Editing Flying squirrel

{{short description|Tribe of mammals}}
{{About|the member of the animal kingdom}}
{{Automatic taxobox
| fossil_range = Early [[Oligocene]] – Recent
| image = Glaucomys sabrinus 248041903 (cropped).jpg
| image_caption = [[Northern flying squirrel]]<br>(''Glaucomys sabrinus'')
| taxon = Pteromyini
| authority = [[Johann Friedrich von Brandt|Brandt]], 1855
| subdivision_ranks = Genera
| subdivision = ''[[Aeretes]]''<br />
''[[Aeromys]]''<br />
''[[Belomys]]''<br />
''[[Biswamoyopterus]]''<br />
''[[Eoglaucomys]]''<br />
''[[Eupetaurus]]''<br />
''[[Glaucomys]]''<br />
''[[Hylopetes]]''<br />
''[[Iomys]]''<br />
''[[Petaurillus]]''<br />
''[[Petaurista]]''<br />
''[[Petinomys]]''<br />
''[[Priapomys]]''<br />
''[[Pteromys]]''<br />
''[[Pteromyscus]]''<br />
''[[Trogopterus]]''
}}

'''Flying squirrels''' (scientifically known  as '''Pteromyini''' or '''Petauristini''') are a [[tribe (biology)|tribe]] of 50 [[species]] of [[squirrel]]s in the [[family (biology)|family]] [[Squirrel|Sciuridae]]. Despite their name, they are not in fact capable of full [[flight]] in the same way as [[bird]]s or [[bat]]s, but they are able to [[gliding flight|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.<ref name=":3" /> 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 [[Monophyly|monophyletic]] (having a common ancestor with no non-flying descendants) and originated some 18–20 million years ago. The genus ''[[Paracitellus]]'' is the earliest lineage to the flying squirrel dating back to the late Oligocene era.<ref name=":3">{{cite journal|last1=Lu|first1=Xuefei|date=24 June 2012|title=The Evolution and Paleobiogeography of Flying Squirrels (Sciuridae, Pteromyini) in Response to Global Environmental Change.|url=https://link.springer.com/article/10.1007/s11692-012-9191-6|journal=Evolutionary Biology|volume=40|issue=40|pages=117–132|doi=10.1007/s11692-012-9191-6|s2cid=15742612|access-date=28 October 2021|url-access=subscription}}</ref> Most are nocturnal and [[Omnivore|omnivorous]], eating [[fruit]], [[seeds]], [[buds]], [[flower]]s, [[insect]]s, [[Gastropoda|gastropods]], [[spider]]s, [[Fungus|fungi]], [[bird]]'s eggs, [[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 squirrel]]s have become domesticated as small household pets, a type of "[[Rodents as pets|pocket pet]]".<ref>{{Cite web|url=http://petcaretips.net/squirrel-keeping-care.html|title=Do Southern Flying Squirrels make Good Pets to Keep?|website=petcaretips.net|access-date=2018-02-23}}</ref>

