How Bison Survived Near Extinction to Become America’s National Mammal

The majestic bison, which once roamed North America in endless herds stretching from Alaska to Mexico, was nearly wiped out in the 19th century in the name of expansion, profit and “progress.” The history of the bison is intertwined with Native Americans, for whom bison were spiritual equals and a life-sustaining resource for more than 10,000 years.

“The bison hunt is the oldest sustained economy for human beings in North America,” says Dan Flores, an environmental writer and historian of the American West. “One of the reasons why that ecological equilibrium lasted so long was because bison were so remarkably adapted to the Great Plains.”

Bison numbers in the United States were reduced from an estimated 30 million animals to barely more than 1,000 by the late 1880s. Thanks to early conservationists and the cooperation of Indigenous tribes, bison were pulled back from the brink of extinction, a fate that befell other native species like the passenger pigeon.

In 2016, President Barack Obama signed legislation naming the bison the U.S. “national mammal,” which distinguishes it from the bald eagle—the national bird and a centuries-old symbol of the United States.

When the first Paleoindian hunters in North America encountered bison between 13,000 and 12,000 years ago, the Great Plains were filled with a menagerie of large grazing animals and predators, writes Geoff Cunfer in Bison and People on the North American Great Plains: A Deep Environmental History.

Paleolithic megafauna included horses and camels—both native to North America—but also the American mastodon, giant armadillos, saber-toothed cats and dire wolves. Bison, which today weigh as much as 1,000 pounds and stand up to 6 feet tall at the shoulder, were also about one-third larger in the past.

Then, around 11,000 to 10,000 years ago, dozens of species of North American megafauna disappeared in what’s known as the “Pleistocene extinction.” The mass extinction event was triggered by a combination of rapid climate change and overhunting by ancient humans, but somehow bison survived, albeit in a smaller form. Due to a lack of grazing competition, bison experienced an “unprecedented ecological emergence,” says Flores, author of Wild New World: The Epic Story of Animals and People in America.

“In the post-Pleistocene period, bison supplanted many of the grazers that had been in North America prior to their arrival, and converted the Great Plains into this gigantic bison belt,” he says.

How many bison were there? Wildlife historians used to claim that as many as 100 million bison roamed the Great Plains in ancient times, but Flores says that a more accurate estimate—based on the biological carrying capacity of the land—is between 20 million and 30 million.

The ancestors of modern Native Americans not only relied on the bison hunt for food and clothing, but also revered the bison as one of the first creatures created on Earth, with a spiritual power equal to or greater than humans. Flores says that over the millennia, Native people developed elaborate ceremonies, rituals and dances to renew “kinship pacts” with the bison that tied together the fates of both the animal and humans.

“The Mandan ceremonies, for example, in the spring and summer, were all about renewing these kinship ties with bison,” Flores says. “People are dressing up in bison robes and bison horns and doing dances that confirm to the bison that humans and bison are the same people, that we’re not superior to them.”

Before horses and rifles, the bison hunt was a communal effort. Bison can run as fast as 35 mph and weigh as much as a small car, so ancient North Americans developed strategies to safely harvest bison in large numbers.

At “kill sites” like the Olsen-Chubbuck site in eastern Colorado, Paleoindians drove 190 bison into a narrow arroyo—a steep-sided dry riverbed—where they had no way of escaping. At the Head-Smashed-In Buffalo Jump in Alberta, Canada, there’s evidence that hundreds of bison could be harvested in a single day by stampeding them off steep cliffs.

Over long stretches of time, the bison population in North America fluctuated with the shifting climate, Flores says. In periods of hot, dry weather, the grasslands could only support 20 million bison. But when the weather was cooler and wetter—as it was during the “Little Ice Age” from roughly 1500 to 1850—it resulted in a bison boom.

“What [the Little Ice Age] does in terms of bison is it produces bumper crops of grasses year after year,” Flores says. “That supports a very large bison population at the upper end of 30 million animals, enough that bison began spilling out of the Great Plains and into places like Virginia, Pennsylvania and Florida.”

Horses disappeared from North America 11,000 years ago during the Pleistocene extinction, but were reintroduced by Spanish settlers in the 16th century. When Native Americans on the Great Plains began riding domesticated horses, it fundamentally changed the bison hunt. “Compared to hunting bison on foot, the horseback chase was safer, faster, more efficient and much more deadly for the bison herds,” writes Cunfer. “With the arrival of horses, ancient communal bison drives began to disappear, replaced by horseback assaults.”

By chance, the adoption of horses by Native Americans overlapped with the Little Ice Age, when the bison population in North America was at its peak. The availability of bison and the new horse “technology” drew increasing numbers of Native tribes away from agriculture and onto the Great Plains.

