The Hamlyn's monkey (''Cercopithecus hamlyni''), also known as the owl-faced monkey, is a species of

Old World monkey Old World monkeys are primates in the family Cercopithecidae (). Twenty-four genera and 138 species are recognized, making it the largest primate family. Old World monkey genera include baboons (genus '' Papio''), red colobus (genus '' Piliocolob ...

that inhabits the

bamboo Bamboos are a diverse group of mostly evergreen perennial plant, perennial flowering plants making up the subfamily (biology), subfamily Bambusoideae of the grass family Poaceae. Giant bamboos are the largest members of the grass family, in th ...

and primary

rainforest Rainforests are forests characterized by a closed and continuous tree Canopy (biology), canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforests can be generally classified as tropi ...

s of the Congo. This species is exceedingly rare and known only from a few specimens; little is known about it. However these specimens tend to be widely dispersed throughout the eastern part of Congo, from the Epulu River to the

Lukuga River The Lukuga River () is a tributary of the Lualaba River in the Democratic Republic of the Congo (DRC) that drains Lake Tanganyika. It is unusual in that its flow varies not just seasonally but also due to longer term climate fluctuations. Location ...

and from the

Congo River The Congo River, formerly also known as the Zaire River, is the second-longest river in Africa, shorter only than the Nile, as well as the third-largest river in the world list of rivers by discharge, by discharge volume, following the Amazon Ri ...

to the Kabale Forest, with one example in northwestern

Rwanda Rwanda, officially the Republic of Rwanda, is a landlocked country in the Great Rift Valley of East Africa, where the African Great Lakes region and Southeast Africa converge. Located a few degrees south of the Equator, Rwanda is bordered by ...

. Geographically it corresponds quite closely to another species of monkey,

L'Hoest's monkey L'Hoest's monkey (''Allochrocebus lhoesti''), also known as the mountain monkey, is a guenon found in the upper eastern Congo Basin. They mostly live in mountainous forest areas in small, female-dominated groups. They have a dark coat and ca ...

''C. lhoesti''. It travels on the ground, and researchers think that it may be awake primarily by night. Schwarz (1928) grouped this species with ''C. l'hoesti'', while Elliot (1913) noted its distinctive cusp pattern on the third molar, and reassigned it to a separate genus, ''Rhinostigma''. This he believed to be an intermediate between '' Cercopithecus'' and '' Cercocebus''. Hamlyn's monkey has one subspecies other than the nominate. In weight, the male is much larger than the female, with the average adult weighing 7 to 10 kg, while females weigh on average 4.5 to 6 kg.Singapore Zoological Gardens Docents (1999).
Cercopithecids (Cercopithecidae)
''. Retrieved on 10 July 2006. It is thought to be a

frugivore A frugivore ( ) is an animal that thrives mostly on raw fruits or succulent fruit-like produce of plants such as roots, shoots, nuts and seeds. Approximately 20% of mammalian herbivores eat fruit. Frugivores are highly dependent on the abundance ...

folivore In zoology, a folivore is a herbivore that specializes in eating leaves. Mature leaves contain a high proportion of hard-to-digest cellulose, less energy than other types of foods, and often toxic compounds.Jones, S., Martin, R., & Pilbeam, D. (1 ...

in diet. Some published reports indicated that Hamlyn's monkey lives in small groups, of ten members or less, with one male and multiple females, with no data to show them occurring in monogamous groups. The species has been found only in higher elevations, above 900m and up to 4600m. In color it is generally dark gray, with a characteristic white stripe which extends from the root of the nose to the upper lip, giving it an owl-like appearance, hence the name "owl-faced monkey". The name "Hamlyn's monkey" and the scientific epithet "''hamlyni''" come from the animal dealer who first brought this species to the

London Zoo London Zoo, previously known as ZSL London Zoo or London Zoological Gardens and sometimes called Regent's Park Zoo, is the world's oldest scientific zoo. It was opened in London on 27 April 1828 and was originally intended to be used as a colle ...

. It has scent glands on its chest with which it marks its territory. Both sexes have bare, blue buttocks, and the mature male has bright red and blue genitals. The juvenile coloration is a yellow-brown coat and a pink face. In captivity it has been known to live for about 33 years. Like others of this genus, it covers a wide area in its daily travels, mostly in a search for food.

Subspecies

* ''Cercopithecus hamlyni hamlyni'' * ''Cercopithecus hamlyni kahuziensis''

Notes

External links

* ARKive
Images of the owl-faced guenon ''(Cercopithecus hamlyni)''
{{Taxonbar, from=Q1077117 Hamlyn's monkey Mammals of the Democratic Republic of the Congo Mammals of Rwanda Fauna of Central Africa Hamlyn's monkey Taxa named by R. I. Pocock