Department of Primatology
Max Planck Institute for Evolutionary Anthropology
Deutscher Platz 6
phone.: +49 (341) 3550 - 200
fax: +49 (341) 3550 - 299
Cooperation without genetic ties: a behavioral endocrine model in bonobos
Humans are distinguished from other species by their high levels of sociality and cooperation with a diverse range of social partners, including relatives and also unrelated individuals. In non-human primates as well, individuals form selective social bonds that confer a range of fitness benefits. Most research on primate social bonds has focused on relationships among the philopatric sex, involving kin or same-sex peers who have grown up together. As a result, we currently know very little about the extent to which nonhuman primates have adaptations to maintain flexible social bonds outside of kinship, and we do not understand the function of differentiated social relationships for primates.
This research project will explore the causes and consequences of individual variation in affiliation and cooperation among unrelated female bonobos. Bonobos deviate from predictions of socio-ecological models in that the closest bonds involve females, the dispersing sex, while the weakest associations occur between the philopatric males. Unrelated females exhibit diverse affiliative behaviours and also cooperate in a range of contexts, including sharing preferred, monopolizable foods and providing coalitionary support, often against males.
The goals of this project are to:
- Characterize the quality and diversity of social relationships among female bonobos using multiple behavioural measures of affiliation,
- Identify factors that influence the exchange of cooperative acts between unrelated females and
- Identify physiological correlates of social relationships by non-invasively measuring peripheral levels of the neuropeptide hormone oxytocin and the steroid hormone cortisol under varied social contexts.