The southern flying squirrel (''Glaucomys volans''), also known commonly as the assapan, is a species of

squirrel Squirrels are members of the family Sciuridae (), a family that includes small or medium-sized rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrel ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Sciuridae Squirrels are members of the family Sciuridae (), a family that includes small or medium-sized rodents. The squirrel family includes tree squirrels, ground squirrels (including chipmunks and prairie dogs, among others), and flying squirrel ...

. ''G. volans'' is one of three

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

flying squirrels Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe (biology), tribe of 50 species of squirrels in the family (biology), family Squirrel, Sciuridae. Despite their name, they are not in fact capable of full flight i ...

found in

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

. It is found in

deciduous In the fields of horticulture and botany, the term deciduous () means "falling off at maturity" and "tending to fall off", in reference to trees and shrubs that seasonally shed Leaf, leaves, usually in the autumn; to the shedding of petals, aft ...

and mixed woods in the eastern half of

, from southeastern

Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...

Florida Florida ( ; ) is a U.S. state, state in the Southeastern United States, Southeastern region of the United States. It borders the Gulf of Mexico to the west, Alabama to the northwest, Georgia (U.S. state), Georgia to the north, the Atlantic ...

. Disjunct populations of this species have been recorded in the highlands of

Mexico Mexico, officially the United Mexican States, is a country in North America. It is the northernmost country in Latin America, and borders the United States to the north, and Guatemala and Belize to the southeast; while having maritime boundar ...

Guatemala Guatemala, officially the Republic of Guatemala, is a country in Central America. It is bordered to the north and west by Mexico, to the northeast by Belize, to the east by Honduras, and to the southeast by El Salvador. It is hydrologically b ...

, and

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. It is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Ocean at the Gulf of Fonseca, ...

. There are 11

subspecies In Taxonomy (biology), biological classification, subspecies (: subspecies) is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (Morphology (biology), morpholog ...

that are recognized as being valid, including the

nominotypical subspecies In biological classification, subspecies (: 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. ...

Description and ecology

Southern flying squirrels have grey-brown fur on top with darker flanks and are a cream colored underneath. They have large dark eyes and flattened tails. They have a furry membrane called a

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

that extends from the front to the rear legs and is used to glide through the air. Total length (including tail) is . The tail can be . Assapans are nocturnal. They feed on fruits and nuts from trees such as red and white oak,

hickory Hickory is a common name for trees composing the genus ''Carya'', which includes 19 species accepted by ''Plants of the World Online''. Seven species are native to southeast Asia in China, Indochina, and northeastern India (Assam), and twelve ...

, and

beech Beech (genus ''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to subtropical (accessory forest element) and temperate (as dominant element of Mesophyte, mesophytic forests) Eurasia and North America. There are 14 accepted ...

. They store food, especially acorns, for winter consumption. They also dine on insects, buds, mushrooms, mycorrhizal fungi, carrion, bird eggs, nestlings, and flowers. Their predators include

snake Snakes are elongated limbless reptiles of the suborder Serpentes (). Cladistically squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales much like other members of the group. Many species of snakes have s ...

s, owls,

hawk Hawks are birds of prey of the family Accipitridae. They are very widely distributed and are found on all continents, except Antarctica. The subfamily Accipitrinae includes goshawks, sparrowhawks, sharp-shinned hawks, and others. This ...

s, and

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the North American, northern or common raccoon (also spelled racoon) to distinguish it from Procyonina, other species of raccoon, is a mammal native to North America. It is the largest ...

s. Domestic cats can also be potential predators. Both in the wild and in captivity, they can produce two litters of young each year (with 2–7 young per litter). The gestation period is approximately 40 days. Young are born without fur or any capabilities of their own. Their ears open at 2 to 6 days old, and fur grows in by 7 days. Their eyes do not open until they are 24–30 days old. Mothers wean their young 65 days after they are born. The young then become fully independent at around 120 days of age. Southern flying squirrels show substantial homing abilities and can return to their nests if artificially removed to distances of up to a kilometer. Their home ranges may be up to 40,000 square meters (0.015 square mile) for females and double that for males, tending to be larger at the northern extreme of their range. Exposure to southern flying squirrels has been linked to cases of epidemic typhus in humans. Typhus spread by flying squirrels is known as "sylvatic typhus" and the

Centers for Disease Control and Prevention The Centers for Disease Control and Prevention (CDC) is the National public health institutes, national public health agency of the United States. It is a Federal agencies of the United States, United States federal agency under the United S ...

has documented a total of 39 such cases in the U.S. from 1976 to 2001. The squirrel acts as host to the '' Rickettsia prowazekii'' bacteria and transmission to humans is hypothesized to occur via aerosolized feces of the fleas and lice associated with ''G. volans''.Kondratieff, B.C., Marquardt, William C..; Biology of Disease Vectors. pg 72.

