Using the same criteria, 67% of the animals were classified the same. Although a higher proportion of the adult animals in this study (50%) exhibited self-recognition than would be inferred on the basis of the previous study (25%), all changes in self-recognition status were in the negative direction. These results show that mirror self-recognition is a highly stable trait in many chimpanzees, but may be subject to decline with age. Connections with human research are briefly discussed.

Pan-African Genetic Structure in the African Buffalo (Syncerus caffer): Investigating Intraspecific Divergence

PubMed Central

Smitz, Nathalie; Berthouly, Cécile; Cornélis, Daniel; Heller, Rasmus; Van Hooft, Pim; Chardonnet, Philippe; Caron, Alexandre; Prins, Herbert; van Vuuren, Bettine Jansen; De Iongh, Hans; Michaux, Johan

2013-01-01

The African buffalo (Syncerus caffer) exhibits extreme morphological variability, which has led to controversies about the validity and taxonomic status of the various recognized subspecies. The present study aims to clarify these by inferring the pan-African spatial distribution of genetic diversity, using a comprehensive set of mitochondrial D-loop sequences from across the entire range of the species. All analyses converged on the existence of two distinct lineages, corresponding to a group encompassing West and Central African populations and a group encompassing East and Southern African populations. The former is currently assigned to two to three subspecies (S. c. nanus, S. c. brachyceros, S. c. aequinoctialis) and the latter to a separate subspecies (S. c. caffer). Forty-two per cent of the total amount of genetic diversity is explained by the between-lineage component, with one to seventeen female migrants per generation inferred as consistent with the isolation-with-migration model. The two lineages diverged between 145 000 to 449 000 years ago, with strong indications for a population expansion in both lineages, as revealed by coalescent-based analyses, summary statistics and a star-like topology of the haplotype network for the S. c. caffer lineage. A Bayesian analysis identified the most probable historical migration routes, with the Cape buffalo undertaking successive colonization events from Eastern toward Southern Africa. Furthermore, our analyses indicate that, in the West-Central African lineage, the forest ecophenotype may be a derived form of the savanna ecophenotype and not vice versa, as has previously been proposed. The African buffalo most likely expanded and diverged in the late to middle Pleistocene from an ancestral population located around the current-day Central African Republic, adapting morphologically to colonize new habitats, hence developing the variety of ecophenotypes observed today. PMID:23437100

Chimpanzees copy dominant and knowledgeable individuals: implications for cultural diversity.

PubMed

Kendal, Rachel; Hopper, Lydia M; Whiten, Andrew; Brosnan, Sarah F; Lambeth, Susan P; Schapiro, Steven J; Hoppitt, Will

2015-01-01

Evolutionary theory predicts that natural selection will fashion cognitive biases to guide when, and from whom, individuals acquire social information, but the precise nature of these biases, especially in ecologically valid group contexts, remains unknown. We exposed four captive groups of chimpanzees ( Pan troglodytes ) to a novel extractive foraging device and, by fitting statistical models, isolated four simultaneously operating transmission biases. These include biases to copy (i) higher-ranking and (ii) expert individuals, and to copy others when (iii) uncertain or (iv) of low rank. High-ranking individuals were relatively un-strategic in their use of acquired knowledge, which, combined with the bias for others to observe them, may explain reports that high innovation rates (in juveniles and subordinates) do not generate a correspondingly high frequency of traditions in chimpanzees. Given the typically low rank of immigrants in chimpanzees, a 'copying dominants' bias may contribute to the observed maintenance of distinct cultural repertoires in neighboring communities despite sharing similar ecology and knowledgeable migrants. Thus, a copying dominants strategy may, as often proposed for conformist transmission, and perhaps in concert with it, restrict the accumulation of traditions within chimpanzee communities whilst maintaining cultural diversity.

Chimpanzees copy dominant and knowledgeable individuals: implications for cultural diversity

PubMed Central

Kendal, Rachel; Hopper, Lydia M.; Whiten, Andrew; Brosnan, Sarah F.; Lambeth, Susan P.; Schapiro, Steven J.; Hoppitt, Will

2015-01-01

Evolutionary theory predicts that natural selection will fashion cognitive biases to guide when, and from whom, individuals acquire social information, but the precise nature of these biases, especially in ecologically valid group contexts, remains unknown. We exposed four captive groups of chimpanzees (Pan troglodytes) to a novel extractive foraging device and, by fitting statistical models, isolated four simultaneously operating transmission biases. These include biases to copy (i) higher-ranking and (ii) expert individuals, and to copy others when (iii) uncertain or (iv) of low rank. High-ranking individuals were relatively un-strategic in their use of acquired knowledge, which, combined with the bias for others to observe them, may explain reports that high innovation rates (in juveniles and subordinates) do not generate a correspondingly high frequency of traditions in chimpanzees. Given the typically low rank of immigrants in chimpanzees, a ‘copying dominants’ bias may contribute to the observed maintenance of distinct cultural repertoires in neighboring communities despite sharing similar ecology and knowledgeable migrants. Thus, a copying dominants strategy may, as often proposed for conformist transmission, and perhaps in concert with it, restrict the accumulation of traditions within chimpanzee communities whilst maintaining cultural diversity. PMID:27053916

Functional Analysis and Treatment of Human-Directed Undesirable Behavior Exhibited by a Captive Chimpanzee

ERIC Educational Resources Information Center

Martin, Allison L.; Bloomsmith, Mollie A.; Kelley, Michael E.; Marr, M. Jackson; Maple, Terry L.

2011-01-01

A functional analysis identified the reinforcer maintaining feces throwing and spitting exhibited by a captive adult chimpanzee ("Pan troglodytes"). The implementation of a function-based treatment combining extinction with differential reinforcement of an alternate behavior decreased levels of inappropriate behavior. These findings further…

Social bonds in the dispersing sex: partner preferences among adult female chimpanzees.

PubMed

Foerster, Steffen; McLellan, Karen; Schroepfer-Walker, Kara; Murray, Carson M; Krupenye, Christopher; Gilby, Ian C; Pusey, Anne E

2015-07-01

In most primate societies, strong and enduring social bonds form preferentially among kin, who benefit from cooperation through direct and indirect fitness gains. Chimpanzees, Pan troglodytes , differ from most species by showing consistent female-biased dispersal and strict male philopatry. In most East African populations, females tend to forage alone in small core areas and were long thought to have weak social bonds of little biological significance. Recent work in some populations is challenging this view. However, challenges remain in quantifying the influence of shared space use on association patterns, and in identifying the drivers of partner preferences and social bonds. Here, we use the largest data set on wild chimpanzee behaviour currently available to assess potential determinants of female association patterns. We quantify pairwise similarities in ranging, dyadic association and grooming for 624 unique dyads over 38 years, including 17 adult female kin dyads. To search for social preferences that could not be explained by spatial overlap alone, we controlled for expected association based on pairwise kernel volume intersections of core areas. We found that association frequencies among females with above-average overlap correlated positively with grooming rates, suggesting that associations reflected social preferences in these dyads. Furthermore, when available, females preferred kin over nonkin partners for association and grooming, and variability was high among nonkin dyads. While variability in association above and below expected values was high, on average, nonkin associated more frequently if they had immature male offspring, while having female offspring had the opposite effect. Dominance rank, an important determinant of reproductive success at Gombe, influenced associations primarily for low-ranking females, who associated preferentially with each other. Our findings support the hypothesis that female chimpanzees form well

Chimpanzees are indifferent to the welfare of unrelated group members.

PubMed

Silk, Joan B; Brosnan, Sarah F; Vonk, Jennifer; Henrich, Joseph; Povinelli, Daniel J; Richardson, Amanda S; Lambeth, Susan P; Mascaro, Jenny; Schapiro, Steven J

2005-10-27

Humans are an unusually prosocial species-we vote, give blood, recycle, give tithes and punish violators of social norms. Experimental evidence indicates that people willingly incur costs to help strangers in anonymous one-shot interactions, and that altruistic behaviour is motivated, at least in part, by empathy and concern for the welfare of others (hereafter referred to as other-regarding preferences). In contrast, cooperative behaviour in non-human primates is mainly limited to kin and reciprocating partners, and is virtually never extended to unfamiliar individuals. Here we present experimental tests of the existence of other-regarding preferences in non-human primates, and show that chimpanzees (Pan troglodytes) do not take advantage of opportunities to deliver benefits to familiar individuals at no material cost to themselves, suggesting that chimpanzee behaviour is not motivated by other-regarding preferences. Chimpanzees are among the primates most likely to demonstrate prosocial behaviours. They participate in a variety of collective activities, including territorial patrols, coalitionary aggression, cooperative hunting, food sharing and joint mate guarding. Consolation of victims of aggression and anecdotal accounts of solicitous treatment of injured individuals suggest that chimpanzees may feel empathy. Chimpanzees sometimes reject exchanges in which they receive less valuable rewards than others, which may be one element of a 'sense of fairness', but there is no evidence that they are averse to interactions in which they benefit more than others.

Reflections of the social environment in chimpanzee memory: applying rational analysis beyond humans

PubMed Central

Marewski, Julian N.; Schooler, Lael J.; Gilby, Ian C.

2016-01-01

In cognitive science, the rational analysis framework allows modelling of how physical and social environments impose information-processing demands onto cognitive systems. In humans, for example, past social contact among individuals predicts their future contact with linear and power functions. These features of the human environment constrain the optimal way to remember information and probably shape how memory records are retained and retrieved. We offer a primer on how biologists can apply rational analysis to study animal behaviour. Using chimpanzees (Pan troglodytes) as a case study, we modelled 19 years of observational data on their social contact patterns. Much like humans, the frequency of past encounters in chimpanzees linearly predicted future encounters, and the recency of past encounters predicted future encounters with a power function. Consistent with the rational analyses carried out for human memory, these findings suggest that chimpanzee memory performance should reflect those environmental regularities. In re-analysing existing chimpanzee memory data, we found that chimpanzee memory patterns mirrored their social contact patterns. Our findings hint that human and chimpanzee memory systems may have evolved to solve similar information-processing problems. Overall, rational analysis offers novel theoretical and methodological avenues for the comparative study of cognition. PMID:27853606

Characterization of a Cardiorenal-like Syndrome in Aged Chimpanzees (Pan troglodytes).

PubMed

Chilton, J; Wilcox, A; Lammey, M; Meyer, D

2016-03-01

Cardiorenal syndrome involves disease and dysfunction of the heart that leads to progressive renal dysfunction. This study investigated the relationship between cardiac and renal disease in 91 aged chimpanzees at the Alamogordo Primate Facility by evaluation of the medical histories, metabolic parameters, functional measurements of the cardiovascular system, clinical pathology, and histopathology focused on the heart and kidney. Cardiac fibrosis was the most frequent microscopic finding in 82 of 91 animals (90%), followed by glomerulosclerosis with tubulointerstitial fibrosis in 63 of 91 (69%). Cardiac fibrosis with attendant glomerulosclerosis and tubulointerstitial fibrosis was observed in 58 of 91 animals (63%); there was a statistically significant association between the 2 conditions. As the severity of cardiac fibrosis increased, there was corresponding increase in severity of glomerulosclerosis with tubulointerstitial fibrosis. Altered metabolic, cardiovascular, and clinical pathology parameters indicative of heart and kidney failure were commonly associated with the moderate to severe microscopic changes, and concurrent heart and kidney failure were considered the cause of death. The constellation of findings in the chimpanzees were similar to cardiorenal syndrome in humans. © The Author(s) 2016.

Discovering Africa through Internet-Based Geographic Information Systems: A Pan-African Summit Simulation

ERIC Educational Resources Information Center

Milson, Andrew J.; Gilbert, Kathleen M.; Earle, Brian D.

2007-01-01

In the United States, people get very little news about Africa, and what news they do get is about war or famine, with little historical information or context. In this article, the authors describe how they developed and implemented a Pan-African Summit simulation project in order to give their approximately 100, 9th-grade students (in five World…

Chimpanzee Personality and the Arginine Vasopressin Receptor 1A Genotype.

PubMed

Wilson, V A D; Weiss, A; Humle, T; Morimura, N; Udono, T; Idani, G; Matsuzawa, T; Hirata, S; Inoue-Murayama, M

2017-03-01

Polymorphisms of the arginine vasopressin receptor 1a (AVPR1a) gene have been linked to various measures related to human social behavior, including sibling conflict and agreeableness. In chimpanzees, AVPR1a polymorphisms have been associated with traits important for social interactions, including sociability, joint attention, dominance, conscientiousness, and hierarchical personality dimensions named low alpha/stability, disinhibition, and negative emotionality/low dominance. We examined associations between AVPR1a and six personality domains and hierarchical personality dimensions in 129 chimpanzees (Pan troglodytes) living in Japan or in a sanctuary in Guinea. We fit three linear and three animal models. The first model included genotype, the second included sex and genotype, and the third included genotype, sex, and sex × genotype. All personality phenotypes were heritable. Chimpanzees possessing the long form of the allele were higher in conscientiousness, but only in models that did not include the other predictors; however, additional analyses suggested that this may have been a consequence of study design. In animal models that included sex and sex × genotype, chimpanzees homozygous for the short form of the allele were higher in extraversion. Taken with the findings of previous studies of chimpanzees and humans, the findings related to conscientiousness suggest that AVPR1a may be related to lower levels of impulsive aggression. The direction of the association between AVPR1a genotype and extraversion ran counter to what one would expect if AVPR1a was related to social behaviors. These results help us further understand the genetic basis of personality in chimpanzees.

Unconstrained cranial evolution in Neandertals and modern humans compared to common chimpanzees

PubMed Central

Weaver, Timothy D.; Stringer, Chris B.

2015-01-01

A variety of lines of evidence support the idea that neutral evolutionary processes (genetic drift, mutation) have been important in generating cranial differences between Neandertals and modern humans. But how do Neandertals and modern humans compare with other species? And how do these comparisons illuminate the evolutionary processes underlying cranial diversification? To address these questions, we used 27 standard cranial measurements collected on 2524 recent modern humans, 20 Neandertals and 237 common chimpanzees to estimate split times between Neandertals and modern humans, and between Pan troglodytes verus and two other subspecies of common chimpanzee. Consistent with a neutral divergence, the Neandertal versus modern human split-time estimates based on cranial measurements are similar to those based on DNA sequences. By contrast, the common chimpanzee cranial estimates are much lower than DNA-sequence estimates. Apparently, cranial evolution has been unconstrained in Neandertals and modern humans compared with common chimpanzees. Based on these and additional analyses, it appears that cranial differentiation in common chimpanzees has been restricted by stabilizing natural selection. Alternatively, this restriction could be due to genetic and/or developmental constraints on the amount of within-group variance (relative to effective population size) available for genetic drift to act on. PMID:26468243

Facial perception of conspecifics: chimpanzees (Pan troglodytes) preferentially attend to proper orientation and open eyes.

PubMed

Hirata, Satoshi; Fuwa, Koki; Sugama, Keiko; Kusunoki, Kiyo; Fujita, Shin

2010-09-01

This paper reports on the use of an eye-tracking technique to examine how chimpanzees look at facial photographs of conspecifics. Six chimpanzees viewed a sequence of pictures presented on a monitor while their eye movements were measured by an eye tracker. The pictures presented conspecific faces with open or closed eyes in an upright or inverted orientation in a frame. The results demonstrated that chimpanzees looked at the eyes, nose, and mouth more frequently than would be expected on the basis of random scanning of faces. More specifically, they looked at the eyes longer than they looked at the nose and mouth when photographs of upright faces with open eyes were presented, suggesting that particular attention to the eyes represents a spontaneous face-scanning strategy shared among monkeys, apes, and humans. In contrast to the results obtained for upright faces with open eyes, the viewing times for the eyes, nose, and mouth of inverted faces with open eyes did not differ from one another. The viewing times for the eyes, nose, and mouth of faces with closed eyes did not differ when faces with closed eyes were presented in either an upright or inverted orientation. These results suggest the possibility that open eyes play an important role in the configural processing of faces and that chimpanzees perceive and process open and closed eyes differently.

Chimpanzees do not take advantage of very low cost opportunities to deliver food to unrelated group members.

PubMed

Vonk, Jennifer; Brosnan, Sarah F; Silk, Joan B; Henrich, Joseph; Richardson, Amanda S; Lambeth, Susan P; Schapiro, Steven J; Povinelli, Daniel J

2008-05-01

We conducted experiments on two populations of chimpanzees, Pan troglodytes , to determine whether they would take advantage of opportunities to provide food rewards to familiar group members at little cost to themselves. In both of the experiments described here, chimpanzees were able to deliver identical rewards to themselves and to other members of their social groups. We compared the chimpanzees' behaviour when they were paired with another chimpanzee and when they were alone. If chimpanzees are motivated to provide benefits to others, they are expected to consistently deliver rewards to others and to distinguish between the partner-present and partner-absent conditions. Results from both experiments indicate that our subjects were largely indifferent to the benefits they could provide to others. They were less likely to provide rewards to potential recipients as the experiment progressed, and all but one of the 18 subjects were as likely to deliver rewards to an empty enclosure as to an enclosure housing another chimpanzee. These results, in conjunction with similar results obtained in previous experiments, suggest that chimpanzees are not motivated by prosocial sentiments to provide food rewards to other group members.

Processing of form stimuli presented unilaterally in humans, chimpanzees (Pan troglodytes), and monkeys (Macaca mulatta)

NASA Technical Reports Server (NTRS)

Hopkins, William D.; Washburn, David A.; Rumbaugh, Duane M.

1990-01-01

Visual forms were unilaterally presented using a video-task paradigm to ten humans, chimpanzees, and two rhesus monkeys to determine whether hemispheric advantages existed in the processing of these stimuli. Both accuracy and reaction time served as dependent measures. For the chimpanzees, a significant right hemisphere advantage was found within the first three test sessions. The humans and monkeys failed to show a hemispheric advantage as determined by accuracy scores. Analysis of reaction time data revealed a significant left hemisphere advantage for the monkeys. A visual half-field x block interaction was found for the chimpanzees, with a significant left visual field advantage in block two, whereas a right visual field advantage was found in block four. In the human subjects, a left visual field advantage was found in block three when they used their right hands to respond. The results are discussed in relation to recent reports of hemispheric advantages for nonhuman primates.

Long-term effects of infant attachment organization on adult behavior and health in nursery-reared, captive chimpanzees (Pan troglodytes).

PubMed

Clay, Andrea W; Bloomsmith, Mollie A; Bard, Kim A; Maple, Terry L; Marr, Marcus J

2015-05-01

This research traces the long-term effects on health, well-being, personality, and behavior of adult chimpanzees as a function of their attachment to a primary human caregiver assessed when they were 1 year of age. Of the 46 chimpanzees assessed at 1 year of age, we assessed health in 43 individuals, adult behavior in 20 individuals, and adult well-being and personality in 21 individuals. Attachment disorganization was found to be a significant predictor of stereotypic rocking in adult chimpanzees, F(1, 18) = 7.50, p = .013. For those subjects (N = 24) with a full 20 years (birth through age 20 years) of health data available, both rearing experience and disorganized attachment were significant predictors of upper respiratory infection frequency, F(2, 21) = 8.86, p = .002. Chimpanzees with disorganized attachment exhibited average subjective well-being as adults, whereas chimpanzees with organized strategies exhibited higher than average subjective well-being as adults. These results support the findings of human attachment research and are in line with attachment-based predictions for chimpanzees, such that the consequences of an early history of disorganized attachment may be adverse and long lasting. (c) 2015 APA, all rights reserved).

Primate archaeology reveals cultural transmission in wild chimpanzees (Pan troglodytes verus).

PubMed

Luncz, Lydia V; Wittig, Roman M; Boesch, Christophe

2015-11-19

Recovering evidence of past human activities enables us to recreate behaviour where direct observations are missing. Here, we apply archaeological methods to further investigate cultural transmission processes in percussive tool use among neighbouring chimpanzee communities in the Taï National Park, Côte d'Ivoire, West Africa. Differences in the selection of nut-cracking tools between neighbouring groups are maintained over time, despite frequent female transfer, which leads to persistent cultural diversity between chimpanzee groups. Through the recovery of used tools in the suggested natal territory of immigrants, we have been able to reconstruct the tool material selection of females prior to migration. In combination with direct observations of tool selection of local residents and immigrants after migration, we uncovered temporal changes in tool selection for immigrating females. After controlling for ecological differences between territories of immigrants and residents our data suggest that immigrants abandoned their previous tool preference and adopted the pattern of their new community, despite previous personal proficiency of the same foraging task. Our study adds to the growing body of knowledge on the importance of conformist tendencies in animals. © 2015 The Author(s).

Color preferences in gorillas (Gorilla gorilla gorilla) and chimpanzees (Pan troglodytes).

PubMed

Wells, Deborah L; McDonald, Claire L; Ringland, Janice E

2008-05-01

Color plays an important biological role in the lives of many animals, with some species exhibiting preferences for certain colors over others. This study explored the color preferences of two species of ape, which, like humans, possess trichromatic color vision. Six western lowland gorillas, and six chimpanzees, housed in Belfast Zoological Gardens, were exposed to three stimuli (cloths, boxes, sheets of acetate) in red, blue, and green. Six stimuli of the same nature, in each of the three colors, were provided to both species for 5 days per stimulus. The amount of interest that the animals showed toward each stimulus of each color was recorded for 1 hr. Results showed that the apes, both when analyzed as two separate groups, and when assessed collectively, showed significant color preferences, paying significantly less attention to the red-, than to the blue- or green-colored stimuli. The animals' interest in the blue- and green-colored stimuli did not differ significantly. Overall, the findings suggest that gorillas and chimpanzees, our closest living relatives, may harbor color preferences comparable to those of humans and other species. PsycINFO Database Record (c) 2008 APA, all rights reserved.

A model of the biogeographical journey from Proto-pan to Pan paniscus.

PubMed

Myers Thompson, Jo A

2003-04-01

Pan paniscus is unique in the group of African apes because of its range south of the Congo River. Examination of the bio-geographical journey of the genus Pan to the species P. paniscus is important when discussing the evolution of African apes. This paper is a review of the paleo-geographic events, the zoogeography, and faunal sorting which influenced P. paniscus divergence from the Proto-pan ancestor within the recent Miocene through Pliocene Epochs, approximately 10-2 MYA. Finally, by elucidating modern day evidence of food plant forms in the southern periphery exploited by P. paniscus in the forest/savanna mosaic habitat, we are able to conclude with those extrinsic events that most influenced the occurrence and distribution of P. paniscus.

Variation in hunting behaviour in neighbouring chimpanzee communities in the Budongo forest, Uganda

PubMed Central

Hobaiter, Catherine; Samuni, Liran; Mullins, Caroline; Akankwasa, Walter John; Zuberbühler, Klaus

2017-01-01

Hunting and sharing of meat is seen across all chimpanzee sites, with variation in prey preferences, hunting techniques, frequencies, and success rates. Here, we compared hunting and meat-eating behaviour in two adjacent chimpanzee communities (Pan troglodytes schweinfurthii) of Budongo Forest, Uganda: the Waibira and Sonso communities. We observed consistent between-group differences in prey-species preferences and in post-hunting behaviour. Sonso chimpanzees show a strong prey preference for Guereza colobus monkeys (Colobus guereza occidentalis; 74.9% hunts), and hunt regularly (1–2 times a month) but with large year-to-year and month-to-month variation. Waibira chimpanzee prey preferences are distributed across primate and duiker species, and resemble those described in an early study of Sonso hunting. Waibira chimpanzees (which include ex-Sonso immigrants) have been observed to feed on red duiker (Cephalophus natalensis; 25%, 9/36 hunts), a species Sonso has never been recorded to feed on (18 years data, 27 years observations), despite no apparent differences in prey distribution; and show less rank-related harassment of meat possessors. We discuss the two most likely and probably interrelated explanations for the observed intergroup variation in chimpanzee hunting behaviour, that is, long-term disruption of complex group-level behaviour due to human presence and possible socially transmitted differences in prey preferences. PMID:28636646

Cardiovascular studies using the chimpanzee (Pan troglodytes)

NASA Technical Reports Server (NTRS)

Hinds, J. E.; Cothran, L. N.; Hawthorne, E. W.

1977-01-01

Despite the phylogenetic similarities between chimpanzees and man, there exists a paucity of reliable data on normal cardiovascular function and the physiological responses of the system to standard interventions. Totally implanted biotelemetry systems or hardwire analog techniques were used to examine the maximum number of cardiovascular variables which could be simultaneously monitored without significantly altering the system's performance. This was performed in order to acquire base-line data not previously obtained in this species, to determine cardiovascular response to specific forcing functions such as ventricular pacing, drug infusions, and lower body negative pressure. A cardiovascular function profile protocol was developed in order to adjust independently the three major factors which modify ventricular performance, namely, left ventricular performance, left ventricular preload, afterload, and contractility. Cardiac pacing at three levels above the ambient rate was used to adjust end diastolic volume (preload). Three concentrations of angiotensin were infused continuously to evaluate afterload in a stepwide fashion. A continuous infusion of dobutamine was administered to raise the manifest contractile state of the heart.

Technical intelligence and culture: Nut cracking in humans and chimpanzees.

