Hardy, compact, and spirited, the horses on Assateague Island run freely over a range bounded by ocean and bay, living in small bands of mares and young led by protective stallions that graze on marsh grasses, drink at freshwater ponds, and retreat into island forests for shelter. Wild ponies can kick and bite even when they look tame, and feeding them is dangerous and unlawful. Bands on the northern section of the island belong to the Maryland herd, which the National Park Service maintains in a wild state with minimal human interference. The larger Virginia herd, the Chincoteague Ponies, graze under permit on the Chincoteague National Wildlife Refuge, and a fence at the state boundary keeps the herds separated. Their arrival on Assateague is uncertain: legend holds that some were shipwrecked there long ago, but no documented evidence has been found, while research shows that English planters pastured horses and other livestock on barrier islands here in the 1600s to avoid fencing costs and taxes, and some of today's ponies may descend from those animals. Every year on the last Wednesday and Thursday in July, the Chincoteague Volunteer Fire Company, owner and manager of the Virginia herd, sponsors a roundup in which horseback riders gather the ponies, drive them across the channel to the Chincoteague carnival ground where some are sold at auction, and return the rest to the island.