Gliding

Flying squirrels do not actually fly, but rather glide using a membrane called a

. 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 m ...

to estimate the distance of the landing area as they often lean out and pivot from side to side before jumping.Walker EP, Paradiso JL. (1975). ''Mammals of the world.'' Baltimore: Johns Hopkins University Press. Once in the air, they spread their long arms forward and out and their long legs backward and out, 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 that abruptly changes their trajectory upwards, and point all of their limbs forward to create a

parachute A parachute is a device designed to slow an object's descent through an atmosphere by creating Drag (physics), drag or aerodynamic Lift (force), lift. It is primarily used to safely support people exiting aircraft at height, but also serves va ...

effect with the membrane in order 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 in order to avoid any potential

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

s. 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.

Habitat

The southern flying squirrel is found in eastern

forests or mixed forests of

.Forsyth A. (1999). ''Mammals of North America: Temperate and Arctic regions.'' Willowdale: Firefly Books. Large

Fridell RA, Litvaitis JA. (1991). Influence of resource distribution and abundance on home-range characteristics of southern flying squirrels. ''Canadian Journal of Zoology.'' 69(10):2589-2593. and

treesHolloway GL, Malcolm JR. (2007). Nest-tree use by northern and southern flying squirrels in central Ontario. ''Journal of Mammalogy.'' 88(1):226-233. are more abundant in intensively used areas of their home ranges. Also,

maple ''Acer'' is a genus of trees and shrubs commonly known as maples. The genus is placed in the soapberry family Sapindaceae.Stevens, P. F. (2001 onwards). Angiosperm Phylogeny Website. Version 9, June 2008 nd more or less continuously updated si ...

and poplar, as well as oak trees, make favorable habitats. Although southern flying squirrels may be present in heavily wooded

suburban A suburb (more broadly suburban area) is an area within a metropolitan area. They are oftentimes where most of a metropolitan areas jobs are located with some being predominantly residential. They can either be denser or less densely populated ...

regions, they never occur in large numbers in these areas. The size of the

home range A home range is the area in which an animal lives and moves on a periodic basis. It is related to the concept of an animal's territory which is the area that is actively defended. The concept of a home range was introduced by W. H. Burt in 1943. ...

of southern flying squirrels varies greatly.Bendel PR, Gates JE. (1987). Home range and microhabitat partitioning of the southern flying squirrel ''Glaucomys volans''. ''Journal of Mammalogy.'' 68(2):243-255. Average home range estimates are 2.45

hectare The hectare (; SI symbol: ha) is a non-SI metric unit of area equal to a square with 100-metre sides (1 hm2), that is, square metres (), and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. ...

s (6.05 acres), 9.0 hectares (22.2 acres),Stone KD, Heidt GA, Caster PT, Kennedy ML. (1997). Using geographic information systems to determine home range of the southern flying squirrel Glaucomys volans. ''American Midland Naturalist.'' 137(1):106-111. and 16.0 hectares (39.5 acres) for adult males, 1.95 hectares (4.82 acres), 3.9 hectares (9.64 acres), and 7.2 hectares (17.8 acres) for adult females, and 0.61 hectares (1.51 acres) for juveniles. Significant overlap exists among the home ranges. Near the northern limit of the southern flying squirrels distribution, home range increases in size as mast-producing trees become more dispersed. This trend is also observed in fragmented forests where nesting and foraging areas become widely spaced.Taulman JF, Smith KG. (2004). Home range and habitat selection of southern flying squirrels in fragmented forests. ''Mammalian Biology.'' 69(1):11-27. Home range is larger in males than females possibly to increase the chance of encountering potential mates. Although males have a larger home range, female home ranges have been shown to increase by as much as 70 percent following the departure of the offspring. Number of nesting sites does not influence the total number of flying squirrelsBrady M, Risch T, Dobson F. (2000). Availability of nest sites does not limit population size of southern flying squirrels. ''Canadian Journal of Zoology.'' 78:1144-1149. but may influence which sex will be present. Male home ranges contain more food as they have been associated with a higher than expected number of large red oaks and white oaks, whereas female home ranges contain lower food resources and more abundant nesting sites possibly to avoid contact with other squirrels while raising the young. Southern flying squirrels nest in natural cavities and

woodpecker Woodpeckers are part of the bird family (biology), family Picidae, which also includes the piculets, wrynecks and sapsuckers. Members of this family are found worldwide, except for Australia, New Guinea, New Zealand, Madagascar and the extreme ...

holes,Loeb SC, Reid SL, Lipscomb DJ. (2012). Habitat and landscape correlates of southern flying squirrel use of Red-cockaded Woodpecker clusters. ''Journal of Wildlife Management.'' 76(7):1509-1518. or build nest out of leaves and twigs. Leaf nests are used as a refuge or a resting site and are used primarily in summer, whereas cavities are used for breeding and more intensively during winter. Cavities used by southern flying squirrels are found in small snags, average in

diameter at breast height Diameter at breast height, or DBH, is a standard method of expressing the diameter of the trunk or bole of a standing tree. DBH is one of the most common dendrometric measurements. Tree trunks are measured at the height of an adult's breast, ...

