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Tasha At Work, Memories of Den Construction - UPDATE October 25, 2021

A few days ago, "Taught" captured video of Tasha hard at work gathering bedding for her den at night https://www.youtube.com/watch?v=BweEHoo2IuM. Great video.

Jewel deep in the denJewel deep in the den Jewel with her one twigJewel with her one twig

That brought back memories of the ingenuity bears have shown in both the kinds of dens they use and the kinds of bedding in those dens, but somehow they find ways get through cold Minnesota winters. The dens varied from burrows to rock crevices, hollow trees, spaces in slash piles, and dens out in the open. Most of the latter were next to wind breaks such as the root masses of fallen trees. To make insulating beds, they usually raked leaves, grass, moss, and other ground vegetation into the dens and arranged it to their liking. When those materials could not be found, they bit small branches off trees, stripped bark off cedar trees, or chewed rotten wood into chips as we saw Lily do.

On July 12, 2004, June Bear also showed ingenuity when she was faced with a heavy (68-pound) rock that blocked her efforts to enlarge a den for the birth of her first litter (Pete and George). Instead of futilely struggling with it, she made changes to the den’s steep entryway. She let the rock be while she dug and dug, reducing the incline. Then she gave the entryway a final smoothing before entering the den and rolling the rock out. To me, that showed forethought and ingenuity.

The biggest, deepest winter bear bed I ever saw was in the middle of an alder swamp where there was enough grass for the bed of a lifetime. On the other hand, bears that made burrows in sandy soil seldom raked bedding into them like we saw with Jewel’s dens in 2012 and 2013—something I don’t quite understand.

One way or another, black bears will find ways to make something suitable.

Thank you for all you do.
Lynn Rogers, Biologist, Wildlife Research Institute and North American Bear Center

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