Chimpanzee Interactions Research Articles

Corpse-directed play parenting by a sterile adult female chimpanzee.

The study of representational play in nonhuman primates, including chimpanzees (Pan troglodytes), provides interspecific perspectives on human cognitive development and evolution. A notable form of representational play in chimpanzees is play parenting, wherein parental behavior is directed at inanimate objects. Though observed in captivity, unambiguous examples of play parenting by wild chimpanzees are rare. Here, we report two cases from Ngogo in Kibale National Park, Uganda, in which a wild adult female chimpanzee (P. t. schweinfurthii) directed parental behaviors at corpses. Both cases involved the same adult female chimpanzee, aged 20-21years. The first case was observed on 5 March 2016, and the play object was the corpse of a bushbaby (Galago thomasi); in the second case, observed on 6 May 2017, the play object was a recently deceased chimpanzee infant postmortally stolen from the mother. The chimpanzee possessed the first and second play objects for approximately 5.5h and 1.8h, respectively. In both cases, she performed a variety of maternal behaviors, including co-nesting, grooming, and dorsally carrying the play objects. In contrast to previous observations of play parenting in captivity, the play parent was a presumably sterile adult female, well beyond the average age of first birth. These observations contribute to the expanding literature on chimpanzee interactions with the corpses of both conspecifics and heterospecifics.

Gestural acquisition in great apes: the Social Negotiation Hypothesis

Scientific interest in the acquisition of gestural signalling dates back to the heroic figure of Charles Darwin. More than a hundred years later, we still know relatively little about the underlying evolutionary and developmental pathways involved. Here, we shed new light on this topic by providing the first systematic, quantitative comparison of gestural development in two different chimpanzee (Pan troglodytes verus and Pan troglodytes schweinfurthii) subspecies and communities living in their natural environments. We conclude that the three most predominant perspectives on gestural acquisition—Phylogenetic Ritualization, Social Transmission via Imitation, and Ontogenetic Ritualization—do not satisfactorily explain our current findings on gestural interactions in chimpanzees in the wild. In contrast, we argue that the role of interactional experience and social exposure on gestural acquisition and communicative development has been strongly underestimated. We introduce the revised Social Negotiation Hypothesis and conclude with a brief set of empirical desiderata for instigating more research into this intriguing research domain.

Mother–infant interactions in captive and wild chimpanzees

We review studies on mother–infant interactions in chimpanzees, our closest living relatives, in captive and wild environments. Infant cognitive development is formed through mother–infant interactions during the long dependent period, which is approximately 5 years. Patterns of interaction between mothers and infants are different from those observed in adult chimpanzees. Mother–infant interactions are relatively altruistic, although solicitation by infants is almost always required. Active teaching has rarely been reported in chimpanzees; instead, infants socially learn new skills through long-term observation. Case studies describing rearing of a disabled infant by a multiparous but inexperienced chimpanzee, and the carrying of dead infants in the wild chimpanzees of Bossou reveal the strong affectionate bond between mothers and infants. Characteristics of human mother–infant interaction are highlighted through comparisons with chimpanzees.

Dyadic interactions, attachment and the presence of triadic interactions in chimpanzees and humans

From a developmental perspective, dyadic interactions with social partners and dyadic interactions with objects underpin early social cognition in humans and chimpanzees. In humans, dyadic social relationships form in the first three months of life, dyadic relations with objects form in the first 6 months of life, and triadic relations begin around 8–12 months. In chimpanzees, a similar developmental pattern is evident with dyadic social relationships forming in the first three months of life, dyadic relations with objects forming in the first 5 months of life, and triadic relations in the latter half of the first year of life. During ontogeny humans and chimpanzees experience emotional engagements, both with social partners and with objects, and these impact outcomes in social cognition. Rather than being considered too complex, diversity of socio-emotional experiences during development can be embraced, with the goal to specify how they influence social cognition outcomes in humans and in chimpanzees. This process may provide the evolutionary and biological foundations for plasticity.

Challenging approaches and crossovers in anthropology and conservation in Guinea-Bissau

This communication presents research conducted according to the theoretical viewpoint held passionately by Claudia Sousa: the need for an interdisciplinary perspective between anthropology, primatology and conservation. Only then can a holistic understanding of human and chimpanzee interactions be achieved that includes local knowledge, and involves local populations in biodiversity conservation.

