The southern flying squirrel or the assapan (''Glaucomys volans'') is one of three

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

'' Glaucomys'' and one of three

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 ...

species 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 ...

. 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 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 ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, covering over , making it the world's second-largest country by tot ...

Florida Florida is a state located in the Southeastern region of the United States. Florida is bordered to the west by the Gulf of Mexico, to the northwest by Alabama, to the north by Georgia, to the east by the Bahamas and Atlantic Ocean, and to ...

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

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Guatemala Guatemala ( ; ), officially the Republic of Guatemala ( es, República de Guatemala, links=no), is a country in Central America. It is bordered to the north and west by Mexico; to the northeast by Belize and the Caribbean; to the east by H ...

, and

Honduras Honduras, officially the Republic of Honduras, is a country in Central America. The republic of Honduras is bordered to the west by Guatemala, to the southwest by El Salvador, to the southeast by Nicaragua, to the south by the Pacific Oce ...

Description and ecology

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

that extends between the front and rear legs and is used to glide through the air. Total length (including tail) is . The tail can be . Southern flying squirrels are nocturnal. They feed on fruit and nuts from trees such as

red Red is the color at the long wavelength end of the visible spectrum of light, next to orange and opposite violet. It has a dominant wavelength of approximately 625–740 nanometres. It is a primary color in the RGB color model and a secondar ...

and

white oak The genus ''Quercus'' contains about 500 species, some of which are listed here. The genus, as is the case with many large genera, is divided into subgenera and sections. Traditionally, the genus ''Quercus'' was divided into the two subgenera '' ...

hickory Hickory is a common name for trees composing the genus ''Carya'', which includes around 18 species. Five or six species are native to China, Indochina, and India (Assam), as many as twelve are native to the United States, four are found in Mexi ...

, and

beech Beech (''Fagus'') is a genus of deciduous trees in the family Fagaceae, native to temperate Europe, Asia, and North America. Recent classifications recognize 10 to 13 species in two distinct subgenera, ''Engleriana'' and ''Fagus''. The ''Engle ...

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

snake Snakes are elongated, Limbless vertebrate, limbless, carnivore, carnivorous reptiles of the suborder Serpentes . Like all other Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales. Ma ...

owl Owls are birds from the order Strigiformes (), which includes over 200 species of mostly solitary and nocturnal birds of prey typified by an upright stance, a large, broad head, binocular vision, binaural hearing, sharp talons, and feathers a ...

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

s and

raccoon The raccoon ( or , ''Procyon lotor''), sometimes called the common raccoon to distinguish it from other species, is a mammal native to North America. It is the largest of the procyonid family, having a body length of , and a body weight of ...

s. Domestic

cat The cat (''Felis catus'') is a domestic species of small carnivorous mammal. It is the only domesticated species in the family Felidae and is commonly referred to as the domestic cat or house cat to distinguish it from the wild members of ...

s can also be potential predators. Glaucomys volans peanut feeder

Both in the wild and in captivity, they can produce two litters 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 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 agency of the United States. It is a United States federal agency, under the Department of Health and Human Services, and is headquartered in Atlanta, Georgi ...

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 ''Rickettsia prowazekii'' is a species of gram-negative, alphaproteobacteria, obligate intracellular parasitic, aerobic bacillus bacteria that is the etiologic agent of epidemic typhus, transmitted in the feces of lice. In North America, the ...

'' 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 of 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 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 form an "X" with their limbs by spreading 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

degree Degree may refer to: As a unit of measurement * Degree (angle), a unit of angle measurement ** Degree of geographical latitude ** Degree of geographical longitude * Degree symbol (°), a notation used in science, engineering, and mathematics ...

s. They maneuver with great efficiency in the air, making 90

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 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 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 where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill th ...

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 forest Temperate broadleaf and mixed forest is a temperate climate terrestrial habitat type defined by the World Wide Fund for Nature, with broadleaf tree ecoregions, and with conifer and broadleaf tree mixed coniferous forest ecoregions. These for ...

s 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 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. He ...

. Also,

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

and poplar, as well as

oak An oak is a tree or shrub in the genus ''Quercus'' (; Latin "oak tree") of the beech family, Fagaceae. There are approximately 500 extant species of oaks. The common name "oak" also appears in the names of species in related genera, notably ''L ...

trees make favorable habitat. Although southern flying squirrels may be present in heavily wooded

suburban A suburb (more broadly suburban area) is an area within a metropolitan area, which may include commercial and mixed-use, that is primarily a residential area. A suburb can exist either as part of a larger city/urban area or as a separate ...

