Over the past couple of months or so, bears across much of the Northern Hemisphere have been exiting their winter dens. From the Rocky Mountains of North America to the taiga of Scandinavia, hikers, mushroom-hunters, anglers, and other outdoorsy types once again need to be diligently “bear-aware.”
And there’s been plenty of bear action already, as it happens: enough to justify something of a springtime “bruins-back-in-action” roundup.
In Wyoming’s Grand Teton National Park alone—part of the Greater Yellowstone Ecosystem in the Northern and Middle Rocky Mountains of the U.S.—grizzly bears have been very much in the news in recent weeks. On May 13th, park biologists there found the carcasses of two yearling grizzlies that showed signs of having been preyed upon by another bear—likely a boar, given male bears represent one of the starkest threats for cubs. The killed yearlings appear to have belonged to a tagged sow, Grizzly Bear 1063, who was observed—alone—in the vicinity as park officials conducted followup monitoring.
“While it is incredibly sad to see a grizzly bear lose its cubs,” Grand Teton National Park Bear Biologist Justin Schwabedissen said in a news release, “predation by other bears is a natural source of cub mortality in the Greater Yellowstone Ecosystem and has previously occurred in Grand Teton.”
And in a happy development, a subsequent Grand Teton National Park social-media post revealed that Grizzly Bear 1063 was seen later that week in the company of her third, very much alive, cub, whose fate till then hadn’t been accounted for:
The loss of two young bears to a boar grizzly is an ancient event; death by vehicle falls in another category of mortality, of course—a more tragic, and much more recent, one associated with human development and activity. On May 6th, a subadult (reckoned at five years old) male grizzly, Grizzly 1058, was found dead in roadside willows near Grand Teton’s Buffalo Fork River, apparently struck on Highway 26. This discouraging development echoed the demise of his mother: the world-famous, much-photographed sow Grizzly 399, who’d given birth to 1058 as part of an astonishing litter of quintuplets in 2020. Last October, a vehicle killed 399 in the Snake River Canyon south of the national park, snuffing out what had become one of the most celebrated grizzlies anywhere and an exceptional matriarch.
On a cheerier front, the start of May saw one of 399’s go-to suitors—the big boar nicknamed “Bruno,” who’s thought to have sired a slew of progeny—trying his hand (paw) at ice-fishing for trout at Oxbow Bend along the Snake River in Grand Teton. His somewhat clumsy but semi-successful efforts were documented by a Roam Wild Photo Tours group, which, according to Cowboy State Daily, observed the grizzly’s on-the-ice tactics for some 45 minutes:
Shortly thereafter at Oxbow Bend (once again as reported by Cowboy State Daily) onlookers filmed a stout-hearted coyote slink through the snow behind Grizzly 610—one of 399’s full-grown daughters—and give her a nip in the rear end, apparently on account the bear was pilfering one of the songdog’s food caches:
That’s not the only ursid/canid run-in caught on film in the Rockies this spring. Last month, photographer Cory Tilley posted some atmospheric footage of a freshly emerged grizzly crossing (peaceful) paths with a black wolf amid swirling April snow:
Earlier yet, on the last day of March, the Old Faithful/Upper Geyser Basin webcam in Yellowstone National Park captured a herd of bison run off a grizzly likely quite fresh out of its den and roaming the still-snowy landscape of the Yellowstone Plateau:
Most northern bear species such as the brown bear—of which the grizzly is a North American subspecies—are facultative hibernators. Indeed, bears are the biggest of all hibernators, a motley assortment of critters that also includes many rodents as well as certain shrews, bats, and dwarf lemurs. Besides their sheer heftiness, bears are unusual among this company in that they don’t as significantly reduce their body temperature during their winter sleep, though their metabolism majorly slows down; they also frequently rouse themselves, and may even leave the den here and there during hibernation season. (The ability of hibernating bears to maintain their muscle mass and bone strength despite months of lethargy has long fascinated medical researchers curious about the potential applications for human health and well-being.)
As observations of bears out and about on the snowpack and in dense flurries attest, the shaggy beasts are plenty resilient in the cold; the ultimate impetus for winter denning is likely the seasonal food shortage, given succulent plant matter, including young shoots and fruits, as well as insects are dietary mainstays for the omnivorous brown and black bears.
That said, the cozy refuge of a den is a good place to bring forth tiny, helpless cubs, as mother bears do in the dead of winter. Polar bears—the most carnivorous of all ursids—find good hunting out on the wintertime sea ice; pregnant sows are typically the only ones that hunker down for the season, bringing forth a new generation in the security and warmth of a snow den—much appreciated by the pipsqueak polar-bear cubs, which lack insulating subcutaneous fat and have but a thin coat of fine fur. (As part of a new study on maternal denning in Svalbard polar bears, some great remote-camera footage came out earlier this year showing sows and cubs emerging from their winter dens.)
Warming spring temperatures and the onset of snowmelt appear to be triggers for bears to exit their dens for good, as a remote camera in the Sierra Madres of Wyoming captured an American black bear doing back in April:
How climate change will affect the denning patterns of bears is an open topic of research.
Meanwhile, a brand-new study out of the Brooks Range of Alaska shows that the Arctic grizzlies there—which tend to emerge in late April in concert with the melt-off of snowcover—spend an average of a whopping 206 days a year in their winter dens, with one griz staying snoozing and sequestered for 233 days: close to what biologists reckon is the physiological limit of a bear’s torpor duration. “These are some of the longest denning durations ever reported in the world, and reflects the difficult living conditions for bears in the Brooks Range,” the study authors wrote in a National Park Service article.
Now that bears are roaming about again, vacationers getting a jump-start on the busy summer tourism season in the national parks of western North America and other corners of Northern Hemisphere bear country need to abide by proper bear-safety practices. These include everything from carrying (and knowing how to use) bear spray—here’s a primer video from Yellowstone National Park—to storing food and garbage in bear-resistant vehicles, storage containers, or devices, whether you’re in a front-country campground or backpacking deep in the wilds.
Speaking of, on May 15th, Yellowstone National Park officials had to euthanize the first grizzly there in some eight years on account the animal—a 400-pound, 11-year-old boar—had been wrenching out bear-resistant trash cans from their concrete footings and upending 800-pound bear-resistant dumpsters in some highly trafficked areas. Yellowstone’s long-serving Bear Management Biologist Kerry Gunther said in a park news release, “It’s unfortunate that this bear began regularly seeking out garbage and was able to defeat the park’s bear-resistant infrastructure. We go to great lengths to protect bears and prevent them from becoming conditioned to human food. But occasionally, a bear outsmarts us or overcomes our defenses. When that happens, we sometimes have to remove the bear from the population to protect visitors and property.”
Another reminder for the 2025 “bear-active” season: The death of Grizzly 1058 in Grand Teton National Park by vehicle strike shows the importance of slowing down and always remaining keen-eyed on roadways passing through prime wildlife habitat.
This article by Ethan Shaw was first published by Earth Touch News Network on 5 June 2025. Lead Image: Grizzly bears are out and about. Image © Gregory “Slobirdr” Smith.
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