Feral horses have roamed freely across the island of Assateague off the coast of Maryland and Virginia for hundreds of years, but exactly how they got there has remained a mystery. In a new study, ancient DNA extracted from a 16th century cow tooth from one of Spain's first Caribbean colonies turns out to be from a horse. Analysis of the DNA suggest that old folk tales claiming that horses were marooned on Assateague following the shipwreck of a Spanish galleon are likely more fact than fiction.