History of the Domestication of Cows and Yaks

How Cattle Came to Be Domesticated - Perhaps Four Times!

Painting of Aurochs and Horses at Lascaux Cave, France
HUGHES Herve© / Getty Images

According to archaeological and genetic evidence, wild cattle or aurochs (Bos primigenius) were likely domesticated independently at least twice and perhaps three times. A distantly related Bos species, the yak (Bos grunniens grunniens or Poephagus grunniens) was domesticated from its still-living wild form, B. grunniens or B. grunniens mutus. As domesticated animals go, cattle are among the earliest, perhaps because of the multitude of useful products they provide humans: food products such as milk, blood, fat, and meat; secondary products such as clothing and tools manufactured from hair, hides, horns, hooves and bones; dung for fuel; as well as load-bearers and for pulling plows. Culturally, cattle are banked resources, which can provide bride-wealth and trade as well as rituals such as feasting and sacrifices.

Aurochs were significant enough to Upper Paleolithic hunters in Europe to be included in cave paintings such as those of Lascaux. Aurochs were one of the largest herbivores in Europe, with the largest bulls reaching shoulder heights of between 160-180 centimeters (5.2-6 feet), with massive frontal horns of up to 80 cm (31 inches) in length. Wild yaks have black upward- and backward-curving horns and long shaggy black to brown coats. The adult males can be 2 m (6.5 ft) high, over 3 m (10 ft) long and can weigh between 600-1200 kilograms (1300-2600 pounds); females weigh only 300 kg (650 pounds) on average.

Domestication Evidence

Archaeologists and biologists are agreed that there is strong evidence for two distinct domestication events from aurochs: B. taurus in the near east about 10,500 years ago, and B. indicus in the Indus valley of the Indian subcontinent about 7,000 years ago. There may have been a third auroch domesticate in Africa (tentatively called B. africanus), about 8,500 years ago. Yaks were domesticated in central Asia about 7,000-10,000 years ago.

Recent mitochondrial DNA (mtDNA) studies also indicate that B. taurus was introduced into Europe and Africa where they interbred with local wild animals (aurochs). Whether these occurrences should be considered as separate domestication events is somewhat under debate. Recent genomic studies (Decker et al. 2014) of 134 modern breeds supports the presence of the three domestication events, but also found evidence for later migration waves of animals to and from the three main loci of domestication. Modern cattle are significantly different today from the earliest domesticated versions.

Three Auroch Domesticates

Bos taurus

The taurine (humpless cattle, B. taurus) was most likely domesticated somewhere in the Fertile Crescent about 10,500 years ago. The earliest substantive evidence for cattle domestication anywhere in the world is the Pre-Pottery Neolithic cultures in the Taurus Mountains. One strong strand of evidence of the locus of domestication for any animal or plant is genetic diversity: places that developed a plant or animal generally have high diversity in those species; places where the domesticates were brought in, have lesser diversity. The highest diversity of genetics in cattle is in the Taurus Mountains.

A gradual decline in overall body size of aurochs, a characteristic of domestication, is seen at several sites in southeastern Turkey, beginning as early as the late 9th at Cayonu Tepesi. Small-bodied cattle do not appear in archaeological assemblages in the eastern Fertile Crescent until relatively late (6th millennium BC), and then abruptly. Based on that, Arbuckle et al. (2016) surmise that domestic cattle arose in the upper reaches of the Euphrates river.

Taurine cattle were traded across the planet, first into Neolithic Europe about 6400 BC; and they appear in archaeological sites as far away as northeastern Asia (China, Mongolia, Korea) by about 5000 years ago.

Bos indicus (or B. taurus indicus)

Recent mtDNA evidence for domesticated zebu (humped cattle, B. indicus) suggests that two major lineages of B. indicus are currently present in modern animals. One (called I1) predominates in southeast Asia and southern China and is likely to have been domesticated in the Indus Valley region of what is today Pakistan. Evidence of the transition of wild to domestic B. indicus is in evidence in Harappan sites such as Mehrgahr about 7,000 years ago.

The second strain, I2, may have been captured in East Asia, but apparently was also domesticated in the Indian subcontinent, based on the presence of a broad range of diverse genetic elements. The evidence for this strain is not entirely conclusive as of yet.

Possible: Bos africanus or Bos taurus

Scholars are divided about the likelihood of a third domestication event having occurred in Africa. The earliest domesticated cattle in Africa have been found at Capeletti, Algeria, about 6500 BP, but Bos remains are found at African sites in what is now Egypt, such as Nabta Playa and Bir Kiseiba, as long ago as 9,000 years, and they may be domesticated. Early cattle remains have also been found at Wadi el-Arab (8500-6000 BC) and El Barga (6000-5500 BC). One significant difference for taurine cattle in Africa is a genetic tolerance to trypanosomosis, the disease spread by the tsetse fly which causes anemia and parasitemia in cattle, but the exact genetic marker for that trait has not been identified to date.

