Genito-Genital Contacts in the Pygmy Chimpanzees (Pan paniscus)

Abstract

This report deals with the pygmy chimpanzee's interactions involving mutual contacts of the ano-genital regions between two individuals, referred to as genito-genital (GG) contacts. Pygmy chimpanzees have unique forms of GG contacts: ventro- ventral copulation, GG rubbing between females, rump-rump contact between males. Moreover, various kinds of GG contacts occur in various combinations of participants, including all age-sex classes. What kinds of GG contact interactions occur in what sorts of dyads is presented. Most of the contacts have a typical pattern for each age-sex class combination. However, the role distribution in these interactions occurring in arbitrary dyads of each combination cannot be explained on the level of behavior patterns exhibited by each participant according to its biological attributes. The regularities seen in how GG contacts occur appear on the level of interaction patterns determined by whether the interactions are intra-set or inter-set. Possibility of a "syntax" analysis of interactions in a certain social system is discussed.