Most of the intergroup aggressive encounters of the common marmoset occur between mature individuals of the same sex (Stevenson and Poole, 1976). This species is thought of to be sexually monogamous, but Evans (1983) found that paired males would solicit unfamiliar females when given the opportunity; she also found that the males would do this less when their mate was present. However the pair bond is maintained by synchronizing behavior patterns which may be a symptom that conception has occurred (Evans and Poole, 1984). Common marmosets generally show aggressive tendencies towards strangers and attraction between familiar conspecifics (Evans, 1983). Sometimes a subordinate female in a group would breed, but would be the only individuals to care for their young. Digby (1995) reported of an infant by a subordinate female being killed by the dominant female in the group.
allogrooming: This is where one individual grooms another (Stevenson and Poole, 1976).