A large percentage of horses that historically run wild in the United States owe their bloodlines to animals imported during the 16th century by the Spanish for exploring. American Mustangs are ancestors of this hardy working stock.
A Little Backstory
Most of the Iberian animals brought over were of Barb, Jennet or Andalusian blood. Once they were no longer needed they were often simply released into the wild. Over centuries herds managed to flourish in many parts of the US and can still be found today. North America is thought to be the cradle of equines, which later migrated across the Bearing Strait to Asia. Almost like they were coming home, horses seemed to find their motherland suitable once again.
The term American Mustang is sort of a blanket term which encompasses all feral horses found in the United States. However there are a variety of types and registries which track them. Some types have existed in relative isolation, making their genetics fairly pure. Others have seen influx of various different types, both wild and domestic. For a feral horse to be a Spanish Mustang they must meet some requirements genetically.
What Makes Them Special
In large part their historical significance to the American people. The idea of a wild horse running free is almost as American as a bald eagle soaring through the sky. Horses helped people build the country and their wild cousins symbolize freedom for many. These same feral genetics have also contributed to many modern breeds native to the country today. Loved for their robust nature, proud bearing and loyal character. To learn more about them, be sure to visit the American Mustang breed page.
Quick Facts
Native to the United States.
There is not a centralized studbook.
Spanish Mustangs are listed as at risk in the DAD-IS.
It is not possible to have an actual head count, but BLM estimates the population to fluctuate somewhere between 70,000-90,000.