The Yunnan snub-nosed monkey is the most endangered of China's three snub-nosed monkey species. The long, shaggy coat is mainly black on the back, arms and legs and white on the front (2). White hair is also present on the flanks and this is particularly long on the adult males. The lips are a deep pink, whilst the face is paler and there are yellowish-grey hairs on the shoulders (2). These monkeys get their common name for their unusual noses; the nasal bones are absent and the nostrils are upturned (2)(5). Young are born white but become grey over several months (2).
Very little is known about these elusive monkeys, and the first comprehensive study of their ecology and behaviour only took place in the 1990s (5). Unusually for langur monkeys (which normally feed on leaves), the diet of the Yunnan snub-nosed monkey is composed primarily of lichens, such as those of the genus Bryotia(7). Lichen is an abundant and easy to digest food source but it is relatively poor nutritionally; this unusual diet has led to other aspects of behaviour that are unique amongst tree-dwelling primates (5). For example, large groups of up to 300 individuals have been observed (5), probably as a result of low food competition between members (7). These troops appear to be made up of small family groups consisting of an adult male, three to five females and their offspring (5), although the whole troop will tend to travel and rest together (7).
Reliance on lichen, which can take between 10 to 15 years to regenerate, has also caused these monkeys to have a more wandering way of life (5). A troop will cover around 1,500 metres in one day and their home range reaches as much as 25 square kilometres (7). The birth rate is also low for this species; scientists estimate that a female gives birth about once every three years (5).
Yunnan snub-nosed monkeys are found at a higher altitude than any other primate, with the exception of man (6). They inhabit coniferous forest, which is found between 3,000 and 4,500 metres above sea level and experiences frost for around 280 days of the year (2)(3); snow to a depth of over one metre can accumulate (6).
Numbers of Yunnan snub-nosed monkeys have declined principally in response to habitat loss and hunting pressure (6). The human population in this remote corner of China has exploded in recent decades and forests are being cleared, both for timber and to make way for agriculture (5). The populations of snub-nosed monkeys that remain are isolated in fragments of the former forest (8). Hunting of this primate was banned in China in 1975, but lack of funds and staff means that this law is hard to enforce, and hunting persists (2). Monkeys are also accidentally trapped in snares set out for other wildlife (6).
The Government of China banned the hunting of snub-nosed monkeys in 1975, although this has proven difficult to enforce (2). Around half the population of the Yunnan snub-nosed monkey occurs within protected reserves such as Baima Snow Mountain Nature Reserve where wardens are trying to work closely with the local people to secure the future of this species (5). In 1998, a national logging ban on all remaining old-growth forests came into force, which will help to preserve some of the monkey's precious habitat (5). Yunnan snub-nosed monkeys are a vital part of the mountain ecosystem, preventing the accumulation of lichen in these ancient forests of the foothills of the Himalayas (5).
A composite organism made up of a fungus in a co-operative partnership with an alga. Owing to this partnership, lichens can thrive in harsh environments such as mountaintops and polar regions. Characteristically forms a crustlike or branching growth on rocks or tree trunks.
Renmei, R., Kirkpatrick, R.C., Jablonski, N.G., Bleisch, W.V. and Canh, L.X. (1998) Conservation status and prospects of the snub-nosed langurs (Colobinae: Rhinopithecus). In: Jablonski, N.G. (Ed) The Natural History of the Doucs and Snub-nosed Monkeys. World Scientific, Singapore.
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