Chimpanzee behavioural flexibility and the sustainability of human-chimpanzee interactions at Cantanhez National Park, Guinea-Bissau

This paper incorporates research conducted by Claudia Sousa and demonstrates the importance of examining chimpanzee behavioural flexibility alongside chimpanzee interactions with local people for the conservation of biodiversity in anthropogenic habitats.

Social grooming network in captive chimpanzees: does the wild or captive origin of group members affect sociality?

Many chimpanzees throughout the world are housed in captivity, and there is an increasing effort to recreate social groups by mixing individuals with captive origins with those with wild origins. Captive origins may entail restricted rearing conditions during early infant life, including, for example, no maternal rearing and a limited social life. Early rearing conditions have been linked with differences in tool-use behavior between captive- and wild-born chimpanzees. If physical cognition can be impaired by non-natural rearing, what might be the consequences for social capacities? This study describes the results of network analysis based on grooming interactions in chimpanzees with wild and captive origins living in the Kumamoto Sanctuary in Kumamoto, Japan. Grooming is a complex social activity occupying up to 25% of chimpanzees' waking hours and plays a role in the emergence and maintenance of social relationships. We assessed whether the social centralities and roles of chimpanzees might be affected by their origin (captive vs wild). We found that captive- and wild-origin chimpanzees did not differ in their grooming behavior, but that theoretical removal of individuals from the network had differing impacts depending on the origin of the individual. Contrary to findings that non-natural early rearing has long-term effects on physical cognition, living in social groups seems to compensate for the negative effects of non-natural early rearing. Social network analysis (SNA) and, in particular, theoretical removal analysis, were able to highlight differences between individuals that would have been impossible to show using classical methods. The social environment of captive animals is important to their well-being, and we are only beginning to understand how SNA might help to enhance animal welfare.

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

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.

Coordination mutuelle des comportements dans les interactions humains-chimpanzés: étude de cas en contexte de laboratoire

This study deepens our understanding of sociality established between chimpanzees and humans by analyzing the sequential organization of interactions in a laboratory setting. We conducted an interaction analysis of two short video clips that recorded a physical measurement event at the Great Ape Research Institute (GARI), Tamano, Japan. The results indicated that captive chimpanzees demonstrated how they perceived their situation, or what they would like, using various kinds of body movements and vocal sounds including hand gestures, scratching, whimpers, and screaming. Human trainers also enacted various meanings using body movements and verbal utterances. In particular, they encouraged chimpanzee–human interactions to include turn-taking, a distinctive style of human communication, by introducing various types of adjacency pairs. They also used other types of utterances, such as providing comments to clarify chimpanzee behaviors to smooth the flow of interactions when a chimpanzee was unlikely to provide a clear response. Analyses of the accumulated interactional histories revealed that most captive chimpanzees and humans in GARI appear to have formed mutually coordinated interaction patterns despite the differences in available semiotic resources between the two species. One exception was an infant chimpanzee raised by humans, who had not yet accumulated a sufficient interactional history to form stable interaction patterns with other chimpanzees. This caused serious problems for the infant and other chimpanzees, making it difficult for them to get along. Our results suggest that captive chimpanzees can adapt to live in accordance with the rhythm of humans in an environment largely constructed by humans, and that humans can coordinate their actions in accordance with the rhythm of chimpanzees. These findings are particularly important and suggest that analyses of human–chimpanzee interactions may help inform research about the foundations of societies built by humans, built by chimpanzees, and co-built by humans and chimpanzees.

Triggering social interactions: chimpanzees respond to imitation by a humanoid robot and request responses from it.

Even the most rudimentary social cues may evoke affiliative responses in humans and promote social communication and cohesion. The present work tested whether such cues of an agent may also promote communicative interactions in a nonhuman primate species, by examining interaction-promoting behaviours in chimpanzees. Here, chimpanzees were tested during interactions with an interactive humanoid robot, which showed simple bodily movements and sent out calls. The results revealed that chimpanzees exhibited two types of interaction-promoting behaviours during relaxed or playful contexts. First, the chimpanzees showed prolonged active interest when they were imitated by the robot. Second, the subjects requested 'social' responses from the robot, i.e. by showing play invitations and offering toys or other objects. This study thus provides evidence that even rudimentary cues of a robotic agent may promote social interactions in chimpanzees, like in humans. Such simple and frequent social interactions most likely provided a foundation for sophisticated forms of affiliative communication to emerge.

