Female-Female Social Relationships in Wild White- Faced Capuchin Monkeys, Cebus capucinus

A single social group of wild white-faced capuchin monkeys was studied for a period of 26 months at Lomas Barbudal Biological Reserve, Costa Rica. A total of 604 hr of focal animal data was collected on six adult females in a group of 21 monkeys. Females could be ranked in a stable, linear dominance hierarchy. Adult females spent much more time in proximity to other adult females than to adult males. Females groomed other females twice as often as they groomed males, and about 55 times more often than males groomed males. Females tended to groom up the dominance hierarchy, and dyads with smaller rank distances groomed more often. Higher-ranking females nursed infants other than their own at lower rates than did lower-ranking females; however, females nursed infants of females ranked both above and below them. Although lower-ranking females were more likely than higher-ranking females to be the victims of aggression, higher-ranking females were not necessarily more aggressive than lower-ranking females. In 96% of female-female coalitions vs. a female, the victim was lower-ranking than both coalition partners; in the remaining 4%, the victim was intermediate in rank between the two coalition partners. Higher-ranking female-female dyads formed coalitions more often than did lower-ranking dyads. Those female-female dyads that groomed more frequently also formed coalitions more frequently. The patterning of social interactions indicates that Cebus capucinus at Lomas Barbudal are female bonded. o 1996 Wiley-Liss, Inc.