LTREB: Female Settlement Patterns and Social Relationships in Chimpanzees, a Male-Philopatric Species

Duke University, Durham NC

Investigators

Abstract

Social connectedness greatly affects human health. Investigation of the evolutionary basis of human relationships through study of factors influencing social bonding in chimpanzees, humans' closest living relatives, will reveal how and why social bonds are important. Chimpanzees, like humans, are very unusual among mammals in that males remain in their birth group, while most females join another group at adolescence. Kinship is a powerful basis for friendly bonds, but dispersing females must leave their kin and join groups of unrelated individuals, many of which are hostile to these new competitors. This project takes advantage of the uniquely long-term field study of the Gombe chimpanzees, initiated by Jane Goodall in 1960, to examine factors influencing whether females disperse, how they integrate into a new community, the kinds of relationships they establish with other females, and how they benefit from these bonds. Results, disseminated in scientific papers, the press, film documentaries, and widely visited websites will keep these iconic chimpanzees in the public eye, and will continue to draw young people (especially women) into science. The project involves undergraduates from underrepresented groups and provides scientific training and education experience to Tanzanians. It provides crucial information for community conservation efforts around Gombe and across Africa. In the first half of the decadal research plan, the objectives have been to compile and analyze 40 years of spatially-explicit ecological and behavioral data to identify factors influencing female distribution and social association, and to initiate collection of behavioral data on young females in three communities as they settle. In the next 5 years, the first objective is to continue data collection on maturing females to produce a sufficient sample to test the hypothesis that female settlement is based on the location of high quality resources, the density and dominance rank of resident females, and the presence of related or familiar females. The second objective is to collect detailed data on adult female behavior to test hypotheses arising from initial analyses about the nature and consequences of female relationships. Do social bonds enhance the ability to compete for resources and/or dominance via coalitionary aggression? Do bonds with other mothers benefit male offspring by promoting their interactions with male peers? Results will contribute to greater understanding of chimpanzee behavior and provide a basis from which to consider the evolution of mammalian social organization and human relationships. Data are compiled in a relational database, stored at Duke University and available to colleagues, worldwide.