Troublesome neighbours: Changing attitudes towards chimpanzees (Pan troglodytes) in a human-dominated landscape in Uganda

Long-term human–wildlife sympatry depends on the willingness and capacity of local people to coexist with wild animals. With human population growth and deforestation for agriculture, farmers increasingly live in proximity to wildlife, including large mammals of conservation concern. Understanding local perspectives and concerns regarding wildlife is essential for informing appropriate management strategies that reduce conflicts and promote sustainable coexistence. Social science approaches therefore have a critical role in integrated conservation programmes. We undertook an attitude survey to understand residents’ perspectives about sharing a landscape with chimpanzees (Pan troglodytes) in an unprotected forest–agriculture mosaic in Uganda. Interviews (n=134) in 12 villages demonstrate residents’ ambivalence towards living alongside these protected yet potentially troublesome mammals. Chimpanzee behaviour is reported to have undergone recent changes. Residents claim apes increasingly enter villages for food, threaten people, and pose a particular threat to children's safety. Chimpanzee numbers are believed to have increased locally. Most interviewees fear chimpanzees, considering them dangerous. Crop losses to chimpanzees were widely reported. Farmers tolerate raiding of domestic fruits, but not cash-crops. Results demonstrate that attitudes towards wildlife are not fixed. Reported changes to chimpanzee behaviour are challenging villagers’ traditionally benign attitude towards them. Even so, residents acknowledge benefits to chimpanzees because they reportedly displace other crop-raiding wildlife which, unlike chimpanzees, damage important staple food crops. Survey findings are contextualised with respect to recent, major land-use changes in Uganda (clearance of unprotected forest for timber and agriculture) that have precipitated a sharp rise in farmer–chimpanzee interactions. We discuss the study's broader implications for protected mammal management and conflict mitigation in human-dominated landscapes, and ask whether it is appropriate to expect impoverished rural farmers to accommodate large-bodied mammals that pose a potential threat to their safety and livelihoods.

Chimpanzee interactions with nonhuman species in an anthropogenic habitat

Interactions between wildlife species are numerous and diverse, ranging from commensalism to predation. Information on cross-species interactions in anthropogenic habitats are rare but can serve to improve our understanding of animal behavioural and ecological flexibility in response to human-induced changes. Here we report direct observations of interactions between chimpanzees (Pan troglodytes verus) and wild and domesticated species in a forest-farm mosaic at Bossou, Guinea, recorded between 1997 and 2009. The low diversity and abundance of wildlife, in particular typical chimpanzee prey species, are reflected in both the low interaction rates (one interaction per 400 observation hours) and the low number of species with which chimpanzees interacted (nine species, mostly mammals, but also birds and reptiles). Chimpanzees generally chose either to make direct physical contact with a species or not; interactions that involved direct contact lasted longer than noncontacts. Interactions with mammals showed the greatest diversity in nature and duration. Adults most often consumed a captured animal, while immatures most often engaged in playful behaviours with other species. Immatures also exhibited distinctive accompanying behaviours whereas adults rarely did so. Species-specific behaviours that depend on the age-class of the interactant are consistent with the idea that chimpanzees categorise different animals. We anticipate that chimpanzee interactions with sympatric species inhabiting humanised habitats will change over time to include more domesticated species. Conservation management strategies should anticipate behavioural flexibility in response to changing landscapes.

Caregiver–chimpanzee interactions with species-specific behaviors

The relationships between captive primates and their caregivers are critical ones and can affect animal welfare. This study tested the effect of caregivers using chimpanzee behaviors or not, in daily interactions with captive chimpanzees. In the Chimpanzee Behavior (CB) condition the caregiver presented chimpanzee behaviors. In the Human Behavior (HB) condition the caregiver avoided using chimpanzee behaviors. The chimpanzees had individual patterns of response and had significant differences in their responses to each condition. These data are compared to a similar study conducted at The Zoo Northwest Florida (ZNWF). Both groups of chimpanzees were sensitive and responsive to the differences in conditions. These data suggest ways to improve animal welfare. Keywords: chimpanzee behavior; animal welfare; species-specific behavior; husbandry

Intergroup conflicts among chimpanzees in Taï National Park: lethal violence and the female perspective

