Excerpt from Wikipedia article:

Southern flying squirrels have grey brown fur on top with darker flanks and are a cream color underneath. They have large dark eyes and a flattened tail. They have a furry membrane called a patagium which extends between the front and rear legs, used to glide through the air. Southern Flying Squirrels feed on fruit and nuts from trees such as red and white oak, hickory and beech. They store food, especially acorns, for winter consumption. They also dine on insects, buds, mushrooms, mycorrhizal fungi, carrion, bird eggs and nestlings and flowers. Predators include snakes, owls, hawks and raccoons. Domestic house cats can be dangerous to these animals. Although graceful in flight, they are particularly vulnerable on the ground.

Although the squirrels will make outside nests, especially in pine woods, they prefer to nest in holes in dead trees, snags or attics. They often use these nesting holes communally, especially in winter, when huddling gives them significant energy savings. They readily use artificial nest boxes. They choose holes with smaller entrances than those used by the sympatric Eastern gray squirrel (Sciurus carolinensis). Sometimes they use holes that have been made by woodpeckers such as the Red-cockaded Woodpecker (Picoides borealis); since this is an endangered species, the squirrels are sometimes removed from areas where the woodpeckers nest, though the usefulness of this practice has been disputed. They tend to avoid areas of forest that have been harvested recently.

Both in the wild and in captivity they can produce two litters each year (with 2-7 young per litter), [citation? it is questionable whether or not the same females will breed twice in one year but males definitely will] in early spring and mid-summer. The gestation period is approximately 40 days. Young are born without fur or any capabilities of its own. Their ears open at 2 to 6 days old, and fur grows in by 7 days. Their eyes don't open until they are 24-30 days old. Parents leave their young 65 days after they are born. The young then become fully independent at 120 days of age.

Southern Flying Squirrels show substantial homing abilities, and can return to their nests if artificially removed to distances of up to a kilometre. Their home ranges may be up to 40,000 square meters for females and double that for males, tending to be larger at the northern extreme of their range.