Southern Flying Squirrel

Glaucomys volans
Chuck Fergus

The southern flying squirrel is found throughout Pennsylvania; it occurs from southern Maine to Florida and from Minnesota to Texas, with isolated populations in Mexico and Central America. The southern flying squirrel is slightly smaller than the closely related northern flying squirrel, and much more common in Pennsylvania. Weights range from 1.5 to 3 ounces. The soft, velvety fur is grayish brown on the back and pearly white on the belly. The large, dark brown eyes are adapted for night vision. The so-called flying membrane is a loose flap of skin between the fore and hind legs on either side of the body; when a flying squirrel extends its legs, they stretch the membrane taut, making an airfoil on which the animal can glide from one tree to another or from a tree to the ground. A flying squirrel can sail up to 40 yards in a downward direction. It uses its broad, flat tail as a rudder.


Flying squirrels are mainly arboreal, although they also forage on the ground. They are rarely seen, since they are nocturnal. They nest in hollow tree limbs and woodpecker cavities and sometimes in large birds’ nests, which they cap with shredded bark and leaves. After a gestation period of about 40 days, 2 to 7 young (on average, 3 or 4) are born in April, May or June. The young are weaned after about two months. Adult males do not help the females rear the young. The southern flying squirrel may produce two litters per year, with the second litter arriving in September. Flying squirrels may be more common than many people think. A good way to look for them is to rap a stick against trees or branches that have cavities; the squirrels may stick their heads out or emerge to see what’s going on.


Flying squirrels eat nuts; seeds; winter buds of hemlock, maple and beech; tree blossoms and sap; fruits; berries; ferns; and fungi, both above-ground and subterranean types. They store surplus nuts in their dens and also bury them in the ground. Although small and apparently docile, flying squirrels are the most predaceous of the tree squirrels eating moths, beetles, insect larvae, spiders, birds and their eggs, small mice and shrews and carrion.


Owls and house cats are major predators of flying squirrels; foxes, coyotes, weasels, skunks, raccoons and black rat snakes also take them. The average life span is estimated at five years. Active year-round, flying squirrels are quite sociable, and in cold weather several individuals may share a tree cavity, sleeping snuggled together for warmth; up to 50 southern flying squirrels have been found in one nest. The southern flying squirrel may become torpid during the coldest part of the winter. One to three individuals typically live on an acre of suitable wooded habitat.


Pennsylvania Game Commission
Bureau of Wildlife Management
Attn: Mammal Atlas Coordinator
2001 Elmerton Avenue
Harrisburg, PA 17110
Pennsylvania Game Commission
Bureau of Wildlife Management