...you wake a bear from hibernation?

“I have heard that bears are dangerous, when they wake up from hibernation. What if you accidentally woke one up?”

For once this is a wildlife danger issue which doesn’t directly affect Australians. But were you to be holidaying abroad in bear country, and accidentally woke a bear from hibernation, there is a risk that it will attack, and anecdotes indicate that it may be a severe attack, because a bear can wake up relatively quickly.

When bears hibernate, their bodily functions are only marginally reduced compared to other animals. Body temperature in bears typically drops only a few degrees, to a state often called ‘torpor’, whereas in many smaller mammals it can drop dramatically, to around zero.

During the Northern Hemisphere’s summer and early autumn, bears store body fat that they burn while hibernating. The bear’s body produces extra proteins that carry fat around the body and enzymes that break down the fat, so muscles and organs

can extract energy. If a bear wakes up too early, it can be particularly aggressive either because it is starving or because it feels threatened. In early 2021, three snowboarders in Alaska accidentally disturbed a brown bear’s hibernation. The bear woke up, grabbed the wrist of 90kg Bart Pieciul, lifted him into the air, and shook him. Pieciul only managed to escape by playing dead after being thrown to the ground.

Of the eight modern bear species, only brown and black bears ‘hibernate’. Outside of the Ursidae bear family, the ability to hibernate is found in several other mammals including hedgehogs, squirrels, and the dwarf lemur. In Australia a number of animals use torpor rather than full hibernation, including echidnas, blue-tongue lizards, and numbats. Tawny frogmouths and many other birds use temporary torpor each day to save energy.