PREDATION AND MALE BONDS IN PRIMATE SOCIETIES

In this paper I consider the effects of predation in relation to other evolutionary influences on the social systems of nonhuman primates, i n particular on the evolution of male bonds in multimale primate group s. Because of the difficulty of documenting its infrequent occurrence, predation on wild nonhuman primates has rarely been studied and its e ffects on behaviour are poorly understood. Male bonds have also been n eglected compared to female bonds in studies of primate societies. Of the accepted evolutionary influences on male bonds - the distribution of females, enhanced individual reproductive success that comes from t he control of females, predator avoidance, and protection from intergr oup aggression by conspecifics - predation is the only one of these th at typically ends all future individual lifetime fitness. I review the widely held hypotheses for the formation of male bonds and consider t he extent to which predation has been an evolutionary influence on the ir formation. It appears that male-bonding for the purpose of repellin g predators is not necessarily based on the kin-selected benefits ofte n attributed to cooperative behavior among primates. I also discuss pr edation risk and predation mortality as agents of natural selection on social behavior. Data are presented from a held study on the effect o f predation on the behavioural ecology and demography of one male-bond ed primate species, the red colobus monkey (Colobus badius). Field dat a show that the influence of predation on the red colobus social syste m appears to be mitigated by behavioral tradeoffs. Predation is a demo nstrably strong influence on the structure of some primate societies, but its effects vary widely between species. Male bonding is one respo nse to the risk of predation, but does not appear to be based on kin-s elected benefts to the participants in most species.