The northern flying squirrel (''Glaucomys sabrinus'') is one of three species of the genus '' Glaucomys'', the only

flying squirrel Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe of 50 species of squirrels in the family Sciuridae. Despite their name, they are not in fact capable of full flight in the same way as birds or bats, but they ar ...

s found in

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

.Walker EP, Paradiso JL. 1975. ''Mammals of the World''. Baltimore: Johns Hopkins University Press.Forsyth A. 1999. ''Mammals of North America: Temperate and Arctic Regions''. Willowdale: Firefly Books. They are found in coniferous and mixed coniferous forests across much of Canada, from Alaska to Nova Scotia, and south to the mountains of North Carolina and west to Utah in the United States. They are light brown with pale underparts and grow to a length of . They are proficient gliders but uncoordinated walkers on the ground. They feed on a variety of plant material as well as tree sap, fungi, insects, carrion, bird eggs and nestlings. They mostly breed once a year in a cavity lined with lichen or other soft material. Except when they have young, they change nests frequently, and in winter a number of individuals may huddle together in a shared nest. Unlike most members of their family, flying squirrels are strictly nocturnal.

Habitat and range

The northern flying squirrel is found in

coniferous Conifers are a group of cone-bearing seed plants, a subset of gymnosperms. Scientifically, they make up the division Pinophyta (), also known as Coniferophyta () or Coniferae. The division contains a single extant class, Pinopsida. All extant ...

and mixed coniferous forests across the top of North America, from Alaska to Nova Scotia, south to the mountains of North Carolina and Tennessee and west to Utah. The

Humboldt's flying squirrel Humboldt's flying squirrel (''Glaucomys oregonensis'') is one of three species of the genus '' Glaucomys'', the only flying squirrels found in North America. The squirrel was named after the naturalist Alexander von Humboldt and California's H ...

was formerly considered conspecific, but was found to be a cryptic species, and now considered distinct. It is generally smaller and darker than northern flying squirrel and occurs in British Columbia, northern California, Washington and Oregon. Two

subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

are found in the southern Appalachians, the Carolina northern flying squirrel, ''G. s. coloratus'', and the West Virginia northern flying squirrel ''G. s. fuscus'', both of which are endangered, although the West Virginia subspecies has recovered enough that it was delisted in August 2008. The U.S. Fish and Wildlife Service temporarily put the West Virginia northern flying squirrel back under protection on June 6, 2011 in response to a court order. On appeal, the delisting was reinstated in March 2013.

Description

These nocturnal, arboreal rodents have thick light brown or cinnamon fur on their upper body and greyish fur on the flanks and whitish fur underneath. They have large eyes and a flat tail. They can also be identified by their long whiskers, common to nocturnal mammals. The adult northern flying squirrel measures from 25 to 37 cm long, and their weight can range from 110 to 230 grams.

Gliding

Flying squirrels do not actually fly, they glide using a

patagium The patagium (plural: patagia) is a membranous body part that assists an animal in obtaining lift when gliding or flight. The structure is found in extant and extinct groups of flying and gliding animals including bats, birds, some dromaeosaurs ...

created by a fold of skin. From atop trees, flying squirrels can initiate glides from a running start or from a stationary position by bringing their limbs under the body, retracting their heads, and then propelling themselves off the tree.Banfield AWF. 1974. The mammals of Canada. Toronto: University of Toronto Press. It is believed that they use

triangulation In trigonometry and geometry, triangulation is the process of determining the location of a point by forming triangles to the point from known points. Applications In surveying Specifically in surveying, triangulation involves only angle me ...

to estimate the distance of the landing as they often lean out and pivot from side to side before jumping. Once in the air, they form an "X" with their limbs, causing their membrane to stretch into a square-like shape and glide down at angles of 30 to 40 degrees. They maneuver with great efficiency in the air, making 90 degree turns around obstacles if needed. Just before reaching a tree, they raise their flattened tails, which abruptly changes their trajectory upwards, and point all of their limbs forward to create a

parachute A parachute is a device used to slow the motion of an object through an atmosphere by creating drag or, in a ram-air parachute, aerodynamic lift. A major application is to support people, for recreation or as a safety device for aviators, who ...

effect with the membrane to reduce the shock of landing. The limbs absorb the remainder of the impact, and the squirrels immediately run to the other side of the trunk or to the top of the tree to avoid any potential predators. Although graceful in flight, they are very clumsy walkers and if they happen to be on the ground in the presence of danger, they will prefer to hide rather than attempt to escape.