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. He ...

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), or 10,000 m2, and is primarily used in the measurement of land. There are 100 hectares in one square kilometre. An acre is a ...

s, 9.0 hectares,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 for adult males, 1.95 hectares, 3.9 hectares, and 7.2 hectares for adult females, and 0.61 hectares 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 oak The genus Oak, ''Quercus'' contains about 500 species, some of which are listed here. The genus, as is the case with many List of the largest genera of flowering plants, large genera, is Taxonomic rank#Ranks in botany, divided into subgenus, subgen ...

s and

s, whereas female home ranges contained 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 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 polar regions. ...

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

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 a closed path that encompasses, surrounds, or outlines either a two dimensional shape or a one-dimensional length. The perimeter of a circle or an ellipse is called its circumference. Calculating the perimeter has several pract ...

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

plantation A plantation is an agricultural estate, generally centered on a plantation house, meant for farming that specializes in cash crops, usually mainly planted with a single crop, with perhaps ancillary areas for vegetables for eating and so on. The ...

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 Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

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 The coefficient of relationship is a measure of the degree of consanguinity (or biological relationship) between two individuals. The term coefficient of relationship was defined by Sewall Wright in 1922, and was derived from his definition of th ...

, they are tolerant of nonrelated but familiar individuals, possibly because in addition to providing heat energy for the aggregation, outsiders will promote

outbreeding Out-crossing or out-breeding is the technique of crossing between different breeds. This is the practice of introducing distantly related genetic material into a breeding line, thereby increasing genetic diversity. Outcrossing can be a useful ...

.Thorington KK, Weigl PD. (2011). Role of kinship in the formation of southern flying squirrel winter aggregations. ''Journal of Mammalogy.'' 92(1):179-189. MullMuul, 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 actually 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 The degree Celsius is the unit of temperature on the Celsius scale (originally known as the centigrade scale outside Sweden), one of two temperature scales used in the International System of Units (SI), the other being the Kelvin scale. The ...

while the normal body temperature of southern flying squirrels varies between 36.3 and 38.9

. 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 this could be a form of

kin selection Kin selection is the evolutionary strategy that favours the reproductive success of an organism's relatives, even when at a cost to the organism's own survival and reproduction. Kin altruism can look like Altruism in animals, altruistic behavio ...

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 the 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 In evolutionary biology, inclusive fitness is one of two metrics of evolutionary success as defined by W. D. Hamilton in 1964: * Personal fitness is the number of offspring that an individual begets (regardless of who rescues/rears/supports them ...

involved in the

hoarding Hoarding is a behavior where people or animals accumulate food or other items. Animal behavior ''Hoarding'' and ''caching'' are common in many bird species as well as in rodents. Most animal caches are of food. However, some birds will a ...

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 The Richmond Flying Squirrels are a Minor League Baseball team based in Richmond, Virginia. The team, which is a part of the Eastern League, is the Double-A affiliate of the San Francisco Giants major league club, and plays at The Diamond. Th ...

- Eastern League affiliate of the

San Francisco Giants The San Francisco Giants are an American professional baseball team based in San Francisco, California. The Giants compete in Major League Baseball (MLB) as a member club of the National League (NL) West division. Founded in 1883 as the New Yor ...

. This

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

-based team draws its name, logo, and mascot from the southern flying squirrel. *The video games

Pokémon Black and White and are 2010 role-playing video games developed by Game Freak, published by The Pokémon Company and Nintendo for the Nintendo DS. They are the first installments in the fifth generation of the Pokémon (video game series), ''Pokémon'' vid ...

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.

Footnotes

References

* *Arbogast, B. S. (1999). Mitochondrial DNA phylogeography of the New World flying squirrels (''Glaucomys''): implications for Pleistocene biogeography. ''

Journal of Mammalogy The ''Journal of Mammalogy'' is a bimonthly peer-reviewed scientific journal published by Oxford University Press on behalf of the American Society of Mammalogists. Both the society and the journal were established in 1919. The journal covers rese ...

'' 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. *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 t ...

'' 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

FlyingSquirrels.com

National Flying Squirrel Association
– Pet squirrel care.

{{Taxonbar, from=Q913350 Glaucomys Fauna of the Eastern United States Mammals of the United States Mammals of Canada Rodents of Central America Mammals of Mexico

Southern flying squirrel The southern flying squirrel or the assapan (''Glaucomys volans'') is one of three species of the genus '' Glaucomys'' and one of three flying squirrel species found in North America. It is found in deciduous and mixed woods in the eastern half o ...