SOCIAL AND GENETIC-ASPECTS OF PATERNITY IN WILD LONG-TAILED MACAQUES (MACACA-FASCICULARIS)

In a field study of three groups of wild long-tailed macaques, Macaca fascicularis, observations on social behaviour could be related to gen etically determined paternity. In contrast to what has been found in m any previous studies on captive primate groups, we found a relatively strong correlation between male dominance rank and reproductive succes s. In a large group the high success of the alpha male compared to oth er males could be explained only partly by his higher copulation score . His success also resulted partly from better timing of his copulatio ns during maximum fertility of the females, in comparison with other m ales. We must conclude either that the alpha-male has more access to f ertile females, or that females have a preference for the alpha-male d uring their maximum fertility. The females clearly displayed promiscuo us behaviour. This behaviour implies a risk to a female that a male ot her than the alpha-male with proven qualities will become the father o f her offspring. One expects that there must be a social advantage rel ated to this female strategy. In the absence of indications of any dir ect social advantages to the female of this sexual behaviour pattern, the ultimate explanation for this female promiscuity is most likely is aggression reduction. This could be either through the devaluating of any single copulation, or through the confusion of paternity and a re sultant reduction in the risk of infanticide.