"In the 1960s, Yellowstone National Park (YNP) threw active herd management to the wind," the lawsuit reads further. “The bison population boomed, spilling brucellosis-infected bison into Montana and forcing the State to pick up YNP's slack in order to protect its livestock industry from the disease."

Bison in Yellowstone National Park may seem calm, but approaching them is extremely dangerous. Learn why these massive animals should always be admired from a safe distance and the steps to ensure your safety while visiting the park.

State officials say they're worried about bison passing on disease to cattle outside the park—but wildlife managers say it's never happened before.