Before researchers from the Wildlife Research Institute videotaped
3-year-old June digging this den in Eagles Nest Township, Minnesota,
they had no idea some bears made dens so early—July 19, 2004. It was
the first time researchers watched a bear dig a den. The most
interesting part happened when she encountered a 68-pound rock. She did
not make futile attempts to roll it up the steep incline of the
entryway.
(see video below)





She backed out of the den, smoothed the entry to make a gentler
slope, and enlarged the entrance. Then she went in and rolled the rock
out. It was humid and hot—78 degrees. She stood panting in the heat.
It's all in the video. The rock is in the Cub Room at the Bear Center
for children to lift and see how strong they are compared to June.
Most bears in northeastern Minnesota make dens in September or October.
























In early fall, June came back to this den and raked bedding into it
and settled down for the winter. In January, she gave birth to her
first litter. She and her two cubs left the den on April 4, 2005.
Not all dens are like this burrow. Some are in rock crevices, hollow
trees, or brush piles. Some are under the upturned roots of windblown
trees leaning 45 degrees. Other are under the trunks of down trees that
are held a foot or two off the ground by the root mass. Some are
simply aboveground nests.
A den, loosely interpreted, is where a bear spends the winter.


In residential areas, a den might be in a road culvert, a storm sewer under a street, or the crawl space under a house.


In the fall, June made a new den. Black bears seldom use the same
den twice. She made a den big enough to hold herself and her cubs
snuggled together. The den was not much bigger than the bears. The
cubs helped rake leaves and other bedding material into the den.
If cubs become orphaned, they instinctively know how to make dens all by themselves.