The smaller flying squirrels are only 10 inches from nose to tip of tail, while gray squirrels reach up to 22 inches long.
Tree squirrels vary in color from species to species. Gray squirrels are the namesakes gray, fox squirrels are dark reddish brown, and flying squirrels are a silky brown with a white belly.
Tree squirrels may be distinguished from ground squirrels and from chipmunks by their long, bushy tails, lack of dorsal stripes, spotting or flecking, and lack of internal cheek pouches. When disturbed, they flee for the security of a tree, rather than to a ground burrow. Tree squirrels nest above ground, in tree trunk cavities or in aerial nests. Tree squirrels are active in the daytime. They can be destructive to wires or other utilities that enter a structure, and commonly find their way into attics where they cause great damage.
Tree squirrels eat primarily nuts, seeds, berries, fruit, and flowers and flower buds. They may also feed on tender bark, and occasionally on insects, bird eggs or young birds, mice or other small animals.
Tree squirrels have one to two litters of young per year, usually in very early spring or late winter, with three to six young per litter. Tree squirrels can live as long as 12 years, but typically live between four and seven years.
Tree squirrels communicate through a series of chirps. The frequency and duration of the notes communicate everything from laughter to alarm.
Tree squirrels are protected animals, and it is illegal to kill them without specific permission from a wildlife agency. If tree squirrels are found to be causing serious damage, permission may be obtained to trap and relocate them, or to kill them if necessary.