The guereza is 20 ½ to 22 ½ inches long with a 21 to 33 inch long tail. It weighs 18 to 30 pounds. Its fur is all black except for a white border around its face, two white stripes down its flanks and rump and a white, bushy tail tip. The face is gray and furless. It has a 3-part stomach. Its stomach has gut microbes which break down the cellulose in plants and allow the animal to gain twice the nutrition as other monkeys from plant food. It has only four fingers and no thumb.
The guereza lives in groups called troops. A troop has a single male and 4 to 5 females with their young. The male defends his territory with roars and giant leaps. It is a very arboreal monkey, spending very little time on the ground. It is awake during the day and sleeps during the night. On member is always awake as they take turns keeping watch for predators while the others sleep.
The female guereza produces a single young every two years. Breeding is not seasonal, however, mating usually occurs at such time that the young will be weaned during times of ample food supply. Mating is initiated most often by the females with a smacking of the lips. During copulation the female remains lying on the ground. Gestation or pregnancy lasts about 6 months. The male helps the female in raising the young. The female becomes sexually mature at 4 years old and remain with her mother’s troop. The male becomes sexually mature at 6 years old and is forced to leave and find its own troop. The guereza’s lifespan in the wild is believed to be about 20 years. In captivity it may live about 29 years.
The main part of the guereza’s diet is leaves. It also eats fruit, leave buds and blossoms. It gets water from morning dew, rainwater in hollow tree trunks and from its food. Captive guerezas eat monkey chow, fruit and vegetables.
The guereza is found in Africa along the equator. It lives in forests, woodlands and wooded grasslands.
The guereza is classified as least concern on the IUCN (International Union of Conservation of Nature and Natural Resources) red list of threatened species. This classification is the lowest and means the species has a large widespread, population and no current threats that would likely decrease its population in the foreseeable future.
Animal: The Definitive Visual Guide to the World’s Wildlife by, David Burnie and Don E. Wilson