Coexisting with Bears
Three of the eight living bear species live in North America: the black bear, brown bear, and polar bear. The taxonomy of brown bears is disputed, with some debate over whether all brown bears belong to one species or different subspecies. It is commonly, but not universally, accepted that grizzly bears and Kodiak bears are subspecies of brown bear.
Bears can be found throughout Canada and at least 40 U.S. states. Polar bears’ North American range is limited to Canada and Alaska. Black bears are more common than brown bears with there being an estimated population of around 600,000 – 900,000 of the former, and around 55,000 of the latter.
Young bears stay with their mothers for two to three years but once dispersed, they are largely solitary animals except during mating season.
Black and brown bears famously hibernate in the colder months, but whether they sleep at all during the winter months and the length of their hibernation if they do will depend on weather and food availability. Those bears in colder climates will hibernate for longer (up to 7 months) and those in warmer locations may hibernate for just two months, or not at all if they have ready access to food. To allow their bodies to survive for such long periods without food, the bears bulk up prior to hibernation and then lower their body temperature to minimize energy use. Contrary to popular belief, bears are not soundly sleeping for the whole time. They will move around their dens and sometimes even venture outside for short periods.
Interestingly, while their more southerly cousins hibernate during the winter, polar bears are most active in the winter as this is the time they have best hunting success. Conversely, the summer months are less bountiful for polar bears and so they have longer periods of rest and inactivity during this time, but do not enter full hibernation.