Diet

A major food source for the squirrels are fungi of various species, although they also eat

lichen A lichen ( , ) is a composite organism that arises from algae or cyanobacteria living among filaments of multiple fungi species in a mutualistic relationship.mushrooms, all mast-crop nuts, tree sap, insects, carrion, bird eggs and nestlings, buds and flowers. The squirrels are able to locate truffles by

olfaction The sense of smell, or olfaction, is the special sense through which smells (or odors) are perceived. The sense of smell has many functions, including detecting desirable foods, hazards, and pheromones, and plays a role in taste. In humans, it ...

, though they also seem to use cues such as the presence of coarse woody debris, indicating a decaying log, and

spatial memory In cognitive psychology and neuroscience, spatial memory is a form of memory responsible for the recording and recovery of information needed to plan a course to a location and to recall the location of an object or the occurrence of an event. Sp ...

of locations where truffles were found in the past. The northern flying squirrel is also known to cache food for when food supplies are lower. These caches can be in cavities in trees, as well as in the squirrels' nest. Lichens and seeds are commonly cached.

Ecology

The northern flying squirrel also disseminates spores of the fungi that they eat.

Behaviour

Sue Cameron installs a new squirrel box (8554236001)

Northern flying squirrels generally nest in holes in trees, preferring large-diameter trunks and dead trees, and will also build outside leaf nests called dreys and will also nest underground. Tree cavities created by woodpeckers as suitable nest sites tend to be more abundant in old-growth forests, and so do the squirrels, though harvested forests can be managed in ways that are likely to increase squirrel numbers. Nests may also be established in buildings, including parts of occupied homes. Except when rearing young, the squirrels shift from nest to nest frequently. They often share nests during winter months, forming aggregations. Usually, aggregate nests contain 4 to 10 individuals. The sharing of nests in winter by northern flying squirrels is important in maintaining body temperature (biothermal regulation), as northern flying squirrels do not hibernate, nor do they enter torpor states. Northern flying squirrels gliding distances tend to be between 5 and 25 metres, though glides of up to 45 m and longer have been observed. Average glides are about 5 m less for females than for males.

Glide angle Gliding flight is heavier-than-air flight without the use of thrust; the term volplaning also refers to this mode of flight in animals. It is employed by gliding animals and by aircraft such as gliders. This mode of flight involves flying a s ...

has been measured at 26.8 degrees and glide ratio at 1.98. Since first documented by Shaw in 1801, the general understanding was that northern flying squirrels bred but once per year. Recently, in southern Ontario, Canada, polyestrous behaviour (two litters per year) has been documented for the first time. This observation has since been confirmed by a second research team in New Brunswick, Canada. In southern Ontario, Canada, genetic evidence has recently shown hybridization with the rapid northward expansion and increased sympatry of southern flying squirrels.

Predation

Northern flying squirrels, along with

pine squirrel Pine squirrels are squirrels of the genus ''Tamiasciurus'', in the Sciurini tribe, of the large family Sciuridae. Species This genus includes three species: *''Tamiasciurus hudsonicus'' — American red squirrel *''Tamiasciurus douglasii'' ...

s, are an important prey species for the spotted owl (''Strix occidentalis'') and

eastern screech owl The eastern screech owl (''Megascops asio'') or eastern screech-owl, is a small typical owl, owl that is relatively common in Eastern North America, from Mexico to Canada. This species is native to most wooded environments of its distribution, a ...

