Rhinoceros — The Rhinoceros often colloquially abbreviated rhino, is one of only five surviving species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia. Three of the five species—the (Javan, Sumatran and Black Rhinoceros)—are critically endangered. The Indian is endangered, with fewer that 2500 individuals remaining in the wild. The White is registered as Vulnerable, with roughly 14,500 remaining in the wild.
The rhinoceros family is characterised by large size (one of the few remaining megafauna alive today) with all of the species capable of reaching one ton or more in weight; herbivorous diet; and a thick protective skin, 1.5–5 cm thick, formed from layers of collagen positioned in a lattice structure; relatively small brains for mammals this size (400–600g); and its large horn. They generally eat leafy material, although their ability to ferment food in their hindgut allows them to subsist on more fibrous plant matter, if necessary. Unlike other perissodactyls, the African species of rhinoceros lack teeth at the front of their mouths, relying instead on their powerful premolar and molar teeth to grind up plant food.
The White Rhinoceros or Square-lipped Rhinoceros (Ceratotherium simum) is, behind the elephant, probably the most massive remaining land animal in the world, along with the Indian Rhinoceros which is of comparable size and some male hippopotamuses. There are two subspecies of White Rhinos; as of 2005, South Africa has the most of the first subspecies, the Southern White Rhino (Ceratotherium simum simum). The population of southern white rhinos is about 14,500, making them the most abundant subspecies of rhino in the world, and the White Rhino the most abundant species.
The name of the species was chosen to distinguish it from the White Rhinoceros (Ceratotherium simum). This can be confusing, as those two species are not really distinguishable by colour. There are four subspecies of black rhino: South-central (Diceros bicornis minor), the most numerous, which once ranged from central Tanzania south through Zambia, Zimbabwe and Mozambique to northern and eastern South Africa; South-western (Diceros bicornis bicornis) which are better adapted to the arid and semi-arid savannas of Namibia, southern Angola, western Botswana and western South Africa; East African (Diceros bicornis michaeli), primarily in Tanzania; and West African(Diceros bicornis longipes) which was tentatively declared extinct in 2006.
The Indian Rhinoceros or the Great One-horned Rhinoceros (Rhinoceros unicornis) is found in Nepal and in Assam, India. The rhino once inhabited areas from Pakistan to Burma and may have even roamed in China. But because of human influence their range has shrunk and now they only exist in small populations in northeastern India and Nepal. It is confined to the tall grasslands and forests in the foothills of the Himalayas.
The Indian Rhinoceros has thick, silver-brown skin which creates huge folds all over its body. Its upper legs and shoulders are covered in wart-like bumps, and it has very little body hair. Its size is comparable to that of the White Rhino in Africa. Fully grown males are larger than females in the wild, weighing from 2200–3000 kg (4,800–6,600 lb). Female Indian rhinos weigh about 1600 kg. The Indian Rhino is from 5.7–6.7 feet tall and can be up to 13 feet long. The record-sized specimen of this rhino was approximately 3500 kg. The Indian Rhino has a single horn that reaches a length of between 20 and 101 cm. They are approximately the same size as white rhinos.
The Javan Rhinoceros (Rhinoceros sondaicus) is one of the rarest and most endangered large mammals anywhere in the world. According to 2002 estimates, only about 60 remain, in Java (Indonesia) and Vietnam. Of all the rhino species, the least is known of the Javan Rhino. These animals prefer dense lowland rain forest, tall grass and reed beds that are plentiful with large floodplains and mud wallows. Though once widespread throughout Asia, by the 1930’s the rhinoceros was nearly hunted to extinction in India, Burma, Peninsular Malaysia, and Sumatra for the medical powers of its horn and blood.
The Sumatran Rhinoceros (Dicerorhinus sumatrensis) is the smallest extant rhinoceros species, as well as the one with the most fur, which allows it to survive at very high altitudes in Borneo and Sumatra. Due to habitat loss and poaching, its numbers have declined and it is one of the world’s rarest mammals. About 300 Sumatran Rhinos are believed to remain.