Stone Age man chose to eat the horse rather than drive or ride it

From A History of Warfare by John Keegan. Page 156.

The horse that homo sapiens first knew was a poor thing; so poor, indeed, that man hunted it for food. Equus, the ancestor of equus caballus, our modern horse, was actually hunted out of existence in the Americas by the Amerindians who crossed into the New World at the end of the last ice age. In the Old World the return of the forests after the end of the ice age drove equus caballus out of Europe on to the treeless steppe, where it was first hunted and then domesticated for its flesh. In the settlements of the so-called Srednij Stog culture on the River Dnieper, above the Black Sea, the bones of apparently domesticated horses form a majority among those excavated from village sites dated to the fourth millennium BC Stone Age man chose to eat the horse rather than drive or ride it, because the animal they knew was almost certainly not strong enough in the back to bear an adult male human, while men themselves had not yet designed a vehicle to which a draught animal might be harnessed. The relationship between man and the equine species is, in any case, extremely complex. Unlike the dog, which, though a pack animal, appears to associate itself as an individual quite easily with a human individual, and may have begun to do so about 12,000 years ago, the horse has to be cut out of a herd and tamed if a useful `mutualism' is to arise between it and its human master.