Abstract and Summary
Sexual differences in play have been reported for a variety of mammalian species, the majority of which arc polygynous and sexually dimorphic in size. These observed sex diflerences in play have been interpreted by the physical training hypothesis as having evolved to train young differentially for adult roles. This study examined sex differences in play behaviour of a polygynous, but isomorphic, ungulate — the scimitar-horned oryx (Oryx dammah).
8 calves were studied in captivity at the National Zoological Park's Conservation and Research Center. Mate calves initiated more bouts of social play and used more components of contact and dominance during play than did ♀♀. Age was an important factor in play partner choice, but sex and genetic relatedness were not. Mixed sex play was common, and the duration of play between ♂♂ and ♀♀ was longer than that between ♀♀. The results supported the physical training hypothesis, but suggested that size dimorphism between the sexes was also important in the ontogeny of sex differences in play.