Abstract # 215:

Scheduled for Monday, August 28, 2017 02:30 PM-02:45 PM: (Grand Ballroom) Oral Presentation


A. A. Sandel
University of Michigan, 101 West Hall, 1085 South University Ave, Ann Arbor, MI 48109, USA
     Social bonds play an important role in primate behavior, including in the lives of adult chimpanzees (Pan troglodytes). Social bonds between adult male chimpanzees are key for cooperation and are formed with maternal brothers and non-relatives, especially peers. Despite their importance in adulthood, little is known about when social bonds develop. Bonds may emerge during adolescence or only later, during adulthood, when male chimpanzees become more gregarious and begin competing for dominance status. To investigate the development of social bonds, I studied the behavior of ten adolescent and eight young adult male chimpanzees at Ngogo, Kibale National Park, Uganda. To assess the effects of age, age difference, and kinship on the formation of social bonds, I conducted generalized linear mixed models. Adolescent male chimpanzees formed social bonds with other males, and they did not differ from young adult males. Adolescent and young adult males formed association and proximity relationships with maternal brothers. In general, adolescent and adult males were more likely to associate, spend time in proximity, and groom with old males rather than middle-aged adults. Unexpectedly, some of strongest grooming relationships were between fathers and sons. Because chimpanzees mate promiscuously, there is no reason to suspect that chimpanzees can recognize their fathers or that fathers can recognize their sons. These findings raise the possibility that fatherhood may have evolved from an ape-like social system.