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Northern Flying Squirrel

When parted, the white hairs of the belly show gray bases, the fur on the upper parts of the body has a reddish brown cast, and the undersurface of the tail is buffy white to tan. Apart from these differences, and larger size, the northern flying squirrel resembles the southern. Adults are 250-298 mm (10-11.7 in) in total length, and weigh 75-125 g (2.6-4.4 oz).

(Glaucomys sabrinus)

From: Saunders, D. A. 1988. Adirondack Mammals. State University of New York, College of Environmental Science and Forestry. 216pp.

Order: Rodentia
Family: Sciuridae

Range and Habitat

The range is southeastern Alaska, most of the forested regions of Canada, and in the U.S. extends into California and Nevada, along the Rocky Mountains to Arizona, the northern portions of the Great Lake states, and into the Northeast. Disjunct populations occur in the Black Hills and Appalachians. The northern flying squirrel occurs throughout the Adirondacks, replacing the southern flying squirrel at higher elevations. Northern flying squirrels prefer coniferous and mixed forests, but they also live in deciduous forests. At lower elevations, both species may live in close proximity, but the duration of their coexistence, and the nature of their interactions such as potential competition for limited nesting cavities, is not well known. The nesting habits of the two species are similar except for the northern’s use of exposed nests which it builds in conifers or old bird’s nests, and inhibits chiefly in the summer.

Food and Feeding Behavior

The diet is similar to the southern flying squirrel’s with a few exceptions. The northern flying squirrel is less carnivorous, and in winter relies on lichens and conifer cones, seeds, and buds for food, instead of stored nuts. The northern flying squirrel eats relatively more fungi, which it collects above ground, excavates from the soil, and pilfers from the caches of the red squirrel.

Activity and Movement

Both species of flying squirrel travel over and tunnel through snow to forage, but the northern is more tolerant to cold, and does not become torpid. The northern spends comparatively more time on the ground searching for food. The methods of locomotion and activity patterns are the same.


The northern flying squirrel breeds later and the average litter size, 2-4 (extremes 1-6) is smaller than the southern’s. The breeding season is from late March through May, perhaps later for some females. Females probably bear only one litter per year. At birth, the young weigh 5-6 g (0.2 oz). Their eyes, closed at birth, open 32 days, and they nurse until 60 days of age. They begin breeding during their second year. Potential longevity is not known; some adults survive at least 4 years.


Barred, great horned, and screech owls, goshawks, and red-tailed hawks are some of the documented predators of the northern flying squirrel. Mammals that are known to prey upon this rodent include the marten, otter weasel, fox, bobcat, and formerly the lynx and wolf.

Social Behavior

  • Social system - Even less in known about the mating relationships and social organization of this species than of the southern flying squirrel. Meager evidence suggests that home ranges are larger. There is no evidence of females defending territories. Communal denning in the winter occurs, although perhaps infrequently.
  • Communication - This species is not as vocal as the southern flying squirrel. The northern flying squirrel’s vocal repertoire includes sharp “squeaks”, soft “chirps”, chuckling sounds, “churring”, “whining”, and musical whistles.

Additional References

Wells-Gosling, N. and L.R. Heany. 1984. Glaucomys sabrinus. Mammalian species, 229, 8pp.