Yak
The yak is a long haired bovine of the Tibetan Plateau and the high mountains of Asia, and one of the few large animals that can live and work above 4,000 meters. This page covers the domestic yak, Bos grunniens, which was tamed on the plateau roughly 7,000 years ago from the wild yak, Bos mutus. A thick double coat of long outer hair and soft down, large lungs and heart, and few sweat glands let it shrug off winters far below freezing and thin mountain air, while broad hooves keep it steady on snow and rock. Herds graze alpine meadows and steppe, moving with the seasons between summer pastures and sheltered winter valleys. About 14 million yaks are kept today, the great majority in China, with smaller herds in Mongolia, Nepal, Bhutan, India, Pakistan, Kyrgyzstan, Tajikistan, Afghanistan and southern Siberia in Russia. They give milk, butter, cheese, meat, wool, leather and dung for fuel, and carry loads on trails where trucks and horses cannot go. Their wild ancestor survives in much smaller numbers on the remote Chang Tang and is listed by the IUCN as Vulnerable, with fewer than 10,000 mature animals.
What is a yak? Domestic and wild yaks
A yak is a member of the cattle family that lives in the high, cold mountains of Asia. There are two kinds. The domestic yak, Bos grunniens, is the one people see on treks in Nepal, in Tibetan villages and on the steppes of Mongolia. Its wild ancestor, Bos mutus, is a bigger, darker animal that survives only in remote parts of the Tibetan Plateau. Genetic studies suggest that people on the Qinghai Tibet Plateau first domesticated yaks around 7,300 years ago, and that herds then spread along trade routes into the Himalaya and Central Asia. The scientific name grunniens means grunting, because yaks grunt rather than moo. In Tibetan, the word yak refers to the male, while the female is called dri or nak, which is why Tibetans smile when visitors ask for yak milk or yak butter. Today about 14 million yaks are kept, around 13 million of them in China, where Qinghai and Tibet hold the largest herds. Yaks can breed with cattle, and the hybrids, called dzo or dzomo in Nepal and Bhutan, are prized as strong work animals at middle altitudes. Despite their shaggy look, yaks are close relatives of bison and of domestic cattle.
How big is a yak? Size, weight, horns and colors
Yaks are large animals, but the wild and domestic forms differ a lot. Wild yak bulls are among the biggest bovines in Asia. They stand about 160 to 205 cm at the shoulder and usually weigh 500 to 1,000 kg, with exceptional bulls said to reach 1,200 kg, while wild females weigh only about a third as much as the bulls. Domestic yaks are much smaller and lighter. Males usually weigh about 350 to 580 kg, and females around 225 to 255 kg, so a domestic yak is often lighter than a dairy cow, though its long hair makes it look bigger. Both have a high hump over the shoulders, a low head and short, sturdy legs. The horns are long, smooth and curved, growing out to the sides and then up, and they are larger in males. Some domestic yaks have no horns at all. Wild yaks are almost always blackish brown, with a pale muzzle and gray hair around it, and a rare golden brown form lives in parts of Tibet. Domestic yaks come in many colors: black, brown, gray, white and patched black and white, the look behind searches for the black and white yak. The long skirt of hair that hangs from the belly almost reaches the ground.
Where do yaks live?
Yaks live on the Tibetan Plateau and the high mountains around it, mostly between about 3,000 and 5,500 meters, and wild yaks go even higher, from about 4,000 to 6,100 meters. China holds by far the most. The province of Qinghai has about 4.9 million yaks and Tibet about 3.9 million, and large herds also live in western Sichuan, Gansu, Xinjiang and northern Yunnan. Mongolia has the second largest population, kept mainly in the Khangai and Khövsgöl mountains, with a smaller share in the Mongolian Altai of the far west. In the Himalaya, yaks are raised in the high valleys of Nepal, around the Everest region, Dolpo and Mustang, in northern Bhutan by the Layap and Brokpa herders, and in India in Ladakh, Sikkim, Arunachal Pradesh and the high parts of Himachal Pradesh. Pakistan has smaller herds in Gilgit Baltistan, in valleys near the Karakoram such as Shimshal. Farther north and west, yaks graze the Tian Shan of Kyrgyzstan, which had about 67,000 at the end of 2025, the eastern Pamir of Tajikistan around Murghab, the Wakhan Corridor and Afghan Pamir, and Tuva and the Altai Republic in southern Siberia. Yaks prefer open alpine grassland, meadows, wet sedge marshes and cold steppe, and they handle snow and wind far better than heat. Below about 3,000 meters they suffer in warm weather, which is why herders move them up the mountains in summer and down to sheltered valleys only in winter. The wild yak lives in a much smaller area, described in its own section below.
The wild yak: how many are left?
