Association and social interactions between strangers and residents in bonobos (Pan paniscus)

Abstract

This study reports on close spatial association and repeated behavioural interactions between two strange adult male bonobos with residents of another community. Over a period of 12 months one of the two males developed friendly social relations to some of the females and other residents, which were indistinguishable from those existing between co-residents. Aggression by resident males against the strangers decreased but the former remained intolerant. The strange males appeared at a time when the number of adult resident males was lower as in the years before and when the adult sex ratio (number of adult females per male) was higher as in the years before. Using definitions from studies on dispersal patterns of male gorillas (Harcourt, 1978) and female bonobos (Furuichi, 1989) the spatial association between the two strange males and residents could be described as male transfer.