"Most of the Southern Flying Squirrel's range is east of the Mississippi River, but it occurs west of the river in central Texas, and as far south as Honduras, in Central America. Like the Northern Flying Squirrel, it has a gliding membrane (patagium) and a flattened tail. Flying squirrels are nocturnal and are much smaller than most tree squirrels, which are diurnal. Although primarily associated with hardwoods, especially oaks and hickories, Southern Flying Squirrels inhabit forests of diverse types, and even live in cities and suburbs. A natural cavity or old woodpecker hole in a live or dead tree is the typical nest site. Where the ranges of the two species of flying squirrels overlap, it appears the Southern Flying Squirrel may out-compete its larger relative."

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This species is found in Texas, Kansas, and Minnesota in the United States, east to Quebec and Nova Scotia in Canada (uncommon to rare in these provinces) and eastern United States; there are montane populations scattered from northwestern Mexico to Honduras (Hoffmann et al., in Wilson and Reeder 1993).

Glaucomys volans is found in southeastern Canada, the eastern United States, and south as far as Mexico and Honduras.

Biogeographic Regions: nearctic (Native ); neotropical (Native )

occurs (regularly, as a native taxon) in multiple nations

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: (>2,500,000 square km (greater than 1,000,000 square miles)) Texas, Kansas, and Minnesota east to Quebec and Nova Scotia (uncommon to rare in these provinces) and eastern U.S.; montane populations scattered from northwestern Mexico to Honduras (Hoffmann et al., in Wilson and Reeder 1993). See Stabb (1988 COSEWIC report) for information on distribution and abundance in Canada.

Flying squirrels are easily distinguished by the "gliding membrane", a flap of loose skin that extends from wrist to ankle. The loose skin along the side of the body is supported by cartilaginous spurs on the wrists and ankles. The soft fur on the back and tail is grey with varying amounts of grey tinge; the belly is white. The tail is dorso-ventrally flattened. The eyes are very large, probably related to the nocturnal habits and the visual requirements of gliding. Total length is 21.1 to 25.7 cm and tail length is 7.9 to 12 cm.

Range mass: 46 to 85 g.

Average mass: 65.38 g.

Range length: 21.2 to 25.7 cm.

Other Physical Features: endothermic ; heterothermic ; bilateral symmetry

Sexual Dimorphism: sexes alike

Average basal metabolic rate: 0.414 W.

Length: 25 cm

Weight: 70 grams

Length:
Average: 231 mm
Range: 198-255 mm

Weight:
Average: 70 g
Range: 46-85 g

Habitat and Ecology

Systems

• Terrestrial

Southern flying squirrels are found in woodlands. They seem to prefer seed-producing hardwoods, particularly maple, beech, hickory, oak, and poplar. They are also found in mixed conifer/deciduous forests.

Habitat Regions: temperate ; terrestrial

Terrestrial Biomes: forest

Comments: Prefers deciduous and mixed forests, particularly beech- maple, oak-hickory and poplar. Also occurs in old orchards. In New Hampshire, preferentially used areas with large shagbark hickories and beeches; males tended to use areas with large oaks, females tended to use areas with abundant snags (Fridell and Litvaitis 1991). Favors small, abandoned woodpecker holes for den sites; also uses nest boxes and abandoned bird and squirrel nests outside tree cavities.

Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.

Locally Migrant: No. No populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).

Locally Migrant: No. No populations of this species make annual migrations of over 200 km.

In Maryland, home range averaged about 2-4 ha for adults, less than 1 ha for juveniles (Bendell and Gates 1987, Gilmore and Gates 1985). In New Hampshire, home range (convex polygon) was 3.4-22.1 (mean 9.9) ha for males, 3.0-4.4 ha for females (Fridell and Litvaitis 1991). In Arkansas, mean home range size was about 4 (female) and 8 (male) ha measured planimetrically, 4 (female) and 9 (male) ha taking into consideration topography via GIS (Stone et al. 1997).

Home ranges of G. volans varied from 5-13 hectares, mean 7.4 hectares (Weigl and Osgood 1974); mean 2.45 hectares for males and 1.95 hectares for females (Bendel and Gates 1987).

Southern flying squirrels are omnivores and eat a wide range of foods, including nuts, acorns, seeds, berries, fruit, moths, junebugs, leaf buds, bark, eggs and young birds, young mice, insects carrion, and fungus. They are especially fond of hickory nuts and acorns; one sure sign of the presence of this species is piles of gnawed hickory nuts at the base of large hickory trees. They will store food for winter use.