PubMed

Boesch, Christophe; Bombjaková, Daša; Boyette, Adam; Meier, Amelia

2017-06-01

According to the technical intelligence hypothesis, humans are superior to all other animal species in understanding and using tools. However, the vast majority of comparative studies between humans and chimpanzees, both proficient tool users, have not controlled for the effects of age, prior knowledge, past experience, rearing conditions, or differences in experimental procedures. We tested whether humans are superior to chimpanzees in selecting better tools, using them more dexteriously, achieving higher performance and gaining access to more resource as predicted under the technical intelligence hypothesis. Aka and Mbendjele hunter-gatherers in the rainforest of Central African Republic and the Republic of Congo, respectively, and Taï chimpanzees in the rainforest of Côte d'Ivoire were observed cracking hard Panda oleosa nuts with different tools, as well as the soft Coula edulis and Elaeis guinensis nuts. The nut-cracking techniques, hammer material selection and two efficiency measures were compared. As predicted, the Aka and the Mbendjele were able to exploit more species of hard nuts in the forest than chimpanzees. However, the chimpanzees were sometimes more efficient than the humans. Social roles differed between the two species, with the Aka and especially the Mbendjele exhibiting cooperation between nut-crackers whereas the chimpanzees were mainly individualistic. Observations of nut-cracking by humans and chimpanzees only partially supported the technical intelligence hypothesis as higher degrees of flexibility in tool selection seen in chimpanzees compensated for use of less efficient tool material than in humans. Nut cracking was a stronger social undertaking in humans than in chimpanzees. © 2017 Wiley Periodicals, Inc.

Cognitive capacities for cooking in chimpanzees

PubMed Central

Warneken, Felix; Rosati, Alexandra G.

2015-01-01

The transition to a cooked diet represents an important shift in human ecology and evolution. Cooking requires a set of sophisticated cognitive abilities, including causal reasoning, self-control and anticipatory planning. Do humans uniquely possess the cognitive capacities needed to cook food? We address whether one of humans' closest relatives, chimpanzees (Pan troglodytes), possess the domain-general cognitive skills needed to cook. Across nine studies, we show that chimpanzees: (i) prefer cooked foods; (ii) comprehend the transformation of raw food that occurs when cooking, and generalize this causal understanding to new contexts; (iii) will pay temporal costs to acquire cooked foods; (iv) are willing to actively give up possession of raw foods in order to transform them; and (v) can transport raw food as well as save their raw food in anticipation of future opportunities to cook. Together, our results indicate that several of the fundamental psychological abilities necessary to engage in cooking may have been shared with the last common ancestor of apes and humans, predating the control of fire. PMID:26041356

An evaluation of video cameras for collecting observational data on sanctuary-housed chimpanzees (Pan troglodytes).

PubMed

Hansen, Bethany K; Fultz, Amy L; Hopper, Lydia M; Ross, Stephen R

2018-05-01

Video cameras are increasingly being used to monitor captive animals in zoo, laboratory, and agricultural settings. This technology may also be useful in sanctuaries with large and/or complex enclosures. However, the cost of camera equipment and a lack of formal evaluations regarding the use of cameras in sanctuary settings make it challenging for facilities to decide whether and how to implement this technology. To address this, we evaluated the feasibility of using a video camera system to monitor chimpanzees at Chimp Haven. We viewed a group of resident chimpanzees in a large forested enclosure and compared observations collected in person and with remote video cameras. We found that via camera, the observer viewed fewer chimpanzees in some outdoor locations (GLMM post hoc test: est. = 1.4503, SE = 0.1457, Z = 9.951, p < 0.001) and identified a lower proportion of chimpanzees (GLMM post hoc test: est. = -2.17914, SE = 0.08490, Z = -25.666, p < 0.001) compared to in-person observations. However, the observer could view the 2 ha enclosure 15 times faster by camera compared to in person. In addition to these results, we provide recommendations to animal facilities considering the installation of a video camera system. Despite some limitations of remote monitoring, we posit that there are substantial benefits of using camera systems in sanctuaries to facilitate animal care and observational research. © 2018 Wiley Periodicals, Inc.

Neuroanatomical asymmetries and handedness in chimpanzees (Pan troglodytes): a case for continuity in the evolution of hemispheric specialization.

PubMed

Hopkins, William D

2013-06-01

Many historical and contemporary theorists have proposed that population-level behavioral and brain asymmetries are unique to humans and evolved as a consequence of human-specific adaptations such as language, tool manufacture and use, and bipedalism. Recent studies in nonhuman animals, notably primates, have begun to challenge this view. Here, I summarize comparative data on neuroanatomical asymmetries in the planum temporale (PT) and inferior frontal gyrus (IFG) of humans and chimpanzees, regions considered the morphological equivalents to Broca's and Wernicke's areas. I also review evidence of population-level handedness in captive and wild chimpanzees. When similar methods and landmarks are used to define the PT and IFG, humans and chimpanzees show similar patterns of asymmetry in both cortical regions, though humans show more pronounced directional biases. Similarly, there is good evidence that chimpanzees show population-level handedness, though, again, the expression of handedness is less robust compared to humans. These results stand in contrast to reported claims of significant differences in the distribution of handedness in humans and chimpanzees, and I discuss some possible explanations for the discrepancies in the neuroanatomical and behavioral data. © 2013 New York Academy of Sciences.

Controlled studies of chimpanzee cultural transmission.

PubMed

Horner, Victoria; de Waal, Frans B M

2009-01-01

Following the first long-term field studies of chimpanzees in the 1960s, researchers began to suspect that chimpanzees from different African populations varied in their behavior, and that some of these variations were transmitted through social learning, thus suggesting culture. Additional reports of chimpanzee culture have since accumulated, which involve an increasing amount of behavioral variation that has no obvious ecological or genetic explanation. To date, close to 50 cultural variants have been reported, including subsistence behavior, tool-use, communication signals, and grooming patterns. Nevertheless, field studies lack the experimental controls and manipulations necessary to conclusively demonstrate that the observed variation results from differential invention and social transmission of behavior. This would require that behavioral variants have been learned from others, a question best addressed in a controlled experimental setting. The following chapter details a series of experimental studies at Yerkes National Primate Research Center of Emory University. In each case, the behavior of two captive groups (each N=12 individuals) was compared before and after the introduction of a novel foraging behavior by a trained conspecific "inventor." The studies were designed to investigate (i) the conditions under which chimpanzees learn from one another, (ii) how behaviors are transmitted, (iii) how cultures are maintained over generations. The results emphasize the importance of integrating both fieldwork and experimental approaches. Previous studies have reported deficits in chimpanzees' cultural capacities, but did so after testing them with human models, which are largely irrelevant to the problem at hand. A representative understanding of culture can only be gained when efforts are made to create a naturalistic learning environment in which chimpanzees have opportunities to learn spontaneously from conspecifics in a familiar social setting.

Brain aging in humans, chimpanzees (Pan troglodytes), and rhesus macaques (Macaca mulatta): magnetic resonance imaging studies of macro- and microstructural changes.

PubMed

Chen, Xu; Errangi, Bhargav; Li, Longchuan; Glasser, Matthew F; Westlye, Lars T; Fjell, Anders M; Walhovd, Kristine B; Hu, Xiaoping; Herndon, James G; Preuss, Todd M; Rilling, James K

2013-10-01

Among primates, humans are uniquely vulnerable to many age-related neurodegenerative disorders. We used structural and diffusion magnetic resonance imaging (MRI) to examine the brains of chimpanzees and rhesus monkeys across each species' adult lifespan, and compared these results with published findings in humans. As in humans, gray matter volume decreased with age in chimpanzees and rhesus monkeys. Also like humans, chimpanzees showed a trend for decreased white matter volume with age, but this decrease occurred proportionally later in the chimpanzee lifespan than in humans. Diffusion MRI revealed widespread age-related decreases in fractional anisotropy and increases in radial diffusivity in chimpanzees and macaques. However, both the fractional anisotropy decline and the radial diffusivity increase started at a proportionally earlier age in humans than in chimpanzees. Thus, even though overall patterns of gray and white matter aging are similar in humans and chimpanzees, the longer lifespan of humans provides more time for white matter to deteriorate before death, with the result that some neurological effects of aging may be exacerbated in our species. Copyright © 2013 Elsevier Inc. All rights reserved.

Brain aging in humans, chimpanzees (Pan troglodytes), and rhesus macaques (Macaca mulatta): magnetic resonance imaging studies of macro- and microstructural changes

PubMed Central

Chen, Xu; Errangi, Bhargav; Li, Longchuan; Glasser, Matthew F.; Westlye, Lars T.; Fjell, Anders M.; Walhovd, Kristine B.; Hu, Xiaoping; Herndon, James G.; Preuss, Todd M.; Rilling, James K.

2013-01-01

Among primates, humans are uniquely vulnerable to many age-related neurodegenerative disorders. We used structural and diffusion magnetic resonance imaging (MRI) to examine the brains of chimpanzees and rhesus monkeys across each species' adult lifespan, and compared these results with published findings in humans. As in humans, gray matter volume decreased with age in chimpanzees and rhesus monkeys. Also like humans, chimpanzees showed a trend for decreased white matter volume with age, but this decrease occurred proportionally later in the chimpanzee lifespan than in humans. Diffusion MRI revealed widespread age-related decreases in fractional anisotropy and increases in radial diffusivity in chimpanzees and macaques. However, both the fractional anisotropy decline and the radial diffusivity increase started at a proportionally earlier age in humans than in chimpanzees. Thus, even though overall patterns of gray and white matter aging are similar in humans and chimpanzees, the longer lifespan of humans provides more time for white matter to deteriorate before death, with the result that some neurological effects of aging may be exacerbated in our species. PMID:23623601

Characterization of a chromosome-specific chimpanzee alpha satellite subset: Evolutionary relationship to subsets on human chromosomes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Warburton, P.E.; Gosden, J.; Lawson, D.

1996-04-15

Alpha satellite DNA is a tandemly repeated DNA family found at the centromeres of all primate chromosomes examined. The fundamental repeat units of alpha satellite DNA are diverged 169- to 172-bp monomers, often found to be organized in chromosome-specific higher-order repeat units. The chromosomes of human (Homo sapiens (HSA)), chimpanzee (Pan troglodytes (PTR) and Pan paniscus), and gorilla (Gorilla gorilla) share a remarkable similarity and synteny. It is of interest to ask if alpha satellite arrays at centromeres of homologous chromosomes between these species are closely related (evolving in an orthologous manner) or if the evolutionary processes that homogenize andmore » spread these arrays within and between chromosomes result in nonorthologous evolution of arrays. By using PCR primers specific for human chromosome 17-specific alpha satellite DNA, we have amplified, cloned, and characterized a chromosome-specific subset from the PTR chimpanzee genome. Hybridization both on Southern blots and in situ as well as sequence analysis show that this subset is most closely related, as expected, to sequences on HSA 17. However, in situ hybridization reveals that this subset is not found on the homologous chromosome in chimpanzee (PTR 19), but instead on PTR 12, which is homologous to HSA 2p. 40 refs., 3 figs.« less

Chimpanzees do not take advantage of very low cost opportunities to deliver food to unrelated group members

PubMed Central

VONK, JENNIFER; BROSNAN, SARAH F.; SILK, JOAN B.; HENRICH, JOSEPH; RICHARDSON, AMANDA S.; LAMBETH, SUSAN P.; SCHAPIRO, STEVEN J.; POVINELLI, DANIEL J.

2015-01-01

We conducted experiments on two populations of chimpanzees, Pan troglodytes, to determine whether they would take advantage of opportunities to provide food rewards to familiar group members at little cost to themselves. In both of the experiments described here, chimpanzees were able to deliver identical rewards to themselves and to other members of their social groups. We compared the chimpanzees’ behaviour when they were paired with another chimpanzee and when they were alone. If chimpanzees are motivated to provide benefits to others, they are expected to consistently deliver rewards to others and to distinguish between the partner-present and partner-absent conditions. Results from both experiments indicate that our subjects were largely indifferent to the benefits they could provide to others. They were less likely to provide rewards to potential recipients as the experiment progressed, and all but one of the 18 subjects were as likely to deliver rewards to an empty enclosure as to an enclosure housing another chimpanzee. These results, in conjunction with similar results obtained in previous experiments, suggest that chimpanzees are not motivated by prosocial sentiments to provide food rewards to other group members. PMID:27011388

Ecological and social correlates of chimpanzee tool use.

PubMed

Sanz, Crickette M; Morgan, David B

2013-11-19

The emergence of technology has been suggested to coincide with scarcity of staple resources that led to innovations in the form of tool-assisted strategies to diversify or augment typical diets. We examined seasonal patterns of several types of tool use exhibited by a chimpanzee (Pan troglodytes) population residing in central Africa, to determine whether their technical skills provided access to fallback resources when preferred food items were scarce. Chimpanzees in the Goualougo Triangle exhibit a diverse repertoire of tool behaviours, many of which are exhibited throughout the year. Further, they have developed specific tool sets to overcome the issues of accessibility to particular food items. Our conclusion is that these chimpanzees use a sophisticated tool technology to cope with seasonal changes in relative food abundance and gain access to high-quality foods. Subgroup sizes were smaller in tool using contexts than other foraging contexts, suggesting that the size of the social group may not be as important in promoting complex tool traditions as the frequency and type of social interactions. Further, reports from other populations and species showed that tool use may occur more often in response to ecological opportunities and relative profitability of foraging techniques than scarcity of resources.

Evidence for cultural differences between neighboring chimpanzee communities.

PubMed

Luncz, Lydia V; Mundry, Roger; Boesch, Christophe

2012-05-22

The majority of evidence for cultural behavior in animals has come from comparisons between populations separated by large geographical distances that often inhabit different environments. The difficulty of excluding ecological and genetic variation as potential explanations for observed behaviors has led some researchers to challenge the idea of animal culture. Chimpanzees (Pan troglodytes verus) in the Taï National Park, Côte d'Ivoire, crack Coula edulis nuts using stone and wooden hammers and tree root anvils. In this study, we compare for the first time hammer selection for nut cracking across three neighboring chimpanzee communities that live in the same forest habitat, which reduces the likelihood of ecological variation. Furthermore, the study communities experience frequent dispersal of females at maturity, which eliminates significant genetic variation. We compared key ecological factors, such as hammer availability and nut hardness, between the three neighboring communities and found striking differences in group-specific hammer selection among communities despite similar ecological conditions. Differences were found in the selection of hammer material and hammer size in response to changes in nut resistance over time. Our findings highlight the subtleties of cultural differences in wild chimpanzees and illustrate how cultural knowledge is able to shape behavior, creating differences among neighboring social groups. Copyright © 2012 Elsevier Ltd. All rights reserved.

Ecological and social correlates of chimpanzee tool use

PubMed Central

Sanz, Crickette M.; Morgan, David B.

2013-01-01

The emergence of technology has been suggested to coincide with scarcity of staple resources that led to innovations in the form of tool-assisted strategies to diversify or augment typical diets. We examined seasonal patterns of several types of tool use exhibited by a chimpanzee (Pan troglodytes) population residing in central Africa, to determine whether their technical skills provided access to fallback resources when preferred food items were scarce. Chimpanzees in the Goualougo Triangle exhibit a diverse repertoire of tool behaviours, many of which are exhibited throughout the year. Further, they have developed specific tool sets to overcome the issues of accessibility to particular food items. Our conclusion is that these chimpanzees use a sophisticated tool technology to cope with seasonal changes in relative food abundance and gain access to high-quality foods. Subgroup sizes were smaller in tool using contexts than other foraging contexts, suggesting that the size of the social group may not be as important in promoting complex tool traditions as the frequency and type of social interactions. Further, reports from other populations and species showed that tool use may occur more often in response to ecological opportunities and relative profitability of foraging techniques than scarcity of resources. PMID:24101626

First GIS Analysis of Modern Stone Tools Used by Wild Chimpanzees (Pan troglodytes verus) in Bossou, Guinea, West Africa

PubMed Central

Arroyo, Adrian; Matsuzawa, Tetsuro; de la Torre, Ignacio

2015-01-01

Stone tool use by wild chimpanzees of West Africa offers a unique opportunity to explore the evolutionary roots of technology during human evolution. However, detailed analyses of chimpanzee stone artifacts are still lacking, thus precluding a comparison with the earliest archaeological record. This paper presents the first systematic study of stone tools used by wild chimpanzees to crack open nuts in Bossou (Guinea-Conakry), and applies pioneering analytical techniques to such artifacts. Automatic morphometric GIS classification enabled to create maps of use wear over the stone tools (anvils, hammers, and hammers/ anvils), which were blind tested with GIS spatial analysis of damage patterns identified visually. Our analysis shows that chimpanzee stone tool use wear can be systematized and specific damage patterns discerned, allowing to discriminate between active and passive pounders in lithic assemblages. In summary, our results demonstrate the heuristic potential of combined suites of GIS techniques for the analysis of battered artifacts, and have enabled creating a referential framework of analysis in which wild chimpanzee battered tools can for the first time be directly compared to the early archaeological record. PMID:25793642

How chimpanzees cooperate in a competitive world

PubMed Central

Suchak, Malini; Eppley, Timothy M.; Campbell, Matthew W.; Feldman, Rebecca A.; Quarles, Luke F.; de Waal, Frans B. M.

2016-01-01

Our species is routinely depicted as unique in its ability to achieve cooperation, whereas our closest relative, the chimpanzee (Pan troglodytes), is often characterized as overly competitive. Human cooperation is assisted by the cost attached to competitive tendencies through enforcement mechanisms, such as punishment and partner choice. To examine if chimpanzees possess the same ability to mitigate competition, we set up a cooperative task in the presence of the entire group of 11 adults, which required two or three individuals to pull jointly to receive rewards. This open-group set-up provided ample opportunity for competition (e.g., freeloading, displacements) and aggression. Despite this unique set-up and initial competitiveness, cooperation prevailed in the end, being at least five times as common as competition. The chimpanzees performed 3,565 cooperative acts while using a variety of enforcement mechanisms to overcome competition and freeloading, as measured by (attempted) thefts of rewards. These mechanisms included direct protest by the target, third-party punishment in which dominant individuals intervened against freeloaders, and partner choice. There was a marked difference between freeloading and displacement; freeloading tended to elicit withdrawal and third-party interventions, whereas displacements were met with a higher rate of direct retaliation. Humans have shown similar responses in controlled experiments, suggesting shared mechanisms across the primates to mitigate competition for the sake of cooperation. PMID:27551075

Chimpanzees (Pan troglodytes) Transfer Tokens Repeatedly with a Partner to Accumulate Rewards in a Self-Control Task

PubMed Central

Parrish, Audrey E.; Perdue, Bonnie M.; Evans, Theodore A.; Beran, Michael J.

2013-01-01

There has been extensive research investigating self-control in humans and nonhuman animals, yet we know surprisingly little about how one’s social environment influences self-control. The present study examined the self-control of chimpanzees in a task that required active engagement with conspecifics. The task consisted of transferring a token back and forth with a partner animal in order to accumulate food rewards, one item per token transfer. Self-control was required because at any point in the trial, either chimpanzee could obtain their accumulated rewards, but doing so discontinued the food accumulation and ended the trial for both individuals. Chimpanzees readily engaged the task and accumulated the majority of available rewards before ending each trial, and they did so across a number of conditions that varied the identity of the partner, the presence/absence of the experimenter, and the means by which they could obtain rewards. A second experiment examined chimpanzees’ self-control when given the choice between immediately available food items and a potentially larger amount of rewards that could be obtained by engaging the token transfer task with a partner. Chimpanzees were flexible in their decision-making in this test, typically choosing the option representing the largest amount of food, even if it involved delayed accumulation of the rewards via the token transfer task. These results demonstrate that chimpanzees can exhibit self-control in situations involving social interactions, and they encourage further research into this important aspect of the self-control scenario. PMID:23381691

How Abnormal Is the Behaviour of Captive, Zoo-Living Chimpanzees?

PubMed Central

Birkett, Lucy P.; Newton-Fisher, Nicholas E.

2011-01-01

Background Many captive chimpanzees (Pan troglodytes) show a variety of serious behavioural abnormalities, some of which have been considered as possible signs of compromised mental health. The provision of environmental enrichments aimed at reducing the performance of abnormal behaviours is increasing the norm, with the housing of individuals in (semi-)natural social groups thought to be the most successful of these. Only a few quantitative studies of abnormal behaviour have been conducted, however, particularly for the captive population held in zoological collections. Consequently, a clear picture of the level of abnormal behaviour in zoo-living chimpanzees is lacking. Methods We present preliminary findings from a detailed observational study of the behaviour of 40 socially-housed zoo-living chimpanzees from six collections in the United States of America and the United Kingdom. We determined the prevalence, diversity, frequency, and duration of abnormal behaviour from 1200 hours of continuous behavioural data collected by focal animal sampling. Results, Conclusion and Significance Our overall finding was that abnormal behaviour was present in all sampled individuals across six independent groups of zoo-living chimpanzees, despite the differences between these groups in size, composition, housing, etc. We found substantial variation between individuals in the frequency and duration of abnormal behaviour, but all individuals engaged in at least some abnormal behaviour and variation across individuals could not be explained by sex, age, rearing history or background (defined as prior housing conditions). Our data support a conclusion that, while most behaviour of zoo-living chimpanzees is ‘normal’ in that it is typical of their wild counterparts, abnormal behaviour is endemic in this population despite enrichment efforts. We suggest there is an urgent need to understand how the chimpanzee mind copes with captivity, an issue with both scientific and welfare

How abnormal is the behaviour of captive, zoo-living chimpanzees?

PubMed

Birkett, Lucy P; Newton-Fisher, Nicholas E

2011-01-01

Many captive chimpanzees (Pan troglodytes) show a variety of serious behavioural abnormalities, some of which have been considered as possible signs of compromised mental health. The provision of environmental enrichments aimed at reducing the performance of abnormal behaviours is increasing the norm, with the housing of individuals in (semi-)natural social groups thought to be the most successful of these. Only a few quantitative studies of abnormal behaviour have been conducted, however, particularly for the captive population held in zoological collections. Consequently, a clear picture of the level of abnormal behaviour in zoo-living chimpanzees is lacking. We present preliminary findings from a detailed observational study of the behaviour of 40 socially-housed zoo-living chimpanzees from six collections in the United States of America and the United Kingdom. We determined the prevalence, diversity, frequency, and duration of abnormal behaviour from 1200 hours of continuous behavioural data collected by focal animal sampling. Our overall finding was that abnormal behaviour was present in all sampled individuals across six independent groups of zoo-living chimpanzees, despite the differences between these groups in size, composition, housing, etc. We found substantial variation between individuals in the frequency and duration of abnormal behaviour, but all individuals engaged in at least some abnormal behaviour and variation across individuals could not be explained by sex, age, rearing history or background (defined as prior housing conditions). Our data support a conclusion that, while most behaviour of zoo-living chimpanzees is 'normal' in that it is typical of their wild counterparts, abnormal behaviour is endemic in this population despite enrichment efforts. We suggest there is an urgent need to understand how the chimpanzee mind copes with captivity, an issue with both scientific and welfare implications.

Learning the rules of the rock-paper-scissors game: chimpanzees versus children.

PubMed

Gao, Jie; Su, Yanjie; Tomonaga, Masaki; Matsuzawa, Tetsuro

2018-01-01

The present study aimed to investigate whether chimpanzees (Pan troglodytes) could learn a transverse pattern by being trained in the rules of the rock-paper-scissors game in which "paper" beats "rock," "rock" beats "scissors," and "scissors" beats "paper." Additionally, this study compared the learning processes between chimpanzees and children. Seven chimpanzees were tested using a computer-controlled task. They were trained to choose the stronger of two options according to the game rules. The chimpanzees first engaged in the paper-rock sessions until they reached the learning criterion. Subsequently, they engaged in the rock-scissors and scissors-paper sessions, before progressing to sessions with all three pairs mixed. Five of the seven chimpanzees completed training after a mean of 307 sessions, which indicates that they learned the circular pattern. The chimpanzees required more scissors-paper sessions (14.29 ± 6.89), the third learnt pair, than paper-rock (1.71 ± 0.18) and rock-scissors (3.14 ± 0.70) sessions, suggesting they had difficulty finalizing the circularity. The chimpanzees then received generalization tests using new stimuli, which they learned quickly. A similar procedure was performed with children (35-71 months, n = 38) who needed the same number of trials for all three pairs during single-paired sessions. Their accuracy during the mixed-pair sessions improved with age and was better than chance from 50 months of age, which indicates that the ability to solve the transverse patterning problem might develop at around 4 years of age. The present findings show that chimpanzees were able to learn the task but had difficulties with circularity, whereas children learned the task more easily and developed the relevant ability at approximately 4 years of age. Furthermore, the chimpanzees' performance during the mixed-pair sessions was similar to that of 4-year-old children during the corresponding stage of training.

Effects of early rearing conditions on problem-solving skill in captive male chimpanzees (Pan troglodytes).

PubMed

Morimura, Naruki; Mori, Yusuke

2010-06-01

Early rearing conditions of captive chimpanzees characterize behavioral differences in tool use, response to novelty, and sexual and maternal competence later in life. Restricted rearing conditions during early life hinder the acquisition and execution of such behaviors, which characterize the daily life of animals. This study examined whether rearing conditions affect adult male chimpanzees' behavior skills used for solving a problem with acquired locomotion behavior. Subjects were 13 male residents of the Chimpanzee Sanctuary Uto: 5 wild-born and 8 captive-born. A pretest assessed bed building and tool use abilities to verify behavioral differences between wild- and captive-born subjects, as earlier reports have described. Second, a banana-access test was conducted to investigate the problem-solving ability of climbing a bamboo pillar for accessing a banana, which might be the most efficient food access strategy for this setting. The test was repeated in a social setting. Results show that wild-born subjects were better able than captive-born subjects to use the provided materials for bed building and tool use. Results of the banana-access test show that wild-born subjects more frequently used a bamboo pillar for obtaining a banana with an efficient strategy than captive-born subjects did. Of the eight captive-born subjects, six avoided the bamboo pillars to get a banana and instead used, sometimes in a roundabout way, an iron pillar or fence. Results consistently underscored the adaptive and sophisticated skills of wild-born male chimpanzees in problem-solving tasks. The rearing conditions affected both the behavior acquisition and the execution of behaviors that had already been acquired. (c) 2010 Wiley-Liss, Inc.

