CreatureData

Hamlyn's monkey

Cercopithecus hamlyni Pocock, 1907

VUVulnerableprimates

The hamlyn's monkey (Cercopithecus hamlyni) is a species in the family Cercopithecidae, order Primates. Recorded adults weigh 3.45 kg to 6.88 kg and live up to 28.5 years. Its IUCN Red List status is Vulnerable.

Hamlyn's monkey (Cercopithecus hamlyni)
Photo: No machine-readable author provided. JoJan assumed (based on copyright claims). · CC BY-SA 3.0 · Wikimedia Commons

Quick facts about the hamlyn's monkey

Weight
3.45 kg – 6.88 kgsrc for Weight
Length
Not recorded
Lifespan
28.5 yearssrc for Lifespan
Diet
Herbivoresrc for Diet
Longest recorded lifespan
28.6 years
Main food
Not recorded
Habitat
Not recorded
Young per litter or clutch
Not recorded
Active
By day (diurnal)src for Active
Lifestyle
Arborealsrc for Lifestyle
Conservation status
Vulnerable (IUCN)src for Conservation status
Countries on record
Not recorded

Where does the hamlyn's monkey live?

Not recorded

What is the hamlyn's monkey?

Quoted from WikipediaCC BY-SA 4.0

The Hamlyn's monkey (Cercopithecus hamlyni), also known as the owl-faced monkey, is a species of Old World monkey that inhabits the bamboo and primary rainforests 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 and from the Congo River to the Kabale Forest, with one example in northwestern Rwanda. Geographically it corresponds quite closely to another species of monkey, L'Hoest's monkey 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. It is thought to be a frugivore-folivore 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. 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.

From the Wikipedia article “Hamlyn's monkey” (en.wikipedia.org/w/index.php?title=Hamlyn%27s_monkey&oldid=1384356239), by Wikipedia contributors, licensed under CC BY-SA 4.0 (creativecommons.org/licenses/by-sa/4.0). This block is kept separate from our own text.

What does the hamlyn's monkey sound like?

Hart JA, Detwiler KM, Gilbert CC, Burrell AS, Fuller JL, et al. (2012) · CC BY 2.5 · Wikimedia Commons

Is the hamlyn's monkey endangered?

The hamlyn's monkey is listed as Vulnerable on the IUCN Red List: it faces a high risk of extinction in the wild.

  1. LCLeast Concern
  2. NTNear Threatened
  3. VUVulnerable
  4. ENEndangered
  5. CRCritically Endangered
  6. EWExtinct in the Wild
  7. EXExtinct

Category via Wikidata (CC0). Find the full assessment on the IUCN Red List. See all Vulnerable species.

How is the hamlyn's monkey classified?

  1. kingdomAnimalia
  2. phylumChordata
  3. classMammalia
  4. orderPrimates
  5. familyCercopithecidae
  6. genusCercopithecus
  7. SpeciesCercopithecus hamlyni Pocock, 1907

Synonyms Cercopithecus hamlyni hamlyni, Cercopithecus hamlyni kahuziensis, Cercopithecus leucampyx aurora

Other names and names in other languages (24)
  • Hamlyn s monkeyEnglish
  • Hamlyn’s monkeyEnglish
  • Hamlyn’s monkeyEnglish
  • Owl-faced guenonEnglish
  • Owl-faced guenonEnglish
  • Owl-faced guenonEnglish
  • Owl-faced monkeyEnglish
  • Owl-faced monkeyEnglish
  • غينون هاملينيArabic
  • kočkodan HamlynůvCzech
  • EulenkopfmeerkatzeGerman
  • Cercopiteco de HamlynSpanish
  • Cercopiteco del Congo OrientalSpanish
  • juovanaamamarakattiFinnish
  • Cercopithèque d'HamlynFrench
  • Cercopithèque à tete de hibouFrench
  • Cercopithèque à tête de hibouFrench
  • フクロウグエノンJapanese
  • HamlynmarekattNorwegian Bokmål
  • UilenkopmeerkatDutch
  • koczkodan sowiogłowyPolish
  • Macaco-corujaPortuguese
  • Совинолицая мартышкаRussian
  • Hamlyns markattaSwedish

Catalogue of LifeWikipediaiNaturalistWikidataIUCN Red List

Relatives of the hamlyn's monkey

Other species in the same genus Cercopithecus.

Lesula

Cercopithecus lomamiensis

CercopithecidaeNo free photo yet

EN, Endangered
Diana monkey (Cercopithecus diana)

Diana monkey

Cercopithecus diana

Cercopithecidae

LC, Least Concern
Blue monkey (Cercopithecus mitis)

Blue monkey

Cercopithecus mitis

Cercopithecidae

NT, Near Threatened
Mona monkey (Cercopithecus mona)

Mona monkey

Cercopithecus mona

Cercopithecidae

CompareHamlyn's monkey vs LesulaHamlyn's monkey vs Diana monkeyHamlyn's monkey vs Blue monkeyHamlyn's monkey vs De Brazza's monkey

Common questions

Answered only where our data holds the answer.

How big is the hamlyn's monkey?

An adult hamlyn's monkey weighs 3.45 kg – 6.88 kg, according to values recorded on Wikidata.

Is the hamlyn's monkey endangered?

The hamlyn's monkey is listed as Vulnerable on the IUCN Red List, meaning it faces a high risk of extinction in the wild.

How long does the hamlyn's monkey live?

The hamlyn's monkey has a recorded lifespan of 28.5 years.

What kind of animal is the hamlyn's monkey?

The hamlyn's monkey (Cercopithecus hamlyni) belongs to the family Cercopithecidae in the order Primates.

Sources and how to cite this page

Data as of 2026-11-11. How this page is put together.

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APA

CreatureData. (2026). Hamlyn's monkey (Cercopithecus hamlyni). Retrieved from https://creaturedata.com/animals/hamlyn-s-monkey

MLA

“Hamlyn's monkey (Cercopithecus hamlyni).” CreatureData, 2026, https://creaturedata.com/animals/hamlyn-s-monkey.

BibTeX
@misc{hamlyn_s_monkey_2026,
  title = {Hamlyn's monkey (Cercopithecus hamlyni)},
  author = {{CreatureData}},
  year = {2026},
  url = {https://creaturedata.com/animals/hamlyn-s-monkey},
  note = {Data as of 2026-11-11}
}