History
The word "Mustang" comes from the Spanish word, mesteno, meaning "stray or ownerless" horse. This term aptly describes all wild horses in the United States.
The modern horse evolved over three million years ago and then disappeared from this hemisphere 10,000 years ago. The horse returned to North America when explorers Cortes and DeSoto came mounted on magnificent Barbs from Morocco, Sorraia from Portugal and Andalusians from Spain. The Pueblo Indians learned to ride and passed this skill on to other Indians. In 1680, the Indians revolted against the Spanish rule and the Spaniards left thousands of horses behind in their hasty retreat. The Indians could have rounded up these horses, but chose to let them run wild. It was much easier to raid the Spanish settlements and steal horses. In an effort to stop the Indian raids, the Spanish government shipped a steady flow of mounts to the New World. It was hoped that the Indians would catch the "wild" horses and leave the Spaniards alone.
Tens of thousands of the Spanish-bred horses were herded to the Rio Grande and turned loose in a 200-year period. These horses soon met up with draft horses and cowboy ponies that escaped from the ranchers and farmers arriving from the East. Their numbers exceeded two million by the year 1900. Ranchers took to killing these horses to protect the range-land for their cattle. Fewer than 17,000 horses remained by the year 1970. Stating that Mustangs were "living symbols of the historic and pioneer spirit of the West," Congress passed the Wild Free-Roaming Horse and Burro Act in 1971. An estimated 41,000 Mustangs roam public range today, but few if any have much original Spanish blood. Today, the Mustang population is managed and protected by the Bureau of Land Management. Controversy surrounds the sharing of land and resources by the free ranging Mustangs with the livestock of the ranching industry, and also with the methods with which the federal government manages the wild population numbers. An additional debate centers on the question if Mustangs—and horses in general—are a native species or an introduced invasive species. Many methods of population management are used, including the adoption by private individuals of horses taken from the range.
Behavior
Since 1978, captured horses have been offered for adoption to individuals or groups willing and able to provide humane, long-term care after payment of an adoption fee; the base fee is $125. Adopted horses are still protected under the Act, for one year after adoption, at which point the adopter can obtain title to the horse. Horses that could not be adopted were to be humanely euthanized. Instead of euthanizing excess horses, the BLM began keeping them in "long term holding," an expensive alternative that can cost taxpayers up to $50,000 per horse over its lifetime. On December 8, 2004, a rider amending the Wild and Free Roaming Horse and Burro Act was attached to an appropriation bill before the United States Congress by former Senator Conrad Burns. This modified the adoption program to also allow the unlimited sale of captured horses that are "more than 10 years of age", or that were "offered unsuccessfully for adoption at least three times." Since 1978, there had been specific language in the Act forbidding the BLM from selling the horses to those would take them to slaughter, but the Burns Amendment removed that language. In order to prevent horses being sold to slaughter, the BLM has implemented policies limiting sales and requiring buyers to certify they will not take the horses to slaughter. In 2017, the Trump administration began pushing Congress to remove barriers to implementing both the option to euthanize and sell excess horses.
Despite such means as the Extreme Mustang Makeover, a promotional competition that gives trainers 100 days to gentle and train 100 mustangs, which are then adopted through an auction, to try increase the number of horses adopted, adoption numbers do not come close to finding homes for the excess horses. Ten thousand foals were expected to be born on range in 2017, whereas only 2500 horses were expected to be adopted. Alternatives to roundups for on range population control include fertility control, either by PZP injection or spaying mares, culling and natural regulation.
Captured horses are freeze branded on the left side of the neck by the BLM, using the International Alpha Angle System, a system of angles and alpha-symbols that cannot be altered. The brands begin with a symbol indicating the registering organization, in this case the U.S. Government, then two stacked figures indicating the individual horse's year of birth, then the individual registration number. Captured horses kept in sanctuaries are also marked on the left hip with four inch-high Arabic numerals that are also the last four digits of the freeze brand on the neck.