Kin recognition by paternal half-siblings in captive Papio cynocephalus.

Our objective in this study was to evaluate whether a group of paternally related, subadult baboons (Papio cynocephalus) would preferentially interact with kin or nonkin when they had been raised apart from kin other than their mothers. Subjects and their mothers were removed from the breeding group and placed in alternate housing within 24 h after birth to ensure that the subjects would not have a social history with either their sire or their half-siblings. At 90 days of age, the 23 subjects were separated from their mothers and assigned to a peer-peer social group. Behavioral performance was measured using focal animal sampling techniques and 12 molecular behavioral criteria. Analyses of the data indicate that in dyadic interactions kin did not interact more frequently than nonkin in performance of affiliative, sociosexual, and agonistic behaviors. The hypothesis that baboons recognize kin in the absence of maternal associations was not supported by the data; moreover, we suggest that social learning and social history are the most likely mechanisms for kin recognition.