Pennant’s red colobus (Procolobus pennantii)

Also known as: Bioko red colobus, Bouvier's red colobus, Niger Delta red colobus
Synonyms: Piliocolobus pennantii
GenusProcolobus (1)
SizeHead-body length: 53 - 63 cm (2)
Tail length: 60 - 70 cm (2)
Weight7 - 11 kg (3)

Pennant’s red colobus is classified as Critically Endangered (CR) on the IUCN Red List (1), and listed on Appendix II of CITES (4).

The IUCN currently recognises three subspecies of Pennant’s red colobus: Bouvier’s red colobus (Procolobus pennantii bouvieri) is classified as Critically Endangered on the IUCN Red List, although it may be extinct, as there have been no reported sightings since the 1970s (1). The Niger Delta red colobus (Procolobus pennantii epieni) is also classified as Critically Endangered (CR), while the Bioko red colobus (Procolobus pennantii pennantii) is classified as Endangered (EN) (1).

Like other red colobus species, Pennant’s red colobus (Procolobus pennantii) has a typically small head, long back and round belly. The limbs are very long and the elongated fingers are aligned to form a powerful hook, well adapted to gripping branches. As with other African colobus species, no thumb exists, only a small remnant bump (5).

The colouration of Pennant’s red colobus varies depending on the subspecies, but can be black or brownish on the upperparts, with red or chestnut brown arms, legs and head (6). The hair on the forehead is characteristically parted down the centre (5).

The taxonomy of Pennant’s red colobus, like that of other red colobus species, is currently under debate. Some scientists place it in the genus Procolobus while others place it in Piliocolobus (1) (3) (6), and further evidence is needed to resolve this issue (1). The subspecies P. p. epieni may potentially be a distinct species (1).

Pennant’s red colobus is found only in a few small areas in Central West Africa (5). The Bioko red colobus (P. p. pennantii) is found on Bioko Island, Equatorial Guinea, while Bouvier’s red colobus (P. p. bouvieri) occurs in the Republic of Congo, and the Niger Delta red colobus (P. p. epieni) inhabits southern Nigeria (1) (3) (7).

Pennant’s red colobus inhabits primary and secondary rainforest, as well as marsh forest (2) (3).

Little is known about the specific behaviour of Pennant’s red colobus, but much can be inferred from what is known about red colobus species in general (5). Red colobus typically live in large troops of 12 to 82 individuals (6), a single troop residing in a territory of 25 to 150 hectares (5). Ownership of the territory is signalled via a variety of barks and chirps given by all group members (5). As in other red colobus species, Pennant’s red colobus groups are multi-male and multi-female, usually with around twice as many females as males (6). Female red colobus tend to remain with the same group throughout their lives, while males may move from group to group (5).

Although little specific information is available on the reproductive biology of Pennant’s red colobus, like other red colobus species it is likely to give birth to a single infant after a gestation period of around 4.5 to 5.5 months (6).

Red colobus are arboreal, often leaping across wide gaps by using the elasticity of a branch to propel themselves between trees (5). The diet of these species consists of leaves, fruit, seeds and flowers (2) (5). Colobines have chambered stomachs specially adapted to help digest tough leaf material (8).

The red colobus monkeys of Central West Africa are probably more threatened than any other taxonomic group of primates in Africa. All the subspecies of Pennant’s red colobus are close to extinction, with very restricted ranges and small numbers as a result of extensive habitat loss and intensive hunting (7).

The loud vocalisations and slow movements of red colobus monkeys make them easy targets for hunters (5). Bouvier’s red colobus (P. p. bouvieri) has not been observed alive by scientists since the 1970s, raising concerns that it may already be extinct (1). The Bioko red colobus (P. p. pennantii) probably has the most restricted range of the other subspecies, found only in the southwest of Bioko Island, which is only around 2,000 square kilometres (1). Here it is threatened by commercial bushmeat hunting and ongoing habitat destruction (1) (7).

Pennant’s red colobus is listed on Appendix II of the Convention on International Trade in Endangered Species (CITES), meaning that international trade in this species should be carefully controlled (4). It is also listed on Class B of the African Convention on the Conservation of Nature and Natural Resources, which means that Pennant’s red colobus may only be captured or killed with special authorisation (9).

Although protected areas do exist within the range of Pennant’s red colobus, none of those in which any of the subspecies occur are particularly well protected. A priority for the conservation of this species must therefore be to rigorously protect all those populations that are known to still exist, as well as to undertake field surveys to better understand the current distributions and abundance of the subspecies (7). Indeed, one of Africa’s highest primate conservation priorities is to create a protected area on Bioko Island (3).

A survey is desperately needed for Bouvier’s red colobus (P. p. bouvieri) to establish whether a population of this subspecies still survives (1). Major international conservation organisations need to work closely with national protected area authorities to help safeguard this rare and little understood red colobus species. For Bouvier’s red colobus (P. p. bouvieri), however, it may already be too late (7).

Learn more about conservation efforts on the island of Bioko:

Authenticated (28/11/05) by Matt Richardson, independent primatologist and writer.

  1. IUCN Red List (January, 2012)
  2. El Zoológico Electrónico (November, 2005)
  3. Richardson, M. (2005) Pers. comm.
  4. CITES (November, 2005)
  5. Bioko Biodiversity Protection Programme (November, 2005)
  6. Nowak, R.M. (1991) Walker's Mammals of the World. The Johns Hopkins University Press, Baltimore and London.
  7. Mittermeier, R.A., Ratsimbazafy, J., Rylands, A.B., Williamson, L., Oates, J.F., Mbora, D., Ganzhorn, J.U., Rodríguez-Luna, E., Palacios, E., Heymann, E.W., Kierulff, M.C., Yongcheng, L., Supriatna, J., Roos, C., Walker, S. and Aguiar, J.M. (2007) Primates in Peril: The World’s 25 Most Endangered Primates, 2006 - 2008. Primate Conservation, 22: 1-40.
  8. Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
  9. African Convention on the Conservation of Nature and Natural Resources (January, 2012)