Male-male interactions on Red-Howler monkeys (Alouatta seniculus)

Within multi-male groups of Red-howler monkeys, there is a hierarchy of males, with an alpha male dominant to the other males in the group as well as being the only male within the group that is able to reproduce. The alpha male is usually physically larger than the subordinate group males and challenges of alpha male status by other males can be violent and result in injuries to one or both parties. Breeding males will not leave a group voluntarily and only leave if forced by challengers. Rates of physical injuries resulting from aggression among red howlers is high, with over a third of individuals in one study population exhibiting scars and physical injuries from encounters with other red howlers. However, rates of actual aggressive behaviors are quite low, even if they can be quite violent when they do occur.

With info from Primate Info net (http://pin.primate.wisc.edu/fa...