Applying remote sensing and GIS for chimpanzee habitat change detection, behaviour and conservation

NASA Astrophysics Data System (ADS)

Pintea, Lilian

Chimpanzees (Pan troglodytes), our closest living relatives, are declining alarmingly in abundance and distribution all across Africa. Clearing of forests and woodlands has one of the most rapid and devastating impacts, leaving chimpanzees in isolated, small populations that face edge effects and elevated risk of extinction. Satellite imagery could be a powerful tool to map chimpanzee habitats and threats at the landscape scale even in the most remote, difficult to access areas. However, few applications exist to demonstrate how remote sensing methods can be used in Africa for chimpanzee research and conservation in practice. In chapter one, I investigate the use of Landsat MSS and ETM+ satellite imagery to monitor dry tropical forests and miombo woodlands change between 1972-1999 inside and outside Gombe National Park, Tanzania. I show that canopy cover increased in the northern and middle parts of the park but with severe canopy loss outside protected area. Deforestation has had unequal effects on the three chimpanzee communities inside the park. The Kasekela chimpanzees have been least affected by canopy loss outside the park. In contrast, the Mitumba and Kalande communities have likely lost key range areas. In chapter two, I use 25 years of data on Gombe chimpanzees to investigate to what extent vegetation variables detected from multi-temporal satellite images can be applied to understand changes in chimpanzee feeding and party size. NDVI positively correlated with the time chimpanzees spent feeding but had no affect on the average number of adult males in the party. Instead the number of males in the party increased with proximity to hostile neighboring communities. In chapter three, I use Landsat and SPOT satellite imagery as the basis for Threat Reduction Assessment to evaluate conservation outcomes of a ten year community based conservation project in Tanzania. The findings suggest that the remote sensing methods applied in this study could provide new

Anthrax in Western and Central African great apes.

PubMed

Leendertz, Fabian H; Lankester, Felix; Guislain, Patrick; Néel, Cécile; Drori, Ofir; Dupain, Jef; Speede, Sheri; Reed, Patricia; Wolfe, Nathan; Loul, Severin; Mpoudi-Ngole, E; Peeters, Martine; Boesch, Christophe; Pauli, Georg; Ellerbrok, Heinz; Leroy, Eric M

2006-09-01

During the period of December 2004 to January 2005, Bacillus anthracis killed three wild chimpanzees (Pan troglodytes troglodytes) and one gorilla (Gorilla gorilla gorilla) in a tropical forest in Cameroon. While this is the second anthrax outbreak in wild chimpanzees, this is the first case of anthrax in gorillas ever reported. The number of great apes in Central Africa is dramatically declining and the populations are seriously threatened by diseases, mainly Ebola. Nevertheless, a considerable number of deaths cannot be attributed to Ebola virus and remained unexplained. Our results show that diseases other than Ebola may also threaten wild great apes, and indicate that the role of anthrax in great ape mortality may have been underestimated. These results suggest that risk identification, assessment, and management for the survival of the last great apes should be performed with an open mind, since various pathogens with distinct characteristics in epidemiology and pathogenicity may impact the populations. An animal mortality monitoring network covering the entire African tropical forest, with the dual aims of preventing both great ape extinction and human disease outbreaks, will create necessary baseline data for such risk assessments and management plans. Copyright 2006 Wiley-Liss, Inc.

The association between imitation recognition and socio-communicative competencies in chimpanzees (Pan troglodytes).

PubMed

Pope, Sarah M; Russell, Jamie L; Hopkins, William D

2015-01-01

Imitation recognition provides a viable platform from which advanced social cognitive skills may develop. Despite evidence that non-human primates are capable of imitation recognition, how this ability is related to social cognitive skills is unknown. In this study, we compared imitation recognition performance, as indicated by the production of testing behaviors, with performance on a series of tasks that assess social and physical cognition in 49 chimpanzees. In the initial analyses, we found that males were more responsive than females to being imitated and engaged in significantly greater behavior repetitions and testing sequences. We also found that subjects who consistently recognized being imitated performed better on social but not physical cognitive tasks, as measured by the Primate Cognitive Test Battery. These findings suggest that the neural constructs underlying imitation recognition are likely associated with or among those underlying more general socio-communicative abilities in chimpanzees. Implications regarding how imitation recognition may facilitate other social cognitive processes, such as mirror self-recognition, are discussed.

The association between imitation recognition and socio-communicative competencies in chimpanzees (Pan troglodytes)

PubMed Central

Pope, Sarah M.; Russell, Jamie L.; Hopkins, William D.

2015-01-01

Imitation recognition provides a viable platform from which advanced social cognitive skills may develop. Despite evidence that non-human primates are capable of imitation recognition, how this ability is related to social cognitive skills is unknown. In this study, we compared imitation recognition performance, as indicated by the production of testing behaviors, with performance on a series of tasks that assess social and physical cognition in 49 chimpanzees. In the initial analyses, we found that males were more responsive than females to being imitated and engaged in significantly greater behavior repetitions and testing sequences. We also found that subjects who consistently recognized being imitated performed better on social but not physical cognitive tasks, as measured by the Primate Cognitive Test Battery. These findings suggest that the neural constructs underlying imitation recognition are likely associated with or among those underlying more general socio-communicative abilities in chimpanzees. Implications regarding how imitation recognition may facilitate other social cognitive processes, such as mirror self-recognition, are discussed. PMID:25767454

Differences between chimpanzees and bonobos in neural systems supporting social cognition

PubMed Central

Scholz, Jan; Preuss, Todd M.; Glasser, Matthew F.; Errangi, Bhargav K.; Behrens, Timothy E.

2012-01-01

Our two closest living primate relatives, chimpanzees (Pan troglodytes) and bonobos (Pan paniscus), exhibit significant behavioral differences despite belonging to the same genus and sharing a very recent common ancestor. Differences have been reported in multiple aspects of social behavior, including aggression, sex, play and cooperation. However, the neurobiological basis of these differences has only been minimally investigated and remains uncertain. Here, we present the first ever comparison of chimpanzee and bonobo brains using diffusion tensor imaging, supplemented with a voxel-wise analysis of T1-weighted images to specifically compare neural circuitry implicated in social cognition. We find that bonobos have more gray matter in brain regions involved in perceiving distress in both oneself and others, including the right dorsal amygdala and right anterior insula. Bonobos also have a larger pathway linking the amygdala with the ventral anterior cingulate cortex, a pathway implicated in both top–down control of aggressive impulses as well as bottom–up biases against harming others. We suggest that this neural system not only supports increased empathic sensitivity in bonobos, but also behaviors like sex and play that serve to dissipate tension, thereby limiting distress and anxiety to levels conducive with prosocial behavior. PMID:21467047

The first chimpanzee sanctuary in Japan: an attempt to care for the "surplus" of biomedical research.

PubMed

Morimura, Naruki; Idani, Gen'ichi; Matsuzawa, Tetsuro

2011-03-01

This article specifically examines several aspects of the human-captive chimpanzee bond and the effort to create the first chimpanzee sanctuary in Japan. We discuss our ethical responsibility for captive chimpanzees that have been used in biomedical research. On April 1, 2007, the Chimpanzee Sanctuary Uto (CSU) was established as the first sanctuary for retired laboratory chimpanzees in Japan. This initiative was the result of the continuous efforts by members of Support for African/Asian Great Apes (SAGA), and the Great Ape Information Network to provide a solution to the large chimpanzee colony held in biomedical facilities. However, the cessation of invasive biomedical studies using chimpanzees has created a new set of challenges because Japan lacks registration and laws banning invasive ape experiments and lacks a national policy for the life-long care of retired laboratory chimpanzees. Therefore, CSU has initiated a relocation program in which 79 retired laboratory chimpanzees will be sent to domestic zoos and receive life-long care. By the end of 2009, the number of chimpanzees living at CSU had decreased from 79 to 59 individuals. A nationwide network of care facilities and CSU to provide life-long care of retired laboratory chimpanzees is growing across Japan. This will result in humane treatment of these research animals. 2010 Wiley-Liss, Inc.

Lineage-specific expansions of retroviral insertions within the genomes of African great apes but not humans and orangutans.

PubMed

Yohn, Chris T; Jiang, Zhaoshi; McGrath, Sean D; Hayden, Karen E; Khaitovich, Philipp; Johnson, Matthew E; Eichler, Marla Y; McPherson, John D; Zhao, Shaying; Pääbo, Svante; Eichler, Evan E

2005-04-01

Retroviral infections of the germline have the potential to episodically alter gene function and genome structure during the course of evolution. Horizontal transmissions between species have been proposed, but little evidence exists for such events in the human/great ape lineage of evolution. Based on analysis of finished BAC chimpanzee genome sequence, we characterize a retroviral element (Pan troglodytes endogenous retrovirus 1 [PTERV1]) that has become integrated in the germline of African great ape and Old World monkey species but is absent from humans and Asian ape genomes. We unambiguously map 287 retroviral integration sites and determine that approximately 95.8% of the insertions occur at non-orthologous regions between closely related species. Phylogenetic analysis of the endogenous retrovirus reveals that the gorilla and chimpanzee elements share a monophyletic origin with a subset of the Old World monkey retroviral elements, but that the average sequence divergence exceeds neutral expectation for a strictly nuclear inherited DNA molecule. Within the chimpanzee, there is a significant integration bias against genes, with only 14 of these insertions mapping within intronic regions. Six out of ten of these genes, for which there are expression data, show significant differences in transcript expression between human and chimpanzee. Our data are consistent with a retroviral infection that bombarded the genomes of chimpanzees and gorillas independently and concurrently, 3-4 million years ago. We speculate on the potential impact of such recent events on the evolution of humans and great apes.

The importance of witnessed agency in chimpanzee social learning of tool use.

PubMed

Hopper, Lydia M; Lambeth, Susan P; Schapiro, Steven J; Whiten, Andrew

2015-03-01

Social learning refers to individuals learning from others, including information gained through indirect social influences, such as the results of others' actions and changes in the physical environment. One method to determine the relative influence of these varieties of information is the 'ghost display', in which no model is involved, but subjects can watch the results that a model would produce. Previous research has shown mixed success by chimpanzees (Pan troglodytes) learning from ghost displays, with some studies suggesting learning only in relatively simple tasks. To explore whether the failure of chimpanzees to learn from a ghost display may be due to neophobia when tested singly or a requirement for more detailed information for complex tasks, we presented ghost displays of a tool-use task to chimpanzees in their home social groups. Previous tests have revealed that chimpanzees are unable to easily solve this tool-use task asocially, or learn from ghost displays when tested singly, but can learn after observing conspecifics in a group setting. In the present study, despite being tested in a group situation, chimpanzees still showed no success in solving the task via trial-and-error learning, in a baseline condition, nor in learning the task from the ghost display. Simply being in the presence of their group mates and being shown the affordances of the task was not sufficient to encourage learning. Following this, in an escalating series of tests, we examined the chimpanzees' ability to learn from a demonstration by models with agency: (1) a human; (2) video footage of a chimpanzee; (3) a live chimpanzee model. In the first two of these 'social' conditions, subjects showed limited success. By the end of the final open diffusion phase, which was run to determine whether this new behavior would be transmitted among the group after seeing a successful chimpanzee use the task, 83% of chimpanzees were now successful. This confirmed a marked overall effect of

Nut-cracking behaviour in wild-born, rehabilitated bonobos (Pan paniscus): a comprehensive study of hand-preference, hand grips and efficiency.

PubMed

Neufuss, Johanna; Humle, Tatyana; Cremaschi, Andrea; Kivell, Tracy L

2017-02-01

There has been an enduring interest in primate tool-use and manipulative abilities, most often with the goal of providing insight into the evolution of human manual dexterity, right-hand preference, and what behaviours make humans unique. Chimpanzees (Pan troglodytes) are arguably the most well-studied tool-users amongst non-human primates, and are particularly well-known for their complex nut-cracking behaviour, which has been documented in several West African populations. However, their sister-taxon, the bonobos (Pan paniscus), rarely engage in even simple tool-use and are not known to nut-crack in the wild. Only a few studies have reported tool-use in captive bonobos, including their ability to crack nuts, but details of this complex tool-use behaviour have not been documented before. Here, we fill this gap with the first comprehensive analysis of bonobo nut-cracking in a natural environment at the Lola ya Bonobo sanctuary, Democratic Republic of the Congo. Eighteen bonobos were studied as they cracked oil palm nuts using stone hammers. Individual bonobos showed exclusive laterality for using the hammerstone and there was a significant group-level right-hand bias. The study revealed 15 hand grips for holding differently sized and weighted hammerstones, 10 of which had not been previously described in the literature. Our findings also demonstrated that bonobos select the most effective hammerstones when nut-cracking. Bonobos are efficient nut-crackers and not that different from the renowned nut-cracking chimpanzees of Bossou, Guinea, which also crack oil palm nuts using stones. © 2016 Wiley Periodicals, Inc.

Sex differences in tool use acquisition in bonobos (Pan paniscus).

PubMed

Boose, Klaree J; White, Frances J; Meinelt, Audra

2013-09-01

All the great ape species are known tool users in both the wild and captivity, although there is great variation in ability and behavioral repertoire. Differences in tool use acquisition between chimpanzees and gorillas have been attributed to differing levels of social tolerance as a result of differences in social structure. Chimpanzees also show sex differences in acquisition and both chimpanzees and bonobos demonstrate a female bias in tool use behaviors. Studies of acquisition are limited in the wild and between species comparisons are complicated in captivity by contexts that often do not reflect natural conditions. Here we investigated tool use acquisition in a captive group of naïve bonobos by simulating naturalistic conditions. We constructed an artificial termite mound fashioned after those that occur in the wild and tested individuals within a social group context. We found sex differences in latencies to attempt and to succeed where females attempted to fish, were successful more quickly, and fished more frequently than males. We compared our results to those reported for chimpanzees and gorillas. Males across all three species did not differ in latency to attempt or to succeed. In contrast, bonobo and chimpanzee females succeeded more quickly than did female gorillas. Female bonobos and female chimpanzees did not differ in either latency to attempt or to succeed. We tested the social tolerance hypothesis by investigating the relationship between tool behaviors and number of neighbors present. We also compared these results to those reported for chimpanzees and gorillas and found that bonobos had the fewest numbers of neighbors present. The results of this study do not support the association between number of neighbors and tool behavior reported for chimpanzees. However, bonobos demonstrated a similar sex difference in tool use acquisition, supporting the hypothesis of a female bias in tool use in Pan. © 2013 Wiley Periodicals, Inc.

Language-trained chimpanzees (Pan troglodytes) name what they have seen but look first at what they have not seen.

PubMed

Beran, Michael J; Smith, J David; Perdue, Bonnie M

2013-05-01

Metacognition can be defined as knowing what one knows, and the question of whether nonhuman animals are metacognitive has driven an intense debate. We tested 3 language-trained chimpanzees in an information-seeking task in which the identity of a food item was the critical piece of information needed to obtain the food. The chimpanzees could either report the identity of the food immediately or first check a container in which the food had been hidden. In two experiments, the chimpanzees were significantly more likely to visit the container first on trials in which they could not know its contents but were more likely to just name the food item without looking into the container on trials in which they had seen its contents. Thus, chimpanzees showed efficient information-seeking behavior that suggested they knew what they had or had not already seen when it was time to name a hidden item.

Selective insectivory at Toro-Semliki, Uganda: comparative analyses suggest no 'savanna' chimpanzee pattern.

PubMed

Webster, Timothy H; McGrew, William C; Marchant, Linda F; Payne, Charlotte L R; Hunt, Kevin D

2014-06-01

Chimpanzee (Pan troglodytes) insectivory across Africa is ubiquitous. Insects provide a significant nutritional payoff and may be important for chimpanzees in dry, open habitats with narrow diets. We tested this hypothesis at Semliki, Uganda, a long-term dry study site. We evaluated prospects for insectivory by measuring insect abundance along de novo transects and trails, monitoring social insect colonies, and surveying available raw materials for elementary technology. We determined the frequency and nature of insectivory through behavioral observation and fecal analysis. We then compared our results with those from 15 other long-term chimpanzee study sites using a cluster analysis. We found that Semliki chimpanzees are one of the most insectivorous populations studied to date in terms of frequency of consumption, but they are very selective in their insectivory, regularly consuming only weaver ants (Oecophylla longinoda) and honey and bees from hives of Apis mellifera. This selectivity obtains despite having a full range of typical prey species available in harvestable quantities. We suggest that Semliki chimpanzees may face ecological time constraints and therefore bias their predation toward prey taxa that can be quickly consumed. Geographical proximity correlated with the results of the cluster analysis, while rainfall, a relatively gross measure of environment, did not. Because broad taxonomic groups of insects were used in analyses, prey availability was unlikely to have a strong effect on this pattern. Instead, we suggest that transmission of cultural knowledge may play a role in determining chimpanzee prey selection across Africa. Further study is needed to test these hypotheses. Copyright © 2014 Elsevier Ltd. All rights reserved.

Favorable ecological circumstances promote life expectancy in chimpanzees similar to that of human hunter-gatherers.

PubMed

Wood, Brian M; Watts, David P; Mitani, John C; Langergraber, Kevin E

2017-04-01

Demographic data on wild chimpanzees are crucial for understanding the evolution of chimpanzee and hominin life histories, but most data come from populations affected by disease outbreaks and anthropogenic disturbance. We present survivorship data from a relatively undisturbed and exceptionally large community of eastern chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. We monitored births, deaths, immigrations, and emigrations in the community between 1995 and 2016. Using known and estimated ages, we calculated survivorship curves for the whole community, for males and females separately, and for individuals ≤2 years old when identified. We used a novel method to address age estimation error by calculating stochastic survivorship curves. We compared Ngogo life expectancy, survivorship, and mortality rates to those from other chimpanzee communities and human hunter-gatherers. Life expectancy at birth for both sexes combined was 32.8 years, far exceeding estimates of chimpanzee life expectancy in other communities, and falling within the range of human hunter-gatherers (i.e., 27-37 years). Overall, the pattern of survivorship at Ngogo was more similar to that of human hunter-gatherers than to other chimpanzee communities. Maximum lifespan for the Ngogo chimpanzees, however, was similar to that reported at other chimpanzee research sites and was less than that of human-hunter gatherers. The absence of predation by large carnivores may contribute to some of the higher survivorship at Ngogo, but this cannot explain the much higher survivorship at Ngogo than at Kanyawara, another chimpanzee community in the same forest, which also lacks large carnivores. Higher survivorship at Ngogo appears to be an adaptive response to a food supply that is more abundant and varies less than that of Kanyawara. Future analyses of hominin life history evolution should take these results into account. Copyright © 2017 Elsevier Ltd. All rights

Favorable ecological circumstances promote life expectancy in chimpanzees similar to that of human hunter-gatherers☆

PubMed Central

Wood, Brian M.; Watts, David P.; Mitani, John C.; Langergraber, Kevin E.

2017-01-01

Demographic data on wild chimpanzees are crucial for understanding the evolution of chimpanzee and hominin life histories, but most data come from populations affected by disease outbreaks and anthropogenic disturbance. We present survivorship data from a relatively undisturbed and exceptionally large community of eastern chimpanzees (Pan troglodytes schweinfurthii) at Ngogo, Kibale National Park, Uganda. We monitored births, deaths, immigrations, and emigrations in the community between 1995 and 2016. Using known and estimated ages, we calculated survivorship curves for the whole community, for males and females separately, and for individuals ≤2 years old when identified. We used a novel method to address age estimation error by calculating stochastic survivorship curves. We compared Ngogo life expectancy, survivorship, and mortality rates to those from other chimpanzee communities and human hunter-gatherers. Life expectancy at birth for both sexes combined was 32.8 years, far exceeding estimates of chimpanzee life expectancy in other communities, and falling within the range of human hunter-gatherers (i.e., 27–37 years). Overall, the pattern of survivorship at Ngogo was more similar to that of human hunter-gatherers than to other chimpanzee communities. Maximum lifespan for the Ngogo chimpanzees, however, was similar to that reported at other chimpanzee research sites and was less than that of human-hunter gatherers. The absence of predation by large carnivores may contribute to some of the higher survivorship at Ngogo, but this cannot explain the much higher survivorship at Ngogo than at Kanyawara, another chimpanzee community in the same forest, which also lacks large carnivores. Higher survivorship at Ngogo appears to be an adaptive response to a food supply that is more abundant and varies less than that of Kanyawara. Future analyses of hominin life history evolution should take these results into account. PMID:28366199

Chimpanzees routinely fish for algae with tools during the dry season in Bakoun, Guinea.

PubMed

Boesch, Christophe; Kalan, Ammie K; Agbor, Anthony; Arandjelovic, Mimi; Dieguez, Paula; Lapeyre, Vincent; Kühl, Hjalmar S

2017-03-01

Wild chimpanzees regularly use tools, made from sticks, leaves, or stone, to find flexible solutions to the ecological challenges of their environment. Nevertheless, some studies suggest strong limitations in the tool-using capabilities of chimpanzees. In this context, we present the discovery of a newly observed tool-use behavior in a population of chimpanzees (Pan troglodytes verus) living in the Bakoun Classified Forest, Guinea, where a temporary research site was established for 15 months. Bakoun chimpanzees of every age-sex class were observed to fish for freshwater green algae, Spirogrya sp., from rivers, streams, and ponds using long sticks and twigs, ranging from 9 cm up to 4.31 m in length. Using remote camera trap footage from 11 different algae fishing sites within an 85-km 2 study area, we found that algae fishing occurred frequently during the dry season and was non-existent during the rainy season. Chimpanzees were observed algae fishing for as little as 1 min to just over an hour, with an average duration of 9.09 min. We estimate that 364 g of Spirogyra algae could be retrieved in this time, based on human trials in the field. Only one other chimpanzee population living in Bossou, Guinea, has been described to customarily scoop algae from the surface of the water using primarily herbaceous tools. Here, we describe the new behavior found at Bakoun and compare it to the algae scooping observed in Bossou chimpanzees and the occasional variant reported in Odzala, Republic of the Congo. As these algae are reported to be high in protein, carbohydrates, and minerals, we hypothesize that chimpanzees are obtaining a nutritional benefit from this seasonally available resource. © 2016 Wiley Periodicals, Inc.

Dental wear, wear rate, and dental disease in the African apes.

PubMed

Elgart, Alison A

2010-06-01

The African apes possess thinner enamel than do other hominoids, and a certain amount of dentin exposure may be advantageous in the processing of tough diets eaten by Gorilla. Dental wear (attrition plus abrasion) that erodes the enamel exposes the underlying dentin and creates additional cutting edges at the dentin-enamel junction. Hypothetically, efficiency of food processing increases with junction formation until an optimal amount is reached, but excessive wear hinders efficient food processing and may lead to sickness, reduced fecundity, and death. Occlusal surfaces of molars and incisors in three populations each of Gorilla and Pan were videotaped and digitized. The quantity of incisal and molar occlusal dental wear and the lengths of dentin-enamel junctions were measured in 220 adult and 31 juvenile gorilla and chimpanzee skulls. Rates of dental wear were calculated in juveniles by scoring the degree of wear between adjacent molars M1 and M2. Differences were compared by principal (major) axis analysis. ANOVAs compared means of wear amounts. Pearson correlation coefficients were calculated to compare the relationship between molar wear and incidence of dental disease. Results indicate that quantities of wear are significantly greater in permanent incisors and molars and juvenile molars of gorillas compared to chimpanzees. The lengths of dentin-enamel junctions were predominantly suboptimal. Western lowland gorillas have the highest quantities of wear and the most molars with suboptimal wear. The highest rates of wear are seen in Pan paniscus and Pan t. troglodytes, and the lowest rates are found in P.t. schweinfurthii and G. g. graueri. Among gorillas, G. b. beringei have the highest rates but low amounts of wear. Coefficients between wear and dental disease were low, but significant when all teeth were combined. Gorilla teeth are durable, and wear does not lead to mechanical senescence in this sample.

Geometric morphometric analysis of mandibular shape diversity in Pan.

PubMed

Robinson, Chris

2012-07-01

The aim of this research is to determine whether geometric morphometric (GM) techniques can provide insights into how the shape of the mandibular corpus differs between bonobos and chimpanzees and to explore the potential implications of those results for our understanding of hominin evolution. We focused on this region of the mandible because of the relative frequency with which it has been recovered in the hominin fossil record. In addition, no previous study had explored in-depth three-dimensional (3D) mandibular corpus shape differences between adults of the two Pan species using geometric morphometrics. GM methods enable researchers to quantitatively analyze and visualize 3D shape changes in skeletal elements and provide an important compliment to traditional two-dimensional analyses. Eighteen mandibular landmarks were collected using a Microscribe 3DX portable digitizer. Specimen configurations were superimposed using Generalized Procrustes analysis and the projections of the fitted coordinates to tangent space were analyzed using multivariate statistics. The size-adjusted corpus shapes of Pan paniscus and Pan troglodytes could be assigned to species with approximately 93% accuracy and the Procrustes distance between the two species was significant. Analyses of the residuals from a multivariate linear regression of the data on centroid size suggested that much of the shape difference between the species is size-related. Chimpanzee subspecies and a small sample of Australopithecus specimens could be correctly identified to taxon, at best, only 75% of the time, although the Procrustes distances between these taxa were significant. The shape of the mandibular symphysis was identified as especially useful in differentiating Pan species from one another. This suggests that this region of the mandible has the potential to be informative for taxonomic analyses of fossil hominoids, including hominins. The results also have implications for phylogenetic hypotheses of

In search of the last common ancestor: new findings on wild chimpanzees

PubMed Central

McGrew, W. C.

