Classification and Range
Black-and-white colobus monkeys belong to the subfamily Colobinae. Four different species of black-and- white colobus monkey are recognized; the guereza (Colobus guereza), Angolan colobus (Colobus angolensis), Guinea forest black colobus (Colobus polykomos) and the satanic black colobus (Colobus satanas). Black-and-white colobus monkeys are found across equatorial Africa.
Guereza monkeys are found in a diversity of habitats including primary and secondary deciduous forest, montane forest, lowland swamp, coastal forest, moist savanna and gallery forest.
Head and body length: 18-28 inches (46-71 cm), tail length: 20-40 inches (51-101 cm), weight: 17-32 pounds (7.6-14.5 kg)
In the wild: up to 20 years. At the zoo: up to 30 years.
In the wild:Leaves, stems, bark, flowers, buds, shoots, fruits and some aquatic plants. In one study area, young leaves of the hackberry tree (Celtis durandii) are the food of choice for guereza monkeys.
At the zoo: Monkey chow and a leafy diet with daily browse (herbaceous plants).
Guerezas have no known breeding season. In the wild, females reach sexual maturity by age 5 and males by age 8. Females initiate courtship by tongue smacking. The gestation period is approximately six months. Females give birth to an average of one offspring every 20 months. Infants are born with eyes open, weighing about 0.9 pound (0.4 kg) and will occasionally cling to the mother's waist like a belt. More often the mother carries them higher, using one arm to secure them while they are very young. Mothers will allow other females in their troop to handle and sometimes even suckle their infants soon after birth. Offspring are born with "natal fur" which is fluffy and white. From 4 to 12 months the infant will acquire adult coloring. Adults are glossy black with a white U-shaped mantle of fur on the back and a white tip on the tail. Adults also have a ring of white fur around their faces.
Guerezas usually live in groups of three to 15 individuals. Groups are made up of one adult male (rarely two) and females with offspring. Females' troop membership is stable but males must earn their status. Young males are forced by the lead male to leave their natal troop before breeding age. Lead males are occasionally ousted by young mature males that grew up with them or moved in from an outside troop. Intragroup relationships are usually friendly and reinforced with lots of grooming. Troop home ranges are about 35-74 acres (15-30 ha). Guerezas defend their ranges vigorously. Males do most of the defending by displaying through the trees with leaps and roars which can be heard a mile (1.6 km) away.
Intergroup meetings are usually hostile, mostly between males, which will make defensive gestures, vocalizations and occasionally chase or fight each other. Rarely, two troops will share a water hole or other resource.
The name "colobus" is derived from the Greek word meaning "docked" or "mutilated." Colobus monkeys once were thought to be abnormal because they have no thumb, or only a small stub where the thumb would usually be. This is actually an adaptation rather than a mutilation which allows colobus monkeys to easily travel along the tops of branches quadripedally.
Colobus monkeys have unusual stomachs which are similar to the digestive systems of cows. The important feature of a colobus' stomach is that it has three or four different regions. The upper "sacculated" regions are very large and are separated from the lower acid region. The sacculated stomach and the specialized bacterial microflora enables the monkeys to digest large volumes of leafy material. If the stomach was not as large as it is these monkeys would not be able to get ample nutrition from their food. Colobus monkeys always have a belly full of food which is in the process of being digested. The contents of the stomach can constitute up to a quarter of the weight of an adult and half the weight of an infant monkey.
Location at the Zoo
Woodland Park Zoo's black-and-white colobus monkeys can be viewed in the Tropical Rain Forest. Other animals which can be viewed in the Tropical Rain Forest are the western lowland gorilla and red ruffed lemur.
Black-and-white colobus monkeys are not an endangered species but are vulnerable to habitat destruction and human overpopulation. Also, many colobus monkeys are killed for their meat and skins. Woodland Park Zoo participates in the Association of Zoos & Aquariums' (AZA) Species Survival Plan (SSP) for the black-and- white colobus monkey, which manages the species and works to educate the public about this and other threatened and endangered species.
How You Can Help!
The effort to save endangered species requires cooperation and support at the international, national, regional and individual levels. You can help in this cause. Join and become active in Woodland Park Zoo and other conservation organizations of your choice. Please do not buy products made from wild animal parts. Contact your elected representatives and express your views about conservation of endangered species and wild habitats.
Contact Woodland Park Zoo at firstname.lastname@example.org to find out about ways you can support conservation programs at the zoo. Learn other ways you can help conserve wildlife and the habitats they require for survival by visiting our How You Can Help page.
Sources and Suggested Reading
Davis, A. Glyn and John F. Oates. 1994. Colobine Monkeys: Their Ecology, Behavior and Evolution. Cambridge University Press, Cambridge, England. 415 p.
Oates, John F. 1977. The Guereza and Its Food. Clutton-Brock, Primate Ecology: Studies of Feeding and Ranging Behavior in Lemurs, Monkeys and Apes. Academic Press, London, England. pp. 275-322.
Greenaway, Theresa. Jungle. Eyewitness Books. 1994. Knopf Publications, New York, NY. 64 p.
Julivert, Maria Angels. The Fascinating World of Primates. 1996. Barron's Educational Series Inc., Hauppauge NY. 31 p.