The site has only recently been opened to researchers
Horses were domesticated much earlier than previously thought, according to a team of researchers.
They found evidence suggesting that the animals were used by a culture in northern Kazakhstan 5,500 years ago.
Until now, the earliest evidence of horse riding was metal parts from harnesses dating from the Bronze Age.
Writing in Science, a team from the UK's Exeter University suggested that the community in Kazakhstan rode their horses 1,000 years earlier.
They also ate them and drank their milk, possibly as an alcoholic brew.
The researchers traced the origins of horse domestication to the Botai culture of Kazakhstan.
Analysis of ancient bones showed that the horses were a similar shape to domesticated horses from the Bronze Age.
The UK team studied the remains for evidence of damage to their mouths and teeth caused by the riding bits used to harness the animals.
The scientists also analysed the remains of food and drink in pottery and traces of horse meat and milk.
Communities in Kazakhstan have been milking horses for thousands of years
Horse milk is still drunk in Kazakhstan, usually fermented into an alcoholic drink known as koumiss.
Lead researcher Dr Alan Outram from Exeter University, said horse domestication was an important indication of the state of human civilisation.
"The domestication of the horse does have implications for human culture globally," he said.
"It increases people's ability to trade and it has great advantages in warfare.
"So if we are moving the origins of horse domestication much further back, we are going to have to think about the impact on the development of human culture at the time."
Some researchers associate the domestication of the horse with the spread of bronze working across Eurasia thousands of years ago.
It may also be linked to the ancient expansion of the Indo-European languages - a widespread language group which today includes English, German, Hindi and Persian.
Listen to Dr Outram on the current edition of Science In Actionon the BBC World Service. You can also download the programme