Yak Scientific name:Bos grunniens

Yak
Scientific name:Bos grunniens
The word yak refers to the male of the species; a female is a dri or nak.Yak is a long-haired bovine found throughout the Himalaya in Nepal which is in region of south Central Asia.Wild yaks stand about two meters tall at the shoulder. Domestic yaks are about half that height. Both types have long shaggy hair to insulate them from the cold.The domesticated yak is smaller, with short horns; its coat, which may be long enough to reach the ground, may be black, brown, reddish, piebald, or albino.
Range and habitat
Wild yaks are found primarily in northern Tibet and western Qinghai, with some populations extending into the southernmost parts of Xinjiang, and into Ladakh in India. Small, isolated populations of wild yak are also found farther afield, primarily in western Tibet and eastern Qinghai. In historic times, wild yaks were also found in Nepal and Bhutan, but they are now considered extinct in both countries, except as domesticated animals.
Domesticated yaks are kept primarily for their milk and meat. They are also used as beasts of burden, transporting goods across mountain passes for local farmers and traders as well as in support of climbing and trekking expeditions.
Physical characteristics
Wild yaks are among the largest bovids, with males standing about 2 to 2.2 metres (6.6 to 7.2 ft) tall at the shoulder and weighing up to 1,000 kg and having a head and body length of 3 to 3.4 m (9.8 to 11 ft).The females weigh about one third of this and are about 30% smaller in their linear dimensions.
Domesticated yaks are much smaller. males weighing 350 to 580 kg and females 225 to 255 kg.
Yaks are heavily built animals with a sturdy frame, short legs, and rounded hooves. They have small ears and a wide forehead, with smooth hollow horns that are generally dark in colour. In males, the horns sweep out from the sides of the head, and then curve forward; they typically range from 48 to 99 centimetres (19 to 39 in) in length. The horns of females are smaller, only 27 to 64 centimetres (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 larger and more visible in males.
Hunting and diet
The diet of wild yaks consists largely of grasses and sedges, such as Carex, Stipa, and Kobresia. They also eat a smaller amount of herbs, winterfat shrubs, and mosses, and have even been reported to eat lichen.
 
Reproduction
Yaks mate in the summer, typically between July and September, depending on the local environment.Yak heifers can be bred as early as 18 months, and gestation is 258 days (8.5 months). Yak bulls are dependable for breeding at age three. Calving is usually real fast! Hardy yak calves grow quickly on the cow’s rich milk. Wild yaks usually calve every other year but domestic yaks, with access to plentiful pasture, reproduce every year, and occasionally have twins. Calves are weaned at one year and become independent shortly thereafter. Wild calves are initially brown in colour, and only later develop the darker adult hair.Females of both the wild and domestic forms typically give birth only once every other year, although more frequent births are possible if the food supply is good.

Predatory
The main natural predator of the wild yak has been the Tibetan wolf, but brown bears and snow leopards.
Life expectancy
Yaks may live for more than twenty years in domestication or captivity, although it is likely that this may be somewhat shorter in the wild.