Conventional wisdom says that in the 17th century Spanish horses escaped, their population exploding on the great plains. Except most of the Spanish horses were geldings, neutered stallions. And horse numbers increased too quickly as mares have one foal at a time.
Some say native horses survived the ice ages to breed with Spanish horses. But why did the Aztecs have no horses? A new theory says that 1000 AD, ponies were abandoned when the Viking deserted North America. They mated with Spanish horses and the Plains Indian culture was born. (Cherokee pony photo)
