Piliocolobus preussi

Geographic Distribution and Habitat

The Preuss’s red colobus (Piliocolobus preussi) is one of the most endangered primates in the world. Although they historically had a larger range, these monkeys are now restricted to dense rainforests in western Cameroon and southeastern Nigeria. The majority of the population is found in Cameroon in Korup National Park, with a small population found in the Cross River National Park in Nigeria, close to the border with Cameroon.

Preuss's red colobus range, IUCN 2017

Size, Weight, and Lifespan

Preuss’s red colobuses are large-bodied and, based on similar species of red colobus, an adult’s body length is likely in the range of 17.75–26.5 in (45–67 cm), excluding the tail. Individuals can weigh 11–24.25 lb (5–11 kg). The lifespan of this species is probably around 20 years.


​Preuss’s red colobuses have a black head with a gray face. As their name suggests, they have some areas of pelage that are varying shades of red, with orange cheeks, a black back tinged with orange, and dark red tails. Their chest, belly, and inner limbs are cream-colored.

Because they live in dense forest, there are few photos of Preuss's red colobus. This is the closely related western red colobus, Piliocolobus badius.

​Like other species of red colobus, the Preuss’s red colobus is primarily a leaf eater, preferring young, immature leaves from a variety of trees. Since these leaves are less nutritious than other types of food, they probably have to eat a large amount of leaves in order to survive. Other species of red colobus have guts that are specially adapted to digest large volumes of leaves.

Behavior and Lifestyle

Preuss’s red colobus monkeys are arboreal and spend their time in the trees of their forest homes. These monkeys are slow-moving and spend a large portion of their day resting in trees. They also spend time foraging for leaves and grooming socially. Very little is known about the behavior of the Preuss’s red colobus, although similar species of red colobus are known to have aggressive inter-group interactions.

Fun Facts

The Critically Endangered Preuss’s red colobus is one of 18 species of red colobus monkeys.

They are confined to small areas of Cameroon and Nigeria but once inhabited a much larger area.

Their biggest threats come from commercial hunting and loss of habitat. 

Daily Life and Group Dynamics 

Preuss’s red colobus monkeys live in groups of up to 70 individuals, although group size may vary considerably and is probably influenced by both habitat quality and predation. Groups contain multiple males and multiple females, as well as juveniles, and there are likely to be more adult females in the group than adult males. Dispersal patterns are not known in the Preuss’s red colobus, but in other species of red colobus monkeys both males and females disperse from their natal group—although many males stay in their natal groups and form coalitions with other males. 


​Very little is known about the communication of the Preuss’s red colobus. Since they live in dense forest, it is likely that auditory communication is important for group cohesion and social interactions. They do use vocalizations to communicate, but their meanings and use are not yet well understood.

Reproduction and Family

​The reproductive life of the Preuss’s red colobus also remains a mystery, but it is likely similar to other species of red colobus monkeys, where females give birth to one infant every two years after a gestational period of between 4 and 6 months.

Facing Korup National Park, home to a majority of extant Preuss's red colobus monkeys. Photo credit: Christos Astaras/Creative Commons
Ecological Role

Preuss’s red colobus monkeys likely play a role in the structuring of the forest ecosystem because of the amount of leaves they consume. Additionally, they are favored prey of chimpanzees, where their ranges overlap.

Conservation Status and Threats

The Preuss’s red colobus is listed as Critically Endangered by the International Union for Conservation of Nature (IUCN, 2019). The species was listed in the IUCN SSC Primate Specialist Group’s “Primates in Peril: The World’s 25 Most Endangered Primate Species 2-14-2016” report. The population is thought to be over 10,000 individuals and rapidly decreasing.

While chimpanzees are known to hunt the Preuss’s red colobus, the most severe threat to this species comes from humans. Preuss’s red colobuses are hunted for both use in traditional medicine and for consumption. The rise of commercialized hunting combined with habitat loss has pushed this species to the edge of extinction. The small remaining habitat of the Preuss’s red colobus is under threat from development of infrastructure and agriculture.

​Conservation Efforts

Preuss’s red colobus monkeys are included in the Red Colobus Action Plan Initiative, which hopes to conserve red colobus monkeys through plans to increase awareness and propose alternatives to bush meat hunting in local areas. More research is needed to get a more accurate estimate of the remaining population and to better understand the behavior of this species.

  • ​Bobo, K. S., Ntumwel, C. B., Aghomo, F. F., & DSCHANG, C. (2012). Hunter’s perception on uses of Preuss’s red colobus (Procolobus preussi) and red-capped mangabey (Cercocebus torquatus), and related conservation issues, in the Nkwende Hills area, southwest Cameroon. Life Sciences Leaflets, 8, 28-34.
  • ​Chapman, C. A., Bonnell, T. R., Gogarten, J. F., Lambert, J. E., Omeja, P. A., Twinomugisha, D., … & Rothman, J. M. (2013). Are primates ecosystem engineers?. International Journal of Primatology34(1), 1-14.
  • Fonkwo, S. N., Mbida, M., Angwafor, T. E., & Ebua, V. B. (2015). Activity budget of Preuss’s red colobus (Procolobus preussi) in Korup National Park, South-West region, Cameroon. International Journal of Biological and Chemical Sciences, 9(4), 1799-1808.
  • Mittermeier R. and colleagues (2017) Red colobus conservation action plan initiative.
  • Morgan, B. J., Suh, J. N., & Abwe, E. E. (2012). Attempted predation by Nigeria-Cameroon chimpanzees (Pan troglodytes ellioti) on Preuss’s red colobus (Procolobus preussi) in the Ebo forest, Cameroon. Folia Primatologica, 83(3-6), 329-331.
  • Schwitzer, Christoph & Mittermeier, Russell & Rylands, Anthony & Chiozza, Federica & Williamson, Liz & Wallis, Janette & Cotton, Alison. (2015). Primates in Peril: The World’s Most Endangered Primates, 2014-2016.
  • Struhsaker, T. T. (2010). The red colobus monkeys: variation in demography, behavior, and ecology of endangered species. Oxford University Press.
  • Struhsaker, T. T. (2010). Variation in adult sex ratios of red colobus monkey social groups : implications for interspecific comparisons. In (Ed) P. Kappeler, Primate Males: Causes and Consequences of Variation in Group Composition. Cambridge University Press.

Written by Jennifer Botting, November 2019