Recently we found two hibernation dens of an adult male brown bear, which suggest complex hibernating of the bear. Initial hibernation den was made by the bear in kind of a wide burrow of 2 metres as long. Nearby this initial hibernation burrow-den there were at least five other tries to dig such a burrow-den. The farthest such a try was found on the distance about 80 meters from the actual one. All found preparation of the bear for hibernation were situated in young spruce-birch thickets with big rotten uprooted spruces.
The November and December of 2022 in Naliboki Forest were snowy and frosty, but then in January 2023 warm air came and the deep snow cover began melting fast. In this thaw situation the bear burrow-den was inundated. The bear was awoken, and it built a huge open den in a kind of nest nearby (42 metres aside). The building materials were mainly spruce branches.
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Initial hibernation burrow-den of the brown bear. -
Inundated sleeping chamber in the hibernating den. -
One of the tries of the bear to dig a hibernation burrow-den. -
The bear digging in rotten trunk nearby the hibernation burrow-den. -
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Young spruces that were broken by the bear for bedding.
You can support the research on large carnivores in Naliboki Forest by buying just a coffee. It will help to keep the study going.
Zoology by Vadim Sidorovich 
Your data about bear show that den are the “key breeding site” for many mammals in Naliboki (wolf, fox, badger, racoon dog, lynx, bear) finally bear looks like a very big badger able to dig a large den for sleeping in winter.
Interesting find, thanks.