LAKE LOUISE – A female grizzly is being given the best chance possible to survive and thrive in the hope she emerges from her den with cubs in spring.
On Nov. 4, Parks Canada closed Jimmy Junior-Hidden Bowl on the eastern slopes of Mount Jimmy Simpson south of Bow Summit, a popular backcountry skiing location, due to an eight-year-old female grizzly bear denning in the area.
Wildlife experts say the female bear was observed with a large male grizzly in June and July, and fear any noise or disturbance near her den may cause her to miscarry, or lose newborn cubs, if she was successfully bred.
“We’re optimistic that she might have another set of cubs this spring, given we observed her with a larger male during breeding season this last summer,” said Jon Stuart-Smith, a human-wildlife management specialist with Lake Louise, Yoho and Kootenay.
Grizzly bears are a threatened species in Alberta and reproductive age female grizzlies are critical to the long-term survival of the grizzly bear population in the mountain national parks.
Bred females experience delayed implantation; the embryo does not implant in the uterus until November or December, but only if the bear has enough fat reserves to sustain her and the developing fetuses through hibernation.
Cubs are born in the den in late January to early February and weigh about half a kilogram. While the female dozes for another several months, the cubs nurse on milk rich in fat.
There have been occasions when bears have abandoned their dens due to human activity.
“It’s a very sensitive time for her … she could potentially lose any cubs if she’s pregnant, or she might not have the reserves to be able to nurse them properly in the spring, if she’s disturbed,” Stuart-Smith said.
“We put this closure in place in order to give her the best chance of getting through that period and hopefully emerging in the spring with cubs.”
Parks Canada put a closure in place in this area in April 2019 after a group of backcountry skiers spotted a grizzly bear inside a den. It’s believed to be the same bear again this year.
Stuart-Smith said this female bear has never been captured or fitted with a GPS collar, but she has been observed in the area this year and it also falls within her larger home range.
“This bear is one that has been using that area for a number of years,” he said, noting she’s the daughter of bear 9301 and granddaughter of Blondie, which both included this region in their home ranges, too.
If this female bear has been successfully bred and emerges with cubs in spring, it will be her second litter.
After the closure of this area in 2019, she came out of the den with two cubs in tow; however, she lost both to what is believed to be natural causes of death.
Natural mortality is highest for young-of-year and is usually related to nutrition. Adult male bears also sometimes kill offspring.
“Grizzly bear survival at that age can be fairly low, probably about one in three that survive past the first couple of years of life,” Stuart-Smith said, noting the cubs’ carcasses were never located and there were no reports of human-caused death.
“We don’t know the exact fate of those two cubs for certain, but as far as we know, it was natural circumstances that those cubs didn’t survive.”
The male bear she was seen with during the breeding season was previously unknown to Parks Canada.
“It’s a bear we had not handled before,” Stuart-Smith said.
“This bear was noticed in the area from Mosquito Creek to Bow Summit during June and July, but we don't have any history what bear this might be.”
Meanwhile, Parks Canada reminds people to be alert and take all the necessary safety precautions such as carrying bear spray and knowing how to use it.
“Some bears are still out,” Stuart-Smith said. “We did have bear 122 on the weekend in the Lake Louise area, are so he’s still out and about.”
Anyone caught violating the closure at Jimmy Junior-Hidden Bowl could face up to a $25,000 fine if found guilty.