Animal Foods: birds; eggs; carrion ; insects

Plant Foods: leaves; wood, bark, or stems; seeds, grains, and nuts; fruit

Other Foods: fungus

Foraging Behavior: stores or caches food

Primary Diet: omnivore

Comments: Eats plant and animal foods. Most "carnivorous" of the squirrels (Dolan and Carter 1977). Feeds on insects in spring; nuts, seeds, and fruits through the rest of the year. May eat birds (especially eggs and young) and carrion. Caches food for winter. In South Carolina, acorns were most important throughout year; pine seeds, other plant material, and a few insects also consumed (Harlow and Doyle 1990).

Flying squirrels consume large numbers of the fruiting bodies of subterranean fungi, dispersing the spores in their feces. The mycelia of these fungi form close associations with the roots of many species of trees and are believed to be essential for tree growth and maintenance. They also disperse the seeds of hardwood trees.

Ecosystem Impact: disperses seeds

Flying squirrels avoid predators by being nocturnal and by being fast and agile in the trees and during their glides. They are alert for predators constantly. The most successful predators on flying squirrels are able to fly, such as hawks and owls, or can climb well, such as domestic cats, bobcats, weasels, raccoons, and climbing snakes.

Known Predators:

• hawks (Accipitridae)
• owls (Strigiformes)
• domestic cats (Felis silvestris)
• bobcats (Lynx rufus)
• weasels (Mustela)
• raccoons (Procyon lotor)
• snakes (Serpentes)

Anti-predator Adaptations: cryptic

Glaucomys volans is prey of:
Squamata
Strigiformes
Accipitridae
Mustela
Procyon lotor
Lynx rufus
Felis silvestris

This list may not be complete but is based on published studies.

Glaucomys volans preys on:
fungi
Insecta
Aves

This list may not be complete but is based on published studies.

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

10,000 to >1,000,000 individuals

Comments: Common throughout most of range.

Highly sociable, particularly in winter, when communal nesting peaks; communal nesting aggregations occur in both northern and southern populations (Layne and Raymond, 1994, J. Mamm. 75:110-120).

Population density was estimated at 31-38/ha in southeastern Virginia (Sawyer and Rose 1985), 10-14/ha in Maryland, 1.5-2.5/ha in Michigan-Massachusetts (see Layne and Raymond). May be ousted from cavities by some large cavity-nesting birds; may kill or oust some small cavity-nesting birds.

Southern flying squirrels have very large eyes in order to see well in low light. They have keen senses of smell, touch, vision, and hearing. They probably communicate about reproductive condition through chemical cues. Vibrissae on the cheeks, chin, and ankles help them in navigating at night. They are relatively quiet but may use some vocalizations in social communication.

Communication Channels: tactile ; acoustic ; chemical

Perception Channels: visual ; acoustic

Comments: Active at night throughout the year, except during extreme winter cold. Will enter a state of torpor in cold periods.

Southern flying squirrels in the wild can live to 5 or 6 years old. In captivity they have been known to live up to 10 years. Most flying squirrels probably die in their first year of life.

Range lifespan

Status: captivity: 10 (high) years.

Typical lifespan

Status: wild: 6 (high) years.

Average lifespan

Status: captivity: 12.0 years.

Maximum longevity: 19 years (captivity) Observations: One wild born specimen was about 19 years old when it died in captivity (Richard Weigl 2005).

Little is known about the mating system in southern flying squirrels. Males and females do not associate much beyond breeding.

Not much is known about mating in southern flying squirrels.

Mating System: polygynous

Females are polyestrous and typically mate twice per year. Births thus have two peaks, from February to May and from July to September. There is, however, some geographic variation in the timing of births. (In Michigan, they court and breed in winter and early spring.) The gestation period is 40 days. Litters can range from one to six young, though two or three is most common. The young are weaned at 65 days (an unusually long time for an animal this small) and are independent at 120 days. Maturity is usually attained at twelve months, though ages as young as nine months have been reported.

Breeding interval: Southern flying squirrels breed twice each year.

Breeding season: Breeding occurs from January to April and from June to August.

Range number of offspring: 1 to 6.

Average number of offspring: 2-3.

Average gestation period: 40 days.

Average time to independence: 120 days.

Range age at sexual or reproductive maturity (female): 9 (low) months.

Average age at sexual or reproductive maturity (female): 12 months.

Average age at sexual or reproductive maturity (male): 12 months.

Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); fertilization (Internal ); viviparous

Average birth mass: 3.35 g.

Average gestation period: 40 days.

Average number of offspring: 4.

Young flying squirrels are born naked and helpless in their mother's nest. Their ears open at 2 to 6 days old, they develop some fur by 7 days old, and their eyes open by their 24th or 30th day of life. Females care for their young in the nest and nurse them for 65 days, which is an unusually long time for an animal of this size. The young become independent by 4 months old unless they are born later in the summer, in which case they usually overwinter as a family.

Parental Investment: altricial ; female parental care

Gestation lasts about 40 days. Births peak April-May and late summer in north, late February-March and September-October in south. Litter size usually is about 2-3 in south, 3-4 in north. Young first breed in spring after birth in north, may breed late in 1st summer in south. Two distinct breeding periods in New Hampshire, February-March and June-July; two litters per year (Stapp and Mautz 1991).

