Grizzly bear standing sentinel in a field
A female brown bear stands guard near its young. A bear cub can be seen rolling in the grass in the foreground of the photograph. These bears live in Lake Clark National Park, Alaska. Just a few hundred miles north of this mild brown bear habitat, arctic polar bears live and hunt. Biologists believe that polar bears evolved from brown bears around 150,000 years ago.
Stock Image #20140716-085501