Most horses are domesticated, but the small numbers of wild horses in the United States live on islands near the East Coast and in 10 Western states, including Oregon, California, Arizona and New Mexico. Approximately 55,000 wild horses live on about 34 million acres managed by the U.S. Bureau of Land Management.
The BLM controls populations of wild horses and wild burros on public lands by various methods, including allowing people to adopt some of the horses. Wild horses are challenging for individuals to manage, and the horses are sometimes neglected or sent to slaughter. The Humane Society Wildlife Land Trust and other groups are working to save wild horses' habitat and help increase their numbers.
Wild horses, known as mustangs, gather in small herds typically including one male and two to eight females, along with foals. Herds graze within a defined territory and typically do not enter other horses' territory, although they sometimes join forces with other herds to deter predators. They have a clear social order, with the herd following a lead mare to safety when a threat materializes. The male, also known as a stallion, remains in the territory to defend the herd. Males snort and paw the ground to raise dust in a show of aggression.