犀牛 Rhinoceros

犀牛是犀科（学名：Rhinocerotidae）动物的總稱，属哺乳纲奇蹄目，主要分佈於非洲和東南亞。是最大的奇蹄目动物，也是仅次于大象体型大的陆地动物。所有的犀牛基本上都是腳短和身体粗壮。体肥笨拙，体长2.2～4.5米，肩高1.2～2米；体重2800～3000公斤，皮厚粗糙，并于肩腰等处成褶皱排列；毛被稀少而硬，甚至大部无毛；耳呈卵圆形，头大而长，颈短粗，长唇延长伸出；头部有实心的独角或双角（有的雌性无角），起源于真皮，角脱落仍能复生；无犬齿；尾细短，身体呈黄褐、褐、黑或灰色。^[1]

現存的4属5种的犀牛除白犀牛外，都瀕臨絕種，其中以爪哇犀牛的數目最少，約50頭左右；而黑犀牛也只有约1萬到3萬頭。

Rhinoceros (/raɪˈnɒsərəs/), often abbreviated as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to Southern Asia.

Members of the rhinoceros family are characterized by their large size (they are some of the largest remaining megafauna, with all of the species able to reach one tonneor more in weight); as well as by an herbivorous diet; 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 (400–600 g); and a 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 two African species of rhinoceros lack teeth at the front of their mouths, relying instead on their lips to pluck food.^[1]

Rhinoceros are killed by humans for their horns, which are bought and sold on the black market, and which are used by some cultures for ornamental or traditional medicinal purposes. East Asia, specifically Vietnam, is the largest market for rhino horns. By weight, rhino horns cost as much as gold on the black market. People grind up the horns and then consume them believing the dust has therapeutic properties.^[2] The horns are made of keratin, the same type of protein that makes up hair andfingernails.^[3] Both African species and the Sumatran rhinoceros have two horns, while the Indian and Javan rhinoceros have a single horn.

The IUCN Red List identifies three of the species as critically endangered.