|Glaucomys sabrinus (Shaw)|
Northern Flying Squirrel
Don Linzey & Christy Brecht
Wytheville Community College
Wytheville, Virginia 24382
- Adult total length:
10 - 11 in. (255 - 275 mm)
4 - 5 1/4 in. (100 - 130 mm)
- Hind foot:
1 1/2 - 1 5/8 in. (36 - 40 mm)
4 - 6 1/2 oz. (110 - 185 g)
Except for being larger, the northern flying squirrel appears
similar to the southern flying squirrel. Both have brownish
upperparts and whitish underparts. Whereas the belly hairs
on the southern flying squirrel are white to their base, the
bases of the belly hairs of the northern flying squirrel are
usually grayish. The tail appears to be dorsoventrally flattened.
A loose fold of furred skin connects the front and hind limbs
from the wrists to the ankles.
These squirrels cannot fly. Rather, they glide from a higher
perch to a lower one. In doing so, they spread their legs, thus
drawing taut the loose skin running along each side of the body.
The membranes support the squirrel as it glides in somewhat the
same fashion as a parachute. The tail acts as a rudder. By
varying the tension on their membranes and by altering the
position of their tail, flying squirrels can control their
direction and speed to some extent. They always land in a head-up
position on the trunk of a tree.
left lateral view of
skull and mandible
dorsal view of skull
ventral view of skull
The northern flying squirrel ranges from eastern Alaska and Canada south through
New England and the Great Lakes region. Its range continues south along the
Appalachian Mountains to western North Carolina and eastern Tennessee, but south
of Pennsylvania, it exists only in isolated, disjunct populations. In the western
United States, the range extends southward in the mountains to southern California
||Mice, rats, hamsters, etc.
||Woodchucks, Chipmunks, and Squirrels
Preferred habitat consists of spruce-fir forests and mixed conifer-northern
hardwood forests. Handley (1953) stated that this squirrel
is "irregularly distributed at high elevations in the spruce and balsam cloud
forests of the southern Appalachian Mountains." The specimen from Blanket
Mountain, however, was found in a deciduous forest "at least seven airline
miles from the nearest spruce and fir" (Handley, 1953).
Great Smoky Mountains National Park:
Northern flying squirrels are uncommon in the park. The first
individual was taken on Blanket Mountain (4,000 feet) southwest
of Elkmont, on February 20, 1935 (Handley, 1953
). In 1980, 40 nest boxes were erected in fire areas from
Newfound Gap to Clingmans Dome and in two areas on Balsam
Mountain to determine the status of this species in the park
(Linzey, 1984). The boxes were used by
southern flying squirrels and red squirrels, but not by northern
flying squirrels. However, eight squirrels were captured, marked,
and released near Indian Gap during 1987 and 1988 (
Weigl, Knowles, and Boynton, 1992).
- Sevier Co.:
Blanket Mountain (4,000 feet); near Walker Prong; Newfound Gap.
- State (Tenn. - N.C.) line:
Most flying squirrels probably breed for the first time when they are
about a year old. The breeding season varies with latitude, occurring
from spring to fall in the north and from late summer to winter in the
south. At any given locality, there are usually two peaks of breeding,
reflecting the difference in the timing of the first breeding of earlier
- and later - born females of the previous year. Nests are composed
primarily of shredded yellow birch bark, moss, and grass and are usually
in a tree cavity or a woodpecker hole (Muul, 1969). A nursing
female was found near Walker Prong on August 22 (Linzey,
1995b). At birth, young squirrels weigh about 5 to 6 g and are blind
and hairless, except for vibrissae and short hairs on the chin and snout.
The ears, which are folded over and sealed at birth, become erect between
two and six days of age, and by seven days hair is visible over most of
the body. The eyes open at about 31 to 32 days of age, by which time
the young are fully furred and their locomotion and coordination are well
developed. Weaning occurs at about 60 days. When they are about 12 weeks
of age, the young begin a molt from the juvenile to the first adult
pelage. At this age they are usually still associated with their mother
and may stay with her until she has another litter. Families frequently
remain together over winter.
