A comparison of infant-adult male relations in a one-male group with those in a multi-male group for yellow baboons (Papio cynocephalus).

We compared interactions between an infant and adult male in a one-male group with those between infants and adult males in a multi-male group in the same area. Proximity interactions in the one-male group were common, like those for dyads in the multi-male group in which the adult male was high-ranking or a likely father of the infant. Contact interactions in the one-male group were rare, like those for dyads in the multi-male group in which the adult male was low-ranking or unlikely to have sired the infant. This suggests that proximity to an adult male is important in coping with the physical environment (similar for both groups), and more contiguous interactions are important in coping with the social environment (more complex in a larger multi-male group).

Social plasticity in the acorn woodpecker.

Acorn woodpeckers (Melanerpes formicivorus) in southeastern Arizona exhibited two different types of social organization: one of highly cooperative and resident groups and another of birds that migrated and formed only temporary male-female pairs during reproduction. The occurrence of both patterns in the same population indicates a high degree of social flexibility in this species.