Indian rhinoceros  (Rhinoceros unicornis)

The Indian rhinoceros is the largest of the Asian rhinos (4). It has a single horn, which can be as long as 53 centimetres (5) and, like all rhino horns, is composed of keratin rather than bone (6). The skin is grey-brown and has many loose folds and tubercles, giving an armour-plated appearance. Indian rhinoceroses are often accompanied by ‘tick birds' (several species, including myna birds) and egrets that ride on their backs, which are thought to feed on parasites between the folds of skin. Egrets also forage on the insects exposed by the moving feet of the rhino. Males have large, sharp incisors that may be used in fights over females in the breeding season (7).

Previously found throughout the northern Indian sub-continent. Scattered populations now occur only in northeast India, Bhutan and Nepal (1).

These rhinos preferentially inhabit floodplain grasslands and adjacent swamps and forests but recent habitat loss has forced them into more cultivated land (2).

Indian rhinos are solitary except when calves accompany their mothers (5). A calf remains with its mother until the birth of the next calf (6), when it is chased away (5). Females reach sexual maturity between five and seven years of age and give birth to a single calf about once every three years (4). Males tolerate intruders in their range except during the breeding season when fights over females can be fierce, and may even end in death where population densities are high (5).

These rhinos are grazers, feeding preferentially on tall grasses, although they also eat other vegetation including leaves, fruit and aquatic plants. They feed in the cool of the evening or early morning. The prehensile lip is used to pluck at grass stems (5). The Indian rhino is more aquatic than most other rhinoceros species, readily swimming and wading (7).

The Indian rhinoceros was already considered a ‘vanishing race' by the beginning of the 20th century, primarily due to the conversion of alluvial plain grassland to cultivated fields (6). Hunting, for sport and as pest control, was also a factor in the decimation of the population. Despite protection measures, poaching remains a serious threat today due to the demand for rhino horn in Oriental medicine; in 1994 for example, a kilogram of rhino horn was worth approximately US$60,000 (8).

The Indian rhinoceros has been brought back from the brink of extinction by a sustained conservation effort and numbers have increased from a few hundred individuals in the 1950s to over 2,000 today (6). The population is concentrated in protected reserves, and both Indian and Nepalese Wildlife Authorities have adopted schemes that involve protecting the species with armed troops; one population in Nepal is protected by 700-armed guards (5). Managed breeding is a successful tool in India and translocations have also been used to move animals from areas where they have become too numerous to other protected reserves (9). Priorities of the Asian Rhino Action Plan include the increase and maintenance of protection zones and sanctuaries and the halting of illegal trade (10). Of the three Asian rhinos, the survival of the Indian species may be the most promising, especially if local people can become directly involved.

For more information on the Indian rhinoceros see:

• International Rhino Foundation:
  www.rhinos-irf.org/
• The Rhino Resource Centre:
  www.rhinoresourcecenter.com/species/indian-rhino/
• Foose, T.J. and Van Strien, N. (1997) Asian Rhino Status Survey and Conservation Action Plan. IUCN, Gland, Switzerland and Cambridge, U.K.
  www.iucn.org/dbtw-wpd/edocs/1997-005.pdf

Authenticated (04/04/05) by Peter Grubb, Natural History Museum, London.