Squirrels have 4 toes on forefeet; 5 on hind feet. Tree squirrels have bushy tails and small feet; ground species have less bushy tails and more robust forefeet. Ground squirrels and chipmunks carry food in internal cheek pouches. The flying squirrel has a skin fold along its flanks and attached to its feet that enables it to glide. There is great variation in size: the largest Canadian squirrel, the hoary marmot, is 80 cm long and weighs 6 kg; the smallest, the least chipmunk, 22 cm and 50 g.
All Canadian species, except flying squirrels, are diurnal. While most ground squirrels hibernate, tree squirrels are active year round. Some are gregarious; others, solitary. Tree squirrels generally build nests; ground-dwelling species dig burrows.
Certain species of squirrels are found throughout Canada; others only inhabit specific areas. Preferred habitats are varied, including forests, prairies, mountains and arctic regions. Primarily herbivorous, squirrels sometimes eat insects, eggs and even small birds and mammals.