The wild yak, Bos mutus, once roamed widely across the Tibetan Plateau and nearby ranges, but today it survives in a much smaller area. Its stronghold is the Chang Tang, the high, empty plateau of northern Tibet, together with Hoh Xil in Qinghai and the Arjin Shan in Xinjiang, where herds live between about 4,000 and 6,100 meters. India has a tiny population in eastern Ladakh, around the Chang Chenmo valley, estimated at only a few dozen animals. The IUCN lists the wild yak as Vulnerable, in an assessment from 2014 published in 2016 and marked as needing an update, with an estimated 7,500 to 9,999 mature individuals and a decreasing trend. It considers the species extinct in Bhutan, and its presence in Nepal uncertain, although a small group was photographed in the Humla region in 2014. Hunting for meat drove the big decline of the twentieth century, and protection in large Chinese reserves has helped some herds recover. Other threats remain: domestic herds take over pastures, fences and roads cut through the plateau, wild bulls mix with domestic cows and dilute the wild gene pool, and diseases can pass from livestock. A rare golden form of the wild yak, with a reddish gold coat, lives in small numbers in parts of Tibet.
What do yaks eat?
Yaks are grazers that feed mainly on grasses, sedges and alpine herbs, adding mosses, lichens and low shrubs when better food runs short. In summer they fatten on the rich, fast growing pastures of the high meadows, gaining the reserves they will need for the long winter. When snow covers the ground, they use their muzzles and broad hooves to push it aside and reach the dry grass underneath, and they can lose a large part of their body weight by the end of a hard winter. Yaks have a wide mouth and a rough tongue that lets them graze very short grass close to the ground, and their digestive system gets more out of coarse, fibrous plants than that of most cattle. They eat snow or ice to get water when streams freeze. Wild yaks rely entirely on what the plateau provides and travel long distances between good grazing areas, while domestic herds are guided by herders between summer and winter pastures and sometimes receive hay or other fodder near winter camps. Because yaks can live on such poor food, herders can keep animals in places where cattle or horses would starve, and the yak's grazing helps shape the alpine grasslands of the region.
How do yaks survive the cold and thin air?
Living above 4,000 meters demands a body built for cold and low oxygen, and yaks have it. Their lungs and heart are large for their size, and their blood carries many small red blood cells with hemoglobin that holds oxygen well, so they can stay active in air with far less oxygen than at sea level. Genetic studies have found changes in genes linked to oxygen use and energy, similar to the ones that help Tibetan people live at altitude. Their coat has three layers: long, coarse outer hair that sheds snow and rain, a middle layer and a soft, dense down underneath, called khullu, which is one of the warmest natural fibers. In winter the down thickens, and in spring it is shed or combed out. A heavy skirt of hair on the belly and legs protects them when they lie on snow. Yaks have very few sweat glands and a thick layer of fat under the skin, which keep heat in but make them suffer when the weather turns warm. They are comfortable at temperatures far below freezing, but above about 15 degrees Celsius they become stressed. Broad, sure hooves let them climb steep, rocky and icy slopes, and they can wade or even swim across cold mountain rivers.
How yaks live: herds, grunts and calves
Yaks are social animals. Wild yaks live in herds of females and young that can number from a few animals to dozens, and sometimes more, while adult bulls live alone or in small bachelor groups for most of the year and join the females only in the breeding season. Domestic yaks keep much of this behavior: cows and calves stay together, and herders often use an experienced cow to lead the rest. Yaks are mostly quiet. Instead of mooing, they make low grunts, which gave the domestic yak its scientific name. Bulls also roar and wallow in dust or mud during the rut. Mating takes place in late summer and autumn, and after a pregnancy of about eight and a half to nine months, calves are born in spring or early summer, when the new grass appears. A cow usually has one calf every other year, because the hard winters leave little energy for breeding each year. Calves can stand and follow the herd within hours. When wolves or snow leopards come near, a herd of yaks bunches together with the calves in the middle and faces the threat with lowered horns, and an angry bull can charge with surprising speed. Domestic yaks generally live about 20 years, and some pass 25.
What are yaks used for? Milk, butter, wool and transport
For millions of people on the Tibetan Plateau and in the Himalaya, the yak is the animal that makes life possible. Dri milk is rich, with much more fat than ordinary cow's milk, and it is churned into butter for butter tea, the salty everyday drink of Tibet, and for the butter lamps that burn in monasteries. It is also made into yogurt and cheese, including chhurpi, a very hard dried cheese chewed for hours by herders and trekkers in Nepal, Bhutan and Sikkim. Yak meat is lean and is eaten fresh or dried in the cold, dry air. The coarse outer hair is woven into ropes, bags and the black tents of nomad families, while the soft down, khullu, is spun into very warm and expensive yarn. Hides become leather, and in the past they covered round boats used to cross rivers in Tibet. Dried dung is a key fuel on a treeless plateau, burned to cook and to heat homes. Yaks also carry loads: they haul supplies, tents and trade goods on high passes, and in Nepal they carry gear for treks and mountaineering expeditions in the Everest region. Festivals in Tibet and other yak regions include yak races, and dressed up yaks appear in dances and celebrations.
Where it is found
The Yak can be found in places such as:
