This winter saw the most wolves from Yellowstone National Park killed in about a century. That's because states neighboring the park changed hunting rules in an effort to reduce the animals' numbers.

Gray wolves were once plentiful in Colorado. As settlers moved west and hunted the gray wolves’ natural prey, such as bison ...

In Yellowstone National Park, when a bison dies it’s not long before wolves or grizzly bears move in on the carcass. If one or two wolves are on the carcass, a lone grizzly bear can usually clear them ...

Wyoming’s Yellowstone bison look miserable when caked in snow and frost, but their thick coats, fat reserves and efficient digestion keep them warm ...