Sumatran rhinoceros  (Dicerorhinus sumatrensis)

The Sumatran rhinoceros is the smallest and most endangered of the five living rhinoceros species (2). It is possibly the world's most endangered large mammal; only one viable population remains in northern Sumatra (7). The squat, thick-statured body is a reddish-brown colour and may be covered with long hair (6), so much so that this species is also known as the 'hairy rhinoceros' (8). It is the only Asian rhinoceros to have two horns, although the posterior horn is much reduced and often absent in females (2). There are two deep skin folds that encircle the body, behind the front legs and in front of the hind legs (3).

The former range of the Sumatran rhinoceros extended from the foothills of the Himalayas, east to Vietnam and China, south along the Malay peninsular and into the islands of Sumatra and Borneo (2). Two subspecies persist, the Eastern Sumatran rhinoceros (Dicerorhinus sumatrensis harrissoni) historically found throughout Borneo may today number fewer than 50 individuals, all located within Sabah (6). The Western Sumatran rhinoceros (D. s. sumatrensis) is found in fragments of Peninsular Malaysia and on the Island of Sumatra in Indonesia (6), numbers are critically low here too and the only viable population is located within the Gunung Leuser National Park in northern Sumatra (7).

Found in a range of habitats from lowland secondary rainforest and swamps to mountain moss forests (4). Due to human pressures however, populations are today concentrated at higher altitudes (2).

Sumatran rhinoceros are a solitary and secretive species (5). They occupy home ranges that are marked conspicuously with faeces, urine and soil scrapes (3). Individuals reach sexual maturity at 6 to 8 years of age and births occur during the wet season, which runs from October to May (3). A single calf is born, and is weaned after around 16 months. The inter-birth interval is around 3 - 4 years (3).

Individuals spend the day in wallows, allowing the mud to cool their skin and protect it from drying out (5). Foraging occurs either at night or during the cool of the early morning and evening; young saplings constitute the preferred food and these trees are cut down and trampled on before being eaten (3). Essential minerals are obtained from salt licks and these are a requirement for each home range (4).

Numbers of the Sumatran rhinoceros are today worryingly low at fewer than 300 individuals (6). Hunting for medicinal properties associated with many parts of the body and particularly the horn, has occurred for centuries; although it is illegal today, poaching remains one of the principal causes of the declining population (2). Much of the lowland forest habitat of this rhinoceros has been lost due to intensive development and the small, fragmented populations that remain may be too small to be viable, with reduced genetic diversity and increased vulnerability to chance events (2).

The Sumatran rhinoceros is fully protected within its native countries and is listed on Appendix I of the Convention on International Trade in Endangered Species (CITES), which prohibits international trade (2). The extent of illegal trade that still occurs is investigated by TRAFFIC (the wildlife trade monitoring network of WWF and the IUCN), and replacements for rhinoceros horn in traditional medicine are being investigated (2). Existing reserves need to be expanded and habitat corridors and buffer zones created so that these rhinoceros can coexist with their human neighbours (2). In 1998, the World Wildlife Fund (WWF) launched the Asian Rhino and Elephant Action Strategy (AREAS), which aims to tackle this issue in key areas of the continent (9). Captive breeding programmes have proved unsuccessful in the past, but recent attempts to breed rhinoceros within sanctuaries in their natural habitat appear to be more encouraging (2).

The International Rhino Foundation:
http://www.rhinos-irf.org/rhinoinformation/sumatranrhino/index.htm
WWF:
http://panda.org/resources/publications/species/threatened/sumatranRhinoceros/index.cfm
TRAFFIC:
http://www.traffic.org/

This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact
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