According to Wikipedia :
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.
Thankfully, we were able to rescue the poor thing in a shoe box and set him free outside.