(''Megascops asio'').Direct observation of Screech Owl nesting box, Tom Knapp 3 Jan 2014 Other predators include various other large birds, especially the great horned owl and hawks, as well as mammals including the

American marten The American marten (''Martes americana''), also known as the American pine marten, is a species of North American mammal, a member of the family Mustelidae. The species is sometimes referred to as simply the pine marten. The name "pine marten" ...

, the Canadian lynx, the

red fox The red fox (''Vulpes vulpes'') is the largest of the true foxes and one of the most widely distributed members of the Order (biology), order Carnivora, being present across the entire Northern Hemisphere including most of North America, Europe ...

References

*Arbogast, B. S. (1999). Mitochondrial DNA phylogeography of the New World flying squirrels '' Glaucomys'': implications for Pleistocene biogeography. '' Journal of Mammalogy'', 80, 142–155. *Arbogast, B. S., Browne, R. A., Weigl, P. D. and Kenagy, G. J. (2005). Conservation genetics of endangered flying squirrels from the Appalachian mountains of eastern North America. ''Animal Conservation'', 8, 123–133. *Bakker, V. J., & Hastings, K. (2002). Den trees used by northern flying squirrels (''Glaucomys sabrinus'') in southeastern Alaska. ''Canadian Journal of Zoology'', 80, 1623–1633. *Carey, A. B., Kershner, J., Biswell, B., & De Toledo, L. D. (1999). Ecological scale and forest development: squirrels, dietary fungi, and vascular plants in managed and unmanaged forests. ''Wildlife Monographs'' 5-71. *Carey, A. B., Wilson, T. M., Maguire, C. C., & Biswell, B. L. (1997). Dens of northern flying squirrels in the Pacific northwest. ''Journal of Wildlife Management'', 61, 684–699. *Cotton, C. L., & Parker, K. L. (2000). Winter activity patterns of northern flying squirrels in sub-boreal forests. ''Canadian Journal of Zoology'', 78, 1896–1901. *Forsman, E. D., Otto, I. A., Aubuchon, D., Lewis, J. C., Sovereign, S. G., Maurice, K. J., & Kaminski, T. (1994). Reproductive chronology of the northern flying squirrel on the Olympic peninsula, Washington. ''Northwest Science'', 68, 273–276. *Martin, K. J., & Anthony, R. G. (1999). Movements of northern flying squirrels in different-aged forest stands of western Oregon. ''Journal of Wildlife Management'', 63, 291–297. *Mitchell, D. (2001). Spring and fall diet of the endangered West Virginia northern flying squirrel (''Glaucomys sabrinus fuscus''). ''American Midland Naturalist'', 146, 439–443. *Pyare, S., & Longland, W. S. (2001). Mechanisms of truffle detection by northern flying squirrels. ''Canadian Journal of Zoology'', 79, 1007–1015. *Pyare, S., Smith, W. P., Nicholls, J. V., & Cook, J. A. (2002). Diets of northern flying squirrels, Glaucomys sabrinus, in southeast Alaska. ''Canadian Field-Naturalist'', 116, 98-103. *Odom, R.H., W.M. Ford, J.W. Edwards, C.W. Stihler, and J.M. Menzel. 2001. Developing a habitat model for the endangered Virginia northern flying squirrel (Glaucomys sabrinus fuscus) in the Allegheny Mountains of West Virginia. Biological Conservation 99: 245–252. *Vernes, K. (2001). Gliding performance of the northern flying squirrel (''Glaucomys sabrinus'') in mature mixed forest of eastern Canada. '' Journal of Mammalogy'', 82, 1026–1033.

External links

Animal Diversity Web - Glaucomys sabrinus
{{Taxonbar, from=Q1094722 Glaucomys Squirrel, northern flying Mammals of Canada Natural history of the Great Smoky Mountains Mammals described in 1801 Taxa named by George Shaw