==Description==
[[File:Flying squirrel in a tree.jpg|left|thumb|A [[northern flying squirrel]] (''Glaucomys sabrinus'') gliding]]
[[File:Glaucomys volans 1zz.jpg|left|thumb|[[Southern flying squirrel]] (''Glaucomys volans'') skeleton at the [[National Museum of Natural History|NMNH]]. The styliform cartilage attached to the wrist supports the wing membrane.<ref name=":2" />]]
Flying squirrels are not capable of flight like [[bird]]s or [[bat]]s; instead, they [[gliding (flight)|glide]] between trees. They are capable of obtaining lift within the course of these flights, with flights recorded to {{convert|90|m|ft}}.<ref name=squirrel>{{cite web |author1=Malamuth, E. |author2=Mulheisen, M. |title=ADW: Glaucomys sabrinus – Northern flying squirrel |url=http://animaldiversity.ummz.umich.edu/site/accounts/information/Glaucomys_sabrinus.html |date=1995–2008 |publisher=University of Michigan Museum of Natural History |access-date=14 July 2009 |url-status=live |archive-url=https://web.archive.org/web/20090812040048/http://animaldiversity.ummz.umich.edu/site/accounts/information/Glaucomys_sabrinus.html |archive-date=12 August 2009 }}</ref><ref name=siberian>{{cite journal |last=Asari |first=Y |author2=Yanagawa, H. |author3=Oshida, T. |year=2007 |title=Gliding ability of the Siberian flying squirrel ''Pteromys volans orii'' |journal=Mammal Study |volume=32 |pages=151–154 |url=http://cstl-csm.semo.edu/scheibe/Advanced%20Ecology/Pteromys%20Gliding.pdf |archive-url=https://web.archive.org/web/20100711135035/http://cstl-csm.semo.edu/scheibe/Advanced%20Ecology/Pteromys%20Gliding.pdf |url-status=dead |archive-date=2010-07-11 |access-date=2009-07-14 |doi=10.3106/1348-6160(2007)32[151:GAOTSF]2.0.CO;2 |issue=4 |s2cid=59025388 }}</ref> The direction and speed of the animal in midair are varied by changing the positions of its limbs, largely controlled by small [[cartilaginous]] wrist bones. There is a cartilage projection from the wrist that the squirrel holds upwards during a glide.<ref name=":1" /> This specialized cartilage is only present in flying squirrels and not other gliding mammals.<ref name=":2">{{Cite journal|last1=Kawashima|first1=Tomokazu|last2=Thorington|first2=Richard W.|last3=Bohaska|first3=Paula W.|last4=Sato|first4=Fumi|date=2017-02-01|title=Evolutionary Transformation of the Palmaris Longus Muscle in Flying Squirrels (Pteromyini: Sciuridae): An Anatomical Consideration of the Origin of the Uniquely Specialized Styliform Cartilage|journal=The Anatomical Record|language=en|volume=300|issue=2|pages=340–352|doi=10.1002/ar.23471|pmid=27611816|s2cid=3628991|issn=1932-8494|doi-access=free}}</ref>  Possible origins for the styliform cartilage have been explored, and the data suggests that it is most likely homologous to the carpal structures that can be found in other squirrels.<ref name=":2" />  This cartilage along with the manus forms a wing tip to be used during gliding. After being extended, the wing tip may adjust to various angles, controlling aerodynamic movements.<ref>{{Cite journal|title = Myology of the Gliding Membranes of Some Petauristine Rodents (Genera: Glaucomys, Pteromys, Petinomys, and Petaurista)|last = Johnson-Murray|first = Jane L.|date = 1977|journal = Journal of Mammalogy|doi = 10.2307/1379336|volume = 58|issue = 3|pages = 374–384|jstor = 1379336}}</ref><ref name=aerodynamic>{{cite journal |last=Thorington |first=R.W Jr. |author2=Darrow, K. |author3=Anderson, C.G. |year=1998 |title=Wing Tip Anatomy and Aerodynamics in Flying Squirrels |journal=Journal of Mammalogy |volume=79 |issue=1 |pages=245–250 |url=http://entomology.si.edu/StaffPages/Darrow/1997WingTipAnatomy.pdf |access-date=2009-07-14 |doi=10.2307/1382860 |jstor=1382860 |url-status=live |archive-url=https://web.archive.org/web/20090409052036/http://entomology.si.edu/StaffPages/Darrow/1997WingTipAnatomy.pdf |archive-date=2009-04-09 |doi-access=free }}</ref> The wrist also changes the tautness of the [[patagium]], a furry parachute-like membrane that stretches from wrist to ankle.<ref name=aerodynamic/> It has a fluffy tail that stabilizes in flight. The tail acts as an adjunct [[airfoil]], working as an [[Air brake (aircraft)|air brake]] before landing on a tree trunk.<ref>{{cite journal |last=Carraway |first=L.N. |author2=Verts, B.J. |year=1994 |title=Sciurus griseus |journal=Mammalian Species |pages=1–7 |url=http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-474-01-0001.pdf |access-date=2009-07-14 |doi=10.2307/3504097 |issue=474 |url-status=live |archive-url=https://web.archive.org/web/20100107120344/http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-474-01-0001.pdf |archive-date=2010-01-07 |jstor=3504097 |s2cid=253911325 }}</ref>

