Red-shanked douc (Pygathrix nemaeus)
|Also known as:||douc, red-shanked douc langur|
|Size||Male head-body length: 55 - 60 cm (2)|
Male tail length: 60 - 74 cm (2)
Female tail length: c. 60 cm (2)
Female head-body length: c. 60 cm (2)
Male weight: 10.9 - 12.6 kg (2)
Female weight: 8.2 - 8.9 kg (2)
The red-shanked douc is classified as Endangered (EN) on the IUCN Red List (1), and listed on Appendix I of CITES (3).
One of the most colourful primate species, the red-shanked douc (Pygathrix nemaeus) has a striking appearance. This distinctive mammal has a boldly patterned body, with yellow-orange to light brown facial skin surrounding the almond-shaped eyes and the nose, and bold white around the mouth and sides of the head (4) (5). The back, top of the head and upper arms are all black-speckled grey, while the backs of the hands and the forearms are white and the underparts of the body are a relatively bright, agouti silver. A wide, black band stretches across the forehead and white whiskers, as long as 12 centimetres, protrude conspicuously from the sides of the head (5). The red-shanked douc can be distinguished form other species of douc by its chestnut-red lower legs, as well as by the chestnut collar that separates the white neck from a black band that stretches between the shoulders, and by the triangle of white fur at the base of the long, white tail (5) (6).
Endemic to Indochina, the red-shanked douc is found in east-central Lao People’s Democratic Republic, northern and central Vietnam, and possibly northern Cambodia (1).
The red-shanked douc inhabits undisturbed evergreen and semi-evergreen forests, including those on limestone formations (1).
Never seen on the ground in the wild, the red-shanked douc spends almost all of its time feeding high in the treetops. While traversing the canopy, it moves with a distinctive gait on all four limbs and swings between the branches using its elongated arms (5). It prefers to eat young, tender leaves, which may comprise up to three quarters of its diet, but will also eat plant buds, fruits, seeds and flowers (1). As this largely leafy diet is of low nutritional value, the red-shanked douc’s stomach can hold large volumes, and the stomach contents may weigh as much as a quarter of an adult’s body weight (4). At night, the red-shanked douc sleeps in carefully selected large trees with a thick canopy (6).
Travelling in groups, the size of which varies with habitat quality, the red-shanked douc is a very social primate, and will readily play and groom together (5). Motherhood is a shared duty within the group, giving mothers time to feed, as well as helping to integrate the young into the group. Social bonds within these douc langur groups are vitally important and communication takes place through a wide variety of vocal and visual signals, as well as through tactile communication in the form of social grooming. Most groups are multi-male and multi-female, with more females than males, and there is a marked dominance hierarchy, with all males dominant over the females (5). Breeding activity is likely to peak between February and June, when there is an abundance of seasonal fruits, and a single infant is born after an estimated gestation period of around 210 days (5). Females reach maturity at around five years of age, and probably breed every two years (5).
The red-shanked douc suffers from intense levels of hunting for food and for use in traditional ‘medicines’, as well as capture for the live pet trade (1) (5) (7). Although laws exist to protect this species from hunting throughout its range, such protective legislation is rarely enforced (1). This rare primate is particularly vulnerable to this exploitation as when disturbed it remains motionless in the canopy instead of fleeing, making it an easy hunting target (1) (5). It has also suffered from extensive habitat loss, particularly in the Central Highlands of Vietnam, where large tracts of forest were damaged during wartimes (1) (8). More recently, a rapidly expanding human population in this region has resulted in agricultural expansion, with forest areas converted to farmlands, and increased logging for coffee, rubber and cashew plantations (1) (5).
The red-shanked douc is afforded the highest level of protection in Vietnam under the Wildlife Protection Law, and should be protected from international trade by its listing on Appendix I of the Convention on International Trade in Endangered Species (CITES) (3) (8). It also receives a degree of protection in a number of national parks and reserves, including several in the Nam Theum basin in Lao PDR, which is thought to support the largest remaining population of the species, although hunting is still prevalent in many protected areas (7). There is also an ongoing captive-breeding programme for the red-shanked douc at the Endangered Primate Rescue Center at Cuc Phuong National Park in Vietnam (9). In addition, the Douc Langur Foundation has been undertaking comprehensive surveys of this species in an effort to understand the distribution of populations, which is vital for any successful conservation programme. The Foundation’s studies are also helping to uncover greater knowledge of this still poorly understood primate, such as group size and composition, and social interactions (10). WWF’s Indochina Programme is also carrying out vital research into the effectiveness of national parks within Vietnam and trains reserve rangers in primate survey techniques (11). The effective enforcement of existing laws and national parks will be the key to ensuring the future of this attractive and appealing primate (7).
To find out more about primate conservation, see:
The IUCN/SSC Primate Specialist Group:
Authenticated (20/11/10) by Matthew Richardson, primatologist and author.
- Agouti: the alternation of light and dark bands of colour in the fur of various animals, producing a grizzled appearance.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Evergreen forest: forest consisting mainly of evergreen trees, which retain leaves all year round. This is in contrast to deciduous trees, which completely lose their leaves for part of the year.
- Gestation: the state of being pregnant; the period from conception to birth.
IUCN Red List (August, 2010)
- Richardson, M. (2010) Pers. comm.
CITES (August, 2010)
- Macdonald, D.W. (2006) The Encyclopedia of Mammals. Oxford University Press, Oxford.
- Nadler, T., Momberg, F., Dang, N.X. and Lormee, N. (2003) Leaf Monkeys: Vietnam Primate Conservation Status Review 2002 – Part 2. Fauna and Flora International Vietnam Program and Frankfurt Zoological Society, Hanoi, Vietnam.
Primate Info Net – Douc langurs (August, 2010)
- Timmins, R.J. and Duckworth, J.W. (1999) Status and conservation of douc langurs (Pygathrix nemaeus) in Laos. International Journal of Primatology, 20: 469-489.
- Nadler, T., Thanh, V.N. and Streicher, U. (2007) Conservation status of Vietnamese Primates. Vietnamese Journal of Primatology, 1: 7-26.
The Endangered Primate Rescue Centre (August, 2010)
Douc Langur Foundation (August, 2010)
WWF (August, 2010)