The Reproductive Strategies of Samango Monkeys (Cercopithecus mitis erythrarchus).

Three bisexual troops of samango monkeys (Cercopithecus mitis) and extratroop males in their vicinity were studied between January 1995 and February 1997 at Cape Vidal, South Africa. Data were collected in order to examine their reproductive strategies, the factors affecting their association patterns, and the ways in which their relationships develop. For male samangos, the most profitable strategy for gaining access to receptive females was to be a resident troop male and to defend females against other males, but males could augment their lifetime reproductive success while not resident, by temporarily associating with troops during the mating season and “sneaking” matings. Examination of the factors affecting the number of males associating with troops revealed no relationship with the number of troop females nor the number of fertile females, but appeared to be related to proceptive behaviour in females, particularly where this proceptivity was directed at extratroop males (proceptivity being defined as “the tendency of females to seek matings and behave in a way that sexually solicits males”). Further evidence that females were able to exert influence on the male membership of their troops and male mating success, was provided by an examination of mating competition and mate choice in samangos. While this revealed a high level of intra-sexual competition among males for sexual access to females, there was also evidence that females could and did choose their mates on occasion. Observations of infanticide by adult males during this study suggested that such behaviour is an adaptive strategy for males after troop takeover, and that infanticide risk may have selected for infanticide avoidance behaviours in males and females. Adult males who stay in association with troops outside the mating season may do so in order to avoid infanticidal attacks on their offspring or to defend their offspring and/or mating partners from predators. Juvenile males appear to invest time in relationships that may benefit them after natal emigration, with males from other troops and with extratroop males