No to Feral Horses
Wild (feral) horse, Monitor Valley, Nevada © George Wuerthner
Editor’s note: Had we wanted to test the alertness of our readers, posting an article titled “Rewilding with Wild Horses” was a way to do it! Seldom before has Rewilding Earth received so many tendentious responses to an article as we got to that one, posted in early November. In retrospect, we should have prefaced it with an editorial note explaining that The Rewilding Institute remains open-minded on the question of whether and where wild horses, mustangs, may belong in North America. We have heard credible arguments, like the one we just ran, suggesting that the wild horses now roaming some parts of the American West are—although brought here by European colonists—appropriate surrogates for the original, native horses that galloped about much of our continent before (more & more evidence suggests) being hunted to extinction by the first peoples on our continent (part of the Overkill Hypothesis, of which our founder, Dave Foreman, was an articulate proponent).
Most of our respondents, so far, have countered that horses in North America today are exotic and destructive. George Wuerthner, an ecologist who has probably visited and photographed as many wild areas as anyone alive in North America today, takes this more purist perspective in his essay below, urging that we recognize wild horses in the American West as a non-native species that ought to be removed.
Opinions expressed in this horse debate are the authors’ and not necessarily endorsed by The Rewilding Institute.
For my own tiny part in this equine saga, I admit to having grown fond of wild horses after admiring their small swift herds while I was backpacking through Wyoming’s Red Desert years ago. To me, the horses looked wild and natural, whereas the cattle looked exotic and destructive.
Whatever your view on this controversial issue, your feedback is encouraged. We’ve long wanted Rewilding Earth to be a forum for healthy debates on complex matters pertaining to the protection and restoration of wild Nature. If we have enlivened that forum by running a controversial piece, we are glad to have added a few sticks to old Uncle Dave’s Campfire.
–John Davis, US Northeast resident, Western wanderer
No to Feral Horses
By George Wuerthner
A recent commentary by Liz Koonce published by The Rewilding Institute titled: “Rewilding with Wild Horses” deserves an alternative perspective. Koonce proposes using horses to “restore” grassland ecosystems, increase carbon sequestration, and provide opportunities for “horse-obsessed girls” to see wild or, more appropriately, feral horses.
Although I can not respond directly to most of Liz Koonce’s assertions, partly because she provided no references, I will attempt to explain why such a plan would be disastrous for rewilding efforts and landscape conservation.
Let’s start with a few of the assertions she got right. Like most feral horse advocates, she correctly notes that there are far more sheep and cattle on public lands than horses. Many ranchers and agency folks ignore the damage done by domestic cattle and sheep and use feral horses as scapegoats.
There is no doubt that livestock are the dominant harmful influence on public lands, and removing domestic animals would benefit ecosystem integrity. However, permitting another exotic animal to colonize and exploit public lands can have a major impact on native wildlife and ecosystems.
However, there still are 83,000 feral horses on public lands, and their numbers are growing rapidly, at a rate of 20% a year. Numerous studies document the ecological impacts of feral horses on native plant communities and other wildlife.
As ranchers, agency managers, and scientists note, horse populations are not managed like livestock. It’s an exaggeration for livestock advocates to claim cows and sheep are effectively managed. Still, putting that aside, it is true that domestic livestock have seasonal grazing schedules, limits on numbers, and other regulations that, when fully implemented, do mitigate to some degree livestock impacts.
Feral horses at Pryor Mountains, Custer Gallatin NF, Montana © George Wuerthner
By contrast, feral horses are on the land year-round, with limited management other than attempts to capture and remove animals. In the Great Basin, where most feral horses are found, the only significant predators are cougars. Cougars stalk horses and ambush them with a sudden run.
Horses are cursorial animals that rely on their ability to outrun predators, which limits cougars as an effective population control. The fact that many horse herds multiply rapidly suggests that cougar predation is not a significant population control agent.
Horses can become an alternative prey that sustains higher cougar populations. This could permit cougars to capture bighorn sheep struggling in many parts of the West—admittedly primarily due to domestic livestock.
Feral horse advocates argue that horses fill a missing niche because they were essential to late Pleistocene faunal assemblages. Animals are not cogs in a wheel. They are part of a complex web of interactions with other plants and animals.
Ranchers and livestock advocates like Allan Savory use the same argument, suggesting that domestic livestock merely replace the missing herbivores that existed at the end of the Ice Age and that plant communities are adapted to the influence of grazers. Horse advocates like Koonce make the same basic argument when they suggest the “grass remembers” the horse.
The problem with this logic is that all plant and animal communities evolve in response to climate, animal, and plant influences. The plant and animal communities that existed at the end of the Pleistocene no longer exist. Substituting either cattle, sheep, or feral horses for the diversity of native herbivores that once existed results in different ecosystem functions.
For instance, one of the major changes in Great Basin plant communities is the absence of large herds of grazing animals. Consequently, many species of Great Basin plants do not tolerate heavy grazing pressure. As a case in point, bluebunch wheatgrass, a common grass species in the Great Basin, can take up to ten years to recover from a grazing event. This long recovery time for the grass is one reason domestic livestock grazing is so destructive to Great Basin plant communities. It is also why this region’s ecosystems are so vulnerable to grazing damage from herds of horses and burro.
