This grizzly bear is not sleeping. She's been in a state of hibernation since November.

When a bison goes down, grizzlies vie for control of the carcass. Ravens and wolves call for reinforcements.

To film a bear in hibernation, NATURE took on the challenge of creating a den which would resemble one a grizzly would make in Yellowstone.

Watch the full episode of The Good, the Bad, and the Grizzly online now.

Scientists have uncovered an evolutionary path suggesting that polar bears are a relatively new species.

Once the home of a notorious Soviet prison camp, the isolated peninsula of Kamchatka remains a haven for one of Earth's last giants, the grizzly bear.

While we had been away for the winter, all our wonderful bears had been killed. Maureen and I could hardly function we were so devastated.

This collection of photographs documents the time that Charlie Russell and Maureen Enns spent with three grizzly cubs in Kamchatka.

In the spring of 1997, naturalist Charlie Russell and artist Maureen Enns became the proud foster parents of three rambunctious daughters.

The moment Charlie Russell and Maureen Enns saw the three orphans in a Russian zoo, they knew what they had to do.