Interactions between free-ranging, adult male polar bears (Ursus maritimus Phipps): a case of adult social play

I observed 73 dyadic interactions (bouts) between adult male polar bears (> 6 years) at Cape Churchill, Manitoba, from 4 October to 9 November 1978. All bouts involved at least one marked bear. I classified these bouts as social play and in this paper I discuss the criteria used for this classification. Social play bouts were composed of discrete motor acts and showed some predictability and structure. Two bouting bears respond to one another in a predictable manner as indicated by the mutuality of initiator-receiver acts. Structuring was suggested by a major three-act sequence for both initiators and receivers. Aggressive acts were found to be characteristic of initiators; the less aggressive, withdrawing acts were characteristic of receivers. The results are interpreted from both the structuralist and functionalist approaches to social play. I hypothesize that social play between adult male polar bears during the noncompetitive period of their annual cycle serves as a socialization process facilitating both opponent assessment and the refinement of social interaction. Both of these are probably important at times of the year when intraspecific competition is more intense.