RHINOCEROS, the name for such perissodactyle mammals (see PERISSODACTYLA) as bear one or two median horns on the head, and for their extinct relatives. Rhinoceroses are large, massively built animals, with little intelligence and a bad temper. The horns, which are composed of modified hairs, are borne on the nose and are used as weapons. The animals are dull of sight, but their hearing and scent are very acute. They are vege tarian in diet and largely nocturnal. The skin is very thick and tough. In the Miocene and Pliocene, rhinoceroses inhabited both eastern and western hemispheres, but they are now restricted to tropical Africa and Asia. An interesting feature is that the horn appears to have been independently evolved in several separate groups of rhinoceroses. Living forms fall into three sub-genera : (I) With a single nasal horn and the thick skin raised into folds on the shoulders and thighs. There are two species. The Indian rhinoceros (Rhinoceros unicornis), standing 5-54ft. high at the shoulder, with a horn 'ft. in length, is now confined to the Assam plain. The Javan rhinoceros (R. sondaicus) is smaller and in the female the horn is often absent. It inhabits Bengal, Burma, the Malay peninsula, Java, Sumatra and Borneo. It prefers hilly forests. (2) With a large nasal and a small frontal horn and the
skin not thrown into folds. The only species is the Sumatran rhinoceros (R. [Dicerorhinus] sumatrensis) with the same range as the Javan species, except that it does not extend into Java. It reaches a height of 42f t. and inhabits hilly forests. A form with hairy ears and skin is regarded as a local race. (3) With two horns, no skin folds and no lower incisors. This group (Diceros) is confined to Africa and comprises two species. The black rhinoceros (R. [Di bicor nis) is the smaller, weighing just over a ton, with a pointed,prehen sile upper lip. It inhabits Africa south of Abyssinia, though in re duced and diminishing numbers, dwelling in the wooded, watered districts. The white rhinoceros (R. [D.] simus) is the largest living land mammal except the elephant and feeds largely on grass. It now inhabits only a re serve in Zululand and the Lado enclave on the Upper Nile. It may stand 5f t. 8in. at the shoulder and measure I 5ft. in length, but is very swift of foot. The flesh is said to be excellent to eat, especially in the autumn and winter.
The woolly rhinoceros (R. antiquitatis), which inhabited Europe, became extinct during the glacial epoch.