A Mustang is a free-roaming feral horse of the North American west that first descended from horses brought to the Americas by the Spanish. Mustangs are often referred to as wild horses but the more correct term is feral horses. In 1971 the United States Congress recognized Mustangs as “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.