, or large living trees, average dbh, with entrances that average in width by in height, which are an average of above the ground. Dens tend to be on the

perimeter A perimeter is the length of a closed boundary that encompasses, surrounds, or outlines either a two-dimensional shape or a one-dimensional line. The perimeter of a circle or an ellipse is called its circumference. Calculating the perimet ...

of the home range and situated away from clearings. To cross disturbances such as

plantation Plantations are farms specializing in cash crops, usually mainly planting a single crop, with perhaps ancillary areas for vegetables for eating and so on. Plantations, centered on a plantation house, grow crops including cotton, cannabis, tob ...

s and logged areas, southern flying squirrels prefer to use mature forest corridors over younger ones, suggesting that they are more sensitive to forest disturbances than previously believed.

Behavior

Southern flying squirrels are highly social

mammal A mammal () is a vertebrate animal of the Class (biology), class Mammalia (). Mammals are characterised by the presence of milk-producing mammary glands for feeding their young, a broad neocortex region of the brain, fur or hair, and three ...

s and have been observed flying and foraging together in large groups. Additionally, they often aggregate together in dens, especially as seasonal temperatures declineLayne JN, Raymond MAV. (1994). Communal nesting of southern flying squirrels in Florida. ''Journal of Mammalogy.'' 75(1):110-120.Reynolds RJ, Fies ML, Pagels JF. (2009). Communal nesting and reproduction of the southern flying squirrel in Montane Virginia. Northeastern Naturalist. 16(4):563-576. in order to conserve energy.Stapp P, Pekins PJ, Mautz WW. (1991). Winter energy expenditure and the distribution of southern flying squirrels. ''Canadian Journal of Zoology''. 69(10):2548-2555.Merritt JF, Zegers DA, Rose LR. (2001). Seasonal thermogenesis of southern flying squirrels ''Glaucomys volans''. ''Journal of Mammalogy.'' 82(1):51-64. Compared to individuals who nest alone in winter, squirrels in aggregates can save 30 percent more energy. Although southern flying squirrels do show a preference for relatedness, they are tolerant of nonrelated but familiar individuals, possibly because in addition to providing heat energy for the aggregation, outsiders will promote outbreeding.Thorington KK, Weigl PD. (2011). Role of kinship in the formation of southern flying squirrel winter aggregations. ''Journal of Mammalogy.'' 92(1):179-189. However, in the summer months, they tend to forage and cache alone in their home range. MuulMuul, I. (1968). Behavioral and physiological influences on the distribution of the flying squirrel ''Glaucomys volans''. Miscellaneous Publications of the Museum of Zoology. University of Michigan, 134:1-66. Cited in: Layne JN, Raymond MAV. (1994). Communal nesting of southern flying squirrels in Florida. ''Journal of Mammalogy.'' 75(1):110-120. stated that communal nesting may be detrimental during warm weather and is unnecessary in the southern parts of the species range. However, Layne and Raymond observed nest boxes in

and discovered that the southern populations also nest in large groups (up to 25 individuals) and that, compared to northern populations, the period of elevated communal nesting extended later in the spring. In this study, nest temperatures occasionally exceeded 38 °C (100.4°F) while the normal body temperature of southern flying squirrels varies between 36.3 and 38.9 °C (97.3 and 102°F). Since southern populations breed later in the spring than northern populations,Raymond MAV, Layne JN. (1988). Aspects of reproduction in the southern flying squirrel in Florida. ''Acta Theriologica.'' 33(26-43):505-518. Cited in: Layne JN, Raymond MAV. (1994). Communal nesting of southern flying squirrels in Florida. ''Journal of Mammalogy.'' 75(1):110-120. these findings suggests that communal nesting serves more than a thermoregulatory function and may actually play a role in the social organization of populations. Proposed advantages of aggregation include increased likelihood of mating, increased defense against predators, or increased foraging success. Populations which nest together were found to be more highly related than expected by chance and it is believed that this could be a form of

kin selection Kin selection is a process whereby natural selection favours a trait due to its positive effects on the reproductive success of an organism's relatives, even when at a cost to the organism's own survival and reproduction. Kin selection can lead ...

