Gombe Stream National Park

A crowd of big monkeys, crashing recklessly through the forest canopy with squeaks of alarm, may be your first impression of these handsome creatures. The eastern red colobus has a blackish back and tail and buff underparts, and a red crown to its head. Males (9-12.5 kgs) are larger than females (7-9 kgs) and have more bushy hair. In Gombe, they live in troops of 30-80 individuals, with numerous males.

Colobus are specialized leaf-eaters. Leaves are very nutritious, but most animals cannot digest their cellulose cell walls. Colobus have solved this problem in the same way as many hoofed animals, by evolving a four-chambered stomach where bacterial fermentation breaks down the cellulose and releases the nutrients. Red colobus are also very selective, and choose the tenderest, most nutritious parts of trees. Their diet consists of about 44% leaves, 20% shoots, 15% new leaves, 11% fruits, 7% flowers and 3% stems. They eat more than 60 different plant species, but half their food comes from just five sources: Newtonia leaves, Albizia leaves and shoots, Sapium shoots and new leaves, Andhocleista leaves, and the new leaves of lianas.

Since new leaves, flowers etc. are only briefly available in any one place, a colobus troop must range widely. A troop of 80 studied at Gombe had a range of about 1.1 sq km. That is 24 times as big as ranges recorded for redtails and blues.

Perhaps because of their peculiar digestive system, red colobus rest for long periods (about 7 hours per day) and spend only about 3 hours per day feeding. Usually they eat in the morning and evening, and in the dry season they also feed at midday.

Colobus are sometimes seen feeding in the same trees as redtail and blue monkeys, but their diet does not overlap much with that of any other primate species in the Park. Although alert and agile, they are occasionally caught by predators, most notably chimpanzees but also by crowned eagles.

Special Thanks to Thomson Safaris and Tanzania National Parks for contributing Tanzanian information.