A note on the social compatibility of an all-male group of hamadryas baboons (Papio hamadryas)

In captive primates, the formation of all-male groups is used as a management tool to deal with surplus males. In the wild, hamadryas baboons ( Papio hamadryas ) live in multilevel societies consisting of reproductive one-male/multi-female units, clans, bands and troops. The social compatibility of all-male groups of hamadryas baboons has not been studied thus far. Here we examined the social compatibility of an all-male group of hamadryas baboons as compared to adult males of a mixed-sex group by focusing on social interactions. Additionally we studied the behavioural effects of reproductive status to evaluate whether surgical castration can assist in the social housing of surplus hamadryas baboons. The results indicate that intact males (n=3) in an all-male group show fairly similar behavioural profiles compared with intact males (n=3) in a mixed-sex group, although they are less often observed in social proximity. Furthermore, intact males within an all-male group engaged less in affiliative and submissive behaviours than castrated males (n=3) within the same group. Overall, our results suggest that the formation of an all-male group of hamadryas baboons can be a feasible management tool in housing surplus males, and that submissive behaviours as expressed by castrated males may contribute positively to the social stability of all-male groups.