Angola colobus monkeys are medium-sized, arboreal monkeys with slender bodies and long tails. The five recognized species of colobus have similar characteristics and these include the following: a reduced thumb, prominent rump callosities, and a complex stomach which aids in the digestion of cellulose.
Angolan colobus monkeys have long, silky hair. They are black with a white brow band, cheeks, and throat. They have long-haired white epaulettes on the shoulders and the lower half of the tail is white.
Size and weight
The tail length is 706 mm for females and 829 mm for males and head and body length ranges from 490 to 680 mm. Mass varies between 6 and 11.4 kg, with males slightly larger than females. Young are born completely white and begin changing to their adult pelage at about three months of age.
Colobus angolensis is polygynous. Dominant adult males control reproductive access to the females within their family group. Younger males from within the group or from other groups may periodically replace the dominant male. Females of the family group mate with the dominant male.
Angolan colobus monkeys are diurnal and arboreal. They occasionally come to the ground near streams to eat herbaceous vegetation but prefer to remain higher in the canopy. They are the most arboreal of all African monkeys. These colobus monkeys live in troops of up to 25 individuals, although temporary gatherings of over 300 have been observed. They typically live in relatively small social groups of one adult male and normally two to six females with offspring. Young males in the group are forced to leave before they reach breeding age but may also challenge the dominant male for control of the females. When a troop is threatened by a predator, the male jumps and roars until the rest of the troop has fled. Groups defend a relatively small core home range from other troops of Colobus monkeys. Morning roaring contests between dominant males may help to maintain group spacing.
Angolan colobus monkeys are primarily faunivorous, although they also feed on stems, bark, flowers, buds, shoots, fruits, some aquatic plants’ fruits and insects. They are also known to eat clay from termite mounds. In many parts of their range, young leaves of the hack berry tree are the food of choice. They can eat up to two to three kilograms of leaves a day and normally feed in the morning and evening.