Integration of New Males into Four Social Groups of Tufted Capuchins (Cebus apella)

We examined how aggressive, affiliative, and sexual behavior function to integrate male capuchins (Cebus apella) into a new social group. Nine males were exchanged among four social groups. We performed instantaneous scans and all-occurrence sampling during baseline, introduction, and follow-up periods. The study included three different introduction situations: 1) males familiar to one another were introduced to a group with no other adult male, 2) males unfamiliar to one another were introduced to a group with no other adult male, and 3) males familiar to one another were introduced to a group with an existing elderly, resident male. Severe aggression occurred in situations 2 and 3, but the introductions were peaceful in situation 1. In all cases proceptive females were among the first individuals to affiliate with the males, and males did not appear to compete for access to proceptive females. Following their period of proceptivity, the females that had cycled remained preferred social partners for the males. Immature animals also quickly affiliated with the new males, and the males tolerated the attention from immatures. Affiliative relationships between the males and nonproceptive females developed slowly, and while male-female aggression was mild, aggression among adult males (familiar and unfamiliar) had the potential to be severe.