Udzungwa red colobus  (Procolobus gordonorum)

The Udzungwa red colobus is classified as Endangered (EN) on the IUCN Red List (1) and listed on Appendix II of CITES (3).

The most distinctive feature of the Udzungwa red colobus (Procolobus gordonorum) is its conspicuous crown of spiky red hair, which stands out dramatically from the black and white fur on the rest of its body (2). The coat is black on the monkey’s upperparts, and white on its underside and inner surfaces of the limbs (2). The arms and thighs of the Udzungwa red colobus are black, but the shanks are a paler, more silvery black (2).

The short, slightly bushy tail of the Udzungwa red colobus is white below and either black or a dull yellowish-black above (2). The cheeks of this species are white and a thick black line runs along the temple, separating the face from the bright red crown (2).

Colobus means ‘docked' in Greek, referring to the small remnant bump that all colobus species have in place of a thumb. However, the other fingers are elongate and aligned to form a powerful hook, well adapted to gripping branches (4).

As with other red colobus species, the taxonomy of the Udzungwa red colobus is widely debated, with some scientists placing it in the genus Procolobus while others place it in Piliocolobus. Further evidence is needed to resolve this issue (1).

As its common name suggests, the Udzungwa red colobus is known only from the fragmented forests of the Udzungwa Mountains in south-western Tanzania, and from a few small patches of forest in the nearby Kilombero Valley in south-central Tanzania (2) (5).

The Udzungwa red colobus is found in primary and secondary forest, from lowland riverine, semi-deciduous forest to montane, mature evergreen forest, at elevations of between 200 and 1,600 metres above sea level (1) (2) (6). It also occurs in miombo woodland (1).

The Udzungwa red colobus lives in multi-male, multi-female groups of anything between 7 and 83 individuals, but usually of around 24 (2) (7). Groups in highly degraded forests where food is scarce are thought to adopt a system of ‘fission-fusion’ society, in which the larger troop breaks up into smaller groups to forage (7).

The Udzungwa red colobus is a diurnal species (8) and feeds mainly on leaves, but will also eat flowers, fruits and fungi (2) (6). The peculiar behaviour of ‘geophagy’ (eating of soil) has occasionally been observed in this species, and is thought to assist digestion in a similar way to charcoal consumption by other animals (6) (9).

The Udzungwa red colobus is preyed upon by crowned hawk-eagles (Stephanoaetus coronatus) and chimpanzees (Pan troglodytes). When a predator has been spotted, these monkeys alert others in the group through a series of calls, which differ to indicate either an aerial or ground predator (2).

Information is rather scant on the reproductive biology of the Udzungwa red colobus. Males attain sexual maturity at around four and a half years of age, and females at about four, after which females are known to have a substantial pink sexual swelling during oestrus. After birth, parental care is performed solely by the female, who carries the infant on her belly for the first three months (2).

The Udzungwa red colobus has a limited range that is continuing to shrink and is becoming increasingly fragmented (2). This species has suffered from habitat destruction and degradation due to construction of a railway within its range, combined with extensive logging, agricultural expansion, collection of firewood and charcoal production (5) (6).

Habitat degradation remains a serious concern due to its impact on the Udzungwa red colobus’ social groups (9). Studies have indicated that reproductive success, group size and group density are significantly reduced in small and degraded forests (5). The small forest remnants in the Kilomero Valley that lie outside of protected areas, or lack the protection they were promised, are particularly vulnerable (5).

Reduced social group size increases the vulnerability of the Udzungwa red colobus to predators (9). It also makes it more vulnerable to poachers, with hunting for Udzungwa red colobus meat, which is considered a delicacy, posing another serious threat to the species (2).

The Udzungwa red colobus is listed as a Class A species under the African Convention on the Conservation of Nature and Natural Resources, which means that capture or killing of this species is prohibited, unless for scientific purposes and with permission (10). Any international trade in the Udzungwa red colobus should also be carefully regulated under its listing on Appendix II of the Convention on International Trade in Endangered Species (CITES) (3).

The Udzungwa red colobus is found in four protected areas in Tanzania: Magombero Forest Reserve, Selous Game Reserve, Udzungwa Mountains National Park (2) and New Dabaga/Ulangambi Forest Reserve (NDUFR) (11). Udzungwa Mountains National Park, which holds the largest population of these monkeys, has no roads and all access is by foot, limiting potential disturbance (8). Elsewhere, however, the Udzungwa red colobus occurs either on public land or in forest reserves that are not effectively protected (5).

Since studies have shown that reduced habitat quality adversely affects the group density, size, composition and recruitment of the Udzungwa red colobus, closed-canopy forest is considered to be crucial for the long-term survival of this endangered primate (6). Indeed, the Udzungwa Mountains contain a rich array of biodiversity, including at least ten primate species, and so constitute an area of global importance for biodiversity conservation (12). Protecting the forests of these mountains must be a priority not only for the Udzungwa red colobus, but for all the fauna and flora that share this diminishing habitat.

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

Find out more about conservation in the Udzungwa Mountains:

• Udzungwa Mountains National Park:
  http://www.udzungwa.org/
• Eastern Arc Mountains Conservation Endowment Fund:
  http://www.easternarc.or.tz/