How Many Times Do Sheep Need to Be Domesticated

Sheep (Ovis aries) were probably domesticated at least three separate times in the Fertile Crescent (western Iran and Turkey, and all of Syria and Iraq). This occurred approximately 10,500 years ago  and involved at least three different subspecies of the wild mouflon (Ovis gmelini). Sheep were the first meat animals domesticated; and they were among the species translocated to Cyprus by 10,000 years ago, as were goats, cattle, pigs, and cats. Since domestication, sheep have become essential parts of farms across the world, in part because of their ability to adapt to local environments. Mitochondrial analysis of 32 different breeds was reported by Lv and colleagues. They showed that many of the characteristics in sheep breeds such as tolerance to temperature variations may be responses to climatic differences, such as day length, seasonality, UV and solar radiation, precipitation, and humidity. Sheep Domestication Some evidence suggests that overhunting of wild sheep may have contributed to the domestication process; there are indications that the wild sheep population decreased sharply in western Asia around 10,000 years ago. Although some have argued for a commensal relationship, a more likely pathway may have been the management of a disappearing resource. Larson and Fuller have outlined a process whereby the animal/human relationship shifts from wild prey to game management, to herd management and then to directed breeding. This didnt happen because baby mouflons  were adorable but because hunters needed to manage a vanishing resource. Sheep, course, were not simply bred for meat, but also provided milk and milk products, hide for leather, and later, wool. Morphological changes in sheep that are recognized as signs of domestication include a reduction in body size, female sheep lacking horns, and demographic profiles that include large percentages of young animals. History and DNA Prior to DNA and mtDNA studies, several different species (urial, mouflon, argali) were hypothesized as the ancestor of modern sheep and goats, because the bones look a lot alike. That has not turned out to be the case: goats are descended from ibexes; sheep from mouflons. Parallel DNA and mtDNA studies of European, African and Asian domestic sheep have identified three major and distinct lineages. These lineages are called Type A or Asian, Type B or European, and Type C, which has been identified in modern sheep from Turkey and China. All three types are believed to have been descended from different wild ancestor species of mouflon (Ovis gmelini spp), someplace in the Fertile Crescent. A Bronze Age sheep in China was found to belong to Type B  and is thought to have been introduced into China perhaps as early as 5000 BC. African Sheep Domestic sheep probably entered Africa in several waves through northeastern Africa and the Horn of Africa, the earliest beginning about 7000  BP. Four types of sheep are known in Africa today: thin-tailed with hair, thin-tailed with wool, fat-tailed and fat-rumped. North Africa has a wild form of sheep, the wild Barbary sheep (Ammotragus lervia), but they dont appear to have been domesticated or made up part of any domesticated variety today. The earliest evidence of domestic sheep in Africa is from Nabta Playa, beginning about 7700 BP; sheep are illustrated on Early Dynastic and Middle Kingdom murals dated about 4500 BP. Considerable recent scholarship has been focused on the history of sheep in southern Africa. Sheep first appears in the archaeological record of southern Africa by ca. 2270 RCYBP and examples of fat-tailed sheep are found on un-dated rock art in Zimbabwe and South Africa. Several  lineages of domestic sheep are found in modern herds in South Africa today, all sharing a common material ancestry,  probably from O. Orientalis, and may represent a single domestication event. Chinese Sheep The earliest record of sheep in China dates is sporadic fragments of teeth and bones at a few Neolithic sites such as Banpo (in Xian), Beishouling (Shaanxi province), Shizhaocun (Gansu province), and Hetaozhuange (Qinghai province). The fragments are not intact enough to be identified as domestic or wild. Two theories are that either domestic sheep were imported from western Asia into Gansu/Qinghai between 5600 and 4000 years ago, or independently domesticated from argali (Ovis ammon) or urial (Ovis vignei) about 8000-7000 years bp. Direct dates on sheep bone fragments from Inner Mongolia, Ningxia and Shaanxi provinces range between 4700 to 4400 cal BC, and stable isotope analysis of the remaining bone collagen indicated that the sheep likely consumed millet (Panicum miliaceum or Setaria italica). This evidence suggests to Dodson and colleagues that the sheep were domesticated. The set of dates are the earliest confirmed dates for sheep in China. Sheep Sites Archaeological sites with early evidence for sheep domestication include: Iran: Ali Kosh, Tepe Sarab, Ganj DarehIraq: Shanidar, Zawi Chemi Shanidar, JarmoTurkey: Çayà ´nu, Asikli Hoyuk, Çatalhà ¶yà ¼kChina: Dashanqian, BanpoAfrica: Nabta Playa (Egypt), Haua Fteah (Libya), Leopard Cave (Namibia) Sources Cai D, Tang Z, Yu H, Han L, Ren X, Zhao X, Zhu H, and Zhou H. 2011. Early. 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A forager–herder trade-off, from broad-spectrum hunting to sheep management at Asikli Hà ¶yà ¼k, Turkey. Proce edings of the National Academy of Sciences 111(23):8404-8409.