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The Colobus Monkey
THE ANGOLAN BLACK AND
WHITE COLOBUS
The Angolan black and white Colobus Monkey has 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.
This subspecies, palliatus, can only be found in the southern
Kenyan coastal forests and the northern Tanzanian highlands.
Although the palliatus subspecies were previously found along the
entire coastal stretch from Somalia in the north to Mozambique in
the south, deforestation in the northern parts have resulted in
their restriction to isolated pockets of forests south of Mombasa.
Traveling further inland, the Guereza black and white Colobus occur.
These are much bigger, have longer coats, have a full cape of white
hair around their backs and full bushy white tail.
Here in Diani over 200 Angolan Colobus monkeys were identified in
2006 a worrying decline compared to over 400 Colobus monkeys
identified during the year 2004. Overall, there are an estimated of
3000-5000 palliatus in Kenya. The largest population of
around 2000 is in the Shimba Hills National Reserve with another 500
in the Shimoni East Forest and 300-400 on Mrima and Dzombo Hills.
There are probably 20,000 to 30,000 Colobus in Kenya. Listed as data
deficit in the IUCN red data list, the Angolan Colobus is believed
to be largely endangered in Kenya because of its declining numbers
in association with the fragmentation of forests along the coast.
The Colobus Trust censuses were the first ever-completed in Kenya,
and will be instrumental in establishing its 'rarity' status for
IUCN. We are currently about to begin a new census to evaluate the
current number of Colobus palliatus in the Diani region.
The Colobus
in Africa
Colobine monkeys (Family
Cercopithecidae; Subfamily colobinae) are found in Africa and
Asia. African species include the Olive, Red and Pied. The Pied
Colobus include the Black, Western Pied, Angola Pied, Geoffroy's
Pied and the Guereza.
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Angolan Black and White Colobus |
Abyssinian Black and White Colobus |
Tana River Red Colobus |
Zanzibar Red Colobus |
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Colobus angolensis ssp palliatus |
Colobus guereza ssp occidentalis |
Procolobus badius ssp tephrosceles |
Procolobus badius ssp kirkii |
Note: Taxonomy of many
primate species is disputed throughout the world. This is based on
the World Conservation Union (ICUN) Status Survey and Conservation
Primate Specialist Group.
Behavior
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.
In Diani, Colobus are rarely a pest to tourists as they do not eat
human food and remain in the tree canopy. Due to their dependence on
forests they are a true "flagship" species in which the overall
health of the forest can be gauged.
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Infants are born
strikingly white, and then turn grey and black and then by three
months of age, 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' where other females
in the group are attracted to the newborn and spend time caring for
the young. This supposedly frees up maternal time for feeding. As is
known amongst the Colobines, the nutritional value to their diet is
low and the stresses of rearing offspring puts enormous pressure on
the female. Aunting behavior thus counteracts the burden of
nursing.