Five Myths About Wild Horses in the West

Despite Bureau of Land Management claims, wild horses do not damage the ecosystems of the American West

Chad Hanson April 21, 2023

Across the American West, the U.S. Bureau of Land Management conducts regular roundups of wild horses to control the population, arguing that, left unchecked, these creatures would overpopulate and damage the environment. In the new book In a Land of Awe: Finding Reverence in the Search for Wild Horses, writer Chad Hanson makes the case that these policies are misguided and unnecessary, removing something valuable from the landscape. In the excerpt below, he pushes against what he says are persistent myths about the wild horse.  

Myth #1: Mustangs Are Overpopulated in the West

It’s the staff of the Bureau of Land Management (BLM) that determines the number of mustangs permitted to live in the nation’s wild horse herd areas. In 2019, the BLM set 26,700 as the maximum number allowed, as a way to maintain what the agency considers an appropriate management level (AML), across the 10 western states with current herds. On this subject, in May of 2020, the BLM published An Analysis of Achieving a Sustainable Wild Horse and Burro Program. In the report, the authors outline the steps the Bureau is taking to reduce our wild horse population to 26,700.

In a 1959 estimate for Geographical Review, Thomas McKnight estimated that 2 to 5 million mustangs roamed the West, historically. An AML of 26,700 represents at least a 98.7% decrease in the number of wild horses in the United States. That figure alone would likely justify a listing of the American mustang as threatened under the terms of the Endangered Species Act, but it’s the loss of genetic diversity that represents the greatest risk to the long-term presence and stability of wild horse populations. According to the International Union for the Conservation of Nature (IUCN), a species becomes threatened when its range is limited to “restricted populations” of less than “250 adults.” Of the original 339 wild horse herd areas identified in 1971, at present, 308 of those areas have AMLs set at less than 250 horses. In other words, 90% of our original mustang herds have either been eliminated or pressed into restricted quarters where potential for inbreeding threatens the health of future generations.

At times, wild horse populations in the West are cited as an “out-of-control problem.” Such claims result from mustang numbers rising above the management levels set by the BLM. The claims are not based on an analysis of the number of wild horses that a region can support, however. It is important to keep in mind that livestock outnumber mustangs on our public lands by ratios that range from 92:1 to 28:1, depending on the year and location. When the BLM implements fertility control programs for mustangs, or when they round up and remove wild horses, in effect, they are reducing the number of free-roaming equines as a way to make room for the larger herds of private sheep and cattle the agency permits on our public property.

Consider New Mexico. The BLM manages wild horses in two different herd areas in the northern and central parts of the state. The areas provide horses with access to 29,000 acres of public land. In the two combined herds, the agency has set the AML at a total of 83 animals. If the population should happen to rise up to 166, double the AML, that’s still short of the number needed to assure enough diversity to avoid birth defects and long-term genetic decline. Even so, critics might charge, “There are twice as many mustangs as our rangelands can support!” In truth, if the population of New Mexico mustangs rose to 290, that would still afford each horse enough space to graze 100 acres each. 

On their own, at present numbers, science does not suggest that wild horses threaten the ecosystems where they’re found. It is rarely science that underlies our decisions about wildlife and the use of public lands, however. According to the BLM’s own documents, specifically, the Report of the Review Team on Forage Allocations for Wild Horses and Livestock, the ultimate decision on the balance between mustangs and cattle is a “social and political one,” based on “perceptions and values.” When wild horse detractors claim, “There are too many mustangs!” it is crucial to remember that these are not statements of fact, but rather, declarations of bias—toward domestic stock and in opposition to wild, free-roaming animals.

Myth #2: Wild Horses Harm Public Grasslands

The prairies and basins overseen by the Bureau of Land Management are often overgrazed. In a 2018 testimony before the House Natural Resources Subcommittee on Public Lands, members of the group, Public Employees for Environmental Responsibility, testified to the effect that 30% of the lands managed by the BLM do not meet the agency’s standards for a sustainable and healthy range. They went on to explain that 70% of the damage is a result of commercial livestock grazing.

Government agencies allow cattle to occupy 251 million acres of our public land, and in contrast, we permit wild horses and burros on a total of 29.4 million acres. In other words, in a given year, we could potentially find wild horses on no more than 12% of the property [permitted to cattle] overseen by the Forest Service and Bureau of Land Management. Critics of the Wild Horse and Burro program often point to the presence of mustangs or wild burros as an explanation for the grim state of our grasslands. Such claims serve as an example of scapegoating. 

When it comes to explaining the problem of overgrazed and unhealthy grasslands, the explanation leans in only one direction: agribusiness.