2010-01-01

Modelling the behaviour of extinct hominins is essential in order to devise useful hypotheses of our species' evolutionary origins for testing in the palaeontological and archaeological records. One approach is to model the last common ancestor (LCA) of living apes and humans, based on current ethological and ecological knowledge of our closest living relations. Such referential modelling is based on rigorous, ongoing field studies of the chimpanzee (Pan troglodytes) and the bonobo (Pan paniscus). This paper reviews recent findings from nature, focusing on those with direct implications for hominin evolution, e.g. apes, using elementary technology to access basic resources such as food and water, or sheltering in caves or bathing as thermoregulatory adaptations. I give preference to studies that directly address key issues, such as whether stone artefacts are detectible before the Oldowan, based on the percussive technology of hammer and anvil use by living apes. Detailed comparative studies of chimpanzees living in varied habitats, from rainforest to savannah, reveal that some behavioural patterns are universal (e.g. shelter construction), while others show marked (e.g. extractive foraging) or nuanced (e.g. courtship) cross-populational variation. These findings allow us to distinguish between retained, primitive traits of the LCA versus derived ones in the human lineage. PMID:20855301

Can chimpanzee infants (Pan troglodytes) form categorical representations in the same manner as human infants (Homo sapiens)?

PubMed

Murai, Chizuko; Kosugi, Daisuke; Tomonaga, Masaki; Tanaka, Masayuki; Matsuzawa, Tetsuro; Itakura, Shoji

2005-05-01

We directly compared chimpanzee infants and human infants for categorical representations of three global-like categories (mammals, furniture and vehicles), using the familiarization-novelty preference technique. Neither species received any training during the experiments. We used the time that participants spent looking at the stimulus object while touching it as a measure. During the familiarization phase, participants were presented with four familiarization objects from one of three categories (e.g. mammals). Then, they were tested with a pair of novel objects, one was a familiar-category object and another was a novel-category object (e.g. vehicle) in the test phase. The chimpanzee infants did not show significant habituation, whereas human infants did. However, most important, both species showed significant novelty-preference in the test phase. This indicates that not only human infants, but also chimpanzee infants formed categorical representations of a global-like level. Implications for the shared origins and species-specificity of categorization abilities, and the cognitive operations underlying categorization, are discussed.

A chimpanzee recognizes synthetic speech with significantly reduced acoustic cues to phonetic content.

PubMed

Heimbauer, Lisa A; Beran, Michael J; Owren, Michael J

2011-07-26

A long-standing debate concerns whether humans are specialized for speech perception, which some researchers argue is demonstrated by the ability to understand synthetic speech with significantly reduced acoustic cues to phonetic content. We tested a chimpanzee (Pan troglodytes) that recognizes 128 spoken words, asking whether she could understand such speech. Three experiments presented 48 individual words, with the animal selecting a corresponding visuographic symbol from among four alternatives. Experiment 1 tested spectrally reduced, noise-vocoded (NV) synthesis, originally developed to simulate input received by human cochlear-implant users. Experiment 2 tested "impossibly unspeechlike" sine-wave (SW) synthesis, which reduces speech to just three moving tones. Although receiving only intermittent and noncontingent reward, the chimpanzee performed well above chance level, including when hearing synthetic versions for the first time. Recognition of SW words was least accurate but improved in experiment 3 when natural words in the same session were rewarded. The chimpanzee was more accurate with NV than SW versions, as were 32 human participants hearing these items. The chimpanzee's ability to spontaneously recognize acoustically reduced synthetic words suggests that experience rather than specialization is critical for speech-perception capabilities that some have suggested are uniquely human. Copyright © 2011 Elsevier Ltd. All rights reserved.

Chimpanzees' (Pan troglodytes) use of gaze cues in object-choice tasks: different methods yield different results.

PubMed

Barth, Jochen; Reaux, James E; Povinelli, Daniel J

2005-04-01

To assess the influence of different procedures on chimpanzees' performance in object-choice tasks, five adult chimpanzees were tested using three experimenter-given cues to food location: gazing, glancing, and pointing. These cues were delivered to the subjects in an identical fashion but were deployed within the context of two distinct meta-procedures that have been previously employed with this species with conflicting results. In one procedure, the subjects entered the test unit and approached the experimenter (who had already established the cue) on each trial. In the other procedure, the subjects stayed in the test unit throughout a session, witnessed the hiding procedure, and waited for a delay of 10 s during which the cue was provided. The subjects scored at high levels far exceeding chance in response to the gaze cue only when they approached the experimenter for each trial. They performed at chance levels when they stayed inside the test unit throughout the session. They scored at chance levels on all other cues irrespective of the procedure. These findings imply that (a) chimpanzees can immediately exploit social gaze cues, and (b) previous conflicting findings were likely due to the different meta-procedures that were used.

The importance of witnessed agency in chimpanzee social learning of tool use☆

PubMed Central

Hopper, Lydia M.; Lambeth, Susan P.; Schapiro, Steven J.; Whiten, Andrew

2015-01-01

Social learning refers to individuals learning from others, including information gained through indirect social influences, such as the results of others’ actions and changes in the physical environment. One method to determine the relative influence of these varieties of information is the ‘ghost display’, in which no model is involved, but subjects can watch the results that a model would produce. Previous research has shown mixed success by chimpanzees (Pan troglodytes) learning from ghost displays, with some studies suggesting learning only in relatively simple tasks. To explore whether the failure of chimpanzees to learn from a ghost display may be due to neophobia when tested singly or a requirement for more detailed information for complex tasks, we presented ghost displays of a tool-use task to chimpanzees in their home social groups. Previous tests have revealed that chimpanzees are unable to easily solve this tool-use task asocially, or learn from ghost displays when tested singly, but can learn after observing conspecifics in a group setting. In the present study, despite being tested in a group situation, chimpanzees still showed no success in solving the task via trial-and-error learning, in a baseline condition, nor in learning the task from the ghost display. Simply being in the presence of their group mates and being shown the affordances of the task was not sufficient to encourage learning. Following this, in an escalating series of tests, we examined the chimpanzees’ ability to learn from a demonstration by models with agency: (1) a human; (2) video footage of a chimpanzee; (3) a live chimpanzee model. In the first two of these ‘social’ conditions, subjects showed limited success. By the end of the final open diffusion phase, which was run to determine whether this new behavior would be transmitted among the group after seeing a successful chimpanzee use the task, 83% of chimpanzees were now successful. This confirmed a marked overall

Developmental patterns of chimpanzee cerebral tissues provide important clues for understanding the remarkable enlargement of the human brain.

PubMed

Sakai, Tomoko; Matsui, Mie; Mikami, Akichika; Malkova, Ludise; Hamada, Yuzuru; Tomonaga, Masaki; Suzuki, Juri; Tanaka, Masayuki; Miyabe-Nishiwaki, Takako; Makishima, Haruyuki; Nakatsukasa, Masato; Matsuzawa, Tetsuro

2013-02-22

Developmental prolongation is thought to contribute to the remarkable brain enlargement observed in modern humans (Homo sapiens). However, the developmental trajectories of cerebral tissues have not been explored in chimpanzees (Pan troglodytes), even though they are our closest living relatives. To address this lack of information, the development of cerebral tissues was tracked in growing chimpanzees during infancy and the juvenile stage, using three-dimensional magnetic resonance imaging and compared with that of humans and rhesus macaques (Macaca mulatta). Overall, cerebral development in chimpanzees demonstrated less maturity and a more protracted course during prepuberty, as observed in humans but not in macaques. However, the rapid increase in cerebral total volume and proportional dynamic change in the cerebral tissue in humans during early infancy, when white matter volume increases dramatically, did not occur in chimpanzees. A dynamic reorganization of cerebral tissues of the brain during early infancy, driven mainly by enhancement of neuronal connectivity, is likely to have emerged in the human lineage after the split between humans and chimpanzees and to have promoted the increase in brain volume in humans. Our findings may lead to powerful insights into the ontogenetic mechanism underlying human brain enlargement.

Developmental patterns of chimpanzee cerebral tissues provide important clues for understanding the remarkable enlargement of the human brain

PubMed Central

Sakai, Tomoko; Matsui, Mie; Mikami, Akichika; Malkova, Ludise; Hamada, Yuzuru; Tomonaga, Masaki; Suzuki, Juri; Tanaka, Masayuki; Miyabe-Nishiwaki, Takako; Makishima, Haruyuki; Nakatsukasa, Masato; Matsuzawa, Tetsuro

2013-01-01

Developmental prolongation is thought to contribute to the remarkable brain enlargement observed in modern humans (Homo sapiens). However, the developmental trajectories of cerebral tissues have not been explored in chimpanzees (Pan troglodytes), even though they are our closest living relatives. To address this lack of information, the development of cerebral tissues was tracked in growing chimpanzees during infancy and the juvenile stage, using three-dimensional magnetic resonance imaging and compared with that of humans and rhesus macaques (Macaca mulatta). Overall, cerebral development in chimpanzees demonstrated less maturity and a more protracted course during prepuberty, as observed in humans but not in macaques. However, the rapid increase in cerebral total volume and proportional dynamic change in the cerebral tissue in humans during early infancy, when white matter volume increases dramatically, did not occur in chimpanzees. A dynamic reorganization of cerebral tissues of the brain during early infancy, driven mainly by enhancement of neuronal connectivity, is likely to have emerged in the human lineage after the split between humans and chimpanzees and to have promoted the increase in brain volume in humans. Our findings may lead to powerful insights into the ontogenetic mechanism underlying human brain enlargement. PMID:23256194

Mapping and discriminating the Pan-African granitoids in the Hoggar (southern Algeria) using Landsat 7 ETM+ data and airborne geophysics

NASA Astrophysics Data System (ADS)

Zerrouk, Siham; Bendaoud, Abderrahmane; Hamoudi, Mohamed; Liégeois, Jean Paul; Boubekri, Hichem; El Khaznadji, Riad Ben

2017-03-01

This study presents a multidisciplinary approach to discriminate and map different types and generations of Pan-African granitoids in the Hoggar, southern Algeria, using remote sensing and airborne geophysics in close correlation with previous works and established geological maps. RGB (Red, Green, Blue) combinations of band ratios; principal component analysis (PCA) and image classification for Landsat 7 ETM+ (Enhanced Thematic Mapper Plus), allow spatial discrimination and mapping of granitoid rocks of the studied area (200*350 km). This area extend over four contrasted Pan-African terranes (In Tedeini, Iskel, Tefedest and Laouni terranes, the two latter belong to the LATEA (Laouni-Azrou-n-Fad-Tefedest-Egéré-Aleksod-Assodé-Issalane) metacraton. The airborne magnetic intensity provides a wide range of responses from high values (youngest granitoids) to low values (volcano-sedimentary and gneissic country-rocks). Radiometric data, displaying radioelements concentration, discriminate efficiently the late alkaline granitoids (high values), the calk-alkaline granitoids (intermediate values) and the Tonalite-Trondhjemite-Granodiorite series (low values). This study led to the establishment of a more accurate geological map where the geochemical characteristics of the Pan-African granitoids are determined, including plutons not yet studied, especially in the poorly known In Tedeini terrane, and brings new constraints for the geodynamic development of the Tuareg Shield, which includes the Hoggar.

Age-related changes in urinary testosterone levels suggest differences in puberty onset and divergent life history strategies in bonobos and chimpanzees.

PubMed

Behringer, V; Deschner, T; Deimel, C; Stevens, J M G; Hohmann, G

2014-08-01

Research on age-related changes in morphology, social behavior, and cognition suggests that the development of bonobos (Pan paniscus) is delayed in comparison to chimpanzees (Pan troglodytes). However, there is also evidence for earlier reproductive maturation in bonobos. Since developmental changes such as reproductive maturation are induced by a number of endocrine processes, changes in hormone levels are indicators of different developmental stages. Age-related changes in testosterone excretion are an indirect marker for the onset of puberty in human and non-human primates. In this study we investigated patterns of urinary testosterone levels in male and female bonobos and chimpanzees to determine the onset of puberty. In contrast to other studies, we found that both species experience age-related changes in urinary testosterone levels. Older individuals of both sexes had significantly higher urinary testosterone levels than younger individuals, indicating that bonobos and chimpanzees experience juvenile pause. The males of both species showed a similar pattern of age-related changes in urinary testosterone levels, with a sharp increase in levels around the age of eight years. This suggests that species-differences in aggression and male mate competition evolved independently of developmental changes in testosterone levels. Females showed a similar pattern of age-related urinary testosterone increase. However, in female bonobos the onset was about three years earlier than in female chimpanzees. The earlier rise of urinary testosterone levels in female bonobos is in line with reports of their younger age of dispersal, and suggests that female bonobos experience puberty at a younger age than female chimpanzees. Copyright © 2014 Elsevier Inc. All rights reserved.

Y-Chromosome Variation in Hominids: Intraspecific Variation Is Limited to the Polygamous Chimpanzee

PubMed Central

Greve, Gabriele; Alechine, Evguenia; Pasantes, Juan J.; Hodler, Christine; Rietschel, Wolfram; Robinson, Terence J.; Schempp, Werner

2011-01-01

Background We have previously demonstrated that the Y-specific ampliconic fertility genes DAZ (deleted in azoospermia) and CDY (chromodomain protein Y) varied with respect to copy number and position among chimpanzees (Pan troglodytes). In comparison, seven Y-chromosomal lineages of the bonobo (Pan paniscus), the chimpanzee's closest living relative, showed no variation. We extend our earlier comparative investigation to include an analysis of the intraspecific variation of these genes in gorillas (Gorilla gorilla) and orangutans (Pongo pygmaeus), and examine the resulting patterns in the light of the species' markedly different social and mating behaviors. Methodology/Principal Findings Fluorescence in situ hybridization analysis (FISH) of DAZ and CDY in 12 Y-chromosomal lineages of western lowland gorilla (G. gorilla gorilla) and a single lineage of the eastern lowland gorilla (G. beringei graueri) showed no variation among lineages. Similar findings were noted for the 10 Y-chromosomal lineages examined in the Bornean orangutan (Pongo pygmaeus), and 11 Y-chromosomal lineages of the Sumatran orangutan (P. abelii). We validated the contrasting DAZ and CDY patterns using quantitative real-time polymerase chain reaction (qPCR) in chimpanzee and bonobo. Conclusion/Significance High intraspecific variation in copy number and position of the DAZ and CDY genes is seen only in the chimpanzee. We hypothesize that this is best explained by sperm competition that results in the variant DAZ and CDY haplotypes detected in this species. In contrast, bonobos, gorillas and orangutans—species that are not subject to sperm competition—showed no intraspecific variation in DAZ and CDY suggesting that monoandry in gorillas, and preferential female mate choice in bonobos and orangutans, probably permitted the fixation of a single Y variant in each taxon. These data support the notion that the evolutionary history of a primate Y chromosome is not simply encrypted in its DNA

More reliable estimates of divergence times in Pan using complete mtDNA sequences and accounting for population structure.

PubMed

Stone, Anne C; Battistuzzi, Fabia U; Kubatko, Laura S; Perry, George H; Trudeau, Evan; Lin, Hsiuman; Kumar, Sudhir

2010-10-27

Here, we report the sequencing and analysis of eight complete mitochondrial genomes of chimpanzees (Pan troglodytes) from each of the three established subspecies (P. t. troglodytes, P. t. schweinfurthii and P. t. verus) and the proposed fourth subspecies (P. t. ellioti). Our population genetic analyses are consistent with neutral patterns of evolution that have been shaped by demography. The high levels of mtDNA diversity in western chimpanzees are unlike those seen at nuclear loci, which may reflect a demographic history of greater female to male effective population sizes possibly owing to the characteristics of the founding population. By using relaxed-clock methods, we have inferred a timetree of chimpanzee species and subspecies. The absolute divergence times vary based on the methods and calibration used, but relative divergence times show extensive uniformity. Overall, mtDNA produces consistently older times than those known from nuclear markers, a discrepancy that is reduced significantly by explicitly accounting for chimpanzee population structures in time estimation. Assuming the human-chimpanzee split to be between 7 and 5 Ma, chimpanzee time estimates are 2.1-1.5, 1.1-0.76 and 0.25-0.18 Ma for the chimpanzee/bonobo, western/(eastern + central) and eastern/central chimpanzee divergences, respectively.

Landsat-based Earth Observations and Crowd-sourced Data Provide Near Real-time Monitoring of Chimpanzee Habitat

NASA Astrophysics Data System (ADS)

Nackoney, J.; Pintea, L.; Jantz, S.; Hansen, M.

2015-12-01

The endangered chimpanzee (Pan troglodytes) is threatened by habitat loss from resource extraction and land conversion, as well as hunting, disease and the illegal pet trade. It has been estimated that more than 70% of chimpanzee's tropical forest habitats in Africa are now threatened by land use change. Recent developments in remote sensing and cloud computing enable the use of satellite observations to provide a synoptic view of chimpanzee habitats at finer spatial and temporal resolutions that are locally relevant and consistent across the entire species' range. We present a practical Decision Support System to be used by the Jane Goodall Institute and partners to annually monitor and forecast chimpanzee habitat health in Africa. The system integrates Earth observations from 30-meter resolution Landsat data with a species-specific habitat model and a model forecasting future land use change, enhanced by crowd-sourced field data collected by local communities and rangers using the Open Data Kit app and Android mobile smartphones and tablets. While coarser-scale and static chimpanzee habitat models have been previously developed, this project is the first to develop a dynamic monitoring system updated annually via Earth observations data that will systematically monitor threats and changes in habitat over time. Since the chimpanzee is an important keystone, flagship and umbrella species, an annual chimpanzee habitat health index would support conservation goals of other species within its large 2.5 million sq. km range and could be an important indicator of overall ecosystem health of tropical forests in Africa.

Detection of Termites and Other Insects Consumed by African Great Apes using Molecular Fecal Analysis

PubMed Central

Hamad, Ibrahim; Delaporte, Eric; Raoult, Didier; Bittar, Fadi

2014-01-01

The consumption of insects by apes has previously been reported based on direct observations and/or trail signs in feces. However, DNA-based diet analyses may have the potential to reveal trophic links for these wild species. Herein, we analyzed the insect-diet diversity of 9 feces obtained from three species of African great apes, gorilla (Gorilla gorilla gorilla), chimpanzee (Pan troglodytes) and bonobo (Pan paniscus), using two mitochondrial amplifications for arthropods. A total of 1056 clones were sequenced for Cyt-b and COI gene libraries, which contained 50 and 56 operational taxonomic units (OTUs), respectively. BLAST research revealed that the OTUs belonged to 32 families from 5 orders (Diptera, Isoptera, Lepidoptera, Coleoptera, and Orthoptera). While ants were not detected by this method, the consumption of flies, beetles, moths, mosquitoes and termites was evident in these samples. Our findings indicate that molecular techniques can be used to analyze insect food items in wild animals. PMID:24675424

Dietary responses to fruit scarcity of wild chimpanzees at Bossou, Guinea: possible implications for ecological importance of tool use.

PubMed

Yamakoshi, G

1998-07-01

A 13-month ecological study was conducted at Bossou, Guinea, West Africa, to elucidate how a community of wild chimpanzees (Pan troglodytes verus) deals with the scarcity of main foods. During the study period, fruit availability fluctuated radically. The chimpanzees were confirmed to depend heavily on three "keystone resources" which were available when their main foods (fruit pulp) were scarce. These were fruits of Musanga cecropioides, oil-palm (Elaeis guineensis) nuts, and oil-palm pith. These are abundant in the chimpanzees' home range and their nutritional contents compensate for a decrease in nutritional intake from fruit pulp. The presence of these excellent backup foods may explain the high reproductive performance of Bossou chimpanzees. Here, chimpanzees consumed two of the three keystone foods using two types of tool behavior: nut-cracking for oil-palm nuts and pestle-pounding for oil-palm pith. These tool-using behaviors accounted for 31.9% of the total feeding time spent in June (the month in which the highest frequency occurred) and 10.4% in total for the year. It is suggested that the Bossou chimpanzees depend strongly on tools for their subsistence. This implies a possible function for tool technology in the evolution of our human ancestors.

Tool-use for drinking water by immature chimpanzees of Mahale: prevalence of an unessential behavior.

PubMed

Matsusaka, Takahisa; Nishie, Hitonaru; Shimada, Masaki; Kutsukake, Nobuyuki; Zamma, Koichiro; Nakamura, Michio; Nishida, Toshisada

2006-04-01

Use of leaves or sticks for drinking water has only rarely been observed during long-term study of wild chimpanzees (Pan troglodytes schweinfurthii) at Mahale. Recently, however, we observed 42 episodes of tool-use for drinking water (73 tools and two cases of using "tool-sets") between 1999 and 2004. Interestingly, all of the performers were immature chimpanzees aged from 2 to 10 years. Immature chimpanzees sometimes observed the tool-using performance of others and subsequently reproduced the behavior, while adults usually paid no attention to the performance. This tool-use did not seem to occur out of necessity: (1) chimpanzees often used tools along streams where they could drink water without tools, (2) they used tools for drinking water from tree holes during the wet season when they could easily obtain water from many streams, and (3) the tool-using performance sometimes contained playful aspects. Between-site comparisons revealed that chimpanzees at drier habitats used tools for drinking water more frequently and in a more "conventional" manner. However, some variations could not be explained by ecological conditions. Such variations and the increase in this tool-use in recent years at Mahale strongly suggest that social learning plays an important role in the process of acquiring the behavior. We should note here that such behaviors that lack obvious benefits or necessity can be prevalent in a group.

Complete genome sequence of Streptococcus troglodytae TKU31 isolated from the oral cavity of a chimpanzee (Pan troglodytes).

PubMed

Okamoto, Masaaki; Naito, Mariko; Miyanohara, Mayu; Imai, Susumu; Nomura, Yoshiaki; Saito, Wataru; Momoi, Yasuko; Takada, Kazuko; Miyabe-Nishiwaki, Takako; Tomonaga, Masaki; Hanada, Nobuhiro

2016-12-01

Streptococcus troglodytae TKU31 was isolated from the oral cavity of a chimpanzee (Pan troglodytes) and was found to be the most closely related species of the mutans group streptococci to Streptococcus mutans. The complete sequence of TKU31 genome consists of a single circular chromosome that is 2,097,874 base pairs long and has a G + C content of 37.18%. It possesses 2082 coding sequences (CDSs), 65 tRNAs and five rRNA operons (15 rRNAs). Two clustered regularly interspaced short palindromic repeats, six insertion sequences and two predicted prophage elements were identified. The genome of TKU31 harbors some putative virulence associated genes, including gtfB, gtfC and gtfD genes encoding glucosyltransferase and gbpA, gbpB, gbpC and gbpD genes encoding glucan-binding cell wall-anchored protein. The deduced amino acid identity of the rhamnose-glucose polysaccharide F gene (rgpF), which is one of the serotype determinants, is 91% identical with that of S. mutans LJ23 (serotype k) strain. However, two other virulence-associated genes cnm and cbm, which encode the collagen-binding proteins, were not found in the TKU31 genome. The complete genome sequence of S. troglodytae TKU31 has been deposited at DDBJ/European Nucleotide Archive/GenBank under the accession no. AP014612. © 2016 The Societies and John Wiley & Sons Australia, Ltd.

The influence of AVPR1A genotype on individual differences in behaviors during a mirror self-recognition task in chimpanzees (Pan troglodytes).

PubMed

Mahovetz, L M; Young, L J; Hopkins, W D

2016-06-01

The mark/rouge test has been used to assess mirror self-recognition (MSR) in many species. Despite consistent evidence of MSR in great apes, genetic or non-genetic factors may account for the individual differences in behavioral responses that have been reported. We examined whether vasopressin receptor gene (AVPR1A) polymorphisms are associated with MSR-related behaviors in chimpanzees since vasopressin has been implicated in the development and evolution of complex social relations and cognition and chimpanzees are polymorphic for the presence of the RS3-containing DupB region. We compared a sample of DupB+/- and DupB-/- chimpanzees on a mark test to assess its role on social behavior toward a mirror. Chimpanzees were administered two, 10-min sessions where frequencies of mirror-guided self-directed behaviors, contingent actions and other social behaviors were recorded. Approximately one-third showed evidence of MSR and these individuals exhibited more mirror-guided self-exploratory behaviors and mouth contingent actions than chimpanzees not classified as passers. Moreover, DupB+/- males exhibited more scratching and agonistic behaviors than other male and female cohorts. Our findings support previous studies demonstrating individual differences in MSR abilities in chimpanzees and suggest that AVPR1A partly explains individual differences in MSR by influencing the behavioral reactions of chimpanzees in front of a mirror. © 2016 John Wiley & Sons Ltd and International Behavioural and Neural Genetics Society.

Social network and dominance hierarchy analyses at Chimpanzee Sanctuary Northwest

PubMed Central

Mayhew, Jessica A.; Mulcahy, John B.

