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The Cat Ba
Langur |
An Extraordinarily Beautiful
Primate |
Identification of the Cat Ba Langur
As indicated
by this species former name (the Golden-headed langur), head and neck down
to the shoulders are bright golden to yellowish-white, with the head and
the crest being most brightly coloured. The rump and the extremities of adult
males and females of the Cat Ba langur are covered by dark chocolate brown,
almost black fur. A grey band runs from the thighs to the back, forming a
V-shape above the tail root and long hair of the back forms a shoulder cape.
Another prominent feature of all Trachypithecus langurs is their long
tail. Its length clearly exceeds head-body length.
The only difference in the colouration between the sexes is a white pubic
patch on the female. The infant coat colouration of the Cat Ba langur as
well as of the other Trachypithecus species in Vietnam is a flamboyant
orange.
Distribution of the Cat Ba Langur and Ecology
The only
known locality of where this langur occurs is the island of Cat Ba. There
is no evidence that the Cat Ba langur ever inhabited the mainland. Immigration
of this species onto Cat Ba Island might have taken place long before the
sea level rose due to a melting of glacial ice. The last time this melting
happened was some 10,000 years ago and it turned the former mountainous Ha
Long Bay into a huge Archipelago.
The Cat Ba langur along with two of its close relatives, the Francois’
langur (Northern Vietnam and Southern China) and the White-headed (Southern
China), are closely associated with limestone areas. These langur species
prefer Karst and forest on limestone as habitat and regularly sleep in caves
throughout the year. Scientists suggest that caves and cracks are important
as shelter against unfavourable weather conditions. One langur group usually
has several (up to 12) different resting caves. The group spends only 1-2
nights in the same cave before moving on to other feeding and sleeping
places.
A significant proportion of a langurs’ daily life is devoted to foraging
and resting. The diet of the Cat Ba langur mainly consists of leaves, but
also includes fresh shoots, flowers, bark and some fruits that are not palatable
to human beings. Most of the langur’s food has very high concentration
of fibre and tannic acids, and often contains substances that would be poisonous
to other animals, including human
beings.
Threat Status
The World
Conservation Union (IUCN) lists the Cat Ba langur as one of the most critically
endangered primate species of the World, due to its small population size
and restricted range. Only 65 langurs currently survive in the wild whilst
an additional two live in the Endangered Primate Rescue Centre at Cuc Phuong
National Park.
In the
past, poaching constituted the primary threat to langur survival and resulted
in a population decline from estimated 2,500-2,800 individuals in the 1960s,
to a mere 53 individuals by 2000.
As a result
of this steep decline in numbers, the remaining langur population is now
highly fragmented and low reproductive output threatens their future survival.
The population of the Cat Ba langur is subdivided into seven isolated
sub-populations. Some of these include all-female groups and are therefore
non-reproducing social units. Langurs were mainly poached for the preparation
of traditional medicine, referred to as “monkey balm”, and only
rarely for use as food, as their meat has a very unpleasant smell.
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The Cat Ba Langur is a member of a primate subfamily that is referred to
as leaf-eating monkeys (Colobinae), due to their food preferences
(Photo Courtesy of Stefan
Kobold)
A Group of Cat Ba Langurs
Like most Colobines, the Cat Ba Langur is a tree dweller and lives in social
groups with one male and several females
(Photo Courtesy of Bavarian
TV)
Sleeping site of the Cat Ba langur
- a limestone cave |
