Medieval knights, the warriors of Saladin, Roy Rogers and fans lining racetracks around the world all owe a debt to the Botai culture, residents of Central Asia who domesticated horses more than 5,000 years ago.

New evidence corralled in Kazakhstan indicates the Botai culture used horses as beasts of burden _ and as a source of meat and milk _ about 1,000 years earlier than had been widely believed, according to the team led by Alan Outram of England's University of Exeter.

"This is significant because it changes our understanding of how these early societies developed," Outram said.

Domestication of the horse was an immense breakthrough _ bringing horsepower to communications, transportation, farming and warfare.

The research, reported in Friday's edition of the journal Science, also shows the development of animal domestication and a fully pastoral economy may well be independent of famous centers of domestication, such as the Near East and China, Outram added.

Compared to dogs, domesticated as long as 15,000 years ago, and such food animals as sheep, goats and pigs, horses are relatively late arrivals in the human relationship.

"It is not so much the domestication of the horse that is important, but the invention of horseback riding," commented anthropologist David W. Anthony of Hartwick College in Oneonta, N.Y. "When people began to ride, it revolutionized human transport."

"For the first time the Eurasian steppes, formerly a hostile ecological barrier to humans, became a corridor of communication across Eurasia linking China to Europe and the Near East. Riding also forever changed warfare. Boundaries were changed, new trading partners were acquired, new alliances became possible, and resources that had been beyond reach became reachable," observed Anthony, who was not part of Outram's research team.

Some researchers believe this new mobility may have led to the spread of Indo-European languages and many other common aspects of human culture, Outram said.

In addition to carrying people and their goods, horses provided meat and even milk, which some cultures still ferment into a mildly alcoholic beverage.

The date and place of horse domestication has long been subject to research, and the steppes of Central Asia and the Botai culture have previously been suggested as possibilities.

But the new report adds extensive detail to the tale.

Outram's team developed a troika of evidence the Botai domesticated horses.

_ Studies of the jaws of horses from the site show tooth wear similar to that caused by bits in modern horses, an indication of riding. A 1998 paper by Anthony raised the possibility of such findings, but the new report is much more extensive and detailed.

_ The leg bones of the Botai horses are more slender than those of wild horses, indicating breeding for different qualities.

The new way of measuring and analyzing horse leg bones "shows here for the first time that the Botai culture horses were closer in leg conformation to domestic horses than to wild horses. That is another first," Anthony said.

_ And complex studies of ancient ceramic pots from the location showed evidence they once contained mare's milk.

"This is, apart from being fascinating, something of a smoking gun for domestication _ would you milk a wild horse?" said Outram.

Anthony agreed: "If you're milking horses, they are not wild!"

"The invention of a method to identify the fat residues left by horse milk in ceramic pots is a spectacular and brilliant advance," he said of Outram's paper. "It is really important to be able to identify the fats in the clay pots as not just from horse tissue, but precisely from horse milk."

Still today mares are milked in Kazakhstan and Mongolia.

"The Kazakhs ferment it into a sour tasting and slightly alcoholic drink called 'koumiss.' It is clear that dated back at least hundreds of years, but beyond that no one knew. Who would have thought it was a practice that went back 5,500 years, at least," Outram said.

The new research was funded by Britain's Natural Environment Research Council, the British Academy and the U.S. National Science Foundation.

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