Spiral Notebook
Evolution, Climate Change, and the Future of America’s Wild Horses
by Kay Frydenborg
October 31, 2012
Evolution, Climate Change, and the Future of America’s Wild Horses

Ever since they set hoof back on American soil after a 10,000-year absence, horses have inspired passion and controversy. Especially wild horses. Today is no exception. The issues are complex and emotions run high, but luckily, science is providing answers.

First, there’s the question of whether wild horses even exist in America. The U.S. Bureau of Land Management (BLM) oversees hundreds of millions of acres of open land where some 33,000 wild horses currently roam free, but the horses share that land with commercially-raised livestock, especially cattle. The BLM divides the ranges into livestock grazing allotments, based on their belief that feral horses are no more native to those lands than the cattle brought to America centuries ago from Europe and Asia.

But that theory has been challenged by a growing body of evidence from archaeological digs and university genetics labs. According to the latest science, today’s wild horses—in fact, even our domestic horses—are genetically linked to their ancient ancestors. Those ancestors evolved here in North America and nowhere else. As such, the science suggests, today’s wild horses are a part of the land, and deserving of protection as a native species. And if this is so, the massive round-ups and removals of wild horses conducted for years by the BLM in western states may need to be rethought. Lawsuits are pending in Federal District Courts to suspend these so-called “gathers” felt by many horse advocates and scientists to be inhumane and harmful to the horses.

Another important question: why did those original horses (along with some other large grass-eating mammals like the bison and wooly mammoth) disappear from North America a few thousand years ago? Was it sudden climate change that caused the extinctions, or something else? If we knew the answer, it might help us to preserve species in the future. As this week’s devastating and unusual Hurricane Sandy reminds us, weather patterns are changing in ways we’ve only begun to grapple with, and all life on Earth will be affected. Understanding how natural climate cycles in the past interacted with human acitivity could allow us to tackle this huge problem more effectively.

Again, science to the rescue! In the first large study combining genetic, archaeological, and climatic data to analyze what happened at the end of the Pleistocene Epoch, scientists concluded that both natural climate change (one of many historic warming cycles) and human activity in places where Ice Age mammals had once thrived account for the loss of horses and other large mammals from the North American continent.

It’s an ancient drama being replayed today in passionate controversies over the place of wild horses in the remaining open lands of our American West. With many more humans on the planet today than in the Pleistocene, and many more dramatic changes to both climate and habitats from human activities, studies like this one are really important. Read more about it here.


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