2018-01-01

Different aspects of sociality bear considerable weight on the individual- and group-level welfare of captive nonhuman primates. Social Network Analysis (SNA) is a useful tool for gaining a holistic understanding of the dynamic social relationships of captive primate groups. Gaining a greater understanding of captive chimpanzees through investigations of centrality, preferred and avoided relationships, dominance hierarchy, and social network diagrams can be useful in advising current management practices in sanctuaries and other captive settings. In this study, we investigated the dyadic social relationships, group-level social networks, and dominance hierarchy of seven chimpanzees (Pan troglodytes) at Chimpanzee Sanctuary Northwest. We used focal-animal and instantaneous scan sampling to collect 106.75 total hours of associative, affiliative, and agonistic data from June to September 2016. We analyzed our data using SOCPROG to derive dominance hierarchies and network statistics, and we diagrammed the group’s social networks in NetDraw. Three individuals were most central in the grooming network, while two others had little connection. Through agonistic networks, we found that group members reciprocally exhibited agonism, and the group’s dominance hierarchy was statistically non-linear. One chimpanzee emerged as the most dominant through agonism but was least connected to other group members across affiliative networks. Our results indicate that the conventional methods used to calculate individuals’ dominance rank may be inadequate to wholly depict a group’s social relationships in captive sanctuary populations. Our results have an applied component that can aid sanctuary staff in a variety of ways to best ensure the improvement of group welfare. PMID:29444112

Social network and dominance hierarchy analyses at Chimpanzee Sanctuary Northwest.

PubMed

Funkhouser, Jake A; Mayhew, Jessica A; Mulcahy, John B

2018-01-01

Different aspects of sociality bear considerable weight on the individual- and group-level welfare of captive nonhuman primates. Social Network Analysis (SNA) is a useful tool for gaining a holistic understanding of the dynamic social relationships of captive primate groups. Gaining a greater understanding of captive chimpanzees through investigations of centrality, preferred and avoided relationships, dominance hierarchy, and social network diagrams can be useful in advising current management practices in sanctuaries and other captive settings. In this study, we investigated the dyadic social relationships, group-level social networks, and dominance hierarchy of seven chimpanzees (Pan troglodytes) at Chimpanzee Sanctuary Northwest. We used focal-animal and instantaneous scan sampling to collect 106.75 total hours of associative, affiliative, and agonistic data from June to September 2016. We analyzed our data using SOCPROG to derive dominance hierarchies and network statistics, and we diagrammed the group's social networks in NetDraw. Three individuals were most central in the grooming network, while two others had little connection. Through agonistic networks, we found that group members reciprocally exhibited agonism, and the group's dominance hierarchy was statistically non-linear. One chimpanzee emerged as the most dominant through agonism but was least connected to other group members across affiliative networks. Our results indicate that the conventional methods used to calculate individuals' dominance rank may be inadequate to wholly depict a group's social relationships in captive sanctuary populations. Our results have an applied component that can aid sanctuary staff in a variety of ways to best ensure the improvement of group welfare.

Foundations of cumulative culture in apes: improved foraging efficiency through relinquishing and combining witnessed behaviours in chimpanzees (Pan troglodytes).

PubMed

Davis, Sarah J; Vale, Gillian L; Schapiro, Steven J; Lambeth, Susan P; Whiten, Andrew

2016-10-24

A vital prerequisite for cumulative culture, a phenomenon often asserted to be unique to humans, is the ability to modify behaviour and flexibly switch to more productive or efficient alternatives. Here, we first established an inefficient solution to a foraging task in five captive chimpanzee groups (N = 19). Three groups subsequently witnessed a conspecific using an alternative, more efficient, solution. When participants could successfully forage with their established behaviours, most individuals did not switch to this more efficient technique; however, when their foraging method became substantially less efficient, nine chimpanzees with socially-acquired information (four of whom witnessed additional human demonstrations) relinquished their old behaviour in favour of the more efficient one. Only a single chimpanzee in control groups, who had not witnessed a knowledgeable model, discovered this. Individuals who switched were later able to combine components of their two learned techniques to produce a more efficient solution than their extensively used, original foraging method. These results suggest that, although chimpanzees show a considerable degree of conservatism, they also have an ability to combine independent behaviours to produce efficient compound action sequences; one of the foundational abilities (or candidate mechanisms) for human cumulative culture.

The Niassa Gold Belt, northern Mozambique - A segment of a continental-scale Pan-African gold-bearing structure?

NASA Astrophysics Data System (ADS)

Bjerkgard, T.; Stein, H. J.; Bingen, B.; Henderson, I. H. C.; Sandstad, J. S.; Moniz, A.

2009-01-01

The Niassa Gold Belt, in northernmost Mozambique, is hosted in the Txitonga Group, a Neoproterozoic rift sequence overlying Paleoproterozoic crust of the Congo-Tanzania Craton and deformed during the Pan-African Orogeny. The Txitonga Group is made up of greenschist-facies greywacke and schist and is characterized by bimodal, mainly mafic, magmatism. A zircon U-Pb age for a felsic volcanite dates deposition of the sequence at 714 ± 17 Ma. Gold is mined artisanally from alluvial deposits and primary chalcopyrite-pyrite-bearing quartz veins containing up to 19 ppm Au have been analyzed. In the Cagurué and M'Papa gold fields, dominantly N-S trending quartz veins, hosted in metagabbro and schist, are regarded as tension gashes related to regional strike-slip NE-SW-trending Pan-African shear zones. These gold deposits have been classified as mesozonal and metamorphic in origin. Re-Os isotopic data on sulfides suggest two periods of gold deposition for the Cagurué Gold Field. A coarse-crystalline pyrite-chalcopyrite assemblage yields an imprecise Pan-African age of 483 ± 72 Ma, dating deposition of the quartz veins. Remobilization of early-formed sulfides, particularly chalcopyrite, took place at 112 ± 14 Ma, during Lower Cretaceous Gondwana dispersal. The ˜483 Ma assemblage yields a chondritic initial 187Os/ 188Os ratio of 0.123 ± 0.058. This implies a juvenile source for the ore fluids, possibly involving the hosting Neoproterozoic metagabbro. The Niassa Gold Belt is situated at the eastern end of a SW-NE trending continental-scale lineament defined by the Mwembeshi Shear Zone and the southern end of a NW-SE trending lineament defined by the Rukwa Shear Zone. We offer a review of gold deposits in Zambia and Tanzania associated with these polyphase lineaments and speculate on their interrelation.

Contagious yawning in chimpanzees.

PubMed Central

Anderson, James R; Myowa-Yamakoshi, Masako; Matsuzawa, Tetsuro

2004-01-01

Six adult female chimpanzees were shown video scenes of chimpanzees repeatedly yawning or of chimpanzees showing open-mouth facial expressions that were not yawns. Two out of the six females showed significantly higher frequencies of yawning in response to yawn videos; no chimpanzees showed the inverse. Three infant chimpanzees that accompanied their mothers did not yawn at all. These data are highly reminiscent of the contagious yawning effects reported for humans. Contagious yawning is thought to be based on the capacity for empathy. Contagious yawning in chimpanzees provides further evidence that these apes may possess advanced self-awareness and empathic abilities. PMID:15801606

The Chimpanzee Model of Viral Hepatitis: Advances in Understanding the Immune Response and Treatment of Viral Hepatitis

PubMed Central

Lanford, Robert E; Walker, Christopher M; Lemon, Stanley M

2017-01-01

Abstract Chimpanzees (Pan troglodytes) have contributed to diverse fields of biomedical research due to their close genetic relationship to humans and in many instances due to the lack of any other animal model. This review focuses on the contributions of the chimpanzee model to research on hepatitis viruses where chimpanzees represented the only animal model (hepatitis B and C) or the most appropriate animal model (hepatitis A). Research with chimpanzees led to the development of vaccines for HAV and HBV that are used worldwide to protect hundreds of millions from these diseases and, where fully implemented, have provided immunity for entire generations. More recently, chimpanzee research was instrumental in the development of curative therapies for hepatitis C virus infections. Over a span of 40 years, this research would identify the causative agent of NonA,NonB hepatitis, validate the molecular tools for drug discovery, and provide safety and efficacy data on the therapies that now provide a rapid and complete cure of HCV chronic infections. Several cocktails of antivirals are FDA approved that eliminate the virus following 12 weeks of once-per-day oral therapy. This represents the first cure of a chronic viral disease and, once broadly implemented, will dramatically reduce the occurrence of cirrhosis and liver cancer. The recent contributions of chimpanzees to our current understanding of T cell immunity for HCV, development of novel therapeutics for HBV, and the biology of HAV are reviewed. Finally, a perspective is provided on the events leading to the cessation of the use of chimpanzees in research and the future of the chimpanzees previously used to bring about these amazing breakthroughs in human healthcare. PMID:29045731

Neutralization Properties of Simian Immunodeficiency Viruses Infecting Chimpanzees and Gorillas

PubMed Central

Barbian, Hannah J.; Decker, Julie M.; Bibollet-Ruche, Frederic; Galimidi, Rachel P.; West, Anthony P.; Learn, Gerald H.; Parrish, Nicholas F.; Iyer, Shilpa S.; Li, Yingying; Pace, Craig S.; Song, Ruijiang; Huang, Yaoxing; Denny, Thomas N.; Mouquet, Hugo; Martin, Loic; Acharya, Priyamvada; Zhang, Baoshan; Kwong, Peter D.; Mascola, John R.; Verrips, C. Theo; Strokappe, Nika M.; Rutten, Lucy; McCoy, Laura E.; Weiss, Robin A.; Brown, Corrine S.; Jackson, Raven; Silvestri, Guido; Connors, Mark; Burton, Dennis R.; Shaw, George M.; Nussenzweig, Michel C.; Bjorkman, Pamela J.; Ho, David D.; Farzan, Michael

2015-01-01

ABSTRACT Broadly cross-reactive neutralizing antibodies (bNabs) represent powerful tools to combat human immunodeficiency virus type 1 (HIV-1) infection. Here, we examined whether HIV-1-specific bNabs are capable of cross-neutralizing distantly related simian immunodeficiency viruses (SIVs) infecting central (Pan troglodytes troglodytes) (SIVcpzPtt) and eastern (Pan troglodytes schweinfurthii) (SIVcpzPts) chimpanzees (n = 11) as well as western gorillas (Gorilla gorilla gorilla) (SIVgor) (n = 1). We found that bNabs directed against the CD4 binding site (n = 10), peptidoglycans at the base of variable loop 3 (V3) (n = 5), and epitopes at the interface of surface (gp120) and membrane-bound (gp41) envelope glycoproteins (n = 5) failed to neutralize SIVcpz and SIVgor strains. In addition, apex V2-directed bNabs (n = 3) as well as llama-derived (heavy chain only) antibodies (n = 6) recognizing both the CD4 binding site and gp41 epitopes were either completely inactive or neutralized only a fraction of SIVcpzPtt strains. In contrast, one antibody targeting the membrane-proximal external region (MPER) of gp41 (10E8), functional CD4 and CCR5 receptor mimetics (eCD4-Ig, eCD4-Igmim2, CD4-218.3-E51, and CD4-218.3-E51-mim2), as well as mono- and bispecific anti-human CD4 (iMab and LM52) and CCR5 (PRO140, PRO140-10E8) receptor antibodies neutralized >90% of SIVcpz and SIVgor strains with low-nanomolar (0.13 to 8.4 nM) potency. Importantly, the latter antibodies blocked virus entry not only in TZM-bl cells but also in Cf2Th cells expressing chimpanzee CD4 and CCR5 and neutralized SIVcpz in chimpanzee CD4+ T cells, with 50% inhibitory concentrations (IC50s) ranging from 3.6 to 40.5 nM. These findings provide new insight into the protective capacity of anti-HIV-1 bNabs and identify candidates for further development to combat SIVcpz infection. PMID:25900654

Chimpanzees trust conspecifics to engage in low-cost reciprocity.

PubMed

Engelmann, Jan M; Herrmann, Esther; Tomasello, Michael

2015-02-22

Many of humans' most important social interactions rely on trust, including most notably among strangers. But little is known about the evolutionary roots of human trust. We presented chimpanzees (Pan troglodytes) with a modified version of the human trust game--trust in reciprocity--in which subjects could opt either to obtain a small but safe reward on their own or else to send a larger reward to a partner and trust her to reciprocate a part of the reward that she could not access herself. In a series of three studies, we found strong evidence that in interacting with a conspecific, chimpanzees show spontaneous trust in a novel context; flexibly adjust their level of trust to the trustworthiness of their partner and develop patterns of trusting reciprocity over time. At least in some contexts then, trust in reciprocity is not unique to humans, but rather has its evolutionary roots in the social interactions of humans' closest primate relatives. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting.

PubMed

Hopper, Lydia M; Kurtycz, Laura M; Ross, Stephen R; Bonnie, Kristin E

2015-01-01

In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel) or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes). The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3). However, when travel was required for both rewards (phase 2), the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more-preferred food, they

Superposition de la tectonique éburnéenne et panafricaine dans les granitoïdes de la bordure nord du craton ouest africain, boutonniére de Zenaga, Anti-Atlas central, Maroc(Pan-african overprint on Eburnian granitoids at the northern boundary of the West African Craton, Zenaga Inlier, central Anti-Atlas, Morocco)

NASA Astrophysics Data System (ADS)

Ennih, N.; Laduron, D.; Greiling, R. O.; Errami, E.; de Wall, H.; Boutaleb, M.

2001-05-01

The Zenaga Inlier shows a comprehensive record of the Eburnian and Pan-African Orogenies. The Eburnian is characterised by high-temperature regional metamorphism and complex magmatism. The early (Azguemerzi) granodiorite has an isotopic mantle signature and was emplaced diapirically during the Eburnian Orogeny causing local thermal metamorphism. The foliation observed in this granitoid is a result of the interference between its primary syn-emplacement foliation and the regional foliation under amphibolite-facies conditions. The northern part of Zenaga has been intruded by the leucocratic granites of Tazenakht. These granites are cut by mylonites and phyllonites, corresponding to the Pan-African shear zones and accompanied with sub-greenschist-facies metamorphism during the Pan-African Orogeny. The deformation was the result of a regional sinistral transpressive event. This study in the northern part of the West African Craton shows the superposition of the Pan-African on the Eburnian Orogeny and the presence of a major fault in the Anti-Atlas.

Neural Correlates of Face and Object Perception in an Awake Chimpanzee (Pan Troglodytes) Examined by Scalp-Surface Event-Related Potentials

PubMed Central

Fukushima, Hirokata; Hirata, Satoshi; Ueno, Ari; Matsuda, Goh; Fuwa, Kohki; Sugama, Keiko; Kusunoki, Kiyo; Hirai, Masahiro; Hiraki, Kazuo; Tomonaga, Masaki; Hasegawa, Toshikazu

2010-01-01

Background The neural system of our closest living relative, the chimpanzee, is a topic of increasing research interest. However, electrophysiological examinations of neural activity during visual processing in awake chimpanzees are currently lacking. Methodology/Principal Findings In the present report, skin-surface event-related brain potentials (ERPs) were measured while a fully awake chimpanzee observed photographs of faces and objects in two experiments. In Experiment 1, human faces and stimuli composed of scrambled face images were displayed. In Experiment 2, three types of pictures (faces, flowers, and cars) were presented. The waveforms evoked by face stimuli were distinguished from other stimulus types, as reflected by an enhanced early positivity appearing before 200 ms post stimulus, and an enhanced late negativity after 200 ms, around posterior and occipito-temporal sites. Face-sensitive activity was clearly observed in both experiments. However, in contrast to the robustly observed face-evoked N170 component in humans, we found that faces did not elicit a peak in the latency range of 150–200 ms in either experiment. Conclusions/Significance Although this pilot study examined a single subject and requires further examination, the observed scalp voltage patterns suggest that selective processing of faces in the chimpanzee brain can be detected by recording surface ERPs. In addition, this non-invasive method for examining an awake chimpanzee can be used to extend our knowledge of the characteristics of visual cognition in other primate species. PMID:20967284

Ingroup-outgroup bias in contagious yawning by chimpanzees supports link to empathy.

PubMed

Campbell, Matthew W; de Waal, Frans B M

2011-04-06

Humans favor others seen as similar to themselves (ingroup) over people seen as different (outgroup), even without explicitly stated bias. Ingroup-outgroup bias extends to involuntary responses, such as empathy for pain. However, empathy biases have not been tested in our close primate relatives. Contagious yawning has been theoretically and empirically linked to empathy. If empathy underlies contagious yawning, we predict that subjects should show an ingroup-outgroup bias by yawning more in response to watching ingroup members yawn than outgroup. Twenty-three chimpanzees (Pan troglodytes) from two separate groups watched videos of familiar and unfamiliar individuals yawning or at rest (control). The chimpanzees yawned more when watching the familiar yawns than the familiar control or the unfamiliar yawns, demonstrating an ingroup-outgroup bias in contagious yawning. These results provide further empirical support that contagious yawning is a measure of empathy, which may be useful for evolutionary biology and mental health.

Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes).

PubMed

Carlitz, Esther H D; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C; van Schaik, Carel P

2016-01-01

Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species.

Comparative social grooming networks in captive chimpanzees and bonobos.

PubMed

Rodrigues, Michelle A; Boeving, Emily R

2018-06-21

Despite similar dispersal patterns, models of Pan sociality emphasize sex differences in social bonding between the two species. Such disparities are attributed to hypothesized differences in environmental selective pressures that structure association patterns. However, recent research documents greater within-species variation in social bonds in both species. Here, we examine grooming networks in captive chimpanzees at the North Carolina Zoo, and captive bonobos at the Columbus Zoo. We hypothesized that male-female grooming relationships would be the strongest in both species, but that males and females of both species would not significantly differ between centrality, strength, or clustering. Via Mantel tests, we found that neither bonobos (t = - 0.070, r = - 0.009, two-tailed p = 0.942) nor chimpanzees (t = - 0.495, r = - 0.0939, two-tailed p = 0.6205) had significant differences in grooming between or within sexes. Neither species had significant sex differences in centrality, strength, or clustering. To account for idiosyncratic factors affecting grooming distribution, we examined the effect of origin, kinship, and group tenure on social network position. We found that wild-born bonobos exhibited greater eigenvector centrality (t = - 2.592, df = 9, p = 0.29) and strength (t = - 2.401; df = 9, p = 0.040), and group tenure was significantly correlated with strength (r = 0.608; N = 11, p - 0 = 0.47). None of these factors varied with social network position in chimpanzees. Our findings suggest that in captive settings, idiosyncratic factors related to individual history play a greater role in structuring social networks. Such variation may point to the behavioral flexibility inherent in fission-fusion networks, and mirror between-site variation found in wild chimpanzees. However, some idiosyncratic factors shaping captive networks may be an artifact of captivity.

Early Pan-African evolution of the basement around Elat, Israel, and the Sinai Peninsula revealed by single-zircon evaporation dating, and implications for crustal accretion rates

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kroener, A.; Eyal, M.; Eyal, Y.

1990-06-01

The authors report {sup 207}Pb/{sup 206}Pb single-zircon evaporation ages for early Pan-African rocks from southern Israel and the northeastern Sinai Peninsula, the northernmost extension of the Arabian-Nubian shield. The oldest rocks are metamorphic schists of presumed island-arc derivation; detrital zircons date the source terrain at ca. 800-820 Ma. A major phase of tonalite-trondhjemite plutonism occurred at ca. 760-780 Ma; more evolved granitic rocks were emplaced at about 745 Ma. A metagabbro-metadiorite complex reflects the youngest igneous phase at ca. 640 Ma. We find no evidence for pre-Pan-African crust, and our data document important crust-forming events that correlate with similar episodesmore » elsewhere in the shield. The widespread presence of early Pan-African juvenile rocks (i.e., ca. 760-850 Ma) in many parts of the Arabian-Nubian shield makes this period the most important in the magmatic history of the shield and supports earlier suggestions for unusually high crust-production rates.« less

PT conditions of metamorphism in the Wami River granulite complex, central coastal Tanzania: implications for Pan-African geotectonics in the Mozambique Belt of eastern Africa

NASA Astrophysics Data System (ADS)

Maboko, M. A. H.

1997-02-01

Solid-solution equilibria for gamet-clinopyroxene pairs in the early Pan-African Wami River granulite complex of central coastal Tanzania indicate metamorphic recrystallization at a temperature of about 700°C and a pressure of 8-9 kb, corresponding to metamorphism at a depth of 30-40 km. This suggests that granulite formation was preceded by an anomalous regional crustal thickening, similar to the crustal doubling that accompanies Phanerozoic continent-continent collisions of the Himalaya type. The analogy prompts the interpretation of the Wami River granulite complex, and possibly the rest of the granulite complexes in the Mozambique Belt, as slices of the underthrusted plate, which were accreted to the present day African plate following a continent-continent collision during early Pan-African time.

Extraction of honey from underground bee nests by central African chimpanzees (Pan troglodytes troglodytes) in Loango National Park, Gabon: Techniques and individual differences.

PubMed

Estienne, Vittoria; Stephens, Colleen; Boesch, Christophe

2017-08-01

A detailed analysis of tool use behaviors can disclose the underlying cognitive traits of the users. We investigated the technique used by wild chimpanzees to extract the underground nests of stingless bees (Meliplebeia lendliana), which represent a hard-to-reach resource given their highly undetectable location. Using remote-sensor camera trap footage, we analyzed 151 visits to 50 different bee nests by 18 adult chimpanzees of both sexes. We quantified the degree of complexity and flexibility of this technique by looking at the behavioral repertoire and at its structural organization. We used Generalized Linear Mixed Models to test whether individuals differed in their action repertoire sizes and in their action sequencing patterns, as well as in their preferences of use of different behavioral elements (namely, actions, and grip types). We found that subjects showed non-randomly organized sequences of actions and that the occurrence of certain actions was predicted by the type of the previous action in the sequences. Subjects did not differ in their repertoire sizes, and all used extractive actions involving tools more often than manual digging. As for the type of grip employed, the grip involving the coordinated use of hands and feet together was most frequently used by all subjects when perforating, and we detected significant individual preferences in this domain. Overall, we describe a highly complex and flexible extractive technique, and propose the existence of inter-individual variation in it. We discuss our results in the light of the evolution of higher cognitive abilities in the human lineage. © 2017 Wiley Periodicals, Inc.

Measuring Hair Cortisol Concentrations to Assess the Effect of Anthropogenic Impacts on Wild Chimpanzees (Pan troglodytes)

PubMed Central

Carlitz, Esther H. D.; Miller, Robert; Kirschbaum, Clemens; Gao, Wei; Hänni, Daniel C.; van Schaik, Carel P.

2016-01-01

Non-human primates face major environmental changes due to increased human impacts all over the world. Although some species are able to survive in certain landscapes with anthropogenic impact, their long-term viability and fitness may be decreased due to chronic stress. Here we assessed long-term stress levels through cortisol analysis in chimpanzee hair obtained from sleeping nests in northwestern Uganda, in order to estimate welfare in the context of ecotourism, forest fragmentation with human-wildlife conflicts, and illegal logging with hunting activity (albeit not of primates), compared with a control without human contact or conflict. Concerning methodological issues, season [F(2,129) = 37.4, p < 0.0001, r2 = 0.18] and the age of nests [F(2,178) = 20.3, p < 0.0001, r2 = 0.11] significantly predicted hair cortisol concentrations (HCC). With regard to effects of anthropogenic impacts, our results neither showed elevation of HCC due to ecotourism, nor due to illegal logging compared to their control groups. We did, however, find significantly increased HCC in the fragment group compared to chimpanzees living in a nearby intact forest [F(1,88) = 5.0, p = 0.03, r2 = 0.20]. In conclusion, our results suggest that hair cortisol analysis is a powerful tool that can help understanding the impact of anthropogenic disturbances on chimpanzee well-being and could be applied to other great ape species. PMID:27050418

Chimpanzees empathize with group mates and humans, but not with baboons or unfamiliar chimpanzees

PubMed Central

Campbell, Matthew W.; de Waal, Frans B. M.

2014-01-01

Human empathy can extend to strangers and even other species, but it is unknown whether non-humans are similarly broad in their empathic responses. We explored the breadth and flexibility of empathy in chimpanzees, a close relative of humans. We used contagious yawning to measure involuntary empathy and showed chimpanzees videos of familiar humans, unfamiliar humans and gelada baboons (an unfamiliar species). We tested whether each class of stimuli elicited contagion by comparing the effect of yawn and control videos. After including previous data on the response to ingroup and outgroup chimpanzees, we found that familiar and unfamiliar humans elicited contagion equal to that of ingroup chimpanzees. Gelada baboons did not elicit contagion, and the response to them was equal to that of outgroup chimpanzees. However, the chimpanzees watched the outgroup chimpanzee videos more than any other. The combination of high interest and low contagion may stem from hostility towards unfamiliar chimpanzees, which may interfere with an empathic response. Overall, chimpanzees showed flexibility in that they formed an empathic connection with a different species, including unknown members of that species. These results imply that human empathic flexibility is shared with related species. PMID:24619445

What School for Africa in the Year 2000? Report of the Proceedings of the Pan-African Conference on Education (Yaounde, Cameroon, April 2-9, 1984).

ERIC Educational Resources Information Center

World Confederation of Organizations of the Teaching Profession, Morges (Switzerland).

The Pan-African Conference on Education was organized by the World Confederation of Organisations of the Teaching Profession, with the cooperation of UNESCO and many other groups. The conference invited representatives of teacher organizations and education ministries in both English- and French-speaking African countries. Of the 26 African…

Ingroup-Outgroup Bias in Contagious Yawning by Chimpanzees Supports Link to Empathy

PubMed Central

Campbell, Matthew W.; de Waal, Frans B. M.

