Most tree-dwelling squirrels, such as red and gray squirrels, do not hibernate during winter and stay active throughout the day as long as the temperature does not fall below 30 degrees Fahrenheit. Ground squirrels, especially those that can be found in the Arctic, Alaska and Canada, do practice hibernation.
Ground squirrels are also called gophers. They are often mistaken for moles because of their similarity in habitat and eating habits. Gophers spend about 85 percent of the winter in hibernation and in a physiological state of torpor. Their body temperature drops to match the temperature of the environment and their respiration, metabolism and heart rate slow down considerably. Pocket gophers, however, are similar to other squirrels as they stay active throughout the cold season.