since an individual's stored food may be beneficial for the survival of its relatives in the event of death.Thorington KK, Metheny JD, Kalcounis-Rueppell MC, Weigl PD. (2010). Genetic relatedness in winter populations of seasonally gregarious southern flying squirrels, Glaucomys volans. ''Journal of Mammalogy.'' 91(4):897-904. Winterrowd and WeiglWinterrowd MF, Weigl PD. (2006). Mechanisms of cache retrieval in the group nesting southern flying squirrel ''Glaucomys volans''. ''Ethology.'' 112(11):1136-1144. performed experiments in controlled conditions to determine whether memory, smell, random searching, or problem solving played a major role in retrieving hidden food. When burying dry nuts in dry substrate, no odors are present and spatial memory is the most effective retrieval mechanism, suggesting that there is no inclusive fitness involved in the

hoarding Hoarding is the act of engaging in excessive acquisition of items that are not needed or for which no space is available. Civil unrest or the threat of natural disasters may lead people to hoard foodstuffs, water, gasoline, and other essentials ...

behavior. However, once placed in a wet environment, smell becomes an effective means to retrieve the food and decreases the individuals' advantage over the other members of the group. Experiments to determine whether a squirrel would steal from others in the group revealed that no particular pattern exists and that the hidden food is recovered according to its availability.

Sports and popular culture

* Richmond Flying Squirrels - Eastern League affiliate of the

San Francisco Giants The San Francisco Giants are an American professional baseball team based in San Francisco. The Giants compete in Major League Baseball (MLB) as a member club of the National League (baseball), National League (NL) National League West, West Div ...

. This

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

-based team draws its name, logo, and mascot from the southern flying squirrel. *The video games Pokémon Black and White take place in the Unova region (based on the eastern United States) and contain Emolga, an Electric/Flying type Pokémon based on the southern flying squirrel. *The animated television series ''The Adventures of Rocky and Bullwinkle and Friends'' features the anthropomorphic

flying squirrel Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe (biology), tribe of 50 species of squirrels in the family (biology), family Squirrel, Sciuridae. Despite their name, they are not in fact capable of full flight i ...

Rocket J. ("Rocky") Squirrel.

Footnotes

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. *Fox, D. & Mulheisen, M. (1999)
Animal Diversity Web - ''Glaucomys volans''
Accessed May 20, 2005. *Fridell, R. A. & Litvaitis, J. A. (1991). Influence of resource distribution and abundance on home-range characteristics of southern flying squirrels. ''Canadian Journal of Zoology'' 69: 2589–2593. * *Mitchell, L. R.; Carlile, L. D. & Chandler, C. R. (1999). Effects of southern flying squirrels on nest success of red-cockaded woodpeckers. ''Journal of Wildlife Management'' 63: 538–545. *Murrant, Meghan N.; Bowman, Jeff; Wilson, Paul J. (2014). "A test of non-kin social foraging in the southern flying squirrel (''Glaucomys volans'')". ''Biological Journal of the Linnean Society'' 113 (4): 1126–1135. https://doi.org/10.1111/bij.12385 *Sawyer, S. L. & Rose, R. K. (1985). Homing in and ecology of the southern flying squirrel ''Glaucomys volans'' in southeastern Virginia. ''American Midland Naturalist'' 113: 238–244. *Stapp, P.; Pekins, P. J. & Mautz, W. W. (1991). Winter energy-expenditure and the distribution of southern flying squirrels. ''Canadian Journal of Zoology'' 69: 2548–2555. *Stone, K. D.; Heidt, G. A.; Baltosser, W. H. & Caster, P. T. (1996). Factors affecting nest box use by southern flying squirrels (''Glaucomys volans'') and gray squirrels (''Sciurus carolinensis''). ''American Midland Naturalist'' 135: 9-13. *Stone, K. D.; Heidt, G. A.; Caster, P. T. & Kennedy, M. L. (1997). Using geographic information systems to determine home range of the southern flying squirrel (''Glaucomys volans''). ''American Midland Naturalist'' 137: 106–111. *Taulman, J. F. (1999). Selection of nest trees by southern flying squirrels (Sciuridae: ''Glaucomys volans'') in Arkansas. ''

Journal of Zoology The ''Journal of Zoology'' is a scientific journal concerning zoology, the study of animals. It was founded in 1830 by the Zoological Society of London and is published by Wiley-Blackwell. It carries original research papers, which are targeted ...

'' 248: 369–377. *Taulman, J. F.; Smith, K. G. & Thill, R. E. (1998). Demographic and behavioral responses of southern flying squirrels to experimental logging in Arkansas. ''Ecological Applications'' 8: 1144–1155. *Thomas, R. B. & Weigl, P.D. (1998). Dynamic foraging behavior in the southern flying squirrel (''Glaucomys volans''): test of a model. ''American Midland Naturalist'' 140: 264–270.

External links

Smithsonian Wild: Glaucomys volans
{{Taxonbar, from=Q913350 Glaucomys Fauna of the Eastern United States Rodents of the United States Rodents of Canada Rodents of Central America Rodents of Mexico Southern flying squirrel Southern flying squirrel