Horses were present on Assateague Island in the 1600's, but how they arrived remains uncertain. One historical explanation holds that during colonial times the island was untaxed for livestock, so farmers let animals graze there freely and eventually only the horses remained. Another tradition says the ship La Galga sank off Assateague and the horses swam ashore as the only survivors; research supports the wreck, but whether horses were aboard is still unknown. The horses now roam freely from the northern tip near Ocean City inlet to the southern boundary at the Virginia state line, often gathering in the marsh where food is abundant and bay waters are cool, while appearances on the beach usually coincide with heat or west winds that drive biting insects onto the island.