25 November 2009

Angola Black & White Colobus










Like all black-and-white colobi, the Angola Colobus has black fur and a black face, surrounded by long, white locks of hair. It also has a mantle of white hair on the shoulders. The long, thin tail can be either black or white, but the tip is always white. There is a significant regional variation in the total amount of white on the body and the length of the fur. Animals that live in the mountains have longer, thicker fur than animals from the lowlands to protect them against the cold.




Angola Colobi have a head-body length of 50 to 70 cm, with the males usually being larger than females. The tail is about 75 cm long, and the body weight varies between 9 to 20 kg.




The Angola Colobus occurs in dense rainforests, both in the lowlands and coastal mountains. It lives in most of the Congo Basin, to the south and northeast of the Congo River, as far as Ruwenzori, Burundi and southwestern Uganda. The species can also be found in East Africa, especially in the coastal forests of Kenya and Tanzania and in isolated mountain areas. Although the species is named after Angola, it is quite rare in that country. Of all Colobus species, the Angola Colobus occurs in the southernmost latitudes. The geographical range lies south of that of the Mantled Guereza.




As are all Colobus, the Angolan Colobus monkey is diurnal, they have flattened nails, pads on their buttocks, and their hind legs are longer than their fore limbs. These are typical characteristics of old world monkeys. However, the specific features of Colobines are due to their unique dietary adaptations.





Colobus eat mostly leaves (and some fruits and flowers), have no cheek pouches, are arboreal (live in the tree canopy and rarely come down to the ground) and have a light-weight bone structure and elongated limbs - making it easier to leap from branch to branch. Additionally, the 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. 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.





Their stomach is large and has three chambers, which carries specific bacteria that helps to ferment and digest leaves, similar to rumination of, for example, cows. 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 two to three 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 is thought to assist in the digestion of toxic leaves.