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Order : PRIMATES
Family : Cercopithecidae
Species : Trachypithecus poliocephalus
Head-body length : 49-59 cm
Tail length : 80-90 cm
Weight : up to 7 kg ?
The Cat Ba Langur, or
Golden-headed Langur, is one of the world's most critically endangered
primates. In 2006, there were only an estimated 64 surviving in Vietnam, on limestone hills on
the island of Cat Ba in the Gulf of Tonkin.
In southern China, a population of around 700-800 of a closely related
subspecies, the White-headed Langur T. p. leucocephalus, survives,
though this may well represent a separate species entirely.
The species name 'poliocephalus' translates as 'grey-headed', however
the head colour is typically pale yellowish, grading downwards to orange-brown on the
upper chest. Its body fur is mainly dark brown, but with a pale grey area
on the rump. Infants are bright orange.
The Cat Ba Langur is a lowland species, occurring up to 200 metres
elevation. Like
its cousin, the Hatinh Langur, it makes use
of limestone caves in which to roost at night. The average group size is
just 3 to 4 individuals.
The species is both arboreal and terrestrial, but
they are comfortable resting on rocky outcrops by day. They feed on young leaves,
leaf shoots, flowers, forest fruits and bark.
These langurs are under many threats including hunting for traditional
medicine, disturbance by tourism, and habitat fragmentation and in-breeding.
It is postulated that the ancestors of the Cat Ba Langur arrived on the
island of Cat Ba during the last ice age, when sea levels were lower, and
they have been isolated there ever since.
Fig 1 : A group of Cat
Ba Langur rest on a limestone outcrop at Cat Ba National Park, Vietnam
Fig 2 : Parent with bright orange infant.
All photos extracted from video taken on Cat
Ba Island, Vietnam by Andie Ang.
References :
Francis, C.M. 2019. A Field Guide to the Mammals of South-east Asia.
Second Edition. New Holland. 416 pp.
Groves, C. P. (2001). Primate taxonomy. Smithsonian Institution
Press, Washington DC. 350 pp.
Rawson, B.M., Leonard, N., Covert, H. & Nadler, T. 2020. Trachypithecus
poliocephalus. The IUCN Red List of Threatened Species 2020:
e.T39871A17959804.
Links :
The Cat Ba Langur: a primate walks the razor’s edge of extinction -
Mongabay.com, 31 Aug 2015
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