Despite falling snow and cold temperatures across much of Alberta this week, staff at fRI Research Grizzly Bear Program are excitedly planning for spring fieldwork on the Cadomin Limestone Quarry. But while we’re hiring summer staff and calculating budgets, what are grizzly bears doing? Hibernating of course!
Hibernation is an adaptive strategy to avoid harsh environmental conditions and seasonal food scarcity. Unlike other hibernators like ground squirrels or marmots, bears are unique in that their metabolic rate and body temperatures only drop slightly during hibernation, and they do not enter the deep torpor bouts typical of rodent hibernators. This means that grizzly bears can be easily disrupted while hibernating in their dens, and disturbances can diminish their energy reserves, potentially affecting reproductive success.
In Alberta, grizzly bears typically dig their dens in a hill or mountainside, in dry, open conifer stands. The exact dates for den entry and exit depend on many factors. Pregnant females enter dens earlier in the fall and emerge with cubs later in the spring, compared to other individuals. The availability of autumn food, like berries, plays an important role in determining when bears will enter their dens, and den exit in the spring is largely linked to temperature and snow cover.
So while we wait for spring, check out our video clip for a tour of a grizzly bear den and a sneak peek into the life of one of our collared bears, G163!