Assateague's Wild Horses

Assateague's wild horses are well known, even to many people who have never been to the island. The ‘wild’ horses on Assateague are actually feral animals, meaning that they are descendants of domestic animals that have reverted to a wild state.

Despite the often told tale of the horses swimming to Assateague from a shipwrecked Spanish galleon, the most plausible explanation is that they are the descendants of horses that were brought to barrier islands like Assateague in the late 17th century by mainland owners to avoid fencing laws and taxation of livestock.

Today's horses are actually the size of ponies (average 12- 13 hands) probably due to their poor diet and harsh environment. Almost 80% of their diet is coarse salt marsh cord grass and American beach grass. Various grass species, greenbrier stems, bayberry twigs, rose hips, seaweeds and poison ivy make up the rest of their diet. The high concentration of salt in their diets causes the horses to drink twice as much fresh water as domestic horses. Because of this, the horses have a "fat" or "bloated" appearance.

The horses are split into two main herds, one on the Virginia side and one on the Maryland side of Assateague. The herds are separated by a fence at the Virginia/Maryland State line and the population size of each herd is kept around 150 animals to lessen their impact on island ecology. These herds have divided themselves into bands of two to twelve animals and each band occupies a home range.

The National Park Service manages the Maryland herd. The Chincoteague Volunteer Fire Company owns and manages the Virginia Herd, which is allowed to graze on Chincoteague National Wildlife Refuge, through a special use permit issued by the U.S. Fish and Wildlife Service. The permit restricts the size of the herd to approximately 150 adult animals in order to protect the other natural resources of the wildlife refuge. It is the Virginia herd which is often referred to as the "Chincoteague" ponies.

The herds are managed differently. In Virginia, the internationally famous "Pony Penning" event is responsible for meeting the limit of 150 adult animals. This event began in some form during the late 17th century when unclaimed horses were captured and marked by colonists in the presence of neighbors on a day of fellowship and festivity. The modern Pony Penning began in 1924 as an effort to raise money for the Chincoteague Volunteer Fire Company and is still held on the last Wednesday and Thursday of July. The Virginia herd, rounded up by local "saltwater cowboys", swims across the channel (at slack tide) to Chincoteague on Wednesday in front of thousands of cheering spectators. The swim takes about 5 - 10 minutes. Most of the foals are auctioned off on Thursday and the remaining horses swim back to Assateague on Friday. New owners must be able to provide safe, humane transportation for their purchases. Most foals are easily tamed and adapt well to domestic life.

The Virginia herd undergoes a veterinary check twice a year. In the spring (April) they are vaccinated against encephalitis (both eastern and western strain), rabies and tetanus and tested for EIA (Equine Infectious Anemia or swamp fever). They are also de-wormed (using ivermectin) and some horses have their hooves trimmed. In the fall they are de-wormed again and all horses have their hooves trimmed. The horses on the Virginia side of the island are also fenced off from road areas to stop people from feeding them and attracting them to cars and roadways.

In Maryland, the number of horses has grown from approximately 28 in 1968 to more than 165 at present, exceeding the desired herd size of 120 to 150 animals. With this growth has come increasing evidence that the horses are having a significant negative impact on the dune and salt marsh habitats due to over grazing. By establishing a population limit of 120 to 150 animals, the National Park Service is attempting to balance the health and well being of the horses with the need to protect the island's other sensitive natural resources and values. Visitors now have the opportunity to "actively" support Assateague's wild horse management in Maryland by becoming a Foster Parent.

To manage population growth on a long term basis, a unique contraceptive has been developed for use in the Maryland herd. Administered by a dart gun, the non-hormonal contraceptive vaccine stimulates the mare's immune system to produce antibodies. At sufficiently high levels these antibodies block fertilization and thereby prevent pregnancy. The contraceptive effect is temporary, lasting about one year, but can be extended with an annual booster shot. During seven years of experimental field trials, the technique has proven better than 95% effective and has exhibited no harmful side effects. Use of the contraceptive as part of a long term horse population management program began in 1994.

Horses are usually seen during visits to either end of the island, but weather and seasonal factors can increase or decrease the odds. They display many interesting social characteristics which are detailed in several books and a free brochure prepared by the National Park Service. The managing agencies are trying hard to keep the wild in these unique creatures: Please do not feed or pet horses! They are very unpredictable and each year a number of visitors receive severe bite or kick injuries. Feeding the horses causes them to hang around roads and several are hit and killed every year.

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