What’s a Mustang?

A Native Species of North America

Origin of the HorseHyracotherium_Eohippus_hharder

The animal that we know today as the horse first had roots in North America about 55 million years ago with its four-toed ancestor, Eohippus, meaning “dawn horse”.  This small animal was about the size of a fox and made its home in swamplands, feeding off plant life.  Eohippus slowly evolved into Mesohippus, the size of an average collie. Mesohippus had three toes and eventually became the inhabitant of the prairie.  As the habitat changed, its shape changed and it grew taller, its teeth and middle toe grew longer and the toes eventually became a hoof.  The evolution continued until Equus Caballus was formed, the horse as we know it today.

When were horses domesticated?

The horse was probably first domesticated about 4,000 to 5,000 years ago in the region of the Black Sea in Asia. Once man learned to tame them, horses served a variety of purposes. They carried the conquering armies of entire civilizations across the old world.  In Europe the horse was soon hitched to the plow to expand society’s agricultural capabilities.

Horses in North America

Even though the horse, equus caballus, evolved in North America, some of them migrated across the Bering Straits land bridge into Asia, continuing across the Iranian Plateau of the Middle East and as far as Europe and northern Africa. For reasons unknown to us, the horse entirely disappeared from the North American continent about 10,000 years ago.  The reintroduction of the horse into the Americas began in 1519 when Cortez came from Spain.  As more and more settlers from Spain and other European countries came, they brought horses with them and returned these animals to their native land.

What is a Mustang?

The word mustang comes from the Spanish word, mustengo, which means “ownerless beast”.  The American mustang originally came from the Spanish stock of horses that were brought to the Americas beginning in the 16th century.  Over time, other kinds of horses banded with wild Spanish horses, including quarter horses, draft horses and others.  There are specific kinds of mustangs, and they have their own unique breeds.

Where can wild horses be found in North America?


Wild horses in North America live on islands off the Atlantic coast (Sable, Assateague, Shakleford, and Cumberland Islands), as well as eleven western states that include Nevada, Wyoming, Utah, Oregon, California, Idaho, Arizona, Montana, North Dakota, and New Mexico. No one really knows for sure how many wild horses there are.  It is likely that fewer than 25,000 horses and 5,000 burros are left on 34 million acres of public land managed by the Bureau of Land Management.

Where did the McCullough Peaks herd come from?

Mustangs in the Big Horn Basin can be traced, via DNA, to the original Spanish horses. However, genetic diversity has occurred here as the result of the introduction of other breeds to the gene pool. At least one McCullough Peaks horse tested as a descendant of horses owned by the Royal Family in England, probably a relative of the horses they gave to Buffalo Bill when he toured England with his show the “Wild West”. There is a history of the McCullough Peaks Mustangs being rounded up over the years by those in need of transportation and ranching assistance. Other ranchers, in the “before fences” era, would allow their horses to graze with the Mustangs over the winter months. Locals tell stories of a round-up to supply mounts for the U.S. Cavalry in World War I.

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