Social
Cooperation/Altruism
Red
colobus groups exhibit reciprocal altruism most readily in their cooperative
defense against chimpanzee predation. All adult males in the troop are
expected to help fend off the attack, with rewards for doing so coming
in the form of priority of access to food, grooming and mates (Stanford
1998). Males exhibit this behavior in protecting one another in part because
of their high degree of genetic relatedness.
Female
black-and-white colobus monkeys, in matrilineal kin groups on their natal
territory, display cooperative behavior in their great amount of alloparenting.
Because these females are related, helping to rear the offspring of their
sisters increases the fitness of that individual. In contrast, groups of
colobus monkeys who live in patrilineal groups do not show this alloparenting
behavior among females.