===Similar gliding animals===
The [[colugo]]s, [[Petauridae]], and [[Anomaluridae]] are gliding mammals which are similar to flying squirrels through [[convergent evolution]], although are not particularly close in relation. Like the flying squirrel, they are [[scansorial]] mammals that use their patagium to glide, unpowered, to move quickly through their environment.

===Evolutionary history===
Prior to the 21st century, the evolutionary history of the flying squirrel was frequently debated.<ref>{{cite journal|last=Arbogast|first=B.S.|title=A brief history of the new world flying squirrels: Phylogeny, biogeography, and conservation genetics|journal=Journal of Mammalogy|year=2007|volume=88|issue=4|pages=840–849|doi=10.1644/06-MAMM-S-322R1.1|doi-access=free}}</ref> This debate was clarified greatly as a result of two molecular studies.<ref>{{cite journal|last=Mercer|first=J.M.|author2=V.L. Roth|s2cid=40366357|title=The effects of cenozoic global change on squirrel phylogeny|journal=Science|year=2003|volume=299|issue=5612|pages=1568–1572|doi=10.1126/science.1079705|pmid=12595609|bibcode=2003Sci...299.1568M}}</ref><ref>{{cite journal|last=Steppan|first=S.J. |author2=B.L. Storz |author3=R.S. Hoffmann|title=Nuclear DNA phylogeny of the squirrels (Mammalia : Rodentia) and the evolution of arboreality from c-myc and RAG1|journal=Molecular Phylogenetics and Evolution|year=2004|volume=30|issue=3|pages=703–719|doi=10.1016/S1055-7903(03)00204-5|pmid=15012949|bibcode=2004MolPE..30..703S }}</ref> 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.<ref>{{Cite journal|title = How to make a flying squirrel: Glaucomys anatomy in phylogenetic perspective|last1 = Thorington|first1 = Richard W.|date = 2007|journal = Journal of Mammalogy|doi = 10.1644/06-mamm-s-325r2.1|first2 = Erica M.|last2 = Santana|volume = 88|issue = 4|pages = 882–896|doi-access = free}}</ref>

Several hypotheses have attempted to explain the evolution of gliding in flying squirrels.<ref>{{cite journal|last=Flaherty|first=E.A. |author2=M. Ben-David |author3=W.P. Smith|title=Quadrupedal locomotor performance in two species of arboreal squirrels: predicting energy savings of gliding|journal=Journal of Comparative Physiology B|year=2010|volume=180|issue=7|pages=1067–1078|doi=10.1007/s00360-010-0470-1|pmid=20361193 |s2cid=240833 }}</ref> One possible explanation is related to energy efficiency and foraging.<ref name=":0">{{Cite journal|title = Evolution of vertebrate flight: an aerodynamic model for the transition from gliding to active flight|last = Norberg|first = Ulla M.|date = 1985|journal = American Naturalist|doi = 10.1086/284419|pages = 303–327|volume = 126|issue = 3|s2cid = 85306259}}</ref><ref name=":1">{{Cite journal|title = Take-off and landing forces and the evolution of controlled gliding in northern flying squirrels Glaucomys sabrinus|last1 = Paskins|first1 = Keith E.|date = 2007|journal = The Journal of Experimental Biology|doi = 10.1242/jeb.02747|pmid = 17401124|last2 = Bowyer|first2 = Adrian|last3 = Megill|last4 = Scheibe|first3 = William M.|first4 = John S.|pages = 1413–1423|volume = 210|issue = Pt 8|doi-access = free}}</ref> 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.<ref name=":0" /> 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.<ref name=":1" />

