Bears hibernate in winter. In some cases, bears are not hibernating at all, staying awake all winter. For every one degree Celsius that minimum temperatures increase in winter, bears hibernate for six fewer days, a study found last fall. The previous fall, regional temperatures were as much as 4.7 degrees Celsius (8.4 degrees Fahrenheit) warmer than the 20th century average. In January temperatures were 5.4 degrees Celsius warmer.

Source: New York Times May 04, 2018 21:00 UTC