Owl-faced guenon  (Cercopithecus hamlyni)

The owl-faced guenon is a graceful monkey from Africa, with a long tail and a silky, olive coat (2) (4). The name ‘guenon' is given to a group of monkeys, all with distinctive ‘moustaches', light nose spots and striped sideburns (4). The owl-faced guenon has a black face with a yellowish patch above the brow, and a thin, white stripe running down the nose (2). The scrotum and perineum are bright blue (2). Two subspecies have been described: Cercopithecus hamlyni hamlyni and Cercopithecus hamlyni kahuziensis (5).

Occurs from eastern Democratic Republic of Congo to northwestern Rwanda (2). Subspecies C. h. kahuziensis is confined to Mount Kahuzi in the Democratic Republic of Congo and Nyungwe Forest in Rwanda (1).

The owl-faced guenon primarily inhabits dense montane rainforest, but can also occur in lowland forest (5).

Owl-faced guenons are arboreal and thus spend nearly all their time in the trees where they run along the branches like squirrels (4). They have two peaks of daily activity; one in the early morning, and then again in the late afternoon or evening (6). Living in small groups with a single male (2), owl-faced guenons are apparently territorial, but avoid serious conflicts with neighbouring groups (6).

This omnivorous monkey feeds on fruit, insects and leaves (2). Their fairly large incisors are perfect for biting into fruit, and their flatter molars are suited to crushing and grinding hard seeds. They also possess cheek pouches, the advantages of which are twofold: in areas where competition for fruit is intense, the monkey can grab as much food as possible before being supplanted by another hungry monkey, at the same time, enzymes in the saliva help break down toxic compounds in unripe fruits and seeds stored in the pouches (7).

Guenons are vulnerable to both the bushmeat trade and human disruption of forests. Destruction of forest habitat throughout its range continues due to agricultural expansion and logging (6). Logging operations result in an increase in workers in the area, causing an increased demand for bushmeat, and logging roads make remote forests more accessible to hunters seeking meat to sell in local markets. In central and west Africa, a guenon carcass can fetch the equivalent of US $5 (7). Forests surrounding Mount Kahuzi are under increasing pressure from rapidly rising human populations. An influx of Rwandan refugees in 1994 and rebel soldiers from 1997 resulted in widespread forest clearance for agriculture and hunting (8). The year 2000 also saw a rush for the valuable industrial mineral coltan, which attracted more than 10,000 miners to the Kahuz-Biéga National Park in which Mount Kahuzi lies, and led to drastic deforestation and poaching (8).

The owl-faced guenon can be found within a number of protected areas, such as the Okapi Faunal Reserve and the Kahuzi-Biéga National Park in the Democratic Republic of Congo (8) (9), but as mentioned above, these generally offer only nominal protection. This species is likely to benefit from the increased protection and management of these areas, but at present, the situation in this volatile region is often too dangerous for action to be taken.

For further information on guenons see:

• Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.

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