From 1980 to 2005, over 37,000 bear sightings from Yellowstone Park visitors have been reported to park managers.
Grizzly bears are active primarily during nocturnal (night time) and crepuscular (dawn and dusk) time periods, said Gunther. Look for grizzly bears with a high power spotting scope in open meadows just after sunrise and just before sunset.
Grizzly bears are most commonly observed in Lamar Valley, Swan Lake Flats, Gardiners Hole, Dunraven Pass, Hayden Valley, and in the wet meadows along the East Entrance Road from Fishing Bridge to the East Entrance of the park.
Black bears are active primarily during crepuscular and diurnal (daylight) time periods. Look for black bears in small openings within or near forested areas.
Black bears are most commonly observed on the northern portion of the park along the road corridor from Elk Creek to Tower Falls, and from Mammoth Hot Springs north to Indian Creek.