Poephagus grunniens

The domestic yak (Bos grunniens) is a long-haired domesticated bovid found throughout the Himalayan region of the Indian subcontinent, the Tibetan Plateau and as far north as Mongolia and Siberia. It is descended from the wild yak (Bos mutus). The English word 'yak' is a loan originating from Tibetan: .mw-parser-output .uchen{font-family:'Qomolangma-Dunhuang','Qomolangma-Uchen Sarchen','Qomolangma-Uchen Sarchung','Qomolangma-Uchen Suring','Qomolangma-Uchen Sutung','Qomolangma-Title','Qomolangma-Subtitle','Qomolangma-Woodblock','DDC Uchen','DDC Rinzin',Kailash,'BabelStone Tibetan',Jomolhari,'TCRC Youtso Unicode','Tibetan Machine Uni',Wangdi29,'Noto Sans Tibetan','Microsoft Himalaya'}.mw-parser-output .ume{font-family:'Qomolangma-Betsu','Qomolangma-Chuyig','Qomolangma-Drutsa','Qomolangma-Edict','Qomolangma-Tsumachu','Qomolangma-Tsuring','Qomolangma-Tsutong','TibetanSambhotaYigchung','TibetanTsugRing','TibetanYigchung'}གཡག་, Wylie: g.yag. In Tibetan and Balti it refers only to the male of the species, the female being called Tibetan: འབྲི་, Wylie: 'bri, or g.nag Tibetan: གནག in Tibetan and Tibetan: ཧཡག་མོ་, Wylie: hYag-mo in Balti. In English, as in most other languages that have borrowed the word, 'yak' is usually used for both sexes, with 'bull' or 'cow' referring to each sex separately. Yaks belong to the genus Bos and are therefore related to cattle (Bos primigenius species). Mitochondrial DNA analyses to determine the evolutionary history of yaks have been inconclusive. The yak may have diverged from cattle at any point between one and five million years ago, and there is some suggestion that it may be more closely related to bison than to the other members of its designated genus. Apparent close fossil relatives of the yak, such as Bos baikalensis, have been found in eastern Russia, suggesting a possible route by which yak-like ancestors of the modern American bison could have entered the Americas. The species was originally designated as Bos grunniens ('grunting ox') by Linnaeus in 1766, but this name is now generally only considered to refer to the domesticated form of the animal, with Bos mutus ('mute ox') being the preferred name for the wild species. Although some authors still consider the wild yak to be a subspecies, Bos grunniens mutus, the ICZN made an official ruling in 2003 permitting the use of the name Bos mutus for wild yaks, and this is now the more common usage. Except where the wild yak is considered as a subspecies of Bos grunniens, there are no recognised subspecies of yak. Yaks are heavily built animals with a bulky frame, sturdy legs, rounded cloven hooves, and extremely dense, long fur that hangs down lower than the belly. While wild yaks are generally dark, blackish to brown in colouration, domestic yaks can be quite variable in colour, often having patches of rusty brown and cream. They have small ears and a wide forehead, with smooth horns that are generally dark in colour. In males (bulls), the horns sweep out from the sides of the head, and then curve forward. They typically range from 48 to 99 cm (19 to 39 in) in length. The horns of females (cows) are smaller, only 27 to 64 cm (11 to 25 in) in length, and have a more upright shape. Both sexes have a short neck with a pronounced hump over the shoulders, although this is larger and more visible in males. Males weigh 350 to 585 kg (772 to 1,290 lb), females weigh 225 to 255 kg (496 to 562 lb). Wild yaks can be substantially heavier, bulls reaching weights of up to 1,000 kilograms (2,200 lb). Depending on the breed, domestic yak males are 111–138 centimetres (44–54 in) high at the withers, while females are 105–117 centimetres (41–46 in) high at the withers. Both sexes have long shaggy hair with a dense woolly undercoat over the chest, flanks, and thighs to insulate them from the cold. Especially in bulls, this may form a long 'skirt' that can reach the ground. The tail is long and horselike rather than tufted like the tails of cattle or bison. Domesticated yaks have a wide range of coat colours, with some individuals being white, grey, brown, roan or piebald. The udder in females and the scrotum in males are small and hairy, as protection against the cold. Females have four teats.