Play profiles of captive adult orangutans: a developmental perspective.

The social play of 6 adult orangutan heterosexual dyads was observed, and the frequencies of the component behaviors extracted. Frequencies were converted to proportions of total play outputs for each individual and for each age/sex class, and then compared to the proportions observed for the social play of juvenile and adolescent orangutans. Adult play was more stationary, and contact maintaining, in style than was the play of younger orangutans. For the females, rolling and grabbing comprised similar proportions of the play repertoires, whereas for males, slapping and biting were developmentally consistent. For adult males, little chasing was observed, although this behavior was prominant in the play of immature males. These developmental changes in orangutan social play are addressed with respect to the natural history and ecology of orangutans, the refinement of communication skills, and the influences of captivity on social play.