Birth in Bonobos (Pan paniscus) : Female Cohesiveness and Emotional Sharing

Sociality around birth has been proposed as a unique feature of our species and traces its origin to the very beginning of human evolution. In traditional societies, the social and practical support to the parturient is almost exclusively provided by women, with absolute cultural taboos preventing the participation of men. Humans surely differ from their closest living relatives in the imperative need for assistance during delivery that is linked to some distinctive traits of birth in our species. Yet, considering the social, cognitive and emotional complexity of many primate species, it is plausible that they may show a certain degree of sociality around birth. It is nowadays impossible to draw a reliable picture of the social dynamics around birth in monkeys and apes since the only available reports on the behaviour of group members during deliveries are scattered and anecdotal. Here we describe three daytime births in bonobos (Pan paniscus) . The observation conditions of the captive environment allowed us to film and quantitatively describe the behaviours of the whole group. Our data show that birth in bonobos is a peculiar social event in which females are particularly concerned. Indeed, females stay closer to the parturient than males do and the frequency of affiliative interactions is higher within female-female dyads, whereas the frequency of agonistic interactions is higher within female-male dyads. Moreover, the more dominant and elderly females also provided a sort of ‘assistance’ to the parturient, by performing the same gesture performed by her to grab the infant during its birth, although only the mother grabbed the infant at the delivery. These results show that the bonds linking bonobo females are also reinforced during rare events, such as births. We suggest that the collective support of females in bonobos might be one of the building blocks of more complex and culturally shaped forms of sociality which are expressed during the delivery event in humans.