Low-energy air transport: flying squirrels
 

The extensions of skin attached to the legs of flying squirrels enables low-energy air transport by serving as a deployable gliding surface.

   
  "Membranes of skin are also used by other mammals to achieve, if not real flight, at least gliding. The flying squirrels and gliding possums have a membrane of skin extending between the wrist and ankle on each side of the body. When the animal launches itself from a high branch it spreads its limbs wide apart and the taut membranes act as a parachute: the great gliding possum can make leaps covering 100 metres in this way. 'Flying' frogs have similar enlarged membranes between their long toes which they use in gliding leaps from tree to tree." (Foy and Oxford Scientific Films 1982)

"Keith Paskins of the University of Bath, is trying to mimic flying squirrels for use in unmanned crafts. The squirrels have floppy skin attached to their wrists and ankles, which they can stretch out to make a gliding surface. The animals also appear to be able to control their gliding through rapid movements while in the air. By incorporating jumping as a flying squirrel does, the craft could conserve energy by using gliding to fly to the surface." (Courtesy of the Biomimicry Guild)

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  Learn more about this functional adaptation.

Wings provide lift for gliding: flying squirrel
 

Wings of flying squirrels provide lift and decrease drag due to being cambered and having a well-developed forewing.

   
  Gliding is a form of locomotion that requires individual variation in rotations to restore equilibrium. "In a steady, non-accelerating glide, the glide ratio is determined by the ratio of lift to drag, the aerodynamic forces perpendicular to the direction of travel and parallel and opposite to the direction of travel, respectively. The lift-to-drag ratio can be increased by increasing lift, decreasing drag, and/or by producing thrust, defined as a force that opposes drag. Flapping has often been assumed to have evolved as a means to increase lift and thrust…thereby increasing the distance traveled." (Bishop 2007: 2594)

"Flying squirrels generated more lift and less drag than sugar gliders…There are several possible reasons why flying squirrels tend to produce greater lift coefficients than sugar gliders. One is that their wings are more cambered in flight (Table·1). In addition, flying squirrels possess a well-developed forewing structure called a propatagium that is present, but much smaller, in sugar gliders… In the case of the squirrels, increasing the lift coefficient increased the forward acceleration, which in turn contributed to greater overall velocity. (Bishop 2007: 2604-2605)

"Aerodynamic performance declines with increasing aspect ratio, particularly at the high angles of attack used by the gliders…But, at higher aspect ratios, aerodynamic performance increases with increasing aspect ratio. This may have presented a kind of adaptive barrier during the transition from a low aspect ratio glider wing to a high aspect ratio bat wing…Understanding the relationships between kinematics, force production and gliding performance across species in the context of disparate performance parameters, not only improves our understanding of and appreciation for gliding as a form of locomotion, but will also lead to more fruitful hypotheses regarding the origin of flight in bats." (Bishop 2007:2605)
  Learn more about this functional adaptation.

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 0
Species: 9
Species With Barcodes: 1

Some subspecies in Central America are rare and may be endangered.

US Federal List: no special status

CITES: no special status

State of Michigan List: no special status

IUCN Red List of Threatened Species: least concern

Canada

Rounded National Status Rank: N3 - Vulnerable

United States

Rounded National Status Rank: N5 - Secure

Rounded Global Status Rank: G5 - Secure

Population

Population Trend

Major Threats

Degree of Threat: D : Unthreatened throughout its range, communities may be threatened in minor portions of the range or degree of variation falls within natural variation

Comments: Threats include loss of habitat and loss of cavity-bearing and mast-producing trees. In Arkansas, a seed-tree harvest regime, particularly without retained overstory hardwoods, produced a level of disturbance and resource depletion that was too severe for flying squirrel persistence (Taulman et al. 1998).

Conservation Actions

Global Protection: Unknown whether any occurrences are appropriately protected and managed

Flying squirrels are sometimes pests when they make nests in houses.

Flying squirrels play important ecosystem roles in hardwood forests. They are also sometimes kept as pets.

Positive Impacts: pet trade

Comments: Pattern of variation in cranial characteristics does not correspond well with current subspecies ranges in southwestern part of range; morphological differences between populations in Middle America and eastern U.S. are no greater than differences between populations in northeastern and southwestern parts of range in U.S. (Braun 1988).

Thorington et al. (1996) examined morphological variation in three genera of flying squirrels and concluded that Glaucomys, Hylopetes, and Eoglaucomys form three distinct clades, with G. volans and G. sabrinus congeneric (contrasting with earlier suggestions by Burt).

Arbogast (1999) examined mtDNA phylogeography based on samples from Louisiana, Tennessee, and West Virginia and found only one major mtDNA lineage.