Grizzly 399 Likely Hibernating While Warm Weather Has Kept Other Bears Out Late

Wildlife photographers who have followed Grizzly 399 for years, say the bear and her super-sized cub have likely gone into hibernation. Not so for many other bears, however, as warm weather has kept them active in the Greater Yellowstone Ecosystem.

Mark Heinz

December 21, 20234 min read

399 in the snow 12 22 23
(Cowboy State Daily Staff)

A warm December has kept some Wyoming bears out late, but the most famous bear of all, Grizzly 399, along her super-sized cub, apparently went into hibernation at a sensible time.

While some grizzlies might be popping in and out of their dens, 399 and her cub Spirit haven’t been spotted in weeks, meaning they’ve likely gone into their winter den to stay, veteran Wyoming wildlife photographer Jack Bales told Cowboy State Daily.

No More Bear Buffet

It’s probably not so much warm weather as it was a lack of fresh elk gut piles left by hunters and other food sources that sent 399 and Spirit into hibernation at roughly their usual time last month.

Their favored denning spot is in an elk hunting area where “only 10-12 (elk) taken,” Bayles said. “So, no wounded loss, and not many gut piles. No real reason to stay awake.”

An Eventful Year

Grizzly 399 usually hangs out around Grand Teton National Park. Over the years, she developed a habit of taking her cubs near roads and other crowded areas. Photographers and biologists speculate she does this because it helps keep the cubs safe from large male grizzlies, which sometimes kill other males’ cubs.

That made her and her cubs easily accessible to the public, and she build up a worldwide fan base as photos and videos of 399 and her broods blew up on social media.

At 27, 399 is of an advanced age for a grizzly. Few of the species live into their 30s. So when she took her time emerging from her den this past spring, there was some concern that she died over the winter.

But those fears were laid to rest May 16, when 399 was finally spotted and – much to the delight of her fans — had a brand-new cub.

Various names were floated for the new cub before a general consensus was reached for Spirit. And probably because of a lack of competition from siblings, Spirit grew to an unusual size over the summer and fall.

There was some worry that 399 might not live long enough to rear Spirit to the age of independence, which is generally around 2 or 3. However, 399’s teeth still seem to be in good shape. And given that, grizzly expert Chuck Neal of Cody has told Cowboy State Daily that he’s confident she’ll live at least long enough to see Spirit go off on his own.

Staying In Her Den

And going to bed at a decent hour, so to speak, might be one of 399’s secrets for a long, healthy life.

Veteran Wyoming wildlife photographer Jorn Vangoidtsenhoven told Cowboy State Daily that he hadn’t heard of any recent activity from 399 and Spirit, even if other grizzlies haven’t fully settled down for the winter.

“It is possible that bears go in and out of their den, especially if the entrance is not snow covered yet,” he said. “Based on what I've seen and learned, bears typically go into the den before a significant storm so that the snow will cover the den entrance — typically north facing.

“Bears in warmer areas don't hibernate as long, or sleep as deep, since the temps and food are ok outside. In the GYE (Greater Yellowstone Ecosystem), the enclosed den provides security from the cold.”

Winter Encounters Possible

Most grizzlies, as well as black bears, den up once the snow really starts flying. But bear experts have told Cowboy State Daily that it’s still possible to run into bears any time of year.

The bears that are still out in the public eye and being featured on social media posts might be drawing lots of attention. But there’s no evidence that an unusual number of grizzlies are still active this month, Wyoming Game and Fish Department Large Carnivore Specialist Dan Thompson told Cowboy State Daily.

Most bears are probably snuggled into high-altitude dens.

“We have a lot of cameras out for monitoring of other species and haven't noticed anything out of the ordinary,” he said. “The high country is quite ‘winter wonderlandish’ where most bears are in slumber.”

Mark Heinz can be reached at

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Mark Heinz

Outdoors Reporter