One hundred years ago the American West was the home of 2 million wild mustangs, all descendents of the horses the Spanish brought to the New World in the 1600s.By 2001 fewer than 50,000 existed, and today only about 30,000 are left. About half live in Nevada, with Wyoming and California containing another 6-7,000.
According to the BLM, the millions of acres of western wilderness cannot support large populations of wild horses. The herds grow quickly due to high birth rates and decreasing amounts of predators such as mountain lions and bears.
Conflicts between the needs of ranching, recreation, and wildlife mean the herds have been targeted for thinning, and every year since 1971 round-ups have been held of wild horses.
The captured horses have either been adopted or put into sanctuaries. The BLM has rounded up nearly 190,000 horses over the last 36 years.
Differing opinions over the handling of the wild horses has led to protests by activist groups, some of whom want the horses to be left alone. Some scientists worry that over-thinning the herds will reduce their long-term genetic viability, maintaining that herds need to be at least 150 in size.