Intercommunity aggression in chimpanzees and primitive warfare in humans possess striking similarities, such as the common occurrence of large male coalitions, systematic control of territory boundaries, and lethal attacks on isolated individuals from neighboring groups. However, an important apparent contrast is the absence of recurrent peaceful interactions between neighboring groups of chimpanzees. We observed a remarkable range of behavior in intergroup encounters among three habituated communities of chimpanzees in Taï National Park, Côte d'Ivoire. Lethal attacks are documented in these study groups for the first time, as well as year-long exchanges of parous adult females and peaceful intergroup visits of mothers with infants. Demographic factors, including group size and number of adult males, are shown to affect the nature of intergroup interactions in ways not considered previously. A reconsideration of the difference in intergroup interactions between eastern and western chimpanzees is proposed including a more important consideration of the female's perspective. The inclusion of the new complexities in intergroup interactions in chimpanzees allows new parallels to be drawn with the evolution of primitive warfare in humans.

What to do after a fight? The determinants and inter-dependency of post-conflict interactions in chimpanzees

Primates resolve conflicts through post-conflict interactions (PCI). However, the occurrence of different PCI in relation to one another is not well understood. Furthermore, the factors influencing the occurrence of PCI are rarely addressed together, and thereby their relative impact is usually ignored. We investigated the occurrence and interrelatedness of five PCI, namely reconciliation, further (or redirected) aggression, third-party affiliation, third-party aggression and 'no PCI' in captive chimpanzees. Most PCI were found to occur independently from each other. Reconciliation was determined by relationship attributes between the opponents. Further aggression was mainly determined by directionality and intensity of conflicts. Opponents received third-party affiliation most often when they were likely to redirect aggression to third parties, although in aggressees this aspect was less clear than in aggressors. The predictors for third-party aggression and 'no PCI' remained unclear or insignificant. Overall, the results indicate that (1) most PCI do not directly depend on one another and that (2) the conflict opponents and the bystanders each make their own 'decisions' about which PCI to employ depending on specific conflict characteristics, the conflict outcome and the relationship attributes among the opponents. This study emphasises the multidimensionality of primate conflict resolution.

Evolutionary roots of intuitive parenting: Maternal competence in chimpanzees

AbstractIntuitive parenting behaviours have been shown to be universal in humans and appear to be based on psychobiological preadaptedness. This study is an exploration of the evolutionary roots of intuitive parenting through naturalistic observation of mother chimpanzees' interaction with their very young infants. Maternal competence is demonstrated initially through the behaviours of carrying the newborn infant and allowing the infant to nurse. Very early mother–infant interactions include play, ‘exercise’, cradling and grooming. Chimpanzee mothers also assess their offspring's behavioural state and muscle tone through visual inspections and movement of legs, arms, fingers and toes. Chimpanzee mothers and infants, as early as 2 weeks of age, spend some time in mutual gaze. Neonatal chimpanzees are capable of sustained face‐to‐face interactions, as these were observed in nursery‐reared chimpanzee interactions with human adults; however, it appears that chimpanzee mothers encourage mutual gaze with their infants for only brief durations. Chimpanzees with good maternal competence exhibit sensitive responsivity to infants' communicatory signals. Thus the results of this study support the claim that there are evolutionary and comparative foundations of intuitive parenting evident in the maternal behaviour and maternal competence of chimpanzees.

Side-Directed Communication and Agonistic Interactions in Chimpanzees

AbstractIn the large colony of chimpanzees in Arnhem Zoo (Netherlands) 70% of the agonistic encounters occurred as part of interactions involving three or more individuals. The present paper treats an example of one such multi-animal interaction. The example serves to illustrate how we analyse and interpret interaction structures, individual roles and strategies. Special attention is paid to side-directed communication: i.e. behaviour that agonistically involved apes show towards non-opponents. A multi-variate analysis of the contexts of this highly variable behaviour indicates that it can be divided into several functional categories; taking refuge; seeking reassurance; enlisting support; begging for support and taking courage. In general, side-directed behaviour facilitates intervention by third parties. But sometimes its function may be to appease potential supporters of the opponent, and thus keep them from interfering.

Notes on chimpanzee interactions with small carnivores in Gombe National Park, Tanzania

Although interspecific interactions between chimpanzees and various mammals have been reported from several field studies, relatively few encounters with carnivores of any size have been observed in natural conditions. The previously documented examples are here supplemented by three events describing wild chimpanzee responses to small carnivores. The observations now available suggest that chimpanzee responses are flexible rather than strictly patterned.