(MAMMOTH) Yellowstone National Park biologists are warning that grizzly bears have begun emerging from hibernation in the Greater Yellowstone Area, so hikers, skiers and snowshoers should take appropriate precautions during their activities. Spokesman Al Nash says that includes staying in groups of three of more, making noise on the trail and carrying bear spray. Park biologists point out that when the bears emerge from hibernation, they are – well, as hungry as bears – and will aggressively defend any carrion they may find. Consequently, people need to keep their distance from any winter-killed wildlife. The first confirmed reports of grizzly bear activity in the Park were received on March 4th. Guides and visitors observed and photographed a grizzly bear along the road in the Hayden Valley area. Meanwhile, the first black bear of the year was observed on February 11th near the south end of the park.