Red-eared guenon (Cercopithecus erythrotis)

Bioko red-eared guenon male in rainforest
IUCN Red List species status – Vulnerable VULNERABLE

Top facts

  • A colourful primate, the red-eared guenon has a blue, red and yellow face.
  • The red-eared guenon feeds on fruit, leaves, shoots and insects.
  • ‘Guenon’ is French for ‘fright’, and refers to the tooth-bearing grimace these primates display when angry or excited.
  • Unlike other guenon species, the red-eared guenon is relatively quiet and produces a soft trill-like contact call.
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Red-eared guenon fact file

Red-eared guenon description

GenusCercopithecus (1)

The red-eared guenon (Cercopithecus erythrotis) is a small, brightly coloured monkey with distinctive facial markings. It has blue fur around its eyes, a brick-red nose and ears, and yellow cheeks (3) (4). While the majority of its silky coat is brown agouti, the red-eared guenon has grey limbs and a red tail (3).

Guenons have extremely long tails which are vital for agility and balance. Infants use their tails like a prehensile limb to cling to the female (4).

A shy species (1), the red-eared guenon produces a quiet trill, unlike other guenons that give loud, long-distance calls (3) (4).

Also known as
red-eared monkey, Russet-eared guenon.
Moustac À Oreilles Rouges.
Mono De Orejas Rojas.
Head-body length: 36 - 51 cm (3)
Male weight: 3.6 kg (3)
Female weight: 2.9 kg (3)

Red-eared guenon biology

Guenon species are omnivorous, and the red-eared guenon is known to eat fruits, leaves, shoots and insects (3) (4) (5). Insects are important for nutrition, especially for pregnant and lactating females (4).

Guenons live in groups which vary greatly in size depending on the species and the quality of the habitat (4). The red-eared guenon typically lives in groups with at least one adult male and around ten females with young (5). Guenon troops are not as hierarchical as some primate societies, and although they are territorial, they usually avoid conflict with other groups. ‘Guenon’ is French for ‘fright’, and refers to the angry or excited grimace displayed by these primates, in which the teeth are exposed (4).
Little is known about breeding in the red-eared guenon. However, guenon species typically give birth to a single infant every one to three years, with gestation lasting around five or six months (3) (4). The timing of the breeding season varies between species. Some breed at the end of the dry season, so that lactation coincides with the peak fruiting season, while others breed throughout the year (4).
Guenons are predated by a number of species including eagles and snakes, and respond to the presence of a predator with a variety of alarm calls (4).

Red-eared guenon range

The red-eared guenon has a small range on mainland Africa, from the Cross River in southeast Nigeria to just south of the Sanaga River in Cameroon. It is also found on the island of Bioko in Equatorial Guinea (1).


Red-eared guenon habitat

An arboreal species, the red-eared guenon is found in lowland tropical and sub-montane forests. On the island of Bioko it has been known to live in close proximity to humans (1).


Red-eared guenon status

The red-eared guenon is classified as Vulnerable (VU) on the IUCN Red List (1) and listed on Appendix II of CITES (2). Subspecies: the Cameroon red-eared monkey (C. e. camerunensis) and the Bioko red-eared guenon (C. e. erythrotis) are listed as Vulnerable (VU) on the IUCN Red List (1).

IUCN Red List species status – Vulnerable


Red-eared guenon threats

The red-eared guenon population is thought to have declined by 30 percent over the last 27 years. Habitat loss as a result of deforestation for timber and farm land is thought to be the main threat to this species, and it is also hunted for the bushmeat trade (1).


Red-eared guenon conservation

The red-eared guenon occurs in a number of protected reserves, most notably the Cross River National Park in Nigeria, Korup National Park in Cameroon, and the Gran Caldera and Southern Highlands Scientific Reserve on the island of Bioko (1) (5).

It is also protected as part of the prominent Bioko Biodiversity Protection Program (BBPP), which organises patrol teams that deter hunters and monitor primate populations. Other conservation measures by the BBPP include running awareness campaigns and promoting ecotourism as part of a wider effort to show that Bioko’s wildlife is more valuable in attracting tourism than as bushmeat (5).
View information on this species at the UNEP World Conservation Monitoring Centre.

Find out more

Find out more about primate conservation and the bushmeat trade:



This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:

This species information was authored as part of the ARKive and Universities Scheme.


An animal which lives or spends a large amount of time in trees.
The state of being pregnant; the period from conception to birth.
Montane forest
Forest occurring in mountains.
Feeding on both plants and animals.
Capable of grasping.
Describes an animal, a pair of animals or a group that occupies and defends an area.


  1. IUCN Red List (November, 2012)
  2. CITES (November, 2012)
  3. Macdonald, D. (2010) The Encyclopedia of Mammals. Oxford University Press, Oxford.
  4. CERCOPAN - Guenons (November, 2012)
  5. Bioko Biodiversity Protection Program (BBPP) (November, 2012)

Image credit

Bioko red-eared guenon male in rainforest  
Bioko red-eared guenon male in rainforest

© Tim Laman /

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