Old World Monkeys: Cercopithecidae

Physical characteristics: The western red colobus monkeys are black or dark gray with bright red undersides. The cheeks and the lower parts of the limbs are also bright red. The Greek word kolobos, meaning "cut short," describes the missing thumbs, which allow for faster brachiation because thumbs do not get caught in the branches. The long tail maintains balance when leaping. Males measure about 23 inches (57 centimeters), with a tail length of 26.5 inches (66.5 centimeters), and weigh 18.4 pounds (8.36 kilograms). Females are slightly smaller.

Geographic range: The monkeys are found in Cameroon, Ivory Coast, the Democratic Republic of the Congo, Gambia, Ghana, Guinea-Bissau, Liberia, Nigeria, Senegal, and Sierra Leone.

The word "colobus" in the western red colobus's common and scientific names comes from the Greek word kolobos, meaning "cut short," referring to the monkey's "missing" thumbs. (Ernest A. Janes/Bruce Coleman Inc. Reproduced by permission.)

Habitat: Red colobus monkeys prefer rainforests that provide young leaves year round. They inhabit primary and secondary forests, forests along rivers and streams, and wooded grasslands.

Diet: Western red colobus monkeys feed mainly on leaves, especially young leaves, but also eat flowers and shoots. They consume only unripe fruits. Ripe fruits contain sugar, which can be broken down by stomach bacteria, causing gas and acid formation that may be fatal.

Behavior and reproduction: Western red colobus monkeys form groups of nineteen to eighty individuals with numerous adult males and females. They do not defend their territory. They are arboreal and diurnal, splitting off into smaller subgroups when foraging. They move through the trees on all fours, with some brachiation. However, they are not agile climbers.

Males have several mating partners. Females give birth to a single infant every two years. The mother alone carries the infant. Young females leave home, transferring from one group to another. Males stay in their birthplace, forming a close association with one another.

Western red colobus monkeys and people: Western red colobus monkeys are hunted for food.

Conservation status: The IUCN lists the western red colobus as Endangered due to hunting for meat, as well as habitat loss and degradation from agriculture, logging, and human settlement. ∎