Bos grunniens Linnaeus, 1766, and Bos mutus (Przewalski, 1883) are the domestic and wild forms, respectively, of the bovid commonly called the yak. B. mutus inhabits remote high-elevation alpine meadows and alpine steppe in rolling to mountainous terrain in the Tibetan Plateau, and B. grunniens is maintained widely in China and other parts of Central Asia, and uncommonly elsewhere in the world. Populations of B. mutus are substantially reduced and fragmented throughout its remaining range; the largest numbers occur in northern Tibet and western Qinghai. B. mutus is vulnerable because of poaching and competition with domestic livestock. Although no complete survey of B. mutus has been conducted, there are probably no more than 15,000 remaining in remote areas of the Tibetan Plateau; B. grunniens numbers about 14 million.
Bos Linnaeus, 1758
Urus Hamilton-Smith, 1827a:417. Type species Urus scoticus 52Hamilton-Smith, 1827, by monotypy; described as “the probable remains [= descendant] of the genuine Urus” and subsequently described as “a variety of fossil Bos urus” (Hamilton-Smith 1827b:376).
Bison: Jardine, 1836:259. First use as a genus.
Gauribos Heude, 1901:3. No type species selected; said to include G. laosiensis, G. brachyrhinus, G. sylvanus, and G. mekongensis.
Microbos Heude, 1901:7. No type species selected; said to include “Bos? leptoceros.”
Context and Content. Order Artiodactyla, suborder Ruminantia, family Bovidae, subfamily Bovinae, tribe Bovini, genus Bos. There are 5 species of Bos (Grubb 2005). Generally, mass and body measurements (e.g., height and length) overlap among species of Bos and do not provide suitable characteristics for a species key (Blanford 1888); for some species, domestication and crossbreeding have altered characteristics of the wild forms (e.g., no horns in domestic females). Color, pattern, and length of pelage, horn characteristics, and morphology were used to develop the following general key.
1. White rump patch on males and females; horns of males connected by a horn-patch on the foreheadB. javanicus
No white rump patch; horns of males not connected by a horn-patch on the forehead2
2. Long skirts of hair on chest, flanks, and rump; tail fully haired and horselike; 14 dorsal and 5 lumbar vertebrae and 14 ribsB. grunniens and B. mutus
Pelage usually short; no skirts; tail not fully haired but tufted on the end; 13 dorsal and 6 lumbar vertebrae and 13 ribs3
3. Concave forehead with gray mat of hair; pronounced shoulder hump in malesB. frontalis
Flat to slightly convex, smooth-haired forehead; generally without developed shoulder hump in males4
4. Adult pelage color always dark brown to black with white leggings; horns in both sexes; range now limited to Cambodia, if not extinctB. sauveli
Color highly variable among domestic breeds from black to white, reddish brown to brown; horns present or absent, particularly in females; under husbandry throughout the worldB. taurus
Bos grunniens Linnaeus, 1766 Domestic Yak
Bos mutus (Przewalski, 1883) Wild Yak
[Bos] grunniens Linnaeus, 1766:99. Type locality “Asia boreali;” first use of the current name combination and now considered the binomial for the domestic form (Gentry et al. 2004; International Commission on Zoological Nomenclature 2003).
[Bos?] corriculus von Schreber, 1789:? Vide Grubb (