A bison is a massive, shaggy mammal that once roamed the North American plains in herds numbering in the millions. Picture an animal that can weigh as much as a small car, standing six feet tall at the shoulder, with a huge humped back, curved horns, and a thick coat of dark brown fur. That's a bison.

Many people call bison “buffalo,” but they're technically different animals (true buffalo live in Africa and Asia). For thousands of years, bison were central to the lives of many Native American tribes, who used every part of the animal: meat for food, hides for clothing and shelter, bones for tools. By the 1880s, hunting had reduced the population from perhaps 30 million bison to fewer than 1,000. Conservation efforts saved them from extinction, and today around 500,000 bison live in North America, though most are on ranches rather than roaming wild.

Bison are surprisingly fast for their size, capable of running 35 miles per hour and jumping six feet high. They look slow and peaceful while grazing, but they're unpredictable and dangerous when people get too close. In Yellowstone National Park, more visitors are injured by bison than by bears.