The red squirrel is usually considered a true arboreal animal with most of its life spent in trees. The squirrel will travel on the ground to feed or to travel from one stand of trees to another but when threatened by danger, it will immediately return to the trees.

The squirrel is usually active during the day only with the main activity occurring shortly after sunrise and shortly before sunset.

The food habits of the squirrel are extremely broad and include mast, green plant matter, fungus, fleshy fruits, birds, eggs and invertebrates. Black and white spruce seeds are a prime food source and in winter buried stores of seeds and mast are important.

Red squirrels generally breed once a year in Canada with the main breeding period occurring in February to March.

Squirrels will nest in left nests, tree cavities, fallen trees, rock piles, burrows, and man-made structures. The litter size may vary from 3 to 7 young and the young are born 38 to 40 days after breeding has occurred. The young squirrels are weaned at 6 to 7 weeks of age but they remain near the nest site until 12 to 13 weeks of age.

At present, the red squirrel is little used for fur or food but squirrel meat (particularly young squirrels) is noted for its fine flavour and tenderness.