In non-human primates, groups often engage in between group aggression. Despite the integral role these social interactions play in models predicting and explaining primate behavior, our knowledge of why individuals choose to engage in this risky behavior remains somewhat limited. In general, aggression between groups is attributed to defense of resources or defense of mates and infants. This project will investigate the factors underlying aggression during between-group encounters in a territorial South American primate: the white-faced saki monkey. This arboreal primate occupies small home ranges which are actively defended from neighboring groups along home range boundaries. In order to comprehensively test the function of this aggression, this project will gather data on between-group encounters among white-faced saki groups at Brownsberg Nature Park, Suriname. Variation in aggression and individual participation in these interactions will be assessed in terms of dependence upon food abundance, female reproductive state, and within group social bonds. Such data will provide valuable information on a little known primate species as well as serve as a case study to help develop models of primate social behavior. The broader impacts of this study include collaboration with the National Herbarium of Suriname and the training of a Surinamese student. This project will also integrate lines of evidence from often distinct aspects of primatology (feeding behavior, social behavior, and endocrine analysis) in order to comprehensively examine a behavioral trait. This doctoral dissertation research project will contribute to the academic training of a female graduate student.
