What Is a Yak? 8 Spectacular Facts About Yaks

Yaks are big, hardy herbivores whose past — and future — is closely linked with ours.

yak standing in grass with mountains in the background
Humans have relied on yaks for thousands of years.

SakSa/Shutterstock

The yak is a large, long-haired, long-horned bovid from the Himalayas, where it has long played a key role in the region's ecology and human culture.

Yaks' hardiness and simple diets of grass have made them popular pack animals, companions, and sources of food and fabric for centuries. And their popularity as livestock is now spreading around the world, as people look for alternatives to traditional livestock like cows. So it's worth learning a bit more about the yak and its place in history.

1. There Are 2 Different Yak Species

wild yak in the Himalayas
Wild yaks are massive, with some males weighing more than 2,000 pounds (900 kg). aleksander hunta/Shutterstock

The wild yak (Bos mutus) is now commonly seen as a separate species from the domestic yak (Bos grunniens). Like a number of bovine species, they likely descended from aurochs, an extinct species of large cattle. Yaks probably split from aurochs between 1 million and 5 million years ago.

A key difference between wild and domestic yaks is size. Domesticated yaks are normally smaller than wild yaks, with males weighing 600 to 1,100 pounds (300 to 500 kilograms) and females weighing 400 to 600 pounds (180 to 270 kg). A male wild yak can weigh more than 2,000 pounds (900 kg). For comparison, an average male cow tops out at around 1,500 pounds (680 kg).

2. Wild Yaks Were Domesticated Around 5,000 Years Ago

domesticated yak
Yaks and humans have a long history in Asia. Arijeet Bannerjee/Shutterstock

The Qiang people lived along the Tibetan Plateau borderlands, near Qinghai Lake, and they are considered to be responsible for the domestication of the yak. Records from the Han dynasty indicate the Qiang had a "Yak state" from 221 B.C. to 220 A.D. This "state" was a trade network that predated the Silk Road. Genetic testing supports this domestication time frame.

The domesticated yak is an incredibly useful animal for humans. It works as a pack animal, and its body can provide meat that's leaner than cow beef, as well as clothing and fabric for shelters and ropes.

3. Yak Milk May Be a Superfood

yak butter tea
Yak butter tea is a high-calorie beverage that lots of communities enjoy. D. Pimborough/Shutterstock

Few parts of a yak are wasted in the highlands of Asia, and this is particularly true of its milk. In 2008, the China Nutrition Society (a research institute backed by the country's Ministry of Health) declared yak milk to contain more amino acids, calcium, and vitamin A than cow milk. According to a 2011 study published in the International Journal of Molecular Sciences, "Yak milk is called natural concentrated milk because of its high fat (5.5-7.5%), protein (4.0-5.9%) and lactose (4.0-5.9%) content during the main lactating period."

Yak butter is the key ingredient in yak butter tea. Made using black tea and salt, the tea is topped off with a helping of butter to add some healthy fats and calories.

4. Yaks Can Handle Temperatures as Low as Minus 40 Degrees

yaks standing in snow in mountains
Yaks have several adaptations for living in frigid weather. ​Darya Sysoeva/EyeEm/Getty Images

All that hair isn't just cosmetic. Yaks evolved to endure bitterly cold winters on the Tibetan Plateau, largely with a thick fleece of coarse outer hair and an undercoat of fine down. Yaks also prepare for winter by adding fat, and their thick skin helps them retain body heat. According to the U.N. Food and Agriculture Organization (FAO), yaks can survive in ambient temperatures as low as minus 40 degrees Celsius.

On the other hand, yaks' sweat glands are mostly not functional, the FAO adds, which is one reason why yaks don't fare well in hot weather.

5. Yak Be Nimble, Yak Be Quick

yak running
Yaks are capable runners and more sure-footed than their size suggests. Ai Ge/EyeEm/Getty Images

Yaks are nimbler than they appear. Not only are domesticated yaks used as racing animals at traditional festivals in some countries, but their wild relatives are also capable of impressive agility for such large creatures.

They are sure-footed enough to walk freely in mountainous areas where horses and sheep can't tread, according to the FAO, and they don't panic like a horse might when they start to sink in a marsh. Instead, they spread out their legs and plod forward with a swimming-like motion until they get free. They can also swim across rapids in a river, and are so adept at trudging through snow that they can help clear paths for people, the FAO adds, "like a biological snow plough."

6. Domestic Yaks Are Thriving While Wild Yaks Are Dying Out

domesticated yaks in the Himalayas
Domesticated yaks have a sizable population in the Himalayas. Guillaume Baviere/Wikimedia Commons/CC BY-SA 2.0

The wild yak, once widespread in the Tibetan Plateau, is considered threatened on the International Union for Conservation of Nature's Red List, with only an estimated 7,500 to 10,000 mature individuals left in the wild.

Domesticated yaks, however, are prevalent across much of the world. An estimated 14 million to 15 million live in the highlands of Asia alone.

7. Yak Ranching Is on the Rise in North America

yaks grazing on tall grass
Yaks are native to Asia, but yak ranching has also expanded to other parts of the world, including North America. Perfect Lazybones/Shutterstock

Yaks may be native to the Himalayas, but they no longer appear only in Asia. While there were only about 600 yaks in North America 30 years ago, according to Kansas State Research and Extension, the continent is now home to at least 5,000 registered yaks, and possibly many more.

Yaks only eat about a third of what cows eat, according to some advocates of yak ranching, and despite their heft, they're known for causing less damage to the environment as they forage. These massive animals have surprisingly small, nimble hooves, resulting in less trampling damage. They can also be more self-reliant than cattle, are relatively disease-resistant, and have a reputation for being calm and docile, lacking the sometimes troublesome demeanor of bison.

8. Yak Fiber Is the New Cashmere

hats made from yak fiber
Yak fiber can be used in a variety of products. Kondoruk/Shutterstock

Cashmere comes from Mongolian goat hair. These large herds of goats can be hard on the grassland environment, however, trampling the ground in a way that may add to the existing threat of desertification driven by climate change. Yaks reportedly have a lighter footprint overall, and their hair is as soft and as warm as cashmere, according to boosters of the fiber. While yak fiber has been used for thousands of years in Asia, getting it to clothing stores in the West has been more challenging.