A recent study (Stock and Gifford-Gonzalez 2013) found that although genetic evidence for African domesticated cattle is not as comprehensive or detailed as that for other forms of cattle, what there is available suggests that domestic cattle in Africa are the result of wild aurochs having been introduced into local domestic B. taurus populations. A genomic study published in 2014 (Decker et al.) indicates that while considerable introgression and breeding practices have altered the population structure of modern day cattle, there is still consistent evidence for three major groups of domestic cattle.

Lactase Persistence

One recent strain of evidence for the domestication of cattle comes from the study of lactase persistence, the ability to digest milk sugar lactose in adults (the opposite of lactose intolerance). Most mammals, including humans, can tolerate milk as infants, but after weaning, they lose that ability. Only about 35% of people in the world are able to digest milk sugars as adults without discomfort, a trait called lactase persistence. This is a genetic trait, and it is theorized that it would have selected for in human populations that had ready access to fresh milk.

Early Neolithic populations who domesticated sheep, goats and cattle would not have yet developed this trait, and probably processed the milk into cheese, yogurt, and butter prior to consuming it. Lactase persistence has been connected most directly with the spread of dairying practices associated with cattle, sheep, and goats into Europe by Linearbandkeramik populations beginning about 5000 BC.

And a Yak (Bos grunniens grunniens or Poephagus grunniens)

The domestication of yaks may well have made human colonization of the high Tibetan Plateau (also known as Qinghai-Tibetan Plateau) possible. Yaks are extremely well adapted to the arid steppes at high elevations, where low oxygen, high solar radiation, and extreme cold are common. In addition to the milk, meat, blood, fat, and pack energy benefits, perhaps the most important yak byproduct in the cool, arid climate is dung. The availability of yak dung as a fuel was a critical factor in allowing for the colonization of the high region, where other fuel sources are lacking.

Yaks possess large lungs and hearts, expansive sinuses, long hair, thick soft fur (very useful for cold-weather clothing), and few sweat glands. Their blood contains a high hemoglobin concentration and red blood cell count, all of which make cold adaptations possible.

Domestic Yaks

The main difference between wild and domestic yaks is their size. Domestic yaks are smaller than their wild relatives: adults are generally no more than 1.5 m (5 ft) tall, with males weighing between 300-500 kg (600-1100 lbs), and females between 200-300 kg (440-600 lbs). They have white or piebald coats and lack gray-white muzzle hairs. They can and do interbreed with wild yaks, and all yaks have the high altitude physiology they are prized for.

There are three types of domestic yaks in China, based on morphology, physiology, and geographical distribution:

  • a valley type distributed in the valleys of north and east Tibet, and some parts of Sichuan and Yunnan provinces;
  • a plateau grassland type mainly found in the high, cold pastures and steppes that maintain an annual average temperature below 2 degrees centigrade;
  • and white yaks found in almost every region in China.

Domesticating the Yak

Historical reports dated to the Chinese Han Dynasty state that yaks were domesticated by the Qiang people during the Longshan culture period in China, about 5,000 years ago. The Qiang were ethnic groups who inhabited the Tibetan Plateau borderlands including Qinghai Lake. Han Dynasty records also say the Qiang people had a "Yak State" during the Han dynasty, 221 BC-220 AD, based on a highly successful trade network. Trade routes involving domestic yak were recorded beginning in the Qin dynasty records (221-207 BC)--predating and no doubt part of precursors to the Silk Road--and cross-breeding experiments with Chinese yellow cattle to create the hybrid dzo are described there as well.

Genetic (mtDNA) studies support the Han Dynasty records that yaks were domesticated on the Qinghai-Tibetan Plateau, although the genetic data does not allow definitive conclusions to be drawn about the number of domestication events. The variety and distribution of mtDNA are not clear, and it is possible that multiple domestication events from the same gene pool, or interbreeding between wild and domesticated animals occurred.

However, the mtDNA and archaeological results also blur the dating of the domestication. The earliest evidence for domesticated yak is from the Qugong site, ca. 3750-3100 calendar years ago (cal BP); and the Dalitaliha site, ca 3,000 cal BP near Qinghai Lake. Qugong has a large number of yak bones with an overall small stature; Dalitaliha has a clay figurine thought to represent a yak, the remnants of a wood-fenced corral, and fragments of hubs from spoked wheels. The mtDNA evidence suggests domestication took place as early as 10,000 years BP, and Guo et al. argue that the Qinghai lake Upper Paleolithic colonizers domesticated the yak.

The most conservative conclusion to draw from this is that yaks were first domesticated in northern Tibet, probably the Qinghai Lake region, and were derived from wild yak for the production of wool, milk, meat and manual labor, at least 5000 cal bp.

How Many Are There?

Wild yaks were widespread and abundant in the Tibetan Plateau up until the late 20th century when hunters decimated their numbers. They are now considered highly endangered with an estimated population of ~15,000. They are protected by law but still illegally hunted.

Domestic yaks, on the other hand, are abundant, an estimated 14-15 million in central highland Asia. The current distribution of yaks is from the southern slopes of the Himalayas to the Altai and Hangai Mountains of Mongolia and Russia. Approximately 14 million yaks live in China, representing about 95% of the world's population; the remaining five percent are in Mongolia, Russia, Nepal, India, Bhutan, Sikkim and Pakistan.