Flying squirrel

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This article is about the member of the animal kingdom. For other uses, see Flying squirrel (disambiguation).

Flying squirrel
Temporal range: Early Oligocene – Recent
Northern flying squirrel (Glaucomys sabrinus)
Scientific classification Edit this classification
Domain: Eukaryota
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
Iomys
Petaurillus

Petaurista
Petinomys
Priapomys

Pteromys

Pteromyscus

Trogopterus

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 are able to glide from one tree to another with the aid of a patagium, a furred skin membrane that stretches from wrist to ankle. Their long tails also provide stability as they glide.[1] Anatomically they are very similar to other squirrels with a number of adaptations to suit their lifestyle; their limb bones are longer and their hand bones, foot bones, and distal vertebrae are shorter. Flying squirrels are able to steer and exert control over their glide path with their limbs and tail.

Molecular studies have shown that flying squirrels are

tree sap
and young birds. The young are born in a nest and are at first naked and helpless. They are cared for by their mother and by five weeks are able to practice gliding skills so that by ten weeks they are ready to leave the nest.

Some captive-bred southern flying squirrels have become domesticated as small household pets, a type of "pocket pet".[2]

Description

A flying squirrel gliding

Flying squirrels are not capable of flight like

air brake before landing on a tree trunk.[9]

The

scansorial
mammals that use their patagium to glide, unpowered, to move quickly through their environment.

Prior to the 21st century, the evolutionary history of the flying squirrel was frequently debated.[10] This debate was clarified greatly as a result of two molecular studies.[11][12] These studies found support that flying squirrels originated 18–20 million years ago, are monophyletic, and have a sister relationship with tree squirrels. Due to their close ancestry, the morphological differences between flying squirrels and tree squirrels reveal insight into the formation of the gliding mechanism. Compared to squirrels of similar size, flying squirrels, northern and southern flying squirrels show lengthening in bones of the lumbar vertebrae and forearm, whereas bones of the feet, hands, and distal vertebrae are reduced in length. Such differences in body proportions reveal the flying squirrels' adaptation to minimize wing loading and to increase maneuverability while gliding. The consequence for these differences is that unlike regular squirrels, flying squirrels are not well adapted for quadrupedal locomotion and therefore must rely more heavily on their gliding abilities.[13]

Several hypotheses have attempted to explain the evolution of gliding in flying squirrels.[14] One possible explanation is related to energy efficiency and foraging.[15][5] Gliding is an energetically efficient way to progress from one tree to another while foraging, as opposed to climbing down trees and maneuvering on the ground floor or executing dangerous leaps in the air.[15] By gliding at high speeds, flying squirrels can rummage through a greater area of forest more quickly than tree squirrels. Flying squirrels can glide long distances by increasing their aerial speed and increasing their lift.[5] Other hypotheses state that the mechanism evolved to avoid nearby predators and prevent injuries. If a dangerous situation arises on a specific tree, flying squirrels can glide to another, and thereby typically escape the previous danger.[5][16] Furthermore, take-off and landing procedures during leaps, implemented for safety purposes, may explain the gliding mechanism. While leaps at high speeds are important to escape danger, the high-force impact of landing on a new tree could be detrimental to a squirrel's health.[5] Yet the gliding mechanism of flying squirrels involves structures and techniques during flight that allow for great stability and control. If a leap is miscalculated, a flying squirrel may easily steer back onto the original course by using its gliding ability.[5] A flying squirrel also creates a large glide angle when approaching its target tree, decreasing its velocity due to an increase in air resistance and allowing all four limbs to absorb the impact of the target.[5][17]

Fluorescence

In 2019 it was observed, by chance, that a flying squirrel fluoresced pink. Subsequent research by biologists at Northland College in Northern Wisconsin found that this is true for all three species of North American flying squirrels. At this time it is unknown what purpose this serves. Non-flying squirrels do not fluoresce under UV light.[18]

Taxonomy

Recent species

The three species of the genus

Glaucomys oregonensis) are native to North America and Central America; many other taxa are found throughout Asia as well, with the range of the Siberian Flying Squirrel (Pteromys volans) reaching into parts of northeast Europe
(Russia, Finland and Estonia).

