Two of the most familiar large carnivores in Canada's wilderness are the grizzly bear and the black bear. Although the two are often confused, they belong to different species and behave in distinct ways. The black bear ranges across most of the forested provinces, from British Columbia to Newfoundland, while the grizzly is now found mainly in the mountains and foothills of the west. Both are powerful omnivores that eat berries, roots, fish, and small mammals. Both were once hunted heavily, and the grizzly in particular was driven from much of its former range before stricter protection was introduced.

Bears share a similar yearly rhythm shaped by the long northern winter. As autumn approaches, both species enter a feeding frenzy, eating almost without pause to build the fat reserves that will sustain them through their winter sleep. They then retreat to a den, where their heart rate drops sharply and their body temperature falls only slightly for several months. Females give birth during this period, and the tiny cubs nurse in the den until spring. By the time the bears emerge, they have lost a large share of their body weight and must begin feeding again at once.