In one instance, park officials were forced to put down a bison calf because of an encounter with a park visitor, CNN reported. According to Yellowstone, bison are vital to the park's ecosystem.

A bison dies in front of horrified tourists when it falls into a hot spring at Yellowstone National Park. USA Today “I thought it was a great photo opportunity.” ...

She said it was about 7:15 p.m., very foggy and "really eerie and mysterious" when they spotted animal prints. "There were bear tracks and bison tracks and we were taking pictures of those.

Last week we featured footage showing bison stampeding toward a snow coach in Yellowstone National Park, as tourists watched with heightened concern. To their relief, the bison navigated around ...

A bison was gruesomely boiled to death in a Yellowstone National Park hot spring last week — as tourists watched in horror. The buffalo met its ghastly end when it apparently stumbled into the ...