Mustang horses are descendants of Spanish, or Iberian,
horses that were brought to the Americas by Spanish explorers in the 16th
century. The name was derived from the Spanish word mustengo, which means
"ownerless beast" or "stray horse." These horses bred with
other breeds of horses, including quarter horses and draft horses, to create
the breed we know today.
Mustang herds vary greatly on how much they can be traced to
the original Iberian horses. Some contain a greater genetic mixture of ranch
stock, while others are relatively unchanged from the original Iberian stock.
In 1971, the United States Congress recognized that
"wild free-roaming horses and burros are living symbols of the historic
and pioneer spirit of the West, which continue to contribute to the diversity
of life forms within the Nation and enrich the lives of the American
people." The free-roaming mustang population is managed and protected by
the Bureau of Land Management (BLM). 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. A policy of rounding up excess population and
offering these horses for adoption to private owners has been inadequate to
address questions of population control, and many animals now live in temporary
holding areas, kept in captivity but not adopted to permanent homes.