Feral horses at Steens Mountain Wilderness, Oregon © George Wuerthner
EVOLUTIONARY HISTORY
The ancestor of today’s horses first appeared in North America approximately 55 million years ago (about 10 million years after the dinosaurs went extinct). The earliest relatives of today’s horse were small forest-dwelling animals.
Due to the changing climate, grassland expansion began about 20 million years ago, and among the species that exploited this expanding habitat were the early relatives of today’s horse. They became larger, longer-legged, and fleet of foot.
As recently as ten million years ago, there were up to a dozen species of horses roaming the North American landscape. Only one branch survived into the modern era. The oldest known species of what is commonly assumed to be a modern horse evolved about 4 million years ago. From North America, the animals dispersed to Asia, Africa, and Europe several times and twice to South America. In the Old World, horses, zebras, and donkeys did not die out. Around 5,500 years ago, people in Kazakhstan began riding horses for the first time.
The horse and numerous other Ice Age mammals disappeared from North America sometime between 12,000 and 10,000 years ago. There is significant debate about the causes, but most theories suggest changing climate, perhaps augmented by early human hunting pressure, led to the demise of the horse and other larger mammals. However, it’s important to point out that horses survived in Asia, where plenty of human hunters existed.
There is controversy about exactly when horses died out in North America. Though most scholars agree with an extinction sometime between 12,000 and 10,000 years ago, some researchers from the Yukon using DNA in the soil suggest horses may have survived until 6,000 years ago.
Some even suggest that Indigenous oral history asserts that horses never went extinct. Oral history is an unreliable source of biological information. As every child knows from grade school, if you whisper a sentence or phrase in the ear of someone and repeat it around a circle, it seldom comes out the same at the other end of the process. To suggest that oral traditions are accurate over hundreds or thousands of years begs credibility, especially without additional physical confirmation.
If horses were still part of North American fauna, why didn’t tribes notice them and utilize them for food or pack animals? And why did Indians adopt horses big-time when they became available after Spanish colonization but chose not to adopt them before the Spanish came?
You must ask yourself why Indians would use inefficient bison jumps if they possessed horses. Why didn’t early Hudson Bay Company traders report horses among the tribes they traded with until the late 1700s and early 1800s? Why were horses buried with chiefs in sites after the spread of horses but not before? Why aren’t there horse remains with mummies (like the mummy cave by North Fork Shoshone) when there are other big animals such as elk and bighorn sheep?
But others assert that the lack of any “hard” evidence, like horse bones younger than 10,000 years, is inconclusive, in part due to uncertainties with carbon dating issues and soil contamination from either burrowing rodents or the freeze-frost of permafrost that could have mixed up DNA from older layers with younger soil samples. One of the problems with archeological studies compared to other sciences, where duplication of results provides some test of conclusions, is that archeological procedures are often destructive. Archaeology is a destructive science—meaning that once a site is excavated, it is gone forever. The artifacts and information gathered remain, but the site can never be recreated.
Still, with a few exceptions that are debated, most archeologists believe the horse was extinct in North America 10,000 years ago or at least so diminished that they were functionally extinct. Extinction for the horse was gradual, with some holdouts that lasted perhaps a few thousand years longer.
Feral horses at Pryor Mountains, Custer Gallatin NF, Montana © George Wuerthner
THE SPANISH AND HORSE ADOPTION BY INDIANS
The Spanish brought the modern horse to North America in the 1500s, and by the 1600s, the horse was being utilized by Indian people. With the coming of the Spanish into what is now the United States, Indians were trained to work with horses on Spanish ranches. The widespread adoption of the horse by tribal people is attributed to the Pueblo Revolt of 1680, where Indians overran the Spanish outposts in New Mexico. The Ute quickly adopted the horse, and horses were traded or stolen by other tribes further north. For instance, by 1730, if not earlier, horses were common among the Shoshone and Nez Perce.
However, there is historical evidence of the presence of horses among Indian tribes by the 1600s. For instance, La Salle documents the presence of horses among the Kiowa by 1682. It can be inferred that the Kiowa and other Caddoan tribes had horses before this date. As Wissler concludes: “It seems quite reasonable to assume that horse raiding by the Pawnee and Kiowa had begun in the early years of 1600. If this is correct and these historic tribes were in the same relative positions as later, 1650 should have found the horse abundant on the Saskatchewan River.”
However, some archeologists push back the adoption of the horse by tribal people by a hundred years or more, although this is based primarily on a few skeletons and oral traditions of Indian people. For instance, researchers found bones from one colt on the Blacks Fork, Wyoming, dated about 1650.
Just because a horse was found in Wyoming does not mean Indians were involved in horse culture. The discovery of horse remains could merely be evidence of individual animal movement rather than a viable population. Even today, there are records of long-distance movement of individual animals to areas well beyond their current ranges.
For instance, a South Dakota cougar managed to move all the way to Connecticut before he was killed. Such long-distance movement of animals in the days before there were freeways, large human populations, and many more people with guns would have been relatively common.
