In 2009-2010 we assisted wildlife managers by providing a bear den for an orphaned black bear cub. We were so fortunate to have this opportunity and to help a small bruin be reintroduced into the wild.

2009-2010 Black Bear in Montana

The above pictures show the orphaned Black Bear that was given a winter den in western Montana. As you can see from the photographs, he didn’t spend the whole time sleeping! Black Bears are not “true hibernators”, but are considered by scientists to enter a “winter lethargy” instead. They only drop their internal temperature by a few degrees (approximately 10°F), and experience a lower heart rate and metabolism. By not significantly lowering their internal temperature, they are able to remain slightly active during the winter and can be aroused very quickly when in danger (true hibernators can take hours or even days to fully awaken from hibernation). While monitoring the above pictured orphaned Black Bear on camera, we were also recording the inside and outside den temperature every 45 minutes. We did this using small iButtons that were preprogrammed before the bear arrived, and recently collected from the den now that the bear has moved on. The data from these iButtons has been downloaded and analyzed to help understand the affect temperature plays during the bear’s winter lethargy. The average difference in temperature between the inside of the den and the outside of the den was 3.09°F while the bear was present and 0.17°F while he was absent, meaning the bear raised the den temperature an average of 3°F. While the outside temperature experienced a standard deviation of approximately 13.0°F, the inside of the den only experienced an approximate standard deviation of 8.6°F. This means that the temperature inside the den remained more consistent throughout the winter months and allowed the bear to keep a cool even temperature while he slept; even on a warm winter day when it was fairly hot outside he wouldn’t become confused and think it was Spring.