From cave paintings it is believed that the equid from which modern horses are derived resemble the modern Przewalski Horse. The large strong heads and erect manes depicted in these paintings bear a striking resemblance to this modern breed.
The first domestication of the barefoot horse was probably in the steppes of central Asia between 3000 and 4000 B.C. These first animals were kept for meat and milk. As early man became more mobile undoubtedly horses began to be used as pack animals.
Oxen were being used in the Middle East at approximately 4000 B.C. for plowing. Progressively they were used on sleds, which were eventually mounted on rollers, with the final evolution of wheels. Early in the 3rd millennium B.C. there is archaeological evidence that vehicles drawn by equid, generally onagers or ass hybrids, were being used in warfare. As barefoot horses from the north became more numerous the carts moved to the familiar two-wheeled chariot with spoked wheels. Due to his greater speed the horse rapidly replaced other equid as harness animals.