Flying squirrel

This article is about the member of the animal kingdom. For other uses, see Flying squirrel (disambiguation).
See also: Gliding possum
Flying squirrel
Temporal range: Early Oligocene – Recent
Northern flying squirrel (Glaucomys sabrinus)
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Rodentia
Family: Sciuridae
Subfamily: Sciurinae
Tribe: Pteromyini
Brandt, 1855
Genera

Aeretes
Aeromys
Belomys
Biswamoyopterus
Eoglaucomys
Eupetaurus
Glaucomys
Hylopetes
Neopetes[1]
Iomys
Petaurillus
Petaurista
Petinomys
Pteromys
Pteromyscus
Trogopterus

Flying squirrels (scientifically known as Pteromyini or Petauristini) are a tribe of 44 species of squirrels (family Sciuridae).

Description

A flying squirrel gliding

Flying squirrels are not capable of powered flight like birds or bats; instead, they glide between trees. They are capable of obtaining lift within the course of these flights, with flights recorded to 90 meters (270 ft).[2][3] The direction and speed of the animal in midair is varied by changing the positions of its two arms and legs, largely controlled by small cartilaginous wrist bones.[4] This changes the tautness of the patagium, a furry parachute-like membrane that stretches from wrist to ankle.[4] It has a fluffy tail that stabilizes in flight. The tail acts as an adjunct airfoil, working as an air brake before landing on a tree trunk.[5]

The colugos, Petauridae, and Anomaluridae are gliding mammals which are similar to flying squirrels because of convergent evolution. These mammals can glide through the trees, but they do not actually fly (like birds and bats). They have a membrane of skin on either side of their body.

Prior to the 21st century, the evolutionary history of the flying squirrel was frequently debated.[6] This debate was clarified greatly as a result of two recent molecular studies.[7][8] These studies found support that flying squirrels originated 18–20 million years ago, are monophyletic, and have a sister relationship with tree squirrels. There are four hypotheses as to why gliding has evolved in mammals: economical locomotion, foraging optimization, evasion of predators, and control of landing forces.[9]

Taxonomy

The largest of the species is the woolly flying squirrel (Eupetaurus cinereus). The two species of the genus Glaucomys (Glaucomys sabrinus and Glaucomys volans) are native to North America, and the Siberian flying squirrel is native to parts of northern Europe (Pteromys volans).

Thorington and Hoffman (2005) recognize 15 genera of flying squirrels in two subtribes.

Tribe Pteromyini – flying squirrels

Three new species of flying squirrel have been been found in the northeastern state of India of Arunachal Pradesh.[10][11][12] These are:

Life cycles

A southern flying squirrel (Glaucomys volans) gliding

The life expectancy of flying squirrels in the wild is about six years, but flying squirrels can live up to fifteen years in zoos. The mortality rate in young flying squirrels is high because of predators and diseases. Predators of flying squirrels include tree snakes, raccoons, owls, martens, fishers, coyotes, bobcats, and feral cats.[2] In the Pacific Northwest of North America, the northern spotted owl (Strix occidentalis) is a common predator of flying squirrels.

Flying squirrels are usually nocturnal,[13] since they are not adept at escaping birds of prey that hunt during the daytime.[2] They eat according to their environment; they are omnivorous, and will eat whatever food they can find. The North American southern flying squirrel eats seeds, insects, gastropods (slugs and snails), spiders, shrubs, flowers, fungi, and tree sap.

Reproduction

The mating season for flying squirrels is during February and March. When the infants are born, the female squirrels live with them in maternal nest sites. The mothers nurture and protect them until they leave the nest. The males do not participate in nurturing their offspring.[14]

At birth, flying squirrels are mostly hairless, apart from their whiskers, and most of their senses are not present. Their internal organs are visible through the skin, and their sex can be signified. By week five, they are almost fully developed. At that point, they can respond to their environment and start to develop a mind of their own. Through the upcoming weeks of their lives, they practice leaping and gliding. After two and a half months, their gliding skills are perfected, they are ready to leave the nest, and are capable of independent survival.[15]

Diet

Flying squirrels can easily forage for food in the night, given their highly developed sense of smell. They harvest fruits, nuts, fungi, and birds' eggs.[2][16] Gliding conserves energy.[3] Many gliders have specialized diets and there is evidence to believe that gliders may be able to take advantage of scattered protein deficient food.[17] Additionally, gliding is a fast form of locomotion and by reducing travel time between patches, they can increase the amount of foraging time.[17]

