Blue monkeys live in groups with a single adult male for most of the year, although other males may join the group during the mating season, even 'moving in' for several months. By measuring paternity in two blue monkey groups in a Kenyan rain forest, this project will assess whether long-term resident males and temporary intruders are equally successful at siring offspring in the group. We will thus test an assumption which underlies theories that explain different social systems, namely that males live in groups to maximize access to females and thus to increase their reproductive success. Reproductive behavior of males and females will be monitored in detail during the breeding season by teams of observers. We will relate patterns of male-male competition (chases and fights) and female mate preferences to offspring paternity. We can then assess whether male dominance correlates with increased reproductive output, and whether female mate preferences influence paternity. Our results will not only provide information on one species with an unexpectedly dynamic social system, but also comparative data from a little-studied primate radiation that can be used in testing and developing theories applicable to other primates and animals.
