The grizzly is a sub-species of the European and Asian brown bear. There are five other closely related species, including black and polar bears.
The grizzly bear has no natural enemies or predators in the wild. It is not really territorial, rarely fighting with other animals and tolerating fellow grizzlies, except during mating season.
Grizzlies spend spring and summer days foraging, resting and sleeping. Heavy feeding goes on in the autumn in order to build up energy reserves for their winter sleep. Grizzlies are not true hibernators, and fall into a torpor (deep sleep) during cold weather, but on sunny days they wake up and go to look for food.
Unlike other bears, grizzlies do not often use natural winter shelters like caves. Instead, they excavate large dens for themselves on a steep, north-facing slope, which will be covered in a thick layer of snow.
Most grizzlies wait for the snows before moving into their dens. Unless there are periods of warm weather, they stay inside until spring. Males and females without cubs generally emerge first, each individual bear usually emerges at slightly different times. When they leave the den, they first need to feed. They will feed near their dens and return to them at night until the weather is milder.Read More: Credit