Grizzly bears are emerging from their dens at Yellowstone National Park.Park officials say that as grizzlies come out of hibernation, people should stay in groups of three of more, make noise on the trail and carry bear spray.
Bears look for food as soon as they emerge from their dens. Park officials say bears are attracted to elk and bison that have died during the winter.
The bears can react aggressively if they're surprised while feeding on the carcasses.
The Jackson Hole Daily reports that there haven't been any reports of bear sightings or tracks in Grand Teton National Park yet but, historically, half of the male population is usually out by now.
Visitors to both parks must stay at least 100 yards from black and grizzly bears.