Crickette Sanz reviews video footage with (from the left) Marcellin Mekoti, Mbembe Simon Boyo, and Raymond Sombo, all members of the Goualougo Triangle Ape Project tracking team. This project employs more than 30 people from the local villages of Bomassa and Makao in the northern Republic of Congo. Photo by Ian Nichols, National Geographic Society (All rights reserved).

Contemporary theoretical approaches to chimpanzee sociality have reached a crucial point where specific information is needed to advance our understanding of the relationship of phylogeny, ecology, and social behavior. In particular, my current research focuses on the variation in social organization and material culture that has been documented across wild chimpanzee populations. As co-principal investigators of the Goualougo Triangle Ape Project in northern Republic of Congo, Dr. David Morgan and I have been conducting field studies over the past 10 years to examine the behavioral ecology of the central subspecies of chimpanzee (Pan troglodytes troglodytes), the social and ecological factors shaping their complex tool-using traditions, and the effects of anthropogenic disturbance on sympatric chimpanzees and gorillas in western equatorial Africa. These studies hold important insights for advancing our understanding of the biological basis of human behavior and constructing valid models of human evolution from our closest living relatives.

The Goualougo Triangle differs dramatically in forest structure, diversity, and seasonality from chimpanzee habitats in east and west Africa. These ecological factors dictate specific aspects of a particular environment, such as resource availability and abundance, which in turn affect the social organization of its primate inhabitants. Specific points of comparison between the Goualougo Triangle chimpanzees and other populations include the demographic composition of social groups, relationships between sexes, and interactions among communities. Our field site in northern Congo and collaborative research with other scientists studying wild primates provides many exciting research opportunities for students of Washington University and for Congolese nationals studying at the University of Marien Ngouabi in Brazzaville. By pinpointing factors shaping intraspecific variation in the behavioral ecology of wild chimpanzees, we hope that our research will aid in elucidating the role of particular ultimate and proximate forces in primate evolutionary history.

Finn is a dominant male chimpanzee in the Moto community of the Goualougo Triangle located in the Nouabalé-Ndoki National Park, Republic of Congo. Celebrating its 10th anniversary, the Goualougo Triangle Ape Project is the longest-running field site studying sympatric central chimpanzees and western lowland gorillas in the Congo Basin. Photo courtesy of Goualougo Triangle Ape Project, Nouabale-Ndoki National Park, Republic of Congo.

The second focus of my research addresses theoretical frameworks of primate tool-using behavior. With the exception of humans, chimpanzees show the most diverse and complex tool-using behaviors of all extant species. Comparisons of the catalogues of tool behaviors recorded at long-term chimpanzee study sites have shown that tool-using repertoires differ between populations and even adjacent groups. Our research team discovered that the chimpanzees in the Goualougo Triangle have one of the largest and most complex tool repertoires reported from any wild ape population. Using a network of 20 remote video units, we record longitudinal observations on chimpanzee tool-using behaviors in several communities to examine complexity, innovation, and social learning. Video data will be archived and analyzed in the Digital Laboratory for Primate Behavioral Research being established here this fall. This laboratory will provide hands-on experience to undergraduate and graduate students interested in using advanced technological applications to collect and analyze visual media from the field.

Although northern Republic of Congo has long been considered a stronghold for the conservation of central chimpanzees and western lowland gorillas, it is becoming increasingly clear that several threats facing wild great apes are converging in these remote forests. As mechanized logging expands throughout central Africa, roads are being constructed into previously inaccessible tracts of intact forest. These transport networks have been directly associated with increases in bushmeat hunting and anthropozoonotic disease transmission. Great apes are especially vulnerable to hunting and habitat destruction due to slow reproduction, prolonged developmental periods, and complex social behavior. Our research team in the Goualougo Triangle is trying to improve the conservation outlook of chimpanzees and gorillas through applied conservation research, enhanced protection of important ape populations and their habitats, and strengthening local capacity to implement conservation programs. Since 2001, we have been conducting transect surveys of chimpanzees and gorillas within the Nouabalé-Ndoki National Park and adjacent logging concession to precisely determine the effects of anthropogenic disturbance on wild apes. As active members of the IUCN/SSC Primate Specialist Group’s Section on Great Apes, Dr. Morgan and I use this forum to present our research findings to local governments and conservation organizations so as to ensure informed decisionmaking and planning on behalf of endangered great apes.