Assateague Island, a captivating coastal barrier island stretching along the Maryland and Virginia shores, is known for its wild horses. These resilient animals roam freely across the diverse landscapes of beaches, dunes, and salt marshes, creating a compelling spectacle for visitors. These horses inspire curiosity about their presence and how they thrive in this environment, contributing to the island’s unique allure.
Current Population Counts
The wild horses of Assateague Island are divided into two herds by a fence at the Maryland-Virginia state line, each managed by a different entity. The Maryland herd, overseen by the National Park Service, reported a population of 79 horses in its March 2025 census. This number includes 32 stallions and 47 mares, with one new foal recorded in the spring of 2025. The population goal for the Maryland herd is maintained within a range of 80 to 100 individuals to ensure ecological balance.
On the Virginia side of the island, the herd is owned and managed by the Chincoteague Volunteer Fire Company. This herd’s population is maintained at approximately 150 adult animals through a special use permit. The target size for the Virginia herd remains consistent.
Managing the Wild Herds
Population control methods differ between the two herds to sustain their numbers and protect the island’s ecosystem. For the Maryland herd, the National Park Service employs a fertility control program using Porcine Zona Pellucida (PZP). This non-hormonal vaccine prevents fertilization. The program, initiated in 1994, aims to stabilize the population within the 80 to 100 horse range, which is considered genetically viable and minimizes environmental impact.
The Virginia herd’s population is managed through the annual Pony Swim and subsequent auction. Each July, volunteers known as “Saltwater Cowboys” round up the ponies and guide them across the Assateague Channel to Chincoteague Island. Foals are then auctioned off, serving both to control the herd’s size and to raise funds for the Chincoteague Volunteer Fire Company, which uses the proceeds for the ponies’ care.
The Origin of Assateague’s Horses
The origins of Assateague’s wild horses are debated. One popular theory suggests they are descendants of horses that survived a Spanish galleon shipwreck off the coast centuries ago, swimming to shore to establish the island population. This tale gained recognition through the children’s novel “Misty of Chincoteague.”
Another explanation, often considered more plausible by historical accounts, posits that the horses descended from domesticated animals brought to the barrier islands by early colonial settlers in the late 17th century. This practice allowed mainland farmers to avoid fencing laws and livestock taxes. Recent scientific research, including DNA analysis of a 16th-century horse tooth from Haiti, has shown genetic similarities between early Spanish colonial horses and the Chincoteague ponies, lending some support to the shipwreck theory. Regardless of their precise arrival, these animals are technically feral, meaning their ancestors were domesticated before adapting to life without human intervention on the island.