Adult male-offspring play interactions within a captive group of Orang-utans (Pongo pygmaeus)

A family of four Sumatran Orang-utans was studied for three months under captive conditions. Thirty discrete playful interactions between a 19-year-old male and his four-year-old male offspring were analyzed from films and notes. Ten behaviors occurred in a typical play-bout, the most frequent of which were hand contact and mouth contact. Developmental studies of the motor patterns involved in orang-utan social behavior are greatly needed, as the orang is the least understood of the great apes. This research is supported by the following sources: National Institute of Health grants to the Emory University experimental psychology program (H0 00208) and to the Yerkes Regional Primate Research Center (HD00165), and a faculty research grant to the third author from Emory University's McCandless Fund for Biological Research.