Myth #3: Mustangs Are an Invasive Species (Non-Native)

The modern horse evolved in North America. The earliest fossil records date back more than 55 million years. Due to abundant skeletal remains, archeologists can easily delineate the evolution of the horse, all the way from the “dawn pony,” the original herbivore, to Equus caballus, the creature that we know today. On this continent, we find strong evidence of horses present in large numbers—from their starting point in the Eocene—up until the most recent discovery, a sample of 5,000-year-old horse DNA uncovered from the soil in the Yukon Territory. The genetic material, collected by a team headquartered at McMaster University, established that the historic North American DNA matches that of the modern horse.

In late 2021, the university released a report under the title, “Ancient DNA found in soil samples reveals mammoths, Yukon wild horses survived thousands of years longer than believed.” The report contains an unequivocal statement from a partner on the project, Ross MacPhee, Senior Curator in the Department of Mammalogy at the American Museum of Natural History. According to MacPhee, “The horse that lived in the Yukon 5,000 years ago is directly related to the horse species we have today, Equus caballus. Biologically, this makes the horse a native North American mammal, and it should be treated as such.”

Like most large creatures in the time of the last ice age, horses migrated from North America into Asia, and then they either vanished from this continent or they saw their populations shrink. Some new evidence suggests that Native American tribes possessed carvings of horse figurines circa 1500, and new data on the genetics of Appaloosas suggest that they migrated, or were brought back, to North America from Asia at a time that’s still unknown. Without question, 500 years ago, Spanish explorers loaded horses onto ships, returned them to their home, and set them free. Until we find a set of horse remains that are 2,000 or 800 years old, it is still questionable, but perhaps fair to assume that horses went regionally extinct and remained so for roughly 4,500 years.

To put this into perspective, if we could reduce the 55-million-year history of horses in America to a single 24-hour period, for the sake of illustration, horses would be present on this continent for the first 23 hours, 59 minutes, and 43 seconds. They would disappear for the last 17 ticks of the clock. Then they would return at the end of the day. Under such circumstances, is there any way to consider them out of place? If horses are not native to the North American continent, then where are they indigenous? The mustangs of the West are often described as a non-native species, but that characterization is dishonest.

Horses evolved in North America. It is possible that they disappeared here for a short time. Then human beings brought them home. The situation is similar to the one we find in the National Parks. For example, in the Badlands of South Dakota, bison and bighorn sheep were both eliminated from the landscape by the middle 1800s. Then in the twentieth century, field biologists trapped specimens in other areas and relocated them to the Badlands, where they once lived in large numbers. This scenario is no different from the one we find in the case of wild horses.

Myth #4: Wild Horses Have No Natural Predators

On its web pages, and in print, the Bureau of Land Management makes a regular claim to the effect that “the wild horse has no natural predators.” In truth, through the 19th and 20th centuries, by means of trapping, hunting, and poison, we exterminated most of the large predators on the North American continent. Historically, wolves and grizzly bears preyed on mustangs. Today, we find no overlap between wild horse herd areas and bear or wolf habitat. But one large carnivore remains—the mountain lion. For millions of years, lions stalked bands of horses across our mountains and prairies. Likewise, in current reports from wildlife biologists, we find a growing body of data on the number of mustangs eaten by cougars.

In herd areas as far flung as Arizona and Montana, horses and mountain lions maintain a working predator–prey relationship. In parts of Nevada, field scientists have discovered cougars with diets that consist almost entirely of mustangs. The big cats tend to prey on foals, although not exclusively, and they eat horses at a rate of roughly one every other week. When it comes to the question of how to create stable mustang populations, we find a scientific consensus on the idea that natural predation offers an important strategy. The only question still unanswered is the one about whether we can find the political will or cultural resolve to protect an ample number of lions.

Myth #5: Mustangs Compete with Other Forms of Wildlife

Wild horses coexist well with a wide range of herbivores. As a photographer, I’ve captured images of mustangs grazing side by side with elk, pronghorn, and mule deer. Through human eyes, they actually appear to enjoy mixed company. The relationship between horses and other herbivores is more directly beneficial, however. In the winter, horses use their strength and weight to break the ice on frozen creeks and ponds. In so doing, they keep water open and available for smaller animals like deer and antelope. In addition, when mustangs eat grass, the seeds pass through their bodies and return to the ground as a component of their manure. As a result, horses reseed the regions where they graze—a boon to all of the animals that depend upon grasses.

Reprinted with permission from In a Land of Awe: Finding Reverence in the Search for Wild Horses by Chad Hanson copyright © 2022 Broadleaf Books. 

Chad Hanson

Chad Hanson serves as a member of the faculty in sociology and religion at Casper College. He is co-founder of the Wyoming Mustang Institute, which works through research and advocacy to ensure healthy and stable wild horse populations on public land. Hanson is also the author of several books, including Trout Streams of the Heart and This Human Shape. He divides his time between Casper, Wyoming, and the Red Feather Lakes region of Colorado.

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