Mustangs are a symbol of the American West, roaming the nation’s vast open rangelands. While often called “wild horses,” they are technically feral, meaning they are descendants of domesticated Spanish horses brought to the Americas centuries ago. They have successfully established self-sustaining, free-roaming populations in the rugged landscapes of the western United States. This article explores the current geographic distribution of these equines and the legal frameworks that govern their existence.
Current Geographic Distribution
Mustang herds roam across nearly 28 million acres of public land throughout 10 western states. The largest concentrations are found in the Great Basin region, particularly Nevada, which is the epicenter for the majority of the free-roaming population. More than half of all Mustangs live in Nevada, which contains 83 separate designated management areas.
Significant populations also exist in Wyoming, featuring large stretches of sagebrush steppe and intermountain basins. Utah, Oregon, and California are other primary states hosting numerous established herds. These horses are concentrated on federal lands managed by both the Bureau of Land Management (BLM) and the U.S. Forest Service (USFS).
The distribution is not uniform, as the horses are confined to areas where they were roaming when federal protection was enacted. Herds in California’s Devil’s Garden area or Utah’s Onaqui Mountains are well-known examples of the specific, non-continuous parcels of land they inhabit. This geographic isolation means each herd has developed distinct traits specific to its local environment.
The Wild Horse and Burro Act: Management Areas
The location and managed size of the Mustang population are tied to the Wild Free-Roaming Horses and Burros Act of 1971. This federal legislation designated these animals as “living symbols of the historic and pioneer spirit of the West.” The Act placed them under the protection of the BLM and USFS, legally confining them to specific federal lands known as Herd Management Areas (HMAs).
HMAs are managed primarily for the benefit of the horses and burros, but the land is also subject to multiple-use management. The law requires federal agencies to maintain a thriving ecological balance on public lands. To achieve this, the BLM establishes an Appropriate Management Level (AML) for each HMA, representing the maximum number of animals the land can sustain.
Since the Mustang population can increase by up to 20 percent annually without natural predators, management techniques keep herd numbers within the AML. These techniques include fertility control measures and the periodic removal, or “gather,” of excess animals. Removed animals are then offered for adoption or placed in long-term holding facilities.
Adaptation to Arid and Semi-Arid Environments
The Mustang’s habitat is characterized by the rugged, challenging conditions of the American West. This primarily consists of arid and semi-arid high desert, sagebrush steppe, and intermountain regions. These environments present obstacles like extreme temperature fluctuations, sparse vegetation, and limited water sources. The horses’ long history of roaming these lands has led to necessary physical and behavioral adaptations.
Mustangs are known for their exceptional endurance and ability to travel vast distances, often ranging five to ten times farther than domestic livestock to locate forage and water. Their metabolism is highly efficient, allowing them to utilize water and energy resources effectively. They have developed strong, sure-footed hooves that can withstand the rough, rocky terrain.
Behaviorally, the horses are adept at locating scarce resources, sometimes digging shallow depressions in dry creek beds to reach subsurface water. They graze on tough, native plants and grasses that other equines may find insufficient. These adaptations have resulted in a hardy, resilient animal that continues to thrive in landscapes where few other large mammals can sustain free-roaming populations.