2011-01-01

Humans favor others seen as similar to themselves (ingroup) over people seen as different (outgroup), even without explicitly stated bias. Ingroup-outgroup bias extends to involuntary responses, such as empathy for pain. However, empathy biases have not been tested in our close primate relatives. Contagious yawning has been theoretically and empirically linked to empathy. If empathy underlies contagious yawning, we predict that subjects should show an ingroup-outgroup bias by yawning more in response to watching ingroup members yawn than outgroup. Twenty-three chimpanzees (Pan troglodytes) from two separate groups watched videos of familiar and unfamiliar individuals yawning or at rest (control). The chimpanzees yawned more when watching the familiar yawns than the familiar control or the unfamiliar yawns, demonstrating an ingroup-outgroup bias in contagious yawning. These results provide further empirical support that contagious yawning is a measure of empathy, which may be useful for evolutionary biology and mental health. PMID:21494669

Captive chimpanzee foraging in a social setting: a test of problem solving, flexibility, and spatial discounting

PubMed Central

Kurtycz, Laura M.; Ross, Stephen R.; Bonnie, Kristin E.

2015-01-01

In the wild, primates are selective over the routes that they take when foraging and seek out preferred or ephemeral food. Given this, we tested how a group of captive chimpanzees weighed the relative benefits and costs of foraging for food in their environment when a less-preferred food could be obtained with less effort than a more-preferred food. In this study, a social group of six zoo-housed chimpanzees (Pan troglodytes) could collect PVC tokens and exchange them with researchers for food rewards at one of two locations. Food preference tests had revealed that, for these chimpanzees, grapes were a highly-preferred food while carrot pieces were a less-preferred food. The chimpanzees were tested in three phases, each comprised of 30 thirty-minute sessions. In phases 1 and 3, if the chimpanzees exchanged a token at the location they collected them they received a carrot piece (no travel) or they could travel ≥10 m to exchange tokens for grapes at a second location. In phase 2, the chimpanzees had to travel for both rewards (≥10 m for carrot pieces, ≥15 m for grapes). The chimpanzees learned how to exchange tokens for food rewards, but there was individual variation in the time it took for them to make their first exchange and to discover the different exchange locations. Once all the chimpanzees were proficient at exchanging tokens, they exchanged more tokens for grapes (phase 3). However, when travel was required for both rewards (phase 2), the chimpanzees were less likely to work for either reward. Aside from the alpha male, all chimpanzees exchanged tokens for both reward types, demonstrating their ability to explore the available options. Contrary to our predictions, low-ranked individuals made more exchanges than high-ranked individuals, most likely because, in this protocol, chimpanzees could not monopolize the tokens or access to exchange locations. Although the chimpanzees showed a preference for exchanging tokens for their more-preferred food, they

First records of tool-set use for ant-dipping by Eastern chimpanzees (Pan troglodytes schweinfurthii) in the Kalinzu Forest Reserve, Uganda.

PubMed

Hashimoto, Chie; Isaji, Mina; Koops, Kathelijne; Furuichi, Takeshi

2015-10-01

Chimpanzees at numerous study sites are known to prey on army ants by using a single wand to dip into the ant nest or column. However, in Goualougo (Republic of Congo) in Central Africa, chimpanzees use a different technique, use of a woody sapling to perforate the ant nest, then use of a herb stem as dipping tool to harvest the army ants. Use of a tool set has also been found in Guinea, West Africa: at Seringbara in the Nimba Mountains and at nearby Bossou. There are, however, no reports for chimpanzees in East Africa. We observed use of such a tool set in Kalinzu, Uganda, for the first time by Eastern chimpanzees. This behavior was observed among one group of chimpanzees at Kalinzu (S-group) but not among the adjacent group (M-group) with partly overlapping ranging areas despite the fact that the latter group has been under intensive observation since 1997. In Uganda, ant-dipping has not been observed in the northern three sites (Budongo, Semliki, and Kibale) but has been observed or seems to occur in the southern sites (Kalinzu and Bwindi), which suggests that ant-dipping was invented by and spread from the southern region after the northern and southern forest blocks became separated. Use of a tool-set by only one group at Kalinzu further suggests that this behavior was recently invented and has not yet spread to the other group via migrating females.

Taï chimpanzees anticipate revisiting high-valued fruit trees from further distances.

PubMed

Ban, Simone D; Boesch, Christophe; Janmaat, Karline R L

2014-11-01

The use of spatio-temporal memory has been argued to increase food-finding efficiency in rainforest primates. However, the exact content of this memory is poorly known to date. This study investigated what specific information from previous feeding visits chimpanzees (Pan troglodytes verus), in Taï National Park, Côte d'Ivoire, take into account when they revisit the same feeding trees. By following five adult females for many consecutive days, we tested from what distance the females directed their travels towards previously visited feeding trees and how previous feeding experiences and fruit tree properties influenced this distance. To exclude the influence of sensory cues, the females' approach distance was measured from their last significant change in travel direction until the moment they entered the tree's maximum detection field. We found that chimpanzees travelled longer distances to trees at which they had previously made food grunts and had rejected fewer fruits compared to other trees. In addition, the results suggest that the chimpanzees were able to anticipate the amount of fruit that they would find in the trees. Overall, our findings are consistent with the hypothesis that chimpanzees act upon a retrieved memory of their last feeding experiences long before they revisit feeding trees, which would indicate a daily use of long-term prospective memory. Further, the results are consistent with the possibility that positive emotional experiences help to trigger prospective memory retrieval in forest areas that are further away and have fewer cues associated with revisited feeding trees.

Imitative Learning of Actions on Objects by Children, Chimpanzees, and Enculturated Chimpanzees.

ERIC Educational Resources Information Center

Tomasello, Michael; And Others

1993-01-01

Compared the abilities of 3 mother-reared and 3 human-raised (enculturated) chimpanzees and 16 human toddlers to imitatively learn novel actions on objects. Found that mother-reared chimpanzees were poorer imitators than both enculturated chimpanzees and human children, who did not differ from one another in imitative learning. On time delay…

Molecular Ecology and Natural History of Simian Foamy Virus Infection in Wild-Living Chimpanzees

PubMed Central

Liu, Weimin; Worobey, Michael; Li, Yingying; Keele, Brandon F.; Bibollet-Ruche, Frederic; Guo, Yuanyuan; Goepfert, Paul A.; Santiago, Mario L.; Ndjango, Jean-Bosco N.; Neel, Cecile; Clifford, Stephen L.; Sanz, Crickette; Kamenya, Shadrack; Wilson, Michael L.; Pusey, Anne E.; Gross-Camp, Nicole; Boesch, Christophe; Smith, Vince; Zamma, Koichiro; Huffman, Michael A.; Mitani, John C.; Watts, David P.; Peeters, Martine; Shaw, George M.; Switzer, William M.; Sharp, Paul M.; Hahn, Beatrice H.

2008-01-01

Identifying microbial pathogens with zoonotic potential in wild-living primates can be important to human health, as evidenced by human immunodeficiency viruses types 1 and 2 (HIV-1 and HIV-2) and Ebola virus. Simian foamy viruses (SFVs) are ancient retroviruses that infect Old and New World monkeys and apes. Although not known to cause disease, these viruses are of public health interest because they have the potential to infect humans and thus provide a more general indication of zoonotic exposure risks. Surprisingly, no information exists concerning the prevalence, geographic distribution, and genetic diversity of SFVs in wild-living monkeys and apes. Here, we report the first comprehensive survey of SFVcpz infection in free-ranging chimpanzees (Pan troglodytes) using newly developed, fecal-based assays. Chimpanzee fecal samples (n = 724) were collected at 25 field sites throughout equatorial Africa and tested for SFVcpz-specific antibodies (n = 706) or viral nucleic acids (n = 392). SFVcpz infection was documented at all field sites, with prevalence rates ranging from 44% to 100%. In two habituated communities, adult chimpanzees had significantly higher SFVcpz infection rates than infants and juveniles, indicating predominantly horizontal rather than vertical transmission routes. Some chimpanzees were co-infected with simian immunodeficiency virus (SIVcpz); however, there was no evidence that SFVcpz and SIVcpz were epidemiologically linked. SFVcpz nucleic acids were recovered from 177 fecal samples, all of which contained SFVcpz RNA and not DNA. Phylogenetic analysis of partial gag (616 bp), pol-RT (717 bp), and pol-IN (425 bp) sequences identified a diverse group of viruses, which could be subdivided into four distinct SFVcpz lineages according to their chimpanzee subspecies of origin. Within these lineages, there was evidence of frequent superinfection and viral recombination. One chimpanzee was infected by a foamy virus from a Cercopithecus

Social Competence of Adult Chimpanzees ("Pan troglodytes") with Severe Deprivation History: I. An Individual Approach

ERIC Educational Resources Information Center

Kalcher-Sommersguter, Elfriede; Preuschoft, Signe; Crailsheim, Karl; Franz, Cornelia

2011-01-01

Early social deprivation in highly social mammals interferes with their varying needs for security and stimulation. Toleration of social stimulation was studied in 18 adult ex-laboratory chimpanzees, who had been deprived for 16 to 27 years, during their 1st year after resocialization into 1 of 3 social groups. For this, a model of social…

A behavioral view on chimpanzee personality: exploration tendency, persistence, boldness, and tool-orientation measured with group experiments.

PubMed

Massen, Jorg J M; Antonides, Alexandra; Arnold, Anne-Marie K; Bionda, Thomas; Koski, Sonja E

2013-09-01

Human and nonhuman animals show personality: temporal and contextual consistency in behavior patterns that vary among individuals. In contrast to most other species, personality of chimpanzees, Pan troglodytes, has mainly been studied with non-behavioral methods. We examined boldness, exploration tendency, persistence and tool-orientation in 29 captive chimpanzees using repeated experiments conducted in an ecologically valid social setting. High temporal repeatability and contextual consistency in all these traits indicated they reflected personality. In addition, Principal Component Analysis revealed two independent syndromes, labeled exploration-persistence and boldness. We found no sex or rank differences in the trait scores, but the scores declined with age. Nonetheless, there was considerable inter-individual variation within age-classes, suggesting that behavior was not merely determined by age but also by dispositional effects. In conclusion, our study complements earlier rating studies and adds new traits to the chimpanzee personality, thereby supporting the existence of multiple personality traits among chimpanzees. We stress the importance of ecologically valid behavioral research to assess multiple personality traits and their association, as it allows inclusion of ape studies in the comparison of personality structures across species studied behaviorally, and furthers our attempts to unravel the causes and consequences of animal personality. © 2013 Wiley Periodicals, Inc.

Chimpanzee Social Responsiveness Scale (CSRS) Detects Individual Variation in Social Responsiveness for Captive Chimpanzees

PubMed Central

Faughn, Carley; Marrus, Natasha; Pruett, John R.; Shuman, Jeremy; Ross, Stephen R.; Constantino, John N.; Povinelli, Daniel J.

2017-01-01

Comparative studies of social responsiveness, a core impairment in autism spectrum disorder (ASD), will enhance our understanding of typical and atypical social behavior. We previously reported a quantitative, cross-species (human–chimpanzee) social responsiveness measure, which included the development of the Chimpanzee Social Responsiveness Scale (CSRS). Here, we augment our prior CSRS sample with 25 zoo chimpanzees at three sites: combined N = 54. The CSRS demonstrated strong interrater reliability, and low-ranked chimpanzees, on average, displayed higher CSRS scores. The CSRS continues to discriminate variation in chimpanzee social responsiveness, and the association of higher scores with lower chimpanzee social standing has implications for the relationship between autistic traits and human social status. Continued comparative investigations of social responsiveness will enhance our understanding of underlying impairments in ASD, improve early diagnosis, and inform future therapies. PMID:25312279

Understanding geographic origins and history of admixture among chimpanzees in European zoos, with implications for future breeding programmes.

PubMed

Hvilsom, C; Frandsen, P; Børsting, C; Carlsen, F; Sallé, B; Simonsen, B T; Siegismund, H R

2013-06-01

Despite ample focus on this endangered species, conservation planning for chimpanzees residing outside Africa has proven a challenge because of the lack of ancestry information. Here, we analysed the largest number of chimpanzee samples to date, examining microsatellites in >100 chimpanzees from the range of the species in Africa, and 20% of the European zoo population. We applied the knowledge about subspecies differentiation throughout equatorial Africa to assign origin to chimpanzees in the largest conservation management programme globally. A total of 63% of the genotyped chimpanzees from the European zoos could be assigned to one of the recognized subspecies. The majority being of West African origin (40%) will help consolidate the current breeding programme for this subspecies and the identification of individuals belonging to the two other subspecies so far found in European zoos can form the basis for breeding programmes for these. Individuals of various degree of mixed ancestry made up 37% of the genotyped European zoo population and thus highlight the need for appropriate management programmes guided by genetic analysis to preserve maximum genetic diversity and reduce hybridization among subspecies.

Social grooming among wild bonobos (Pan paniscus) at Wamba in the Luo Scientific Reserve, DR Congo, with special reference to the formation of grooming gatherings.

PubMed

Sakamaki, Tetsuya

2013-10-01

Chimpanzees (Pan troglodytes) groom in gatherings in which many individuals may be connected via multiple chains of grooming and they often exchange partners with each other. They sometimes groom another while receiving grooming; that is, one animal can play two roles (i.e., groomer and groomee) simultaneously. Although this feature of chimpanzees is notable from the viewpoint of the evolution of human sociality, information on our other closest living relative, the bonobo (Pan paniscus), is still lacking. In this study, I describe grooming interactions of bonobos at Wamba in the Luo Scientific Reserve, Democratic Republic of the Congo (DR Congo), with a particular focus on the formation of grooming gatherings. Like chimpanzees, the bonobos also performed mutual grooming (two individuals grooming each other simultaneously) and polyadic grooming (three or more individuals). However, unlike chimpanzees, these sessions lasted for only a short time. Bonobos rarely groomed another while receiving grooming. Because social grooming occurred not only in trees but also in open spaces, including treefall gaps, the conditions did not necessarily limit the opportunity to make multiple chains of grooming. However, bonobos also engaged in social grooming in different ways from chimpanzees; That is, many individuals were involved simultaneously at a site, in which they separated for dyadic grooming. Some cases clearly showed that bonobos preferred a third party not to join while grooming in a dyad, suggesting that bonobos have a preference for grooming in dyads and that immature individuals formed the preference that was shared among adults while growing up. Most members of the study group ranged together during the majority of the study period. Although bonobos show a fission-fusion grouping pattern, when group members frequently encounter one another on a daily basis, they may not be motivated to form multiple grooming chains at this site, as do chimpanzees.

Young and juvenile chimpanzees' (Pan troglodytes) reactions to intentional versus accidental and inadvertent actions.

PubMed

Povinelli, D J; Perilloux, H K; Reaux, J E; Bierschwale, D T

1998-02-01

Chimpanzees were tested for their ability to discriminate between accidental/inadvertent and intentional actions with equivalent adverse consequences. Subjects were first trained to `point' to human trainers in order to receive food rewards. In Experiment 1, six 5-year-old subjects were alternately presented with two unfamiliar human actors. In condition 1, each actor either started to hand a cup of juice to the trainer but then pulled it back and intentionally poured it onto the floor, or accidentally spilled it while handing it to the trainer. In condition 2, the actors either accidentally spilled it as above, or aggressively threw the juice onto the floor. The subjects were then presented with both actors and were allowed to choose between them. In Experiment 2, seven 6-7-year-old chimpanzees were confronted with unfamiliar actors who either (a) intentionally withheld and consumed food intended for the subjects, (b) attempted to hand the intended food to the subjects but were victimized by a third party who consumed the food, or (c) always succeeded in delivering the food to the subjects. In general, the subjects showed little evidence of using the accidental/inadvertent versus intentional distinction in their choices between the actors, although they did display some evidence of favoring the actor involved in the most passive role in both conditions in Experiment 1.

Translating chimpanzee personality to humans: Investigating the transportability of chimpanzee-derived personality scales to humans.

PubMed

Latzman, Robert D; Sauvigné, Katheryn C; Hopkins, William D

2016-06-01

There is a growing interest in the study of personality in chimpanzees with repeated findings of a similar structure of personality in apes to that found in humans. To date, however, the direct translational value of instruments used to assess chimpanzee personality to humans has yet to be explicitly tested. As such, in the current study we sought to determine the transportability of factor analytically-derived chimpanzee personality scales to humans in a large human sample (N = 301). Human informants reporting on target individuals they knew well completed chimpanzee-derived and human-derived measures of personality from the two most widely studied models of human personality: Big Five and Big Three. The correspondence between informant-reported chimpanzee- and human-derived personality scales was then investigated. Results indicated high convergence for corresponding scales across most chimpanzee- and human-derived personality scales. Findings from the current study provide evidence that chimpanzee-derived scales translate well to humans and operate quite similarly to the established human-derived personality scales in a human sample. This evidence of transportability lends support to the translational nature of chimpanzee personality research suggesting clear relevance of this growing literature to humans. Am. J. Primatol. 78:601-609, 2016. © 2015 Wiley Periodicals, Inc. © 2015 Wiley Periodicals, Inc.

No third-party punishment in chimpanzees

PubMed Central

Riedl, Katrin; Jensen, Keith; Call, Josep; Tomasello, Michael

2012-01-01

Punishment can help maintain cooperation by deterring free-riding and cheating. Of particular importance in large-scale human societies is third-party punishment in which individuals punish a transgressor or norm violator even when they themselves are not affected. Nonhuman primates and other animals aggress against conspecifics with some regularity, but it is unclear whether this is ever aimed at punishing others for noncooperation, and whether third-party punishment occurs at all. Here we report an experimental study in which one of humans' closest living relatives, chimpanzees (Pan troglodytes), could punish an individual who stole food. Dominants retaliated when their own food was stolen, but they did not punish when the food of third-parties was stolen, even when the victim was related to them. Third-party punishment as a means of enforcing cooperation, as humans do, might therefore be a derived trait in the human lineage. PMID:22927412

Autonomy in chimpanzees.

PubMed

Beauchamp, Tom L; Wobber, Victoria

2014-04-01

Literature on the mental capacities and cognitive mechanisms of the great apes has been silent about whether they can act autonomously. This paper provides a philosophical theory of autonomy supported by psychological studies of the cognitive mechanisms that underlie chimpanzee behavior to argue that chimpanzees can act autonomously even though their psychological mechanisms differ from those of humans. Chimpanzees satisfy the two basic conditions of autonomy: (1) liberty (the absence of controlling influences) and (2) agency (self-initiated intentional action), each of which is specified here in terms of conditions of understanding, intention, and self-control. In this account, chimpanzees make knowledge-based choices reflecting a richly information-based and socially sophisticated understanding of the world. Finally, two major theories of autonomy (Kantian theory and two-level theory) are rejected as too narrow to adequately address these issues, necessitating the modifications made in the present approach.

The right time to happen: play developmental divergence in the two Pan species.

PubMed

Palagi, Elisabetta; Cordoni, Giada

2012-01-01

Bonobos, compared to chimpanzees, are highly motivated to play as adults. Therefore, it is interesting to compare the two species at earlier developmental stages to determine how and when these differences arise. We measured and compared some play parameters between the two species including frequency, number of partners (solitary, dyadic, and polyadic play), session length, and escalation into overt aggression. Since solitary play has a role in developing cognitive and physical skills, it is not surprising that chimpanzees and bonobos share similar developmental trajectories in the motivation to engage in this activity. The striking divergence in play developmental pathways emerged for social play. Infants of the two species showed comparable social play levels, which began to diverge during the juvenile period, a 'timing hotspot' for play development. Compared to chimpanzees, social play sessions in juvenile bonobos escalated less frequently into overt aggression, lasted longer, and frequently involved more than two partners concurrently (polyadic play). In this view, play fighting in juvenile bonobos seems to maintain a cooperative mood, whereas in juvenile chimpanzees it acquires more competitive elements. The retention of juvenile traits into adulthood typical of bonobos can be due to a developmental delay in social inhibition. Our findings show that the divergence of play ontogenetic pathways between the two Pan species and the relative emergence of play neotenic traits in bonobos can be detected before individuals reach sexual maturity. The high play motivation showed by adult bonobos compared to chimpanzees is probably the result of a long developmental process, rooted in the delicate transitional phase, which leads subjects from infancy to juvenility.

Preparing chimpanzees for laboratory research.

PubMed

Bloomsmith, Mollie A; Schapiro, Steven J; Strobert, Elizabeth A

2006-01-01

The chimpanzee is the only representative of the Great Apes that is extensively involved in biomedical research in primate laboratories. These apes are used as animal models in a variety of studies, including research on infectious disease, parasitic disease, pharmacokinetic studies, neuroscience, cognition, and behavior. Chimpanzees used in biomedical research in the United States reside largely in six specialized research and holding facilities, and most of the research with them is conducted at these sites. Given the relatively small population of chimpanzees and its importance to biomedical research, it is imperative that we carefully manage the care, production, and use of these animals in biomedical research studies. Selection criteria and preparation techniques are reviewed in this article in an effort to begin a discussion on best practices for choosing and handling chimpanzees participating in biomedical research. The use of routine health assessment information is described for subject selection, as are behavioral issues to be considered. Due to the relatively small number of chimpanzees available, issues related to experimental design and multiple uses of chimpanzees are discussed. Practices related to the transportation and acclimation of chimpanzees are described. Finally, behavioral conditioning procedures are discussed, including habituation, desensitization, and positive reinforcement training that have been applied to reduce animal distress and improve the quality of the science being conducted with chimpanzee subjects.

Chimpanzee and human midfoot motion during bipedal walking and the evolution of the longitudinal arch of the foot.

PubMed

Holowka, Nicholas B; O'Neill, Matthew C; Thompson, Nathan E; Demes, Brigitte

2017-03-01

The longitudinal arch of the human foot is commonly thought to reduce midfoot joint motion to convert the foot into a rigid lever during push off in bipedal walking. In contrast, African apes have been observed to exhibit midfoot dorsiflexion following heel lift during terrestrial locomotion, presumably due to their possession of highly mobile midfoot joints. This assumed dichotomy between human and African ape midfoot mobility has recently been questioned based on indirect assessments of in vivo midfoot motion, such as plantar pressure and cadaver studies; however, direct quantitative analyses of African ape midfoot kinematics during locomotion remain scarce. Here, we used high-speed motion capture to measure three-dimensional foot kinematics in two male chimpanzees and five male humans walking bipedally at similar dimensionless speeds. We analyzed 10 steps per chimpanzee subject and five steps per human subject, and compared ranges of midfoot motion between species over stance phase, as well as within double- and single-limb support periods. Contrary to expectations, humans used a greater average range of midfoot motion than chimpanzees over the full duration of stance. This difference was driven by humans' dramatic plantarflexion and adduction of the midfoot joints during the second double-limb support period, which likely helps the foot generate power during push off. However, chimpanzees did use slightly but significantly more midfoot dorsiflexion than humans in the single limb-support period, during which heel lift begins. These results indicate that both stiffness and mobility are important to longitudinal arch function, and that the human foot evolved to utilize both during push off in bipedal walking. Thus, the presence of human-like midfoot joint morphology in fossil hominins should not be taken as indicating foot rigidity, but may signify the evolution of pedal anatomy conferring enhanced push off mechanics. Copyright © 2016 Elsevier Ltd. All rights

Early Precambrian gneiss terranes and Pan-African island arcs in Yemen: Crustal accretion of the eastern Arabian Shield

NASA Astrophysics Data System (ADS)

Windley, Brian F.; Whitehouse, Martin J.; Ba-Bttat, Mahfood A. O.

1996-02-01

Within the Precambrian of Yemen, we have identified four gneiss terranes and two island-arc terranes on the basis of existing literature, mapping, and our own field observations, together with new Sm-Nd isotopic data. The two western gneiss terranes can be correlated with well-documented terranes (Asir and Afif) in Saudi Arabia. To the east of these, the Abas and Al-Mahfid gneiss terranes yield Sm-Nd model ages (tDM) of 1.7 2.3 Ga and 1.3 2.7 Ga, respectively, and cannot be correlated with any documented terranes in Saudi Arabia. These two terranes are separated by a Pan-African island-arc terrane that has been obducted onto one or both of the gneiss terranes, and a second arc bounds the Al-Mahfid gneiss terrane to the east. Our discovery of extensive Proterozoic to late Archean gneisses in Yemen provides important constraints upon the much-discussed tectonic framework of northeast Gondwana and the rate of Pan-African crustal growth. The terranes in Yemen may be correlated with comparable terranes on the eastern margin of the Arabian Shield and in northern Somalia. Thus Yemen provides a link between the arc collage of the Arabian Shield and the gneissic Mozambique belt of East Africa.

Occurrence of Giardia and Cryptosporidium in captive chimpanzees (Pan troglodytes), mandrills (Mandrillus sphinx) and wild Zanzibar red colobus monkeys (Procolobus kirkii).

PubMed

Debenham, John J; Atencia, Rebeca; Midtgaard, Fred; Robertson, Lucy J

2015-04-01

The aim of this study was to investigate the occurrence of Giardia duodenalis and Cryptosporidium spp. in primates and determine their zoonotic or anthropozoonotic potential. Direct immunofluorescence was used to identify Giardia and Cryptosporidium from faecal samples. PCR and DNA sequencing was performed on positive results. Giardia cysts were identified from 5.5% (5/90) of captive chimpanzees and 0% (0/11) of captive mandrills in the Republic of Congo; 0% (0/10) of captive chimpanzees in Norway; and 0% of faecal samples (n = 49) from wild Zanzibar red colobus monkeys. Two Giardia positive samples were also positive on PCR, and sequencing revealed identical isolates of Assemblage B. Cryptosporidium oocysts were not detected in any of the samples. In these primate groups, in which interactions with humans and human environments are quite substantial, Giardia and Cryptosporidium are rare pathogens. In chimpanzees, Giardia may have a zoonotic or anthropozoonotic potential. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Can Chimpanzee Infants ("Pan Troglodytes") Form Categorical Representations in the Same Manner as Human Infants ("Homo Sapiens")?

