The word “colobus” stems from the Greek word for “docked,” referring to this monkey’s nearly absent thumb, which is greatly reduced to a small bump and remnant nail. These leaf-eating primates have multi-chambered stomachs, which makes them the only primates with foregut fermentation. This adaptation allows them to occupy and survive in areas other primates cannot.

Family Matters

Colobus monkeys live high in the trees, coming to the ground only occasionally. Males roar and snort to establish their group’s well-defined territory. Groups of up to 15 members are typical, with one dominant male, several females, and their young. Females become sexually mature at four years old, while males mature between four and five years of age. There is no set breeding season. Gestation lasts about six months. Births are timed for weaning when food is plentiful. Usually, one infant is born, and multiple females care for it–called allomothering. At birth, the clinging infant weighs almost one pound and is all white. It gets its black trim at about three-and-a-half months old and full adult coloration between five and ten months. Under human-care, colobuses can live up to 30 years.


These monkeys are found throughout the equatorial belt region of Africa in the rainforests around the Ngong Escarpment, Mount Kenya, and the Aberdare Mountain Range in Kenya.


Colobus monkeys are herbivorous, eating leaves and plants.


  • Length: 18–28 inches
  • Weight: 14.5–32 pounds