Chimpanzee Activity and Behavioral Diversity Extends Across 24 Hours in Both Captive and Wild Settings.

Studying nocturnal behavior is crucial for understanding the full scope of a species' behavioral flexibility so as to inform the conservation of wild populations and the care of captive individuals. However, this aspect of primate behavior is understudied, especially in great apes, which exhibit some of the widest documented behavioral diversity and flexibility. Our investigation is among the first to systematically compare the 24 h activity patterns and behavioral activities of captive chimpanzees (Saint Louis Zoo, USA) with those of wild chimpanzees (three sites across the Nouabalé-Ndoki National Park in the Republic of Congo) and a published data set of the nocturnal behavior of all chimpanzee subspecies.

Chimpanzees employ context-specific behavioral strategies within fission-fusion societies.

Fission-fusion social systems allow individuals to make flexible choices about where, with whom, and in what contexts to spend their time in response to competing social and ecological pressures. The ability for fission-fusion societies to support individual behavioral strategies that vary across contexts has been suggested, but the potential function of such context-specific social choices remains largely understudied. We adopted the concept of social niche construction to explore possible differences in social complexity at the individual and group level across feeding contexts.

Extending the conservation impact of great ape research: Flagship species sites facilitate biodiversity assessments and land preservation.

To inform regional conservation planning, we assessed mammalian and avian biodiversity in the Djéké Triangle, which is an intact forest with long-term research and tourism focused on western lowland gorillas (Gorilla gorilla gorilla). This critical region serves as a conservation conduit between the Nouabalé-Ndoki National Park (NNNP) in the Republic of Congo and the Dzanga-Ndoki National Park in Central African Republic. Wildlife inventories were conducted to determine if biodiversity in the Djéké Triangle (initially part of a logging concession) was equivalent to the NNNP.

Interspecific interactions between sympatric apes.

Gorillas reside in sympatry with chimpanzees over the majority of their range. Compiling all known reports of overlap between apes and augmenting these with observations made over twenty years in the Ndoki Forest, we examine the potential predation-related, foraging, and social contexts of interspecific associations between gorillas and chimpanzees. We reveal a greater diversity of interactions than previously recognized, which range from play to lethal aggression.

Human caregivers are integrated social partners for captive chimpanzees.

In a captive environment, it is challenging to ensure the highest level of social and psychological well-being for species with naturally complex social organizations and structures. There is a growing need to meet the social requirements for individuals of these species, especially chimpanzees, housed in zoos, sanctuaries, rehabilitation centers, and laboratories. Complex social interactions and broader social structures can be aptly described via social network analysis.

Comparative Investigations of Social Context-Dependent Dominance in Captive Chimpanzees (Pan troglodytes) and Wild Tibetan Macaques (Macaca thibetana).

Theoretical definitions of dominance, how dominance is structured and organized in nature, and how dominance is measured have varied as investigators seek to classify and organize social systems in gregarious species. Given the variability in behavioral measures and statistical methods used to derive dominance rankings, we conducted a comparative analysis of dominance using existing statistical techniques to analyze dominance ranks, social context-dependent dominance structures, the reliability of statistical analyses, and rank predictability of dominance structures on other social behaviors. We investigated these topics using behavioral data from captive chimpanzees (Pan troglodytes) and wild Tibetan macaques (Macaca thibetana).

Playing it cool: Characterizing social play, bout termination, and candidate play signals of juvenile and infant Tibetan macaques (Macaca thibetana).

Play behaviors and signals during playful interactions with juvenile conspecifics are important for both the social and cognitive development of young animals. The social organization of a species can also influence juvenile social play. We examined the relationships among play behaviors, candidate play signals, and play bout termination in Tibetan macaques (Macaca thibetana) during juvenile and infant social play to characterize the species play style.

Social network and dominance hierarchy analyses at Chimpanzee Sanctuary Northwest.

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.