Group living confers a variety of benefits to individuals within the group, including predator detection and defense and high rates of food acquisition. Animals that form groups with close genetic relatives may also benefit from opportunities to help kin at minimal cost, thus increasing the helper’s indirect fitness. Additionally, individuals in kin groups gain direct fitness advantages through decreased within group aggression, lowered risk of infanticide, and coalitionary support. However, much of what we know about the effects of kinship comes from relatively simple, single level social systems. We know very little about how kinship works in complex, multi-level societies like those found in modern humans. Moreover, until recently only long-term studies have had the pedigree data to map maternal relatives. Now, molecular genetic techniques that combine non-invasive sampling with PCR-based genotyping allow researchers to evaluate the interaction between relatedness and social systems in species where longitudinal data are lacking.

We apply these new genetic techniques, together with detailed behavioral sampling, to the unusual, highly complex social system of the gelada. Their social structure appears to be considerably more complex than that of their close phylogenetic relatives, the well-studied baboons. Therefore this research will provide important new data on kinship-behavior interactions and the evolution of complex societies in mammals. The goal if this research is to understand the patterns of relatedness in gelada’s multi-level society and how relatedness influences social interactions.