Bio Facts: Colobus, Angolan
Congo Basin to the south and northeast of the Congo River, as far as Ruwenzori, Burundi and southwestern Uganda; although named for Angola, it is rare in that country.
Lowland and coastal rainforests
Black hair with a white brow band, cheeks, and throat. Long haired white epaulettes stream from the shoulders. The lower part of the tail is white as is the band (males have a band, females have a patch) on the buttocks. Nails are flattened, buttocks are padded, and their hind legs are longer than their fore limbs. Head-body length of 19.7 – 27.6 in (50-70 cm); weight averages 19.8 – 44 lbs. (9-20 kg).
In the wild, up to 20 years of age; in captivity up to 30 years of age.
Females at approximately 2 years of age; males at approximately 4 years of age.
In the wild, they feed mostly on leaves and eat fruits and flowers; in the Zoo they are fed a scientifically prepared, commercially available food supplemented with fresh greens, fruits and vegetables. Keepers provide fresh cut vegetation as part of their daily diet.
IUCN – Least concern; CITES – Appendix II
Angolan colobus are diurnal and highly arboreal, which may help avoid predators that feed at night. The leaping ability of Colobines is unsurpassed among other African old world monkeys. Wide gaps between trees are crossed by taking long leaps involving considerable vertical descent. Drops of nearly 50 ft (15m) into the undergrowth are made to escape predators, and displaying territorial males also make spectacular jumps. Although colobus can jump great distances on a falling leap, their ability to leap horizontally, although still impressive, is in question. Colobus have occasionally been known to swim water moats.
The majority of their diet is made up of young and mature leaves - 46 species eaten but only five species make the greatest proportion of their diet. Because of the poor nutritional quality of their food, they browse intensively for many hours each day. They digest 4.5 – 6.6 lbs. (2-3 kg) of leaves per day (one third of their full body weight), and also eat seeds, unripe fruits and flowers. Some species of Colobus are known to eat soil, clay and charcoal which are thought to assist in the digestion of toxic leaves.
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. A behavior called presenting is performed by the female to communicate to the male that she is ready for copulation. The gestation period ranges from 147 to 178 days and a single offspring is generally born, though twins are possible.
Infants are born strikingly white, and then turn grey and black. By three months of age they change to the adult coloration of black and white. They are born throughout the year but a birth peak is seen in September and October. Colobine infants are known for their flamboyant coloration, which is remarkably different than the adult. This is considered an adaptation for encouraging ‘aunting behavior’ by attracting other females in the group to the newborn. This supposedly frees up maternal time for feeding while other females care for the young. The nutritional value to their diet is low and the stress of rearing offspring puts enormous pressure on the female. Aunting behavior thus counteracts the burden of nursing. Infants are weaned by 15 months of age.
Females typically remain in their natal troops for life. The dominant male defends the territory and troop from predators whereas the dominant female leads the troop. Young males leave their natal troop to start bachelor groups or to travel alone until they are able to take over their own troop.
They 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 multiple females with offspring, however multi-male groups have been observed. Young males in the group are usually 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.
Their stomach is large and has three chambers, which carries specific bacteria that help to ferment and digest leaves, similar to rumination of, for example, cows.
Light-weight bone structure and elongated limbs are adaptations for arboreal living and makes it easier to leap from branch to branch. The reduction of the thumb is an adaptation to arboreal living as the fingers have become aligned into a single, narrow curved arc that allows the hand to act as a flexible hook.
Colobus have no thumbs though they retain an opposable big toe. “Colobus” in fact acquired their name from the Greek word “kolobos” meaning maimed or mutilated.
Of all Colobus species, the Angola Colobus occurs in the southernmost latitudes. They are less tolerant of cold temperatures than Colobus guereza, a colobus species that inhabits more northern geographic ranges.
Of the twelve currently recognized colobus species, one is near threatened, three vulnerable, three endangered, and two critically endangered. Angolan colobus are not currently considered endangered and may be fairly abundant in parts of their range. However, they are vulnerable to habitat destruction and have suffered extensively by hunting for bushmeat and skins, especially in highly populated areas. Populations are declining fairly rapidly in some areas such as the Kakamega forest in Kenya
Jacksonville Zoo History:
The Angolan colobus was a new first time species to the Jacksonville Zoo collection in 2008.