An adept climber, the eastern fox squirrel has sharp, curved claws which give it good grip (4) (6), as well as unusually flexible ankle joints which allow it to rotate its feet by 180 degrees as it descends tree trunks head-first (6). This species is also able to hang by its hind limbs while grasping food in its front feet (2) (4), and its long tail assists with balance as it moves through the trees (6). However, although it is well adapted to life in the trees, the eastern fox squirrel also spends a considerable amount of its time on the ground (2) (3) (5) (6).
The eastern fox squirrel is active year-round and usually forages during the day. This species builds leaf nests, known as dreys, in which to shelter and to raise its young. The drey is built in a tree and consists of a large ball of leaves and shredded material on a platform of twigs, with an entrance at the side and with a lining of shredded material (2) (3) (4) (5) (6). Each squirrel may use a number of different leaf nests (2), and this species will also nest inside tree cavities, particularly in winter (2) (3) (4) (6).
The diet of the eastern fox squirrel is quite varied, but consists mostly of the nuts and seeds of trees such as oak, hickory, walnut, beech and pine. The eastern fox squirrel also consumes other seeds as well as fruits, buds, flowers, bark, twigs, sap, fungi, and crops such as corn, wheat and soybeans (4). Some animal food is occasionally taken, such as insects, birds and their eggs, and even dead fish (2) (3) (4) (5) (6). The eastern fox squirrel has also been known to gnaw on bones, antlers and turtle shells to obtain calcium and other minerals (2) (3). This species stores nuts by burying them in the ground, giving it a supply of food for the winter months. Many of these nuts are never retrieved, and can go on to sprout into new trees (2) (3) (4) (5) (6).
The eastern fox squirrel is not particularly social, although some individuals occasionally share a nest in winter (2) (3) (5). The home ranges of different individuals overlap, but females with young often defend a small core area of their range (4) (5) (6). Body and tail postures play an important role in communication in the eastern fox squirrel, as do scents and sounds (4) (6). The most common vocalisation is a series of barks (2) (4) (5) (6), while a chatter bark is given in alarm and the teeth are chattered as a sign of aggression (6).
The eastern fox squirrel usually has two main breeding periods each year, the first occurring between November and February and the second between April and July (4) (5). During these breeding periods, each female is receptive for less than one day (5) (6), and noisy chases take place as dominant males pursue females with which to mate (2) (3). The female eastern fox squirrel usually gives birth to 2 or 3 young after a gestation period of 44 to 45 days (3) (4) (5) (6), although up to 7 young are sometimes born (5) (6).
The young eastern fox squirrels are naked at birth, with their eyes and ears closed. Their fur begins to grow after about a week, but their eyes do not open until they are about five weeks old (2) (3) (4) (6). The young squirrels first leave the nest at 7 to 8 weeks old, but are not fully weaned until they are about 12 weeks old (2) (4) (5). Some female eastern fox squirrels can raise two litters of young each year (2) (5), with the young from the second litter occasionally staying in the nest with the female for their first winter (3) (6).
Male eastern fox squirrels reach sexual maturity at about 10 to 11 months old (3) (4). Females have been known to give birth as early as eight months old, but most do not breed until the year following their birth (2) (4) (5). The eastern fox squirrel is hunted by a variety of predators, including bobcats, foxes, coyotes, raccoons, hawks, owls and snakes (2) (3) (4) (5) (6), but individuals that survive can potentially live for up to 13 years in the wild, with females tending to live longer than males (4) (5) (6).