ERIC Educational Resources Information Center

Murai, Chizuko; Kosugi, Daisuke; Tomonaga, Masaki; Tanaka, Masayuki; Matsuzawa, Tetsuro; Itakura, Shoji

2005-01-01

We directly compared chimpanzee infants and human infants for categorical representations of three global-like categories (mammals, furniture and vehicles), using the familiarization-novelty preference technique. Neither species received any training during the experiments. We used the time that participants spent looking at the stimulus object…

Guns, germs, and trees determine density and distribution of gorillas and chimpanzees in Western Equatorial Africa

PubMed Central

Blake, Stephen; Stokes, Emma J.; Aba’a, Rostand; Abitsi, Gaspard; Agbor, Anthony; Ambahe, Ruffin D.; Bakabana, Parfait C.; Bechem, Martha; Berlemont, Antoine; Bokoto de Semboli, Bruno; Boundja, Patrick R.; Campbell, Genevieve; De Wachter, Pauwel; Ella Akou, Marc; Esono Mba, Fidel; Feistner, Anna T. C.; Fosso, Bernard; Fotso, Roger; Greer, David; Inkamba-Nkulu, Clement; Iyenguet, Calixte F.; Jeffery, Kathryn J.; Kokangoye, Max; Madzoke, Bola; Makoumbou, Calixte; Malanda, Guy-Aimé F.; Malonga, Richard; Mbolo, Victor; Morgan, David B.; Motsaba, Prosper; Moukala, Gabin; Mowawa, Brice S.; Ndzai, Christian; Nishihara, Tomoaki; Nzooh, Zacharie; Pintea, Lilian; Rainey, Hugo J.; Rayden, Tim; Sanz, Crickette M.; Vanleeuwe, Hilde; Vosper, Ashley; Warren, Ymke; Wilkie, David S.

2018-01-01

We present a range-wide assessment of sympatric western lowland gorillas Gorilla gorilla gorilla and central chimpanzees Pan troglodytes troglodytes using the largest survey data set ever assembled for these taxa: 59 sites in five countries surveyed between 2003 and 2013, totaling 61,000 person-days of fieldwork. We used spatial modeling to investigate major drivers of great ape distribution and population trends. We predicted density across each taxon’s geographic range, allowing us to estimate overall abundance: 361,900 gorillas and 128,700 chimpanzees in Western Equatorial Africa—substantially higher than previous estimates. These two subspecies represent close to 99% of all gorillas and one-third of all chimpanzees. Annual population decline of gorillas was estimated at 2.7%, maintaining them as Critically Endangered on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List. We quantified the threats to each taxon, of which the three greatest were poaching, disease, and habitat degradation. Gorillas and chimpanzees are found at higher densities where forest is intact, wildlife laws are enforced, human influence is low, and disease impacts have been low. Strategic use of the results of these analyses could conserve the majority of gorillas and chimpanzees. With around 80% of both subspecies occurring outside protected areas, their conservation requires reinforcement of anti-poaching efforts both inside and outside protected areas (particularly where habitat quality is high and human impact is low), diligent disease control measures (including training, advocacy, and research into Ebola virus disease), and the preservation of high-quality habitat through integrated land-use planning and implementation of best practices by the extractive and agricultural industries. PMID:29707637

Guns, germs, and trees determine density and distribution of gorillas and chimpanzees in Western Equatorial Africa.

PubMed

Strindberg, Samantha; Maisels, Fiona; Williamson, Elizabeth A; Blake, Stephen; Stokes, Emma J; Aba'a, Rostand; Abitsi, Gaspard; Agbor, Anthony; Ambahe, Ruffin D; Bakabana, Parfait C; Bechem, Martha; Berlemont, Antoine; Bokoto de Semboli, Bruno; Boundja, Patrick R; Bout, Nicolas; Breuer, Thomas; Campbell, Genevieve; De Wachter, Pauwel; Ella Akou, Marc; Esono Mba, Fidel; Feistner, Anna T C; Fosso, Bernard; Fotso, Roger; Greer, David; Inkamba-Nkulu, Clement; Iyenguet, Calixte F; Jeffery, Kathryn J; Kokangoye, Max; Kühl, Hjalmar S; Latour, Stephanie; Madzoke, Bola; Makoumbou, Calixte; Malanda, Guy-Aimé F; Malonga, Richard; Mbolo, Victor; Morgan, David B; Motsaba, Prosper; Moukala, Gabin; Mowawa, Brice S; Murai, Mizuki; Ndzai, Christian; Nishihara, Tomoaki; Nzooh, Zacharie; Pintea, Lilian; Pokempner, Amy; Rainey, Hugo J; Rayden, Tim; Ruffler, Heidi; Sanz, Crickette M; Todd, Angelique; Vanleeuwe, Hilde; Vosper, Ashley; Warren, Ymke; Wilkie, David S

2018-04-01

We present a range-wide assessment of sympatric western lowland gorillas Gorilla gorilla gorilla and central chimpanzees Pan troglodytes troglodytes using the largest survey data set ever assembled for these taxa: 59 sites in five countries surveyed between 2003 and 2013, totaling 61,000 person-days of fieldwork. We used spatial modeling to investigate major drivers of great ape distribution and population trends. We predicted density across each taxon's geographic range, allowing us to estimate overall abundance: 361,900 gorillas and 128,700 chimpanzees in Western Equatorial Africa-substantially higher than previous estimates. These two subspecies represent close to 99% of all gorillas and one-third of all chimpanzees. Annual population decline of gorillas was estimated at 2.7%, maintaining them as Critically Endangered on the International Union for Conservation of Nature and Natural Resources (IUCN) Red List. We quantified the threats to each taxon, of which the three greatest were poaching, disease, and habitat degradation. Gorillas and chimpanzees are found at higher densities where forest is intact, wildlife laws are enforced, human influence is low, and disease impacts have been low. Strategic use of the results of these analyses could conserve the majority of gorillas and chimpanzees. With around 80% of both subspecies occurring outside protected areas, their conservation requires reinforcement of anti-poaching efforts both inside and outside protected areas (particularly where habitat quality is high and human impact is low), diligent disease control measures (including training, advocacy, and research into Ebola virus disease), and the preservation of high-quality habitat through integrated land-use planning and implementation of best practices by the extractive and agricultural industries.

Tracking the displacement of objects: a series of tasks with great apes (Pan troglodytes, Pan paniscus, Gorilla gorilla, and Pongo pygmaeus) and young children (Homo sapiens).

PubMed

Barth, Jochen; Call, Josep

2006-07-01

The authors administered a series of object displacement tasks to 24 great apes and 24 30-month-old children (Homo sapiens). Objects were placed under 1 or 2 of 3 cups by visible or invisible displacements. The series included 6 tasks: delayed response, inhibition test, A not B, rotations, transpositions, and object permanence. Apes and children solved most tasks performing at comparable levels except in the transposition task, in which apes performed better than children. Ape species performed at comparable levels in all tasks except in single transpositions, in which chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) performed better than gorillas (Gorilla gorilla) and orangutans (Pongo pygmeaus). All species found nonadjacent trials and rotations especially difficult. The number of elements that changed locations, the type of displacement, and having to inhibit predominant reaching responses were factors that negatively affected the subjects' performance.

Brief Report: Chimpanzee Social Responsiveness Scale (CSRS) Detects Individual Variation in Social Responsiveness for Captive Chimpanzees.

PubMed

Faughn, Carley; Marrus, Natasha; Shuman, Jeremy; Ross, Stephen R; Constantino, John N; Pruett, John R; Povinelli, Daniel J

2015-05-01

Comparative studies of social responsiveness, a core impairment in autism spectrum disorder (ASD), will enhance our understanding of typical and atypical social behavior. We previously reported a quantitative, cross-species (human-chimpanzee) social responsiveness measure, which included the development of the Chimpanzee Social Responsiveness Scale (CSRS). Here, we augment our prior CSRS sample with 25 zoo chimpanzees at three sites: combined N = 54. The CSRS demonstrated strong interrater reliability, and low-ranked chimpanzees, on average, displayed higher CSRS scores. The CSRS continues to discriminate variation in chimpanzee social responsiveness, and the association of higher scores with lower chimpanzee social standing has implications for the relationship between autistic traits and human social status. Continued comparative investigations of social responsiveness will enhance our understanding of underlying impairments in ASD, improve early diagnosis, and inform future therapies.

How the great apes (Pan troglodytes, Pongo pygmaeus, Pan paniscus, Gorilla gorilla) perform on the reversed reward contingency task II: transfer to new quantities, long-term retention, and the impact of quantity ratios.

PubMed

Uher, Jana; Call, Josep

2008-05-01

We tested 6 chimpanzees (Pan troglodytes), 3 orangutans (Pongo pygmaeus), 4 bonobos (Pan paniscus), and 2 gorillas (Gorilla gorilla) in the reversed reward contingency task. Individuals were presented with pairs of quantities ranging between 0 and 6 food items. Prior to testing, some experienced apes had solved this task using 2 quantities while others were totally naïve. Experienced apes transferred their ability to multiple-novel pairs after 6 to 19 months had elapsed since their initial testing. Two out of 6 naïve apes (1 chimpanzee, 1 bonobo) solved the task--a proportion comparable to that of a previous study using 2 pairs of quantities. Their acquisition speed was also comparable to the successful subjects from that study. The ratio between quantities explained a large portion of the variance but affected naïve and experienced individuals differently. For smaller ratios, naïve individuals were well below 50% correct and experienced ones were well above 50%, yet both groups tended to converge toward 50% for larger ratios. Thus, some apes require no procedural modifications to overcome their strong bias for selecting the larger of 2 quantities. PsycINFO Database Record (c) 2008 APA, all rights reserved.

The spread of a novel behavior in wild chimpanzees: New insights into the ape cultural mind.

PubMed

Gruber, Thibaud; Poisot, Timothée; Zuberbühler, Klaus; Hoppitt, William; Hobaiter, Catherine

2015-01-01

For years, the animal culture debate has been dominated by the puzzling absence of direct evidence for social transmission of behavioral innovations in the flagship species of animal culture, the common chimpanzee. Although social learning of novel behaviors has been documented in captivity, critics argue that these findings lack ecological validity and therefore may not be relevant for understanding the evolution of culture. For the wild, it is possible that group-specific behavioral differences emerge because group members respond individually to unspecified environmental differences, rather than learning from each other. In a recent paper, we used social network analyses in wild chimpanzees (Pan troglodytes schweinfurthii) to provide direct evidence for social transmission of a behavioral innovation, moss-sponging, to extract water from a tree hole. Here, we discuss the implications of our findings and how our new methodological approach could help future studies of social learning and culture in wild apes.

The scramble for Africa: pan-temperate elements on the African high mountains

PubMed Central

Gehrke, Berit; Linder, H. Peter

2009-01-01

The composition of isolated floras has long been thought to be the result of relatively rare long-distance dispersal events. However, it has recently become apparent that the recruitment of lineages may be relatively easy and that many dispersal events from distant but suitable habitats have occurred, even at an infraspecific level. The evolution of the flora on the high mountains of Africa has been attributed to the recruitment of taxa not only from the African lowland flora or the Cape Floristic Region, but also to a large extent from other areas with temperate climates. We used the species rich, pan-temperate genera Carex, Ranunculus and Alchemilla to explore patterns in the number of recruitment events and region of origin. Molecular phylogenetic analyses, parametric bootstrapping and ancestral area optimizations under parsimony indicate that there has been a high number of colonization events of Carex and Ranunculus into Africa, but only two introductions of Alchemilla. Most of the colonization events have been derived from Holarctic ancestors. Backward dispersal out of Africa seems to be extremely rare. Thus, repeated colonization from the Northern Hemisphere in combination with in situ radiation has played an important role in the composition of the flora of African high mountains. PMID:19403534

The scramble for Africa: pan-temperate elements on the African high mountains.

PubMed

Gehrke, Berit; Linder, H Peter

2009-07-22

The composition of isolated floras has long been thought to be the result of relatively rare long-distance dispersal events. However, it has recently become apparent that the recruitment of lineages may be relatively easy and that many dispersal events from distant but suitable habitats have occurred, even at an infraspecific level. The evolution of the flora on the high mountains of Africa has been attributed to the recruitment of taxa not only from the African lowland flora or the Cape Floristic Region, but also to a large extent from other areas with temperate climates. We used the species rich, pan-temperate genera Carex, Ranunculus and Alchemilla to explore patterns in the number of recruitment events and region of origin. Molecular phylogenetic analyses, parametric bootstrapping and ancestral area optimizations under parsimony indicate that there has been a high number of colonization events of Carex and Ranunculus into Africa, but only two introductions of Alchemilla. Most of the colonization events have been derived from Holarctic ancestors. Backward dispersal out of Africa seems to be extremely rare. Thus, repeated colonization from the Northern Hemisphere in combination with in situ radiation has played an important role in the composition of the flora of African high mountains.

A new Pan African polyspecific antivenom developed in response to the antivenom crisis in Africa.

PubMed

Laing, G D; Renjifo, J M; Ruiz, F; Harrison, R A; Nasidi, A; Gutierrez, J-M; Rowley, P D; Warrell, D A; Theakston, R D G

2003-07-01

Currently there is a crisis in the supply of antivenom for treatment of snake bite in sub-Saharan Africa. Commercial pressures have resulted in the reduction or even cessation of production of antivenom by European manufacturers while continued production of antivenom in Africa has been threatened by the privatisation of the only remaining company based in Africa. As a consequence, there has been an increase in snake bite morbidity and mortality in many African countries. Two Latin American antivenom manufacturers have agreed to produce antivenom suitable for Africa, using venoms from the species which are of the greatest medical importance in sub-Saharan Africa. Preclinical in vivo assays of neutralising potency demonstrated that a new Pan African antivenom produced in Colombia compared favourably with the existing commercial monospecific and polyspecific antivenoms. This new antivenom, and a similar product being manufactured in Costa Rica, are now candidates for clinical testing at an appropriate site in Africa.

Imprints of a Pan-African transpressional orogen superimposed on an inferred Grenvillian accretionary belt in central East Antarctica

NASA Astrophysics Data System (ADS)

Ferraccioli, Fausto; Seddon, Samuel; Finn, Carol; Bell, Robin; Wu, Guochao; Jordan, Tom

2017-04-01

The Gamburtsev Subglacial Mountains in interior East Antarctica are underlain by 50-60 km thick crust imaged by gravity and seismic models (Ferraccioli et al., 2011; An et al., 2015). In contrast, the composite Archean to Mesoproterozoic Mawson craton that occupies the Wilkes and Terre Adelie sector of East Antarctica typically features only 40-45 km thick crust (Aitken et al., 2014). Over 200 km thick and seismically fast lithosphere underlies the Gamburtsev Province, as typically observed over Precambrian lithosphere that has not been substantially reworked during Phanerozoic subduction or collision. Satellite and airborne magnetic data indicate that the Gamburtev Province is sandwiched in between distinct Precambrian lithospheric blocks including the Ruker, Princess Elizabeth Land, Vostok, Nimrod (Goodge and Finn, 2010), South Pole and Recovery provinces. Ferraccioli et al., (2011) proposed that a segment of a stalled orogen (i.e. an orogen where widespread orogenic collapse and root delamination has not occurred) is preserved in the Gamburtsev Province and further hypothesised that its origin relates to widespread accretionary and subsequent collisional events at ca 1 Ga, linked to the assembly of the Rodinia supercontinent. However, recent passive seismic interpretations (An et al., 2015) indicate that crustal thickening may relate instead to Pan-African age assembly of Greater India, East Antarctica and Australia within Gondwana (at ca 550 Ma). Here we interpret a set of enhanced magnetic and gravity images, depth to magnetic and gravity sources and preliminary 2D and 3D forward and inverse models to characterise in detail the crustal architecture of the Gamburtsev Province. Enhanced aeromagnetic images reveal a system of subglacial faults that segment the Gamburtsev Province into three distinct geophysical domains, the northern, central and southern domains. Apparent offsets in high-frequency magnetic anomalies within the central domain are interpreted here

Evidence of leopard predation on bonobos (Pan paniscus).

PubMed

D'Amour, Danielle E; Hohmann, Gottfried; Fruth, Barbara

2006-01-01

Current models of social organization assume that predation is one of the major forces that promotes group living in diurnal primates. As large body size renders some protection against predators, gregariousness of great apes and other large primate species is usually related to other parameters. The low frequency of observed cases of nonhuman predation on great apes seems to support this assumption. However, recent efforts to study potential predator species have increasingly accumulated direct and indirect evidence of predation by leopards (Panthera pardus) on chimpanzees and gorillas. The following report provides the first evidence of predation by a leopard on bonobos (Pan paniscus). Copyright 2006 S. Karger AG, Basel.

Understanding geographic origins and history of admixture among chimpanzees in European zoos, with implications for future breeding programmes

PubMed Central

Hvilsom, C; Frandsen, P; Børsting, C; Carlsen, F; Sallé, B; Simonsen, B T; Siegismund, H R

2013-01-01

Despite ample focus on this endangered species, conservation planning for chimpanzees residing outside Africa has proven a challenge because of the lack of ancestry information. Here, we analysed the largest number of chimpanzee samples to date, examining microsatellites in >100 chimpanzees from the range of the species in Africa, and 20% of the European zoo population. We applied the knowledge about subspecies differentiation throughout equatorial Africa to assign origin to chimpanzees in the largest conservation management programme globally. A total of 63% of the genotyped chimpanzees from the European zoos could be assigned to one of the recognized subspecies. The majority being of West African origin (40%) will help consolidate the current breeding programme for this subspecies and the identification of individuals belonging to the two other subspecies so far found in European zoos can form the basis for breeding programmes for these. Individuals of various degree of mixed ancestry made up 37% of the genotyped European zoo population and thus highlight the need for appropriate management programmes guided by genetic analysis to preserve maximum genetic diversity and reduce hybridization among subspecies. PMID:23531981

Oxytocin and Vasopressin Receptor Gene Variation as a Proximate Base for Inter- and Intraspecific Behavioral Differences in Bonobos and Chimpanzees

PubMed Central

Staes, Nicky; Stevens, Jeroen M. G.; Helsen, Philippe; Hillyer, Mia; Korody, Marisa; Eens, Marcel

2014-01-01

Recent literature has revealed the importance of variation in neuropeptide receptor gene sequences in the regulation of behavioral phenotypic variation. Here we focus on polymorphisms in the oxytocin receptor gene (OXTR) and vasopressin receptor gene 1a (Avpr1a) in chimpanzees and bonobos. In humans, a single nucleotide polymorphism (SNP) in the third intron of OXTR (rs53576 SNP (A/G)) is linked with social behavior, with the risk allele (A) carriers showing reduced levels of empathy and prosociality. Bonobos and chimpanzees differ in these same traits, therefore we hypothesized that these differences might be reflected in variation at the rs53576 position. We sequenced a 320 bp region surrounding rs53576 but found no indications of this SNP in the genus Pan. However, we identified previously unreported SNP variation in the chimpanzee OXTR sequence that differs from both humans and bonobos. Humans and bonobos have previously been shown to have a more similar 5′ promoter region of Avpr1a when compared to chimpanzees, who are polymorphic for the deletion of ∼360 bp in this region (+/− DupB) which includes a microsatellite (RS3). RS3 has been linked with variation in levels of social bonding, potentially explaining part of the interspecies behavioral differences found in bonobos, chimpanzees and humans. To date, results for bonobos have been based on small sample sizes. Our results confirmed that there is no DupB deletion in bonobos with a sample size comprising approximately 90% of the captive founder population, whereas in chimpanzees the deletion of DupB had the highest frequency. Because of the higher frequency of DupB alleles in our bonobo population, we suggest that the presence of this microsatellite may partly reflect documented differences in levels of sociability found in bonobos and chimpanzees. PMID:25405348

Sister grouping of chimpanzees and humans as revealed by genome-wide phylogenetic analysis of brain gene expression profiles

PubMed Central

Uddin, Monica; Wildman, Derek E.; Liu, Guozhen; Xu, Wenbo; Johnson, Robert M.; Hof, Patrick R.; Kapatos, Gregory; Grossman, Lawrence I.; Goodman, Morris

2004-01-01

Gene expression profiles from the anterior cingulate cortex (ACC) of human, chimpanzee, gorilla, and macaque samples provide clues about genetic regulatory changes in human and other catarrhine primate brains. The ACC, a cerebral neocortical region, has human-specific histological features. Physiologically, an individual's ACC displays increased activity during that individual's performance of cognitive tasks. Of ≈45,000 probe sets on microarray chips representing transcripts of all or most human genes, ≈16,000 were commonly detected in human ACC samples and comparable numbers, 14,000–15,000, in gorilla and chimpanzee ACC samples. Phylogenetic results obtained from gene expression profiles contradict the traditional expectation that the non-human African apes (i.e., chimpanzee and gorilla) should be more like each other than either should be like humans. Instead, the chimpanzee ACC profiles are more like the human than like the gorilla; these profiles demonstrate that chimpanzees are the sister group of humans. Moreover, for those unambiguous expression changes mapping to important biological processes and molecular functions that statistically are significantly represented in the data, the chimpanzee clade shows at least as much apparent regulatory evolution as does the human clade. Among important changes in the ancestry of both humans and chimpanzees, but to a greater extent in humans, are the up-regulated expression profiles of aerobic energy metabolism genes and neuronal function-related genes, suggesting that increased neuronal activity required increased supplies of energy. PMID:14976249

Do chimpanzees (Pan troglodytes schweinfurthii) exhibit sleep related behaviors that minimize exposure to parasitic arthropods? A preliminary report on the possible anti-vector function of chimpanzee sleeping platforms.

PubMed

Samson, David R; Muehlenbein, Michael P; Hunt, Kevin D

2013-01-01

Great apes spend half of their lives in a nightly "nest" or sleeping platform (SP), a complex object created by modifying foliage, which functions as a stable substrate on which to sleep. Of the several purported functions of SPs, one hypothesis is that they protect against parasitic infection. Here we investigate the role of SP site choice in avoiding molestation by arthropods. This study presents preliminary data on the insect-repellent properties of preferred sleeping tree species Cynometra alexandri. Insect traps were deployed in gallery forest habitats in which chimpanzees typically "nest." We compared traps placed adjacent to SPs artificially manufactured with C. alexandri trees to an open area within the same habitat. Multiple measures of arthropod counts indicate that simulated C. alexandri SP sites have fewer arthropods than similar non-SP sites. Volatile compounds secreted by C. alexandri foliage are hypothesized to repel annoying arthropods and/or mask chimpanzee olfactory signals. Of the total insects captured (n = 6,318), n = 145 were mosquitoes. Of the total mosquitoes captured, n = 47 were identified as Anopheles (female, n = 12). The prominent malarial vector Anopheles gambiae was identified among the captured mosquito sample. These results suggest that the presence of broken branches of the tree species C. alexandri reduce the amount of insects a chimpanzee is exposed to throughout a night's sleep. This great ape behavioral and socio-technological adaptation may have evolved, in part, to increase quality of sleep as well as decrease exposure to vectors of disease.

The saliva microbiome of Pan and Homo

PubMed Central

2013-01-01

Background It is increasingly recognized that the bacteria that live in and on the human body (the microbiome) can play an important role in health and disease. The composition of the microbiome is potentially influenced by both internal factors (such as phylogeny and host physiology) and external factors (such as diet and local environment), and interspecific comparisons can aid in understanding the importance of these factors. Results To gain insights into the relative importance of these factors on saliva microbiome diversity, we here analyze the saliva microbiomes of chimpanzees (Pan troglodytes) and bonobos (Pan paniscus) from two sanctuaries in Africa, and from human workers at each sanctuary. The saliva microbiomes of the two Pan species are more similar to one another, and the saliva microbiomes of the two human groups are more similar to one another, than are the saliva microbiomes of human workers and apes from the same sanctuary. We also looked for the existence of a core microbiome and find no evidence for a taxon-based core saliva microbiome for Homo or Pan. In addition, we studied the saliva microbiome from apes from the Leipzig Zoo, and found an extraordinary diversity in the zoo ape saliva microbiomes that is not found in the saliva microbiomes of the sanctuary animals. Conclusions The greater similarity of the saliva microbiomes of the two Pan species to one another, and of the two human groups to one another, are in accordance with both the phylogenetic relationships of the hosts as well as with host physiology. Moreover, the results from the zoo animals suggest that novel environments can have a large impact on the microbiome, and that microbiome analyses based on captive animals should be viewed with caution as they may not reflect the microbiome of animals in the wild. PMID:24025115

Differential seed handling by two African primates affects seed fate and establishment of large-seeded trees

NASA Astrophysics Data System (ADS)

Gross-Camp, Nicole D.; Kaplin, Beth A.

