Diana guenon  (Cercopithecus diana)

Classified as Vulnerable (VU) on the IUCN Red List (1), and listed on Appendix I of CITES (3).

The Diana guenon is one of the most threatened and yet least known African monkeys. It is a medium sized guenon, with a slender build, long legs and a long tail that is often carried in a ‘question mark’ curve (4). Its face is black and framed with white cheeks, beard and brow line. The front of the chest and inner arms are also white, while the outer limbs, tail and belly are covered in black fur. Running down the outer thighs is a conspicuous diagonal white stripe (4), and the rump bears red or cream fur (5). Males and females are similar in appearance, though males are significantly larger in size (5).

The Diana guenon occurs in West Africa, in the Ivory Coast, Liberia and Sierra Leone (2).

This rare primate inhabits primary and some secondary rainforest, as well as semi-deciduous forests and gallery forests (2) (4).

Diana guenons are arboreal and live in the high canopy of forests where they forage during the day for fruit, leaves and insects (4) (6). They occur in fairly large groups (5 to 50 individuals), which are composed of a single male with up to ten females, and their young (2) (5). It is well known that living in groups is the primary defence strategy amongst diurnal primates, as there is safety in numbers, and individuals can alert others when they sense danger (5). However, Diana guenons seem to have perfected this behaviour and are so alert that other primate species have come to live with them to benefit from their watchful eyes (5). Olive colobus (Procolobus verus) in the Tai National Park, Cote d’Ivoire, are known to form permanent attachments with Diana guenon groups, and other species, such as the red colobus monkey (Piliocolobus badius), form more transient bonds (5). These relationships are successful because, while they benefit from the greater group sizes, they do not suffer from competition for food as each species has a slightly different niche and food source (5).

Breeding in this species is thought to occur year round, with females giving birth to a single offspring after a six month gestation period (4) (6).

The main subpopulations of the Diana guenon occur in Liberia, where civil war has prevented any comprehensive surveys being conducted on this species’ distribution and status (1). It is estimated that 50 percent of the population in this country could have been lost over the last three generations due to hunting for bushmeat. With no wildlife protection, the increase in availability of firearms, and the continued demand for food, this primate has suffered dramatically (1). Hunting is also intense in other countries, as firearms have become readily available.

Human population increases and settlement in forested areas has caused habitat destruction and degradation in these countries. To accommodate the growing populations, and those people who have moved on from areas where resources have run out, forests have been cleared for wood, crops and cattle (4). As the forests become fragmented, this monkey is less able to establish home ranges, forage widely for food and move safely through the forest (1). Their large body size, conspicuous coat pattern and loud vocalisations render them even more susceptible to being hunted (7).

The instability of these countries, especially Liberia, makes it very hard to provide and promote protection for this species. There are a number of protected areas across its range, though hunting is thought to go on inside them. There is an urgent need for up-to-date information on this species, but this will not be easy to obtain (1).

View information on this species at the UNEP World Conservation Monitoring Centre.