Black-and-white Colobus

The mantled guereza is a black-and-white colobus, an Old World monkey native to much of west central and east Africa, including Cameroon, Nigeria, Ethiopia, Kenya, Tanzania, Uganda and Chad. Long white fringes of hair, the mantle, run along each side of its black trunk, and it has a large white tail tuft. It is diurnal and arboreal, found in deciduous and evergreen forests, and prefers secondary forest close to rivers or lakes. Besides leaves it eats seeds, fruits and arthropods, digesting high-fibre plant material with a specialised stomach. Groups of three to fifteen usually include a dominant male, several females and their offspring.

About the black-and-white colobus

The black-and-white colobus most commonly seen in U.S. zoos is the mantled guereza (Colobus guereza), an Old World monkey named for the long white fringes of hair, called a mantle, that run along each side of its otherwise black trunk. Its face is framed in white, and a bushy white tail tuft finishes the look. Infants are born with pink skin and white fur; the coloration darkens to the adult pattern by three to four months, with males typically coloring in before females.

The species belongs to the Colobinae, a subfamily of leaf-eating Old World monkeys split among Africa's colobus monkeys, Asia's langurs, and an "odd-nosed" group that includes proboscis monkeys. Within Africa, the mantled guereza is one of three black-and-white colobus species, alongside the king colobus and the Angola colobus. Seven subspecies are recognized, differing mainly in the color and proportion of the mantle and tail tuft — from the gray tail with a white half-tip seen in the Ethiopian subspecies to a tail that is nearly all white in the Kilimanjaro form. Like other colobus monkeys, it has only a vestigial thumb, an adaptation named directly in its genus: Colobus comes from the Greek for "mutilated," a reference to that reduced digit.

Males average 61.5 centimeters (24.2 in) in head-and-body length, females 57.6 centimeters (22.7 in), with males heavier than females as well. In the wild, the species ranges across a broad swath of west-central and East Africa, from Nigeria and Cameroon eastward to Ethiopia, Kenya, Uganda, and northern Tanzania, inhabiting both primary and secondary forest, savanna woodland, and highland forest at elevations as high as 3,300 meters (10,800 ft).

The species was first classified by the German naturalist Eduard Rüppell during his travels in Abyssinia between 1830 and 1834, and its common name, guereza, comes from the animal's native name in Ethiopia. It was first exhibited in Europe in 1890, when three individuals arrived at the Berlin Zoological Garden after being purchased from a dealer in Massawa, Eritrea. Taxonomists recognize seven subspecies, distinguished mainly by how much of the tail is covered by white fur and by variation in the mantle's color, which ranges from white to cream or yellow.

Behavior and diet

The mantled guereza is diurnal and largely arboreal, though it comes to the ground to forage more often than many of its colobine relatives. Groups leave their sleeping trees shortly after dawn and return at dusk, with long rest periods punctuating bouts of feeding and travel. Grooming, greeting, play, and vigilance round out the day in smaller amounts.

Despite a reputation as a strict leaf-eater, its diet is more varied: leaves usually make up over half of what it eats, but fruit, seeds, flowers, bark, and arthropods are also on the menu, and it has even been recorded eating soil and concrete from buildings. It favors young leaves over old ones and tends to eat fruit while still unripe, which may reduce competition with primates that prefer ripe fruit. A large, multi-chambered stomach with resident bacteria lets it break down high-fiber plant material.

Groups of three to fifteen animals typically include one dominant male, several females, and their offspring, and are held together by matrilineally related females who rarely leave their natal group; males disperse as they mature. The mating system is polygynous, and after a gestation period of just over five months, infants are born roughly every 16 to 22 months. The species is well known for the male "roar," a long-distance call given mainly at dawn that can carry for up to a mile and helps space out neighboring groups without direct conflict.

Range and habitat

The mantled guereza occupies west-central and East Africa, with confirmed populations in Cameroon, Equatorial Guinea, Nigeria, Ethiopia, Kenya, Tanzania, Uganda, and Chad. It lives in both deciduous and evergreen forest, including primary forest, secondary forest, riparian forest near rivers and lakes, and montane forest at higher elevations.

Given a choice, the species actually prefers secondary forest over old-growth stands, likely because regenerating forest offers more food trees with weaker chemical defenses. It is adaptable enough to persist in disturbed habitat, including swamps and human-modified landscapes such as eucalyptus plantations, which it may visit when its usual diet falls short nutritionally.

Conservation status

The mantled guereza is listed as Least Concern (LC) by the IUCN, reflecting its wide distribution across multiple countries. That overall status masks local pressure, however: the species is threatened in some areas, and one subspecies found in Kenya is listed as Endangered.

Its main threats are hunting for bushmeat and for its distinctive black-and-white skin. Its tolerance of degraded habitat works somewhat in its favor — in some regions it is more common in logged forest than in untouched forest. It is preyed on in the wild by birds of prey such as the crowned hawk-eagle and Verreaux's eagle, as well as by common chimpanzees and leopards.