Tana River mangabey  (Cercocebus galeritus)

Classified as Endangered (EN) on the IUCN Red List and listed on Appendix I of CITES (3).

The Tana River mangabey is a medium-sized, long-tailed monkey with a yellowish-brown coat, and a centre parting on the crown with very long, darker fur diverging from it on either side (2) (4). Like all Cercocebus, this species possesses white eyelids that contrast with the dark colour of the face, a feature thought to aid visual communication through facial expression (5). The molars of this species are long and the incisors are very large, allowing this mangabey to exploit hard seeds in its diet (4) (6).

Endemic to Kenya. Restricted to the lower Tana River region between Garsen and Wenje (7).

Found in dry gallery forests and Acacia woodland along the floodplain of the Tana River (2) (7). This species is largely terrestrial (4).

The Tana River mangabey is a diurnal species that primarily feeds on seeds, leaves and fruit (4) (6). This monkey occupies multimale-multifemale groups (5) that range from 10 to 36 individuals (8). Mating behaviour is not fully understood, but a single offspring is known to be usual (6), after a gestation period of around 170 to 180 days (2) (8). Life-expectancy is thought to be between 19 and 21 years (9), but little else is known about the life history of this species.

The Tana River mangabey has a restricted range of just 60 km of the Tana River (10), and a highly fragmented population that is in continuing decline due to rapid habitat destruction (1). Without urgent action, there is a high probability of this mangabey becoming extinct over the next 50 - 100 years (11). In 1994 it was estimated that just 1,000 to 1,200 individuals remained (1). The population is possibly much lower today, since their habitat has been severely degraded since then, with an approximate 30 % loss of original vegetation (10) (12). In addition, local communities continue to degrade the remaining forest for products used in the construction of homes and canoes, the collection of wild honey and the topping of date palms to make palm wine (12). As the average number of mangabey groups has been found to correlate with forest area and density of trees, the loss and degradation of forest is a major cause for concern. Mangabey-human conflict has also increased in recent years due to crop-raiding, resulting in traps being set (1).

The Tana River National Primate Reserve was established in 1976 to preserve the endemic and endangered Tana River mangabey and Tana River red colobus (Colobus rufomitratus) (13), but only covers part of the mangabey’s range. A 5-year project with the World Bank and Global Environment Facility (GEF) was also started in 1996. Originally designed to relocate several hundred families that presently live within the reserve, financial support was ultimately withdrawn before completion of the project (12). Sadly, forests continue to decline and a new conservation approach is desperately needed to protect them, where past approaches have failed. Their failure was largely due to disregard of land-tenure issues within the Reserve, exclusion of local people from decision-making and neglect of forests outside the reserve (10). Solutions must be found for the problem of forest clearing, and the harvesting of forest products must be better managed, if there is any chance of protecting the habitat of this critically endangered primate and evading its otherwise imminent extinction.

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

For further information on the Tana River mangabey see:

African Mammals Databank:
http://www.gisbau.uniroma1.it/amd/amd040.html

Primate Info Net:
http://pin.primate.wisc.edu/news/cons/peril10.html