YELLOWSTONE NATIONAL PARK, Wyo. — Grizzly bears have started to emerge from hibernation in Yellowstone National Park.

Park staff spotted an 11-year-old male grizzly bear wearing a radio collar in the west-central part of the park on March 6. The next day, park employees reported seeing a grizzly bear in the east-central part of the park.

Male grizzlies come out of hibernation in mid-to-late March. Females with cubs emerge later, in April to early May.

When bears emerge from hibernation, they look for food and often feed on elk and bison that died over the winter.

All of Yellowstone is classified as protected bear habitat, including the boardwalks around Old Faithful. The park advises visitors to stay at least 100 yards (91 meters) away from bears.