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.<ref name=":1" /><ref>{{Cite journal|title = Morphological attributes of gliding rodents: a preliminary analysis|last1 = Scheibe|first1 = John S.|date = 1990|journal = Transactions of the Missouri Academy of Science|last2 = Figgs|first2 = Daylan|first3 = Jeff|last3 = Heiland|volume = 24|pages = 49–56}}</ref> 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.<ref name=":1" /> 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.<ref name=":1" /> 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.<ref name=":1" /><ref>{{Cite journal|title = Ecological and Biomechanical Insights into the Evolution of Gliding in Mammals|last1 = Byrnes|first1 = Greg|date = 2011|journal = Integrative and Comparative Biology|doi = 10.1093/icb/icr069|pmid = 21719434|last2 = Spence|first2 = Andrew J.|pages = 991–1001|volume = 51|issue = 6|doi-access = free}}</ref>

=== Fluorescence ===
In 2019 it was observed, by chance, that a flying squirrel [[Fluorescence|fluoresced]] pink under UV light. Subsequent research by biologists at [[Northland College (Wisconsin)|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.<ref>{{Cite journal|last1=Anich|first1=Paula Spaeth|last2=Martin|first2=Jonathan G.|last3=Olson|first3=Erik R.|last4=Kohler|first4=Allison M.|title=Ultraviolet fluorescence discovered in New World flying squirrels (Glaucomys)|journal=Journal of Mammalogy|volume=100|pages=21–30|language=en|doi=10.1093/jmammal/gyy177|year=2019}}</ref>

==Taxonomy==

=== Recent species ===
'''New World''' flying squirrels belong to the genus ''[[Glaucomys]]'' (Greek for ''gleaming mouse''). '''Old World''' flying squirrels belong to the genus ''[[Pteromys]]'' (Greek for ''winged mouse'').

The three species of the genus ''[[Glaucomys]]'' (''[[Glaucomys sabrinus]]'', ''[[Glaucomys volans]]'' and ''[[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 (''[[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
* Subtribe [[Glaucomyina]]
** Genus ''[[Eoglaucomys]]''
*** [[Kashmir flying squirrel]], ''Eoglaucomys fimbriatus''
**** [[Afghan flying squirrel]], ''E. f. baberi''
** Genus ''[[New World flying squirrel|Glaucomys]]'' – New World flying squirrels (American flying squirrels), [[North America]]
*** [[Southern flying squirrel]], ''Glaucomys volans''
*** [[Northern flying squirrel]], ''Glaucomys sabrinus''
*** [[Humboldt's flying squirrel]], ''Glaucomys oregonensis''
** Genus ''[[Hylopetes]]'', [[Southeast Asia]]
*** [[Particolored flying squirrel]], ''Hylopetes alboniger''
*** [[Bartel's flying squirrel]], ''Hylopetes bartelsi''
*** [[Gray-cheeked flying squirrel]], ''Hylopetes lepidus''
*** [[Palawan flying squirrel]], ''Hylopetes nigripes''
*** [[Indochinese flying squirrel]], ''Hylopetes phayrei''
*** [[Jentink's flying squirrel]], ''Hylopetes platyurus''
*** [[Sipora flying squirrel]], ''Hylopetes sipora''
*** [[Red-cheeked flying squirrel]], ''Hylopetes spadiceus''
*** [[Sumatran flying squirrel]], ''Hylopetes winstoni''
** Genus ''[[Iomys]]'', [[Malaysia]] and [[Indonesia]]
*** [[Javanese flying squirrel|Javanese flying squirrel (Horsfield's flying squirrel)]], ''Iomys horsfieldi''
*** [[Mentawi flying squirrel]], ''Iomys sipora''
** Genus ''[[Petaurillus