Mom/4 bear cubs doin well

[Lee Borgersen]

Mom, four bear cubs doing well near Cloquet

Mar 28, 2017 at 7:04 a.m.


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Last spring, the News Tribune featured a sow bear and her three yearling cubs in story and video after a visit to the bear's den near the Cloquet Forestry Center. The bear was located by signals from her VHF radio collar

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On March 18 this year, DNR wildlife researchers again located the sow, this time at an above-ground den near the center. She had four cubs with her that likely had been born in January. They each weighed from 3 to 4 pounds, DNR officials said.

Two of the yearling cubs from last year had been fitted with VHF radio collars. One of those yearlings was hit by a car and killed in August, DNR officials said. The surviving collared yearling is denned up about a mile from its mother.

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Sow black bears in Minnesota give birth to four cubs just 5 percent of the time, said Dave Garshelis, DNR bear project leader in Grand Rapids. Sows have either two or three cubs about 90 percent of the time. He has seen a litter of five cubs just three times in his career in Minnesota.

Also, it isn't unusual for bears to use exposed rather than underground dens, Garshelis said.

"It's much more common than you'd think," he said. "We have a lot of bears in exposed dens, mainly males but also females and females with young cubs."

In the accompanying photo, two of the sow's four cubs are visible and the others are tucked down by the sow's hip. Frost can be seen on the sow's fur, and an ear tag is visible in her ear.

 
"In the middle of winter, she probably had a coating of snow on her," Garshelis said. "She probably gave birth in January with a coating of snow on her."

Minnesota's bear population is estimated at 12,000 to 15,000, Garshelis said. The DNR has about 30 bears wearing GPS radio collars, primarily in the Chippewa National Forest north of Grand Rapids. The main focus of the DNR's bear research there is to determine the effects of changes in forest composition — tree species — on bears.

Bears in the study have both GPS collars and heart-rate monitors, Garshelis said. Heart rate monitors help researchers learn when bears are stressed, he said. Heart rates typically increase when bears approach well-traveled main roads and also when they approach hunters' baiting sites, Garshelis said.

Heart rates also indicate when bears are awake or sleeping. Bears usually are awake during the day and resting at night until about mid-August, Garshelis said. After that time, they switch to sleeping mostly during the day and moving at night, he said.

"That change happens right at the time hunters start baiting, but that might be coincidental," Garshelis said.


Two bear cubs are visible along with their mother in this photo from March 18 at the sow's above-ground "den" near the Cloquet Forestry Center. Department of Natural Resources officials located the site by VHF radio signals from the sow's collar. Two more healthy cubs were found below the ones shown. The cubs weighed between 3 and 4 pounds, DNR officials said. The same sow was located near the Cloquet Forestry Center last spring, when she had three yearling cubs with her. Dave Garshelis photo.