Paternal kinship in a matrilocal society of olive baboons (Papio hamadryas anubis) in Laikipia district, Kenya

Relationships with relatives are arguably the principal organizing feature of mammalian sociality. Studies of nonhuman primates, in particular, demonstrate the importance of kinship in the evolution of affiliative behaviors. The majority of these studies, however, have focused on relatedness expressed through the mother. Although all individuals have a father, less is known about the importance of paternal kinship. My dissertation seeks to expand our understanding of the role of paternal kinship in a matrilocal society by answering the following questions: 1) how do social bonds between different kin types vary?; 2) how does the presence of both mothers and fathers in groups influence the foraging behaviors of juveniles?; and 3) how do juveniles feed near same-aged peers of different kin types? I examined these questions using behavioral and genetic data collected on wild olive baboons (Papio hamadryas anubis) during a 14 month study in Kenya. My research indicates that both maternal and paternal kinship play several important roles in the social and foraging behaviors of young baboons. First, paternal half-siblings maintained social bonds with one another of intermediate strength, i.e., weaker than those characterizing maternal half-siblings, but significantly stronger than the relations of unrelated conspecifics. Moreover, these bonds of paternal half siblings were significantly stronger when their shared father was present in the group than when he was absent, suggesting familiarity through associating with the father is the mechanism underlying recognition of paternal half-siblings. This study also found that both mothers and fathers enhanced the foraging success of juveniles under certain conditions. In resource patches likely to engender contest competition, juveniles fed for longer periods when mothers were present. For foods requiring skill to extract and consume, immatures fed longer when near a parent of the same sex. These data suggest that parents may: 1) mitigate the costs of feeding competition; and 2) facilitate the learning process for consuming difficult-to-acquire food. Finally, the foraging of immature baboons was also improved by the presence of paternal and maternal juvenile half-siblings. This study contributes to our understanding of the adaptive significance of kinship in expanding our understanding of the evolution of social behavior.Ph.D.Includes bibliographical referencesby Emily Claire Lync