1Department of Anthropology, University of Michigan, 2Department of Evolutionary Anthropology, Duke University, 3Department of Psychology, University of Michigan, 4Department of Ecology and Evolutionary Biology, University of Michigan
Thursday All day, Clinch Concourse
Socioecology predicts that females should form strong, kin-based social bonds in species that exhibit within-group competition for clumped food resources. Females from many primate species support this prediction, demonstrating strong preferential social relationships with close female kin. Furthermore, in at least two species, these bonds are linked to measures of reproductive success. Here we test the predictions of the socioecological model in one primate, the gelada (Theropithecus gelada). Geladas forage on an extremely dispersed food resource (grass) and thus are not expected to exhibit the typical cercopithecine pattern of strong female-female bonds. We examined 3 years of behavioral observations of grooming and spatial proximity with molecular genetic analyses to determine whether female geladas form strong and enduring social bonds with close relatives within units. We found that, even within a unit of close female kin, mother-daughter pairs formed the strongest bonds. Finally, we examined how social bonds influenced unit cohesion and how changes in unit composition altered these relationships. Whether such bonds among female geladas lead to reproductive advantages (as in other papionins) or whether they are merely an example of ‘phylogenetic inertia,’ remains a future question.