This award will provide supplementary support to enable Dr. David Sprague of Yale University to conduct collaborative research for one year with Dr. Toshisada Nishida at Kyoto University in Japan. They will investigate the social behavior and demography of Japanese Macaques on Yakushima Island, in order to illuminate the process of mating across the boundaries of macaque troops, and hence the social structure of this primate family generally. The processes by which females initiate mating consorts with alien males will be observed, in order to clarify the role of female choice in the mating success of these males and the criteria by which females choose mating partners. Dr. Nishida and his colleagues have developed a respected school of behavioral studies on the basis of their experience with Japanese primates, and their approaches to the explanation of primate behavior is somewhat different from, and therefore refreshing to, those of western primatologists. Dr. Sprague has worked with his Kyoto colleagues before and their experience will complement the expertise which he has developed on this subject over the past eight years.