Male takeover in Colobus vellerosus at Boabeng-Fiema Monkey Sanctuary, central Ghana.

We describe a case of male takeover in the ursine black-and-white colobus (Colobus vellerosus). In April 2001, an all-male group attacked and eventually invaded our uni-male study group. Aggression increased following the takeover and the former resident male, severely wounded, became peripheral. The youngest immature received severe aggression from the new males but survived. The immature's mother intervened in most instances of this aggression. Eventually, the former resident male re-established relationships with some of the females and concurrently intervened to protect the immature. Defeated males that stay in their group can contribute to the protection of infants born during their tenure from infanticidal males. The females mated with the new males. Takeovers may be a means by which males acquire groups of females in C. vellerosus.