Play behaviour: A functional approach by focussing on adult-adult social play in the bonobo (Pan paniscus)

Abstract

It is hard to find an appropriate definition of ‘play’ in animals that encompasses all its forms and varieties. Consequently, the adaptive function of play is a highly debated subject. Here, we review earlier proposed hypotheses about the functionality of play. Specifically, we describe hypotheses for a less common form of play: adult-adult social play. In addition, a case study on social play in adult bonobos (Pan paniscus) is provided. We use recordings of social play in European zoos (Apenheul, Frankfurt, Stuttgart and Wuppertal) to test predictions drafted from earlier proposed hypotheses. These entail that adult social play is used to assess and manipulate uncertain social relationships. Our preliminary results seem to confirm that the certainty of inter-individual relations play an important role in the adaptive function of (adult) social play.