Sumatran rhinoceros

Physical description 

The Sumatran (or hairy) rhino is the smallest of the living rhinoceroses.

Characteristics include fringed ears, reddish-brown skin variably covered with long hair, and wrinkles around its eyes. Calves are born with a dense covering of hair which turns reddish brown in young adults and becomes sparse, bristly and almost black in older animals. 

The front horn is usually 25-80 cm long, while the posterior horn is usually quite small and often no more than 10 cm. 

Size: 2-4m long, 1-1.5m in height, 600-950kg

Colour: Reddish-brown

Living in lowland swamps and forests

Sumatran rhinos prefer lower altitudes, especially secondary forests where low-growing plants are more abundant. Their habitat ranges from lowland swamps to montane forests, with the species generally favouring forests with thick vegetation.

Social structure
In the wild, Sumatran rhinos live at low densities and are mostly solitary. Females are thought to be territorial and to avoid one another. Adults of both sexes regularly mark their ranges with scrapes, saplings, faeces, and urine.

Life cycle
Calves gain independence at 16-17 months and may join other juveniles before taking up a solitary lifestyle.

Females are thought to reach sexual maturity at 6-7 years while males reach sexual maturity at 10 years.

Life span is thought to be similar to other rhinos at around 35-40 years.

Breeding
Sumatran rhinos give birth to one calf at a time, every 3-4 years. Calves are born from October to May, which corresponds to the rainy season in the region.

Diet
The Sumatran rhino is a browser and feeds on fruit (especially wild mangoes and figs), leaves, twigs, and bark. Sometimes the animal will venture into cultivated crops to eat.

Population & distribution

Previous population & distribution
The Sumatran rhino once occurred widely from the foothills of the Himalayas in Bhutan and eastern India, through Myanmar, Thailand, possibly to Vietnam and China, and south through the Malay Peninsula, to the islands of Sumatra and Borneo.

There are two surviving subspecies:

• Western Sumatran rhinoceros (Dicerorhinus sumatrensis sumatrensis)
• Borneo (or eastern) Sumatran rhinoceros (Dicerorhinus sumatrensis harrissoni) 

Current population & distribution
The species is found now in small populations scattered through its former range.

The largest and possibly most viable populations are found in Sumatra. These populations are mainly confined to Gunung Leuser, Kerinci-Seblat and Bukit Barisan Selatan National Parks.

The Borneo subspecies is now possibly extinct in Sarawak (Malaysia) and Kalimantan (Indonesia), with perhaps fewer than 25 surviving in Sabah (Malaysia).

Recent evidence suggests that perhaps a few survive in Thailand along the border with Malaysia, in northern Myanmar, and possibly in India along the border with Myanmar.

Overall, Sumatran rhino numbers are thought to have at least halved between 1985 and 1995, with the total number of individuals now estimated at fewer than 200.

Potentially most endangered rhino
The Sumatran rhino competes with the Javan rhino for the unenviable title of most endangered rhino species. While surviving in greater numbers than the Javan rhino, Sumatran rhinos are more threatened by poaching. There is no indication that the population is stabilizing and just one captive female has reproduced in the last 15 years.

What are the main threats?

Habitat loss
Habitat loss due to forest conversion and subsequent disturbance is threatening to push the Sumatran rhino towards extinction. Most populations are very small and in fact may not be viable, and changes in land use destroy dispersion corridors.

Bukit Barisan Selatan National Park, Sumatra, Indonesia - which is now estimated to have the largest single population of Sumatran rhinos - is still losing forest cover due to conversion of forest for coffee and rice by illegal settlers.

Sumatran rhinos are known to use logged areas where there is an abundance of regenerating plants. However, the construction of logging roads makes areas more accessible to poachers. While it is desirable to retain large tracts of undisturbed habitat for rhino conservation, it may not be possible to stop logging in all places (e.g. forest concessions in Sabah).

Thus WWF would like to see such logging taking place in a controlled and sustainable manner.

• More on habitat loss and degradation

Poaching
The 1970s saw increased demand for horn from prosperous Asian communities. Horn is used in traditional Asian medicine for the treatment of a variety of ailments ranging from epilepsy, fevers and strokes to AIDS. Although hunting is now illegal, poaching continues.

Even though the use of rhino horn in traditional medicine is banned in most countries, investigations by TRAFFIC and WWF reveal that use of rhino horn in traditional medicine still persists in many countries.

• More on wildlife trade

Genetic loss
No single Sumatran rhino population is estimated to have more than 75 individuals, making them extremely vulnerable to extinction due to natural catastrophes, diseases, poaching, political disturbances, and genetic drift. The biology of the Sumatran rhino is poorly understood and techniques for estimating their numbers are not fully developed.

How you can help

• Don't buy rhino horn products. Illegal trade in rhino horn is a continuing problem, posing one of the greatest threats to rhinos today.
  
  
• Use and support sustainable wood, paper and palm oil. By purchasing certified sustainable palm oil and FSC-certified forest products, retailers, traders, and manufacturers help protect Sumatran rhino habitat by limiting illegal logging and forest conversion to oil palm plantations. Consumers can also help by demanding certified products.
   
• Adopt a Sumatran rhino through WWF-US.
   
• Donate to WWF to support the Asian Rhino and Elephant Action Strategy.
   
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