Rhinoceros

Rhinoceros Temporal range: Eocene–Present PreꞒ Ꞓ O S D C P T J K Pg N
Rhinoceros species of different genera; from top-left, clockwise: white rhinoceros (Ceratotherium simum), Sumatran rhinoceros (Dicerorhinus sumatrensis), Indian rhinoceros (Rhinoceros unicornis), black rhinoceros (Diceros bicornis)
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Perissodactyla
Superfamily:	Rhinocerotoidea
Family:	Rhinocerotidae Owen, 1845
Type genus
Rhinoceros Linnaeus, 1758
Extant and subfossil genera
Ceratotherium Dicerorhinus Diceros Rhinoceros †Coelodonta †Stephanorhinus †Elasmotherium Fossil genera, see text
Rhinoceros range

A rhinoceros (/raɪˈnɒsərəs/; from Ancient Greek ῥινόκερως (rhinókerōs) 'nose-horned'; from ῥίς (rhis) 'nose', and κέρας (kéras) 'horn';^[1] pl.: rhinoceros or rhinoceroses), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae; it can also refer to a member of any of the extinct species of the superfamily Rhinocerotoidea. Two of the extant species are native to Africa, and three to South and Southeast Asia.

Rhinoceroses are some of the largest remaining megafauna: all weigh at least one tonne in adulthood. They have a herbivorous diet, small brains 400–600 g (14–21 oz) for mammals of their size, one or two horns, and a thick 1.5–5 cm (0.59–1.97 in), protective skin formed from layers of collagen positioned in a lattice structure. They generally eat leafy material, although their ability to ferment food in their hindgut allows them to subsist on more fibrous plant matter when necessary. Unlike other perissodactyls, the two African species of rhinoceros lack teeth at the front of their mouths; they rely instead on their lips to pluck food.^[2]

Rhinoceroses are killed by poachers for their horns, which are bought and sold on the black market for high prices, leading to most living rhinoceros species being considered endangered. The contemporary market for rhino horn is overwhelmingly driven by China and Vietnam, where it is bought by wealthy consumers to use in traditional Chinese medicine, among other uses. Rhino horns are made of keratin, the same material as hair and fingernails, and there is no good evidence of any health benefits.^[3][4][5] A market also exists for rhino horn dagger handles in Yemen, which was the major source of demand for rhino horn in the 1970s and 1980s.^[6]