“During these years between 1500 and 1850 or so, you have really ripe conditions for what becomes the classic Native American pursuit of bison,” Flores says.

Cunfer points out that horses not only supercharged the bison hunt, but also transformed Native American cultural practices. Over the course of just a few generations, fierce competition for the best hunting grounds led to the rise of “warrior societies” on the Great Plains, where bravery and battlefield skill became supremely important.

The Little Ice Age started waning in the 1830s, bringing hotter, drier conditions to the Great Plains. The timing couldn’t have been worse for the bison. Before the arrival of the horse, bison could retreat to buffer grazing zones in times of climate stress. But by the mid-1800s, there were hundreds of thousands of horses on the Great Plains competing with the bison for grazing land.

Worse, white settlers were crossing the Great Plains in increasing numbers. Not only did they indiscriminately shoot bison, but the oxen pulling their wagons carried Old World bovine diseases like anthrax and bovine tuberculosis that infected the wild bison herds. “So you get this kind of perfect storm that starts in the 1830s and begins drawing the bison numbers down," Flores says.

After the Civil War, Americans looked west and built the first railroad lines to frontier outposts like Montana, Colorado and New Mexico, where the last large populations of wild bison persisted. “The whole country appeared one mass of buffalo,” wrote Colonel Richard Dodge when he walked the Santa Fe Trail in 1871.

To the white hunter, the seemingly inexhaustible supply of bison on the Great Plains was a gold mine. The most valuable part of the animal was not the meat, says Flores, but the hide, which was shipped back east and converted into a tough industrial leather. “Bison leather was used to make the suspensions for wagons and stagecoaches and for industrial belting in factories," he explains. "This tough leather from bison hides actually played a major role in the Industrial Revolution.”

From 1871 to 1883, white hunters flooded the Great Plains and worked in coordinated teams of sharpshooters and skinners. Flores says that the unrelenting pace at which millions of bison were killed and skinned in the late 19th century transformed the Great Plains into an “open-air industrial slaughterhouse” resulting in “the largest destruction of animal life in modern history.”

When the National Museum in Washington, D.C., sent an expedition to Montana in 1886 to bring back specimens from the fast-disappearing bison herds of the Great Plains, they determined that no more than 30 animals were alive in Montana and only 1,073 bison were left in all of North America.

There’s a persistent myth that the U.S. Army conspired with white hunters to eradicate the bison as a way of forcing Native Americans onto reservations. Flores traced that false claim to a bison hunter named John Cook, who tried to deflect criticism of the wholesale slaughter of bison by claiming hunters were secretly working with the government to make the West safe for “civilization.” That wasn’t true.

“A story like that is supposed to make us feel better about ourselves,” says Flores, “that it wasn’t regular Americans who did this to the buffalo, but the federal government as part of a secret conspiracy. But in fact, what really did the buffalo in was capitalism; a global capitalist market that saw these animals as a way to make money.”

The U.S. government might not have called for the eradication of the bison, but it did nothing to stop it. It took a grassroots effort by everyday Americans to save the last of the bison, lobby for federal protection and slowly build back the wild herds.

Starting in the 1880s, individual ranchers like Charles Goodnight in Texas and Frederick Dupree in Montana were alarmed by the rapid disappearance of bison and took it upon themselves to do something about it. They captured wild buffalo calves and raised small herds on their lands, where they were protected from hunters. Some of those “founding herds” are the ancestors of the roughly 50,000 wild bison alive today that live on federal land and tribal land.

In the 1890s, George Bird Grinnell, an anthropologist and journalist, used the pages of the magazine Forest & Stream to expose the illegal poaching of the last wild herd of bison in Yellowstone National Park. Grinnell won the support of Theodore Roosevelt, then a civil service commissioner in Washington, D.C., who aggressively lobbied Congress to pass a law imposing steep fines and jail time for the killing of Yellowstone’s bison. It was the first animal protection law in the United States.

When the bald eagle was threatened with extinction due to hunting and habitat loss, Congress passed the Bald Eagle Protection Act in 1940. That law, along with the Endangered Species Act of 1973, helped save the bald eagle, which was chosen as America’s national symbol in 1782.

Flores sees real significance in naming the bison the U.S. national mammal. Given how close the bison came to total eradication, it can serve as an “avatar species” for the need to protect other endangered wildlife in America.

“It elevates the bison alongside the bald eagle, really, as one of the symbols of the American story,” Flores says. “And it gives us an opportunity to tell this story, not just about the bison, but about all these other creatures—passenger pigeons, the great auk, Carolina parakeets—that became extinct or nearly so.”