Lewis and Clark described for science at least 120 mammals, birds, reptiles and fish, as well as at least 182 plant species. Yet for many people, the Lewis and Clark Expedition is forever linked with the American buffalo/bison as a symbol of the great, unspoiled American west.
As the Corps of Discovery entered the Indian country up the Missouri in August 1804, it also got its first view of the great symbol of the Northern Plains, the buffalo. This animal quickly became the fuel that fired the hungry men of the expedition.Lewis and Clark encountered numerous herds of buffalo on their travels, some of which numbered thousands of animals. In Lewis' journal he describes: "immense buffalo herds ... in every direction,” and says the creatures were “so gentle that we pass near them ... without appearing to excite any alarm.”
Other journals describe " herds “so numerous” that they “darkened the whole plains.”
A fatal combination of events came together against the bison in the second half of the 19th century. American Indian tribes acquired horses and guns and were able to kill bison in larger numbers than ever before. A drought dried out the animals’ grassland habitat, which was already overburdened by new populations of horses and cattle. Farmers and ranchers began killing bison to make room for their animals. Some soldiers killed bison to spite their American Indian enemies, who depended on the animals for food and clothing.
Railroads were laid through the bison’s territory, dividing herds and accelerating the arrival of hunters, whose kills fed the high demand for bison hides back East and in Europe. Sport shooters traveled west to shoot the animals by the dozens, sometimes from the open windows of moving trains, and often left their bodies out on the plains to rot once the hunt was over.
By the beginning of the 20th century, there were only several hundred bison left in North America.
The efforts of early 20th century organizations like the American Bison Society, headed by zoologist William Hornaday and former president Theodore Roosevelt, were able to rescue the bison from its impending extinction. Today’s bison population is higher than 500,000 and steadily growing.