There are 25 subspecies across North America with Interior Alaska being the most northern and western limit of the species' range. The tail is broad, flattened, and feather-like. This squirrel is nocturnal and has large eyes that are efficient on the darkest nights.
Eye shine color is a distinctive reddish-orange.
Flying squirrel pelage is silky and thick with the top of the body light brown to cinnamon, the sides grayish, and the belly whitish. Den sites include tree cavities and witches' brooms. Tree cavities are most numerous in old forests where wood rot, frost cracking, woodpeckers, and carpenter ants have created or enlarged cavities. Witches' brooms, clumps of abnormal branches caused by tree rust diseases, are the most common denning sites of flying squirrels in Interior Alaska. About November or December, when temperatures begin to drop sharply, flying squirrels move out of cavities and into brooms.