Why Did American Bison Nearly Go Extinct? History and Recovery

How many bison were there before the slaughter?

Nobody counted bison before the slaughter, so all figures are estimates. Around 1800, the American bison probably numbered in the tens of millions, with most estimates between about 30 million and 60 million. The higher figures come from early travelers’ descriptions of herds that took days to pass; modern historians, using estimates of how many grazers the prairies could feed, often favor the lower end.

Either way, the bison was the most numerous large mammal in North America, and the Great Plains were its stronghold.

The decline before 1870

The fall began well before the famous slaughter. Through the early 1800s, horses, guns and growing trade allowed both Indigenous hunters and European traders to kill more bison than before. Buffalo robes, the thick winter hides tanned with the hair on, were sold in large numbers to markets in the East and in Europe.

At the same time, settlers’ livestock and the horses of wagon trains competed with bison for grass and water along the river valleys, and severe droughts in parts of the plains reduced food. Historian Andrew Isenberg argues that bison numbers were already falling by the mid-1800s, before commercial hide hunting arrived.

The hide hunters of the 1870s

The decisive blow came in the early 1870s. Tanneries found ways to turn bison hides into strong industrial leather, used for machine belts and other goods in eastern US and European factories. Suddenly a bison hide was worth money in any season, not just the thick winter robe.

New railroads across the plains, such as the Kansas Pacific and the Santa Fe, carried hunters out and hides back to market. Professional hunters with long-range rifles could shoot dozens of animals from one spot, while skinners stripped the hides and usually left the meat to rot. Hornaday estimated that hunters killed more than 3 million bison on the southern plains alone in 1872–1874. The southern herd was almost gone by about 1878, and the northern herd was destroyed in the early 1880s after the Northern Pacific Railroad reached Montana.

The role of government policy

The US government did little to stop the killing. Congress passed a bill to protect bison in 1874, but President Ulysses S. Grant did not sign it. Many army officers and officials openly welcomed the slaughter, because Plains nations such as the Lakota, Cheyenne, Comanche and Kiowa depended on bison for food, clothing and shelter.

The loss of the herds was devastating for those nations and helped force them onto reservations. Many historians therefore describe the destruction of the bison as part of a wider campaign against Indigenous peoples, not only an environmental disaster.

How close did bison come to extinction?

In 1886, William Hornaday of the Smithsonian traveled to Montana to collect specimens and was shocked at how few bison he could find. His 1889 report, The Extermination of the American Bison, estimated that only about 1,091 bison were left. Roughly 200 survived in Yellowstone National Park, about 550 wood bison lived in northern Canada, and most of the rest were in a few private herds and zoos. Only a few dozen wild plains bison remained outside Yellowstone.

Even Yellowstone was not safe. Poachers kept killing bison inside the park, and by 1902 only about two dozen wild animals were left there.

How were bison saved?

Recovery came from several directions at once:

• A few private herds. In the 1870s and 1880s, a handful of ranchers and Indigenous and Métis families caught calves and kept small herds, including the Walking Coyote and Pablo-Allard herd in Montana, Charles and Mary Goodnight’s herd in Texas, and herds in Manitoba, Kansas and South Dakota. Nearly all plains bison today descend from these few dozen animals and the Yellowstone survivors.
• Protection in Yellowstone. After a notorious poaching case, Congress passed a law in 1894 making it illegal to kill wildlife in the park. In 1902, bison from private herds were added to the remnant wild herd, and the army guarded them.
• The American Bison Society. Founded in 1905 by Hornaday and others, with President Theodore Roosevelt as honorary president, it helped create public herds such as the Wichita Mountains refuge in Oklahoma, stocked in 1907 with 15 bison from the Bronx Zoo, and the National Bison Range in Montana, established in 1908.
• Canada’s purchase. Between 1907 and 1912, Canada bought the Pablo herd, more than 700 animals, and moved them to parks in Alberta. Wood Buffalo National Park was created in 1922 to protect the last wood bison.

Bison recovery today

Bison numbers rose slowly through the 20th century and then quickly as ranching grew. Today there are roughly 400,000 bison in North America, but most are raised for meat. Only a small share live in conservation herds, and many herds carry traces of cattle genes from crossbreeding experiments in the early recovery years. The IUCN lists the species as Near Threatened.

Indigenous nations play a growing role. The InterTribal Buffalo Council, formed in 1990, helps dozens of tribes restore herds to their lands, often using surplus bison from Yellowstone. Full numbers are explained in how many bison are left?, and the story continues across the Atlantic with the European bison, which was saved from extinction in a similar way in the 20th century.