Bear Hibernation and Reemergence in Yellowstone

When do the Yellowstone bears hibernate and when do they wake and come out of their dens? See photos and watch a video.
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Grizzly bear in Yellowstone Park

Grizzly bear in Yellowstone National Park. 

Visitors to Yellowstone National Park has an excellent chance of seeing grizzly and black bears. Bears are seen many places in the park such as the Lamar Valley. Since bears hibernate in the winter, and much of the park's best bear habitat has seasonal closures to protect both bears and humans, make sure you are familiar with the regulations before embarking into the backcountry in search of a bear observation.

When do Yellowstone Bears Hibernate and For How Long?

Grizzly bear in the canyon area on Nove 20, 2014

Grizzly bear in the canyon area on Nov 20, 2014. 

Depending on snowfall, temperature and food supply, bears get ready for winter hibernation in late November. The denning period in Yellowstone National Park is approximately 5 months.

Grizzly bears and black bears generally do not eat, drink, defecate, or urinate during hibernation. They live off of a layer of fat which was built-up during summer and autumn. Bears maintain a body temperature close to normal during hibernation which lets them react to danger and sources of food faster than many other hibernating animals.

Video of a Grizzly Bear in Hibernation

Transcript - Christmas in Yellowstone: "High in the fiercest peaks, there's a small retreat that winter will never reach - the den of a grizzly bear. The bear is not asleep. Since November, she's been in a state of hibernation. Her heart beats a third of its normal rate. She breathes less than twice a minute. She won't eat or drink for up to five months. She won't urinate or defecate. She'll recycle her own waste into protein, losing weight yet building muscle, all while barely moving. Safe from cold and hunger, she has mastered the winter wilderness."

In Springtime, Bears Emerge From Their Dens

Grizzly Bear near Obsidian Creek on April 24, 2009

Grizzly Bear near Obsidian Creek on April 24, 2009

Grizzly Bears

Male grizzlies come out of hibernation in mid to late March. Females with cubs emerge later, in April to early May. After an unseasonably warm winter, bears may come out of hibernation as early as January or February.

Black Bears

Black bears den in lower elevations and therefore wake earlier, typically in late February.Sometimes, if there is a warm winter and food is available, the bears might emerge out of their dens to eat.


When bears come out of hibernation, they look for easy food sources. Often, the quick meal is a carcass of an animal that has died during the winter (winter-kill), namely elk and bison. Later in the Spring, young new-born elk and bison calves become the meal of choice.

It is a bit of a myth that bears awake super hungry. Kerry Gunther, who leads Yellowstone's bear management program told the Yellowstone Forever Institute, "When they first come out they don't eat that much, and they are lethargic. For a week or two they spend more time sleeping on the carcass than eating it. Their metabolisms are not totally kicked in--they are in a kind of walking hibernation."

Learn more about What Yellowstone Bears Eat

Keep a Safe Distance from Bears

It's very important to remember that bears are dangerous animals. Bears have killed people in the park, so if you do see a bear from the road, make sure you remain in your car as you observe the animal from a safe distance.


Black bear crossing the road in Yellowstone. Photo by NPS Jim Peaco.

Yellowstone Bear Jams on Roads

When Yellowstone National Park visitors behave appropriately around roadside bears it's a positive experience for both bears and people.

Black bear near Indian Creek Campground in Yellowstone.

What Do Yellowstone Bears Eat?

Bears are omnivores. That means they eat both meat and plants. But bears also have seasonal needs for food based on a hibernation period.

"Lunch Counter - For Bears Only" at Old Faithful, southeast of the upper Hamilton Store, and Ranger Naturalist Walter Phillip Martindale;

No More Lunch Counter for Yellowstone Bears

Today, it would be unheard of for people to intentionally feed bears but in the early 1900s it was common practice.

Grizzly Bear

Where to See Bears in Yellowstone

From 1980 to 2005, over 37,000 bear sightings from park visitors have been reported to park managers...

Grizzly bear and cub.

Yellowstone Bear FAQs

Here are the answers to the difference between a grizzly and black bear, the odds of seeing a bear in the park, and if you should be afraid of bears.

Grizzly bear eating in Yellowstone

Yellowstone Bears Eat 40,000 Moths a Day In August

Bears climb high above timberline in Yellowstone National Park to feed on moths that come from farmland many miles away.

Grizzly bear closeup

What to Do If You Encounter a Bear at Yellowstone

Ahhhh. You turn a corner - only to find yourself way too close to a real-live bear! It turns to look at you, almost in slow motion, and you freeze...


Yellowstone Grizzly Bears vs. Wolves

For decades, the sole rulers of Yellowstone were grizzly bears. They are now re-learning how to cope with the rise of an equal competitor - the reintroduced gray wolf.

Grizzly bear. Photo by Jeff Vanuga

Where to See Bears, Wolves and More in Yellowstone and Grand Teton

Wildlife is abundant throughout these two national parks. See them in their natural habitat in the areas they frequent most.