Eastern Black-and-white Colobus - Behaviour

Behaviour

These primates live in social groups of 3 to 15 individuals. Each group has a single adult male, three or four adult females, and their offspring. Adult males that have not been strong enough to form their own troop may also travel together in all-male bachelor troops. Young animals are raised cooperatively by all troop members, and infants may nurse from any female in the troop. Troop members also cooperate to defend each other from predators or from potentially aggressive neighboring colobus troops. Because of these large, protective troops, black and white colobus have relatively few predators, though they may be hunted by Crowned Eagles, leopards, and chimpanzees.

Females bear a single offspring every two years, after a 158 day gestation. Males mature at 6 years old, and females at 4 years old. The lifespan is 15 to 20 years in the wild and up to 30 years in captivity.

Black and white colobus are strict herbivores. While they occasionally eat fruit, their diet consists primarily of tree leaves, a very low-calorie, nutrient-poor food. To survive on this poor diet, colobus have evolved multi-chambered stomachs similar to those of cows. In the first chamber, bacteria ferment the leaves, increasing the nutrient availability. In the second chamber, the partially digested leaves are broken down further by enzymes and gastric acid. Because this digestive process takes so long and is so inefficient, up to a third of a colobus's weight may consist of the undigested leaves carried in its gut.