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

Tribe Pteromyini – flying squirrels

The Mechuka, Mishmi Hills, and Mebo giant flying squirrels were discovered in the northeastern state of India of Arunachal Pradesh in the late 2000s.[20][21][22] Their holotypes are preserved in the collection of the Zoological Survey of India, Kolkata, India.

Fossil species

Flying squirrels have a well-documented fossil record from the Oligocene onwards. Some fossil genera go far back as the Eocene, and given that the flying squirrels are thought to have diverged later, these are likely misidentifications.[23]

Life cycles

A southern flying squirrel (Glaucomys volans) gliding

The life expectancy of flying squirrels in the wild is about six years, and 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

feral cats.[3] In the Pacific Northwest of North America, the northern spotted owl
(Strix occidentalis) is a common predator of flying squirrels.

Flying squirrels are usually

gastropods (slugs and snails), spiders, shrubs, flowers, fungi, and tree sap.[citation needed
]

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.[26]

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.[27]

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.[3][28][4] Many gliders have specialized diets and there is evidence to believe that gliders may be able to take advantage of scattered protein deficient food.[29] Additionally, gliding is a fast form of locomotion and by reducing travel time between patches, they can increase the amount of foraging time.[29]

See also

References

  1. ^
    S2CID 15742612
    . Retrieved 28 October 2021.
  2. ^ "Do Southern Flying Squirrels make Good Pets to Keep?". petcaretips.net. Retrieved 2018-02-23.
  3. ^ a b c d Malamuth, E.; Mulheisen, M. (1995–2008). "ADW: Glaucomys sabrinus – Northern flying squirrel". University of Michigan Museum of Natural History. Archived from the original on 12 August 2009. Retrieved 14 July 2009.
  4. ^
    S2CID 59025388. Archived from the original
    (PDF) on 2010-07-11. Retrieved 2009-07-14.
  5. ^
    PMID 17401124
    .
  6. ^
    S2CID 3628991
    .
  7. JSTOR 1379336
    .
  8. ^
    JSTOR 1382860. Archived
    (PDF) from the original on 2009-04-09. Retrieved 2009-07-14.
  9. S2CID 253911325. Archived
    (PDF) from the original on 2010-01-07. Retrieved 2009-07-14.
  10. doi:10.1644/06-MAMM-S-322R1.1
    .
  11. S2CID 40366357
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  12. PMID 15012949
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  13. doi:10.1644/06-mamm-s-325r2.1
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  14. S2CID 240833
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  15. ^
    S2CID 85306259
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  16. ^ Scheibe, John S.; Figgs, Daylan; Heiland, Jeff (1990). "Morphological attributes of gliding rodents: a preliminary analysis". Transactions of the Missouri Academy of Science. 24: 49–56.
  17. PMID 21719434
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  18. doi:10.1093/jmammal/gyy177
    .
  19. PMID 34047079
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  20. ^ 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.
  21. ^ 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.
  22. ^ 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.
  23. PMID 30296996
    .
  24. ^ a b Daxner-Höck G. (2004). "Flying Squirrels (Pteromyinae, Mammalia) from the Upper Miocene of Austria". Annalen des Naturhistorischen Museums in Wien 106A: 387–423. PDF.
  25. S2CID 12443674. Archived from the original
    (PDF) on 2011-06-11. Retrieved 2009-07-14.
  26. ^ Studelska, Rebecca. (1997). "Northern Flying Squirrels". Northern State University. Archived from the original on February 19, 2008. Retrieved 2009-09-14. {{cite journal}}: Cite journal requires |journal= (help)
  27. ^ Patterson., Robert (2009). "Life Cycle". Archived from the original on 2009-01-30. Retrieved 2009-09-14. {{cite journal}}: Cite journal requires |journal= (help)
  28. S2CID 86779270. Archived from the original
    (PDF) on 2010-06-10. Retrieved 2009-07-14.
  29. ^
    PMID 21719434
    .

Further reading

External links

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