See also

References

  1. ↑ 1.0 1.1 Daxner-Höck G. (2004). "Flying Squirrels (Pteromyinae, Mammalia) from the Upper Miocene of Austria". Annalen des Naturhistorischen Museums in Wien 106A: 387–423. PDF.
  2. ↑ 2.0 2.1 2.2 2.3 Malamuth, E. & Mulheisen, M. (1995–2008). "ADW: Glaucomys sabrinus – Northern flying squirrel". University of Michigan Museum of Natural History. Retrieved 14 July 2009.
  3. ↑ 3.0 3.1 Asari, Y; Yanagawa, H. & Oshida, T. (2007). "Gliding ability of the Siberian flying squirrel Pteromys volans orii" (PDF). Mammal Study 32 (4): 151–154. doi:10.3106/1348-6160(2007)32[151:GAOTSF]2.0.CO;2. Retrieved 2009-07-14.
  4. ↑ 4.0 4.1 Thorington Jr., R.W; Darrow, K. & Anderson, C.G. (1998). "Wing Tip Anatomy and Aerodynamics in Flying Squirrels" (PDF). Journal of Mammalogy (American Society of Mammalogists) 79 (1): 245–250. doi:10.2307/1382860. JSTOR 1382860. Retrieved 2009-07-14.
  5. ↑ Carraway, L.N.; Verts, B.J. (1994). "Sciurus griseus" (PDF). Mammalian Species 474 (474): 1–7. doi:10.2307/3504097. Retrieved 2009-07-14.
  6. ↑ Arbogast, B.S. (2007). "A brief history of the new world flying squirrels: Phylogeny, biogeography, and conservation genetics". Journal of Mammalogy 88 (4): 840–849. doi:10.1644/06-MAMM-S-322R1.1.
  7. ↑ Mercer, J.M.; V.L. Roth (2003). "The effects of cenozoic global change on squirrel phylogeny". Science 299 (5612): 1568–1572. doi:10.1126/science.1079705. PMID 12595609.
  8. ↑ Steppan, S.J.; B.L. Storz, R.S. Hoffmann (2004). "Nuclear DNA phylogeny of the squirrels (Mammalia : Rodentia) and the evolution of arboreality from c-myc and RAG1". Molecular Phylogenetics and Evolution 30 (3): 703–719. doi:10.1016/S1055-7903(03)00204-5. PMID 15012949.
  9. ↑ Flaherty, E.A.; M. Ben-David, W.P. Smith (2010). "Quadrupedal locomotor performance in two species of arboreal squirrels: predicting energy savings of gliding". Journal of Comparative Physiology B-Biochemical Systemic and Environmental Physiology 180 (7): 1067–1078. doi:10.1007/s00360-010-0470-1.
  10. ↑ Choudhury, A.U. (2007). A new flying squirrel of the genus Petaurista Link from Arunachal Pradesh in north-east India. The Newsletter & Journal of the Rhino Foundation for nat. in NE India 7: 26–34, plates.
  11. ↑ Choudhury, A.U. (2009). One more new flying squirrel of the genus Petaurista Link, 1795 from Arunachal Pradesh in north-east India. The Newsletter & Journal of the Rhino Foundation for nat. in NE India 8: 26–34, plates.
  12. ↑ Choudhury, A.U. (2013). Description of a new species of giant flying squirrel of the genus Petaurista Link, 1795 from Siang Basin, Arunachal Pradesh in North East India. The Newsletter & Journal of the Rhino Foundation for nat. in NE India 9: 30–38, plates.
  13. ↑ Thorington, Jr., R.W; Pitassy, D. & Jansa, S.A. (2002). "Phylogenies of Flying Squirrels (Pteromyinae)" (PDF). Journal of Mammalian Evolution 9 (1–2): 99–135. doi:10.1023/A:1021335912016. Retrieved 2009-07-14.
  14. ↑ Studelska, Rebecca. (1997). "Northern Flying Squirrels". Northern State University. Retrieved 2009-09-14.
  15. ↑ Patterson., Robert (2009). "Life Cycle". Retrieved 2009-09-14.
  16. ↑ North, M.; Trappe, J. & Franklin, J. (1995). "Standing crop and animal consumption of fungal sporocarps in Pacific Northwest forests" (PDF). Ecology 78 (5): 1543–1554. doi:10.1890/0012-9658(1997)078[1543:SCAACO]2.0.CO;2. Retrieved 2009-07-14.
  17. ↑ 17.0 17.1 Byrnes, G.; A.J. Spence (2011). "Ecological and biomechanical insights into the evolution of gliding in mammals". Integrative and Comparative Biology 51 (6): 991–1001. doi:10.1093/icb/icr069. PMID 21719434.

Further reading

External links

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