According to archaeological and genetic evidence, wild cattle (Bos primigenius) were likely domesticated independently at least twice and perhaps three times. Cattle are terrifically useful forms of domesticates: they are useful for food, including milk, blood, and meat; for secondary products such as clothing and tools from hides, hoofs and bones; and for use as load-bearers and plows.
Archaeologists and biologists are fairly well agreed that there is strong evidence for two distinct domestication events: B. taurus in the near east, and B. indicus in the Indus valley of the Indian subcontinent. Recent mitochondrial DNA 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.
Three Cattle Domesticates
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, circa 10,500 BP. One strong 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 the plants or animals; places where the domesticates were were brought in, have lesser diversity. The highest diversity of genetics in cattle is in the Taurus Mountains.
Taurine cattle were apparently traded across the planet, and appear in archaeological sites of as far away as northeastern Asia (China, Mongolia, Korea) by about 5000 years ago. Some evidence (Zhang and colleagues 2013), however, suggests that domestic taurines may have reached (or even been domesticated in?) northeastern China at 10,500-10,700 cal BP. A well-preserved conjoined mandible from a bovid, aged about 7-9 years at the time of death, was recovered from the Kongni Ditch near Harbin, China in 2005.
Morphological characteristics of the Kongni Ditch teeth include a sharply concave chewing surface, which, among other characteristics, suggest to scholars that this resulted from human management. AMS dates from two independent laboratories returned dates of 10,756-10,565 and 10,758-10,565 cal BP. Finally, the aDNA aligns most closely with taurines, although there is a distinct mitochondrial pattern. This is definitely an outlier, and the context isn't great, so as the scholars admit, additional evidence will be required to understand the data.
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 is not entirely clear as of yet.
Possible: Bos africanus
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).
A recent study (Stock and Gifford-Gonzalez 2013) suggests that although genetic evidence for African domesticated cattle is not as comprehensive or detailed as that for the 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.
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 had 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.
This article is part of the About.com Guide to the History of Animal Domestication.
See page two for sources used in this article.