Life expectancy in the wild is probably less than four years
- Terrestrial Ecology
Flying squirrels are nocturnal and active throughout the year, although
they may remain inactive for several weeks at a time during severe
winter weather. Northern flying squirrels nest communally during the
colder months. This communal behavior is thought to either be a behavior
for heat conservation and/or social or physiological function.
In the southern Appalachians, these squirrels feed mostly on lichens,
mushrooms, seeds, buds, fruit, conifer cones, meat, and arthropods (Weigl, 1977). They appear to be more carnivorous than
many other squirrels, eating insects and other invertebrates, birds,
eggs and nestlings, mice, and carrion. In the fall, they are active in
hoarding acorns or other kinds of nuts. The nuts are typically cached in
crevices or cavities in tree trunks.
- Predators and Defense
No predators recorded from the park.
None recorded in the park.
Links to Other Sites
- Special Protection Status
The northern flying squirrel inhabiting the southern
( Glaucomys sabrinus coloratus
) is listed as an endangered species by the U.S.
Fish and Wildlife Service.
- In Park:
All plants and animals are protected within
Great Smoky Mountains National Park.
Collection requires a permit which is usually
granted only for
research or educational purposes.
- Map development
- Web page design & coding
- Denise Lim, University of Georgia, Athens
- John Pickering, University of Georgia, Athens
Fleetwood, R. J. 1934 - 35.
Journal of Raymond J. Fleetwood, wildlife technician,
Great Smoky Mountains National Park, for the period May
27, 1934 - June 27, 1935. 499 pp. (Typewritten).
Handley, C. O., Jr. 1953.
A new flying squirrel from the southern Appalachian Mountains.
Proceedings of the Biological Society. Washington 66: 191 - 194.
Heaney, L. R. 1999.
Northern flying squirrel. Pages 462 - 463. In: D.E. Wilson, and
S. Ruff (eds.). The Smithsonian Book of North American
Mammals. Washington, D.C.: Smithsonian Institution Press.
Jackson, H.H.T. 1961.
Mammals of Wisconsin. Madison: University of Wisconsin Press.
Komarek, E. V. and R. Komarek. 1938.
Mammals of the Great Smoky Mountains. Bulletin of the Chicago
Academy of Sciences 5 (6): 137 - 162.
Linzey, D.W. 1984.
Distribution and status of the northern flying squirrel and the
northern water shrew in the southern Appalachians. The Southern
Appalachian Spruce-Fir Ecosystem: Its Biology and Threats. National
Park Service Research/Resource Management Report SER-71: 193-200.
Linzey, D. W. 1995a.
Mammals of Great Smoky Mountains National Park.
Blacksburg, Virginia: The McDonald & Woodward Publishing
Linzey, D. W. 1995b.
Mammals of Great Smoky Mountains National Park-1995 Update.
Journal of the Elisha Mitchell Scientific Society 111(1):1-81.
Linzey, D. W. 1998.
The Mammals of Virginia. Blacksburg, Virginia: The
McDonald & Woodward Publishing Company, Inc.
Muul, I. 1969.
Mating behavior, gestation period, and development of Glaucomys
sabrinus. Journal of Mammalogy 50 (1): 121.
Stupka, A. 1935 - 63.
Nature Journal, Great Smoky Mountains National Park. 28 vols.
(years) each with index. (Typewritten copy in files of Great
Smoky Mountains National Park library).
Weigl, P. D. 1977.
Glaucomys sabrinus coloratus Handley. Northern flying
squirrel. Pp. 398 - 400 In: Cooper, J. E., S. S. Robinson, and
J. B. Funderburg (editors). Endangered and threatened plants
and Animals of North Carolina. Raleigh: North Carolina State
Museum of Natural History.
Weigl, P. D., T. W. Knowles, and A. C. Boynton. 1992.
The distribution and ecology of the northern flying squirrel,
Glaucomys sabrinus coloratus, in the Southern Appalachians.
Final Report to U.S. Fish and Wildlife Service.
Wells-Gosling, N. and L. R. Heaney. 1984.
Glaucomys sabrinus. Mammalian Species No. 229: 1 - 8.
American Society of Mammalogists.
Last modified: 8 May, 2002