An international team of archaeologists has uncovered the earliest known evidence of horses being domesticated by humans. The discovery suggests that horses were both ridden and milked. The findings could point to the very beginnings of horse domestication and the origins of the horse breeds we know today. Led by the Universities of Exeter and Bristol (UK), the research is published on Friday 6 March 2009 in leading academic journal Science.
     The researchers have traced the origins of horse domestication back to the Botai Culture of Kazakhstan circa 5,500 years ago. This is about 1,000 years earlier than thought and about 2,000 years earlier than domestic horses are known to have been in Europe. Their findings strongly suggest that horses were originally domesticated, not just for riding, but also to provide food, including milk.
     The team of archaeologists developed three independent lines of evidence for early horse domestication. The shape and size of the skeletons from four sites was analyzed and compared with bones of wild horses in the region from the same time, with domestic horses from centuries later in the Bronze Age and with Mongolian domestic horses. The researchers said the Botai animals were 'appreciably more slender' than robust wild horses and more similar to domestic horses. This suggests that people were selecting wild horses for their physical attributes, which were then exaggerated through breeding. The second pieces of evidence were the marks on the horses' teeth and damage to skeletal tissue in the mouths. The researchers said this was caused by the wearing of mouthpieces, bits, inserted for harnessing with a bridle or similar restraint to control working animals. Botai pottery yielded the third strand of evidence. Embedded in the clay pots were residues of carcass fat and fatty acids that 'very likely' came from mare's milk, the researchers said. This "confirms that at least some of the mares of Botai were domesticated," they concluded.
     Lead author Dr Alan Outram of the University of Exeter said: "The domestication of horses is known to have had immense social and economic significance, advancing communications, transport, food production and warfare. Our findings indicate that horses were being domesticated about 1,000 years earlier than previously thought. This is significant because it changes our understanding of how these early societies developed."
     The steppe zones, east of the Ural Mountains in Northern Kazakhstan, are known to have been a prime habitat for wild horses thousands of years ago. They were a commonly hunted animal. This may have set the stage for horse domestication by providing indigenous cultures with access to plentiful wild herds and the opportunity to gain an intimate knowledge of equine behaviour. Horses appear to have been domesticated in preference to adopting a herding economy based upon domestic cattle, sheep and goats. Horses have the advantage of being adapted to severe winters and they are able to graze year round, even through snow. Cattle, sheep and goats need to be to be provided with winter fodder, and were a later addition to the prehistoric economies of the region.
     The discovery may revise thinking about the development of some preagricultural Eurasian societies and put an earlier date to their dispersal into Europe and elsewhere. These migrations are believed to have been associated with horse domestication and the spread of Indo-European languages.

Sources: EurekAlert!, The New York Times, LiveScience (5 March 2009)