Another issue is the relative dates for a mere presence of horses among tribes vs a significant population of tribal horses. Some evidence suggests tribes killed horses for food before they learned to breed and use them for transportation.
The widespread adoption of the horse that led to the Plains bison hunting culture is a relatively recent and short-lived phenomenon. Research suggests that the Sioux, Crow, Arapahoe, Blackfeet, Cheyenne, Comanche, and other horse-mounted bison hunting people only adopted bison hunting culture in the 1600s-1800s. The Crow and Cheyenne lived along the Missouri River, growing corn and other crops in the 1600s, and only gradually adopted the typical plains bison hunting culture. The Sioux lived along the Great Lakes and only moved out to the plains in the 1700s. The Cheyenne only moved into Wyoming and Montana in the 1830s.
The DNA from archeological findings still links these horses to Spanish animals introduced in the Southwest sometime in the 1500s. Here, we get to the heart of the argument about whether horses are a “native” species that should be reintroduced across its former territory or an invasive exotic species no different from cattle. Putting aside whether horses survived somewhere in North America until 5,000 or 6,000 years ago, the fact remains that horses were no longer a prominent influence on grassland ecosystems by the end of the Ice Age.
Wild horses on snowfield Pryor Mountains, Montana © George Wuerthner
CLIMATE CHANGE AND FAUNA EXTINCTIONS
When people suggest that our continent was populated with horses, mammoths, camels, giant sloths, and other now-extinct North American Ice Age mammals at the end of the Ice Age and thus the mega-fauna could and should be reintroduced, they neglect to consider the entire ecological landscape is changed. The plant communities in the Great Basin 12,000 years ago were different. Water was more abundant, and the climate was cooler. Many species once common in the region are wholly gone or restricted to higher elevations and smaller footprints. Creosote bush, a common species found today in North American deserts, was utterly absent from the region 12,000 years ago.
Creosote did not become established in the region until 6,000 years ago. Juniper and pinyon covered much of the area that today sustains desert cacti. At the same time, ponderosa pine, a species common today in many mountain ranges in the Southwest, is virtually absent from the paleo vegetation record of the Great Basin.
With these changes in plant communities, there was a corresponding change in animal communities. The idea that you can reintroduce animals from Ice Age America back into the same regions today ignores the fact that there have been substantial changes in vegetation and wildlife.
For instance, at the end of the Ice Age, there were many more herbivore species residing in the West including camels, llamas, and giant sloths. These herbivores competed with horses for forage and habitat and had to deal with numerous predators like cheetahs, giant bears, and jaguars.
Climate changes resulted in changes in human predation influence. For instance, the warming and drying climate led to the extinction of mammoths approximately 11,000 years ago and a switch to human predation on bison. But by 8,000 years ago, even bison numbers were diminished, and Paleo-Indians had to switch to a diet of smaller mammals and plant materials.
CARBON SEQUESTRATION
The idea that horse grazing will sequester carbon is another myth that livestock advocates like Allan Savory perpetuated. The issue of carbon sequestration is complicated and dependent on many factors, including climate, plant communities, and current carbon storage.
For instance, carbon may for a time be stored most rapidly in depleted rangelands. As rangelands improve in ecological conditions, the rate of carbon sequestration slows, though the amount already stored is likely much higher than in degraded lands. It is similar to putting water into a glass. The more water already in the glass, the less additional water the container can hold.
While it is true that horses, as cecal digesters, do not emit nearly the amount of methane that results from domestic cattle, they still can damage rangelands and thus the ability to absorb and store carbon.
Wild horse, Pryor Mountains, Montana © George Wuerthner
SHELDON NATIONAL WILDLIFE REFUGE
Domestic cattle were removed from Sheldon NWR in 1994, but feral horses remained. Horses severely impacted riparian areas, competed with native herbivores for forage and water, and caused soil erosion.
An aerial survey in July of 2012 showed the 575,000-acre refuge along the Oregon border is home to at least 2,508 antelope, 973 wild horses, and 182 wild burros, said Aaron Collins, a park ranger at Sheldon.
An effort to remove feral horses was largely successful. Sheldon NWR is the largest expanse in the Great Basin without domestic or feral livestock, including horses.
SUMMARY
The bulk of evidence suggests horses once were abundant members of the late Pleistocene fauna; however, the plant and animal communities they once were members of no longer exist. Today’s feral horses were introduced into North America by the Spanish colonists. While they are not nearly as abundant on public lands as domestic cattle and sheep, they threaten ecosystem integrity.
To suggest that conservationists should ignore the impacts of horses merely because the damage from domestic livestock is more widespread is analogous to suggesting that society should ignore the impacts of heroin abuse because alcoholism affects more people. Domestic livestock and feral horses are problematic and must be removed from public lands.
George Wuerthner, resident of the US West, is an ecologist, photographer, and wilderness explorer. He has published 38 books on various topics related to environmental and natural history. He has visited over 400 designated wilderness areas and over 200 national park units.
George’s Books: On Amazon
George’s interview on Public Lands Grazing on Rewilding Earth podcast.
