Male-female social relationships in wild white-faced capuchins (Cebus capucinus)

This paper describes male-female dyadic social relationships in C. capucinus, detailing the types of costs and benefits exchanged between the sexes. A single group of wild white-faced capuchin monkeys (Cebus capucinus) was studied in Lomas Barbudal Biological Reserve, Costa Rica, for 24 months. A total of 953 hours of focal animal data were collected on 4 adult males and 6 adult females. The patterning of social interactions was studied in an attempt to assess the outcome of disputes between males and females. In dyadic interactions, females avoided and cowered to males roughly 50 times more often than males avoided or cowered to females. Females responded fearfully to 12% of males' neutral approaches, whereas males never responded fearfully to females' neutral approaches. Males supplanted females 15 times more often than females supplanted males. The alpha male spent more lime with females than did lower-ranking males. In general, males were more responsible for proximity maintenance within male-female dyads than were the females. Females behaved aggressively to males slightly more often than vice versa, but males inflicted more severe aggression on females. The types of benefits that each sex conferred on the other were largely different. Females groomed males, but males virtually never reciprocated. Both males and females aided one another in coalitions, which were primarily directed against adult male capuchins and non-monkeys. During one portion of the study, comparison among heterosexual dyads revealed associations between male coalitionary support and both (a) female coalitionary support and (b) female grooming, suggesting interchanges of benefits. Females were able to compensate, in part, for their subordinate status relative to males, by frequently forming coalitions with other females against males. Males did not form coalitions with other adult males against females. Female-female coalitions were effective for achieving immediate goals, such as evicting males from feeding trees. However, even determined coalitions of females were ineffective in their attempts to control male group membership, without receiving aid from adult males.