Winter is here, which means that bears all over the world are fattening up on food and getting ready to hibernate.
However, new research from the University of Primorska in Slovenia suggests that bears sleeping patterns are changing, largely as a result of the food that humans are making available to them.
The new study, published in the Journal of Zoology, suggests that bears no longer spend the entirety of winter in their dens, but instead wake up and wander around throughout the cold months. Hibernation periods were shortened by 45% for female bears and 56% for males.
Less predictable bear hibernation patterns can have several implications. For one thing, it can increase the potential interactions between bears and other species — including humans. This can have troubling and potentially violent outcomes
“Human-bear conflicts occur basically wherever bears live,” Dr. Miha Krofel, a mammal ecologist from the University of Primorska and lead author of the study, told Business Insider. “Unfortunately these conflicts sometimes include bear attacks on people.
Krofel and his team believe that all the extra food humans are leaving around is interfering with bears’ sleeping patterns.
“By keeping bears awake, [human] food sources can increase the potential for encounters with people,” Krofel said. “This is especially likely when bears find this food close to residential areas.”
According to Krofel, the main reason bears hibernate is to conserve energy during a period with a lack of food. If there’s suddenly more food available, the bears have less reason to stay in bed.
The researchers used GPS data to locate the dens of European brown bears and to estimate when bears entered and emerged from them. Then they analysed how much bears were using feeding sites during winter, and compared their findings to published data on bear denning behaviour from other brown bear populations.
Hibernation isn’t always a continuous state
There are two types of hibernating animals: those that maintain their hibernation even when there is extra food (obligate hibernators), and other species that get up and walk around depending on the level of food available (faculative hibernators.)
Bears are faculative, and they have a lower reduction in body temperature than many other hibernating mammals, which means they aren’t in such a deep slumber. This is why they are more likely than some other animals to get up in the middle of winter. Their hibernation is usually triggered by the availability of food in autumn and the amount of snowfall.
With global warming causing increasingly unpredictable weather conditions, and people encroaching more and more on nature, there could be a lot more human interaction with bears in all of their habitats to be wary of.