2011-11-01

We examined the influence of seed handling by two semi-terrestrial African forest primates, chimpanzees ( Pan troglodytes) and l'Hoest's monkeys ( Cercopithecus lhoesti), on the fate of large-seeded tree species in an afromontane forest. Chimpanzees and l'Hoest's monkeys dispersed eleven seed species over one year, with quantity and quality of dispersal varying through time. Primates differed in their seed handling behaviors with chimpanzees defecating large seeds (>0.5 cm) significantly more than l'Hoest's. Furthermore, they exhibited different oral-processing techniques with chimpanzees discarding wadges containing many seeds and l'Hoest's monkeys spitting single seeds. A PCA examined the relationship between microhabitat characteristics and the site where primates deposited seeds. The first two components explained almost half of the observed variation. Microhabitat characteristics associated with sites where seeds were defecated had little overlap with those characteristics describing where spit seeds arrived, suggesting that seed handling in part determines the location where seeds are deposited. We monitored a total of 552 seed depositions through time, recording seed persistence, germination, and establishment. Defecations were deposited significantly farther from an adult conspecific than orally-discarded seeds where they experienced the greatest persistence but poorest establishment. In contrast, spit seeds were deposited closest to an adult conspecific but experienced the highest seed establishment rates. We used experimental plots to examine the relationship between seed handling, deposition site, and seed fate. We found a significant difference in seed handling and fate, with undispersed seeds in whole fruits experiencing the lowest establishment rates. Seed germination differed by habitat type with open forest experiencing the highest rates of germination. Our results highlight the relationship between primate seed handling and deposition site and seed

Bonobos and chimpanzees exhibit human-like framing effects

PubMed Central

Krupenye, Christopher; Rosati, Alexandra G.; Hare, Brian

2015-01-01

Humans exhibit framing effects when making choices, appraising decisions involving losses differently from those involving gains. To directly test for the evolutionary origin of this bias, we examined decision-making in humans' closest living relatives: bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). We presented the largest sample of non-humans to date (n = 40) with a simple task requiring minimal experience. Apes made choices between a ‘framed’ option that provided preferred food, and an alternative option that provided a constant amount of intermediately preferred food. In the gain condition, apes experienced a positive ‘gain’ event in which the framed option was initially presented as one piece of food but sometimes was augmented to two. In the loss condition, apes experienced a negative ‘loss' event in which they initially saw two pieces but sometimes received only one. Both conditions provided equal pay-offs, but apes chose the framed option more often in the positive ‘gain’ frame. Moreover, male apes were more susceptible to framing than were females. These results suggest that some human economic biases are shared through common descent with other apes and highlight the importance of comparative work in understanding the origins of individual differences in human choice. PMID:25672997

Bonobos and chimpanzees exhibit human-like framing effects.

PubMed

Krupenye, Christopher; Rosati, Alexandra G; Hare, Brian

2015-02-01

Humans exhibit framing effects when making choices, appraising decisions involving losses differently from those involving gains. To directly test for the evolutionary origin of this bias, we examined decision-making in humans' closest living relatives: bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). We presented the largest sample of non-humans to date (n = 40) with a simple task requiring minimal experience. Apes made choices between a 'framed' option that provided preferred food, and an alternative option that provided a constant amount of intermediately preferred food. In the gain condition, apes experienced a positive 'gain' event in which the framed option was initially presented as one piece of food but sometimes was augmented to two. In the loss condition, apes experienced a negative 'loss' event in which they initially saw two pieces but sometimes received only one. Both conditions provided equal pay-offs, but apes chose the framed option more often in the positive 'gain' frame. Moreover, male apes were more susceptible to framing than were females. These results suggest that some human economic biases are shared through common descent with other apes and highlight the importance of comparative work in understanding the origins of individual differences in human choice. © 2015 The Author(s) Published by the Royal Society. All rights reserved.

Ground-nesting by the chimpanzees of the Nimba Mountains, Guinea: environmentally or socially determined?

PubMed

Koops, Kathelijne; Humle, Tatyana; Sterck, Elisabeth H M; Matsuzawa, Tetsuro

2007-04-01

The chimpanzees (Pan troglodytes verus) of the Nimba Mountains, Guinea, West Africa, commonly make both elaborate ("night") and simple ("day") nests on the ground. In this study we investigated which factors might influence ground-nesting in this population, and tested two ecological hypotheses: 1) climatic conditions, such as high wind speeds at high altitudes, may deter chimpanzees from nesting in trees; and 2) a lack of appropriate arboreal nesting opportunities may drive the chimpanzees to nest on the ground. In addition to testing these two hypotheses, we explored whether ground-nesting is a sex-linked behavior. Data were collected monthly between August 2003 and May 2004 along transects and ad libitum. To identify the sex of ground-nesting individuals, we used DNA extracted from hair samples. The results showed that the occurrence and distribution of ground nests were not affected by climatic conditions or a lack of appropriate nest trees. Support was found for the notion that ground-nesting is a sex-linked behavior, as males were responsible for building all of the elaborate ground nests and most of the simple ground nests sampled. Elaborate ground nests occurred mostly in nest groups associated with tree nests, whereas simple ground nests usually occurred without tree nests in their vicinity. These results suggest that ground-nesting may be socially, rather than ecologically, determined.

Tradition over trend: Neighboring chimpanzee communities maintain differences in cultural behavior despite frequent immigration of adult females.

PubMed

Luncz, Lydia V; Boesch, Christophe

2014-07-01

The notion of animal culture has been well established mainly through research aiming at uncovering differences between populations. In chimpanzees (Pan troglodytes verus), cultural diversity has even been found in neighboring communities, where differences were observed despite frequent immigration of individuals. Female chimpanzees transfer at the onset of sexual maturity at an age, when the behavioral repertoire is fully formed. With immigrating females, behavioral variety enters the group. Little is known about the diversity and the longevity of cultural traits within a community. This study is building on previous findings of differences in hammer selection when nut cracking between neighboring communities despite similar ecological conditions. We now further investigated the diversity and maintenance of cultural traits within one chimpanzee community and were able to show high levels of uniformity in group-specific behavior. Fidelity to the behavior pattern did not vary between dispersing females and philopatric males. Furthermore, group-specific tool selection remained similar over a period of 25 years. Additionally, we present a study case on how one newly immigrant female progressively behaved more similar to her new group, suggesting that the high level of similarity in behavior is actively adopted by group members possibly even when originally expressing the behavior in another form. Taken together, our data support a cultural transmission process in adult chimpanzees, which leads to persisting cultural behavior of one community over time. © 2014 Wiley Periodicals, Inc.

A newborn infant chimpanzee snatched and cannibalized immediately after birth: Implications for "maternity leave" in wild chimpanzee.

PubMed

Nishie, Hitonaru; Nakamura, Michio

2018-01-01

This study reports on the first observed case of a wild chimpanzee infant being snatched immediately after delivery and consequently cannibalized by an adult male in the Mahale Mountains, Tanzania. We demonstrate "maternity leave" from long-term data from the Mahale M group and suggest that it functions as a possible counterstrategy of mother chimpanzees against the risk of infanticide soon after delivery. The subjects of this study were the M group chimpanzees at Mahale Mountains, Tanzania. The case of cannibalism was observed on December 2, 2014. We used the long-term daily attendance record of the M group chimpanzees between 1990 and 2010 to calculate the lengths of "maternity leave," a perinatal period during which a mother chimpanzee tends to hide herself and gives birth alone. We observed a very rare case of delivery in a wild chimpanzee group. A female chimpanzee gave birth in front of other members, and an adult male snatched and cannibalized the newborn infant immediately after birth. Using the long-term data, we demonstrate that the length of "maternity leave" is longer than that of nonmaternity leave among adult and adolescent female chimpanzees. We argue that this cannibalism event immediately after birth occurred due to the complete lack of "maternity leave" of the mother chimpanzee of the victim, who might lack enough experience of delivery. We suggest that "maternity leave" taken by expecting mothers may function as a possible counterstrategy against infanticide soon after delivery. © 2017 Wiley Periodicals, Inc.

Chimpanzees in an anthropogenic landscape: Examining food resources across habitat types at Bossou, Guinea, West Africa.

PubMed

Bryson-Morrison, Nicola; Matsuzawa, Tetsuro; Humle, Tatyana

2016-12-01

Many primate populations occur outside protected areas in fragmented anthropogenic landscapes. Empirical data on the ecological characteristics that define an anthropogenic landscape are urgently required if conservation initiatives in such environments are to succeed. The main objective of our study was to determine the composition and availability of chimpanzee (Pan troglodytes verus) food resources across fine spatial scales in the anthropogenic landscape of Bossou, Guinea, West Africa. We examined food resources in all habitat types available in the chimpanzees' core area. We surveyed resource composition, structure and heterogeneity (20 m × 20 m quadrats, N = 54) and assessed temporal availability of food from phenology trails (total distance 5951 m; 1073 individual trees) over 1 year (2012-2013). Over half of Bossou consists of regenerating forest and is highly diverse in terms of chimpanzee food species; large fruit bearing trees are rare and confined to primary and riverine forest. Moraceae (mulberries and figs) was the dominant family, trees of which produce drupaceous fruits favored by chimpanzees. The oil palm occurs at high densities throughout and is the only species found in all habitat types except primary forest. Our data suggest that the high densities of oil palm and fig trees, along with abundant terrestrial herbaceous vegetation and cultivars, are able to provide the chimpanzees with widely available resources, compensating for the scarcity of large fruit trees. A significant difference was found between habitat types in stem density/ha and basal area m 2 /ha of chimpanzee food species. Secondary, young secondary, and primary forest emerged as the most important habitat types for availability of food tree species. Our study emphasizes the importance of examining ecological characteristics of an anthropogenic landscape as each available habitat type is unlikely to be equally important in terms of spatial and temporal availability

Is wounding aggression in zoo-housed chimpanzees and ring-tailed lemurs related to zoo visitor numbers?

PubMed

Hosey, Geoff; Melfi, Vicky; Formella, Isabel; Ward, Samantha J; Tokarski, Marina; Brunger, Dave; Brice, Sara; Hill, Sonya P

2016-05-01

Chimpanzees in laboratory colonies experience more wounds on weekdays than on weekends, which has been attributed to the increased number of people present during the week; thus, the presence of more people was interpreted as stressful. If this were also true for primates in zoos, where high human presence is a regular feature, this would clearly be of concern. Here we examine wounding rates in two primate species (chimpanzees Pan troglodytes and ring-tailed lemurs Lemur catta) at three different zoos, to determine whether they correlate with mean number of visitors to the zoo. Wounding data were obtained from a zoo electronic record keeping system (ZIMS™). The pattern of wounds did not correlate with mean gate numbers for those days for either species in any group. We conclude that there is no evidence that high visitor numbers result in increased woundings in these two species when housed in zoos. Zoo Biol. 35:205-209, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Field studies of Pan troglodytes reviewed and comprehensively mapped, focussing on Japan's contribution to cultural primatology.

PubMed

McGrew, William C

2017-01-01

Field studies done over decades of wild chimpanzees in East, Central and West Africa have yielded impressive, cumulative findings in cultural primatology. Japanese primatologists have been involved in this advance from the outset, over a wide variety of topics. Here I review the origins and development of field studies of Pan troglodytes, then assess their progress based on analogy between cultural primatology and cultural anthropology, through four stages: natural history, ethnography, ethnology, and intuition. Then, I focus on six topics that continue to yield informative debate: technology, universals, nuanced variation, archaeology, applied primatology, and ecology. Finally, I offer a map of sites of field study of wild chimpanzees. It is clear that Japanese primatologists have made a significant contribution to East-West scientific exchange, especially at the field sites of Bossou and Mahale.

Newtonian chimpanzees? A molecular dynamics approach to understanding decision-making by wild chimpanzees

NASA Astrophysics Data System (ADS)

Westley, Matthew; Sen, Surajit; Sinha, Anindya

2014-07-01

In this study, we computationally investigate decision-making by individuals and the ensuing social structure of a primate species, chimpanzees, using Newton's equations of classical mechanics, as opposed to agentbased analyses in which individual chimpanzees make independent decisions. Our model uses molecular dynamics simulation techniques to solve Newton's equations and is able to approximate the movements of female and male chimpanzees, especially in relation to the available food resources, in a manner that is consistent with their observed behavior in natural habitats. It is noteworthy that our Newtonian dynamics-based model may allow us to make certain specific observations of their behaviour, some of which may be difficult to achieve through agent-based modelling exercises or even field studies. Chimpanzees tend to live in fission-fusion social groups, with varying number of individuals, in which both females and males tend to display intrasexual competition for valuable food resources while the males also compete for oestrus females. Most populations of the species are also restricted to a small range of habitats, a clear indication that they are especially vulnerable to the availability and distribution of food sources. With reasonable assumptions of chimpanzee behaviour, we have been able to analyse the clustering behaviour of individuals in relation to local food sources as also patterns of their migration across groups. Our simulated results are qualitatively consistent with field observations conducted on a particular semi-isolated population of chimpanzees in Bossou, Guinea, in western Africa.

Morphological integration in the gorilla, chimpanzee, and human neck.

PubMed

Arlegi, Mikel; Gómez-Robles, Aida; Gómez-Olivencia, Asier

2018-06-01

Although integration studies are important to understand the evolution of organisms' traits across phylogenies, vertebral integration in primates is still largely unexplored. Here we describe and quantify patterns of morphological integration and modularity in the subaxial cervical vertebrae (C3-C7) in extant hominines incorporating the potential influence of size. Three-dimensional landmarks were digitized on 546 subaxial cervical vertebrae from 141 adult individuals of Gorilla gorilla, Pan troglodytes, and Homo sapiens. Integration and modularity, and the influence of size effects, were quantified using geometric morphometric approaches. All subaxial cervical vertebrae from the three species show a strong degree of integration. Gorillas show the highest degree of integration; conversely, humans have the lowest degree of integration. Analyses of allometric regression residuals show that size is an important factor promoting integration in gorillas, with lesser influence in chimpanzees and almost no effect in humans. Results point to a likely ancestral pattern of integration in non-human hominines, whereby the degree of integration decreases from cranial to caudal positions. Humans deviate from this pattern in the cranialmost (C3) and, to a lesser extent, in the caudalmost (C7) vertebrae, which are less integrated. These differences can be tentatively related to the emergence of bipedalism due to the presence of modern human-like C3 in australopiths, which still preserve a more chimpanzee-like C7. © 2018 Wiley Periodicals, Inc.

A 3 million year index for North African humidity/aridity and the implication of potential pan-African Humid periods

NASA Astrophysics Data System (ADS)

Grant, Katharine M.; Rohling, Eelco J.; Westerhold, Thomas; Zabel, Matthias; Heslop, David; Konijnendijk, Tiuri; Lourens, Lucas

2017-09-01

Mediterranean sediments are valuable archives of both African monsoon variability and higher-latitude climate processes, and can also be used to provide an environmental context for early human migrations and settlements. However, the long history of Mediterranean palaeoclimate studies largely pre-dates the advent of widespread x-ray fluorescence (XRF) core-scanning, so there are few continuous and high-resolution geochemical records from this key region that extend beyond the last glacial cycle. Here we present XRF core-scanning results for ODP Site 967 (Eastern Mediterranean) that have been fully-calibrated into element concentrations spanning the last 3 million years (My). Comparison with independent geochemical data from conventional XRF highlights disparities for certain element/element ratios, thus suggesting the need for caution when taking ratios of scanning XRF data. Principal component analysis of the calibrated XRF dataset reveals two dominant components: detrital inputs (PC1) and a 'sapropel' (≈monsoon run-off) signal (PC2), which we use to establish a new orbitally-tuned chronology. We observe inverse covariation between PC2 and a previously published aeolian dust record from ODP Site 967 (Larrasoaña et al., 2003), and combine these records to produce a composite index of humidity and aridity for the wider North African region over the past 3 My. We propose that by combining run-off and dust signals in a single metric, our index captures the effects of both strengthening/northward migration (increased run-off) and weakening/southward retreat (increased dust) of the North African monsoon. Comparison of the index with published records of Northwest and East African palaeohumidity suggests that it tracks the timing of ;Green Sahara Periods; throughout the Plio-Pleistocene, and that at least 30 of these intervals coincided with increased humidity across East Africa. We tentatively suggest that these specific episodes may be termed ;pan-African Humid

Chimpanzees prioritise social information over pre-existing behaviours in a group context but not in dyads.

PubMed

Watson, Stuart K; Lambeth, Susan P; Schapiro, Steven J; Whiten, Andrew

2018-05-01

How animal communities arrive at homogeneous behavioural preferences is a central question for studies of cultural evolution. Here, we investigated whether chimpanzees (Pan troglodytes) would relinquish a pre-existing behaviour to adopt an alternative demonstrated by an overwhelming majority of group mates; in other words, whether chimpanzees behave in a conformist manner. In each of five groups of chimpanzees (N = 37), one individual was trained on one method of opening a two-action puzzle box to obtain food, while the remaining individuals learned the alternative method. Over 5 h of open access to the apparatus in a group context, it was found that 4/5 'minority' individuals explored the majority method and three of these used this new method in the majority of trials. Those that switched did so after observing only a small subset of their group, thereby not matching conventional definitions of conformity. In a further 'Dyad' condition, six pairs of chimpanzees were trained on alternative methods and then given access to the task together. Only one of these individuals ever switched method. The number of observations that individuals in the minority and Dyad individuals made of their untrained method was not found to influence whether or not they themselves switched to use it. In a final 'Asocial' condition, individuals (N = 10) did not receive social information and did not deviate from their first-learned method. We argue that these results demonstrate an important influence of social context upon prioritisation of social information over pre-existing methods, which can result in group homogeneity of behaviour.

Lateralization and performance asymmetries in the termite fishing of wild chimpanzees in the goualougo triangle, republic of Congo.

PubMed

Sanz, Crickette M; Morgan, David B; Hopkins, William D

2016-11-01

The nearly universal right hand preference manifested by human populations is one of the most pronounced manifestations of population-level lateralization. Morphological and archeological evidence indicate that this behavioral specialization may have emerged among our hominin ancestors. Whether population-level behavioral asymmetries are evident in non-human animals remains a topic of considerable scientific debate, with the most consistent evidence of population-level trends emerging from studies of chimpanzees (Pan troglodytes). However, previous studies of population-level lateralization in wild apes have relied upon data sets pooled across populations to reach adequate sample sizes. Our aim was to test for population-level handedness within a single wild chimpanzee population, and also to determine if performance asymmetries were associated with handedness. To address these questions, we coded handedness and duration of fishing probe insertions from remote video footage of chimpanzee visitation to termite nests (totaling 119 hr) in the Goualougo Triangle, Republic of Congo. Similar to reports from other populations, chimpanzees in the Goualougo Triangle showed robust individual hand preferences for termite fishing. There were 46 right-handed, 39 left-handed, and 4 ambiguously-handed individuals. Though we did not detect an overall significant population-level handedness (t(88) = 0.83, n.s.) in this study, males showed a greater right hand preference than females. Further, we found that average dipping latencies were significantly faster for right- compared to left-handed chimpanzees. Possible explanations and evolutionary implications of taxa- and task-specific patterns of population-level laterality are discussed. Am. J. Primatol. 78:1190-1200, 2016. © 2016 Wiley Periodicals, Inc. © 2016 Wiley Periodicals, Inc.

Sex differences in the relationship between planum temporale asymmetry and corpus callosum morphology in chimpanzees (Pan troglodytes): A combined MRI and DTI analysis.

PubMed

Hopkins, William D; Hopkins, Anna M; Misiura, Maria; Latash, Elitaveta M; Mareno, Mary Catherine; Schapiro, Steven J; Phillips, Kimberley A

2016-12-01

Increases brain size has been hypothesized to be inversely associated with the expression of behavioral and brain asymmetries within and between species. We tested this hypothesis by analyzing the relation between asymmetries in the planum temporale (PT) and different measures of the corpus callosum (CC) including surface area, streamline count as measured from diffusion tensor imaging, fractional anisotropy values and the ratio in the number of fibers to surface area in a sample of chimpanzees. We found that chimpanzees with larger PT asymmetries in absolute terms had smaller CC surface areas, fewer streamlines and a smaller ratio of fibers to surface area. These results were largely specific to male but not female chimpanzees. Our results partially support the hypothesis that brain asymmetries are linked to variation in corpus callosum morphology, although these associations may be sex-dependent. Copyright © 2016 Elsevier Ltd. All rights reserved.

The risk of disease to great apes: simulating disease spread in orang-utan (Pongo pygmaeus wurmbii) and chimpanzee (Pan troglodytes schweinfurthii) association networks.

PubMed

Carne, Charlotte; Semple, Stuart; Morrogh-Bernard, Helen; Zuberbühler, Klaus; Lehmann, Julia

2014-01-01

All great ape species are endangered, and infectious diseases are thought to pose a particular threat to their survival. As great ape species vary substantially in social organisation and gregariousness, there are likely to be differences in susceptibility to disease types and spread. Understanding the relation between social variables and disease is therefore crucial for implementing effective conservation measures. Here, we simulate the transmission of a range of diseases in a population of orang-utans in Sabangau Forest (Central Kalimantan) and a community of chimpanzees in Budongo Forest (Uganda), by systematically varying transmission likelihood and probability of subsequent recovery. Both species have fission-fusion social systems, but differ considerably in their level of gregariousness. We used long-term behavioural data to create networks of association patterns on which the spread of different diseases was simulated. We found that chimpanzees were generally far more susceptible to the spread of diseases than orang-utans. When simulating different diseases that varied widely in their probability of transmission and recovery, it was found that the chimpanzee community was widely and strongly affected, while in orang-utans even highly infectious diseases had limited spread. Furthermore, when comparing the observed association network with a mean-field network (equal contact probability between group members), we found no major difference in simulated disease spread, suggesting that patterns of social bonding in orang-utans are not an important determinant of susceptibility to disease. In chimpanzees, the predicted size of the epidemic was smaller on the actual association network than on the mean-field network, indicating that patterns of social bonding have important effects on susceptibility to disease. We conclude that social networks are a potentially powerful tool to model the risk of disease transmission in great apes, and that chimpanzees are

The Risk of Disease to Great Apes: Simulating Disease Spread in Orang-Utan (Pongo pygmaeus wurmbii) and Chimpanzee (Pan troglodytes schweinfurthii) Association Networks

PubMed Central

Carne, Charlotte; Semple, Stuart; Morrogh-Bernard, Helen; Zuberbühler, Klaus; Lehmann, Julia

2014-01-01

All great ape species are endangered, and infectious diseases are thought to pose a particular threat to their survival. As great ape species vary substantially in social organisation and gregariousness, there are likely to be differences in susceptibility to disease types and spread. Understanding the relation between social variables and disease is therefore crucial for implementing effective conservation measures. Here, we simulate the transmission of a range of diseases in a population of orang-utans in Sabangau Forest (Central Kalimantan) and a community of chimpanzees in Budongo Forest (Uganda), by systematically varying transmission likelihood and probability of subsequent recovery. Both species have fission-fusion social systems, but differ considerably in their level of gregariousness. We used long-term behavioural data to create networks of association patterns on which the spread of different diseases was simulated. We found that chimpanzees were generally far more susceptible to the spread of diseases than orang-utans. When simulating different diseases that varied widely in their probability of transmission and recovery, it was found that the chimpanzee community was widely and strongly affected, while in orang-utans even highly infectious diseases had limited spread. Furthermore, when comparing the observed association network with a mean-field network (equal contact probability between group members), we found no major difference in simulated disease spread, suggesting that patterns of social bonding in orang-utans are not an important determinant of susceptibility to disease. In chimpanzees, the predicted size of the epidemic was smaller on the actual association network than on the mean-field network, indicating that patterns of social bonding have important effects on susceptibility to disease. We conclude that social networks are a potentially powerful tool to model the risk of disease transmission in great apes, and that chimpanzees are

Why do chimpanzees hunt? Considering the benefits and costs of acquiring and consuming vertebrate versus invertebrate prey.

PubMed

Tennie, Claudio; O'Malley, Robert C; Gilby, Ian C

2014-06-01

Understanding the benefits and costs of acquiring and consuming different forms of animal matter by primates is critical for identifying the selective pressures responsible for increased meat consumption in the hominin lineage. Chimpanzees (Pan troglodytes) are unusual among primates in the amount of vertebrate prey they consume. Still, surprisingly little is known about the nutritional benefits of eating meat for this species. In order to understand why chimpanzees eat vertebrates, it is critical to consider the relative benefits and costs of other types of faunivory - including invertebrates. Although we lack specific nutritional data on the flesh and organs of chimpanzee prey, the macronutrient profiles of insects and wild vertebrate meat are generally comparable on a gram-to-gram basis. There are currently very few data on the micronutrient (vitamin and mineral) content of meat consumed by chimpanzees. With few exceptions, the advantages of hunting vertebrate prey include year-round availability, rapid acquisition of larger packages and reduced handling/processing time (once prey are encountered or detected). The disadvantages of hunting vertebrate prey include high potential acquisition costs per unit time (energy expenditure and risk of injury) and greater contest competition with conspecifics. Acquiring an equivalent mass of invertebrates (to match even a small scrap of meat) is possible, but typically takes more time. Furthermore, in contrast to vertebrate prey, some insect resources are effectively available only at certain times of the year. Here we identify the critical data needed to test our hypothesis that meat scraps may have a higher (or at least comparable) net benefit:cost ratio than insect prey. This would support the 'meat scrap' hypothesis as an explanation for why chimpanzees hunt in groups even when doing so does not maximize an individual's energetic gain. Copyright © 2014 Elsevier Ltd. All rights reserved.

Chimpanzees know that others make inferences

PubMed Central

Schmelz, Martin; Call, Josep; Tomasello, Michael

2011-01-01

If chimpanzees are faced with two opaque boards on a table, in the context of searching for a single piece of food, they do not choose the board lying flat (because if food was under there it would not be lying flat) but, rather, they choose the slanted one— presumably inferring that some unperceived food underneath is causing the slant. Here we demonstrate that chimpanzees know that other chimpanzees in the same situation will make a similar inference. In a back-and-forth foraging game, when their competitor had chosen before them, chimpanzees tended to avoid the slanted board on the assumption that the competitor had already chosen it. Chimpanzees can determine the inferences that a conspecific is likely to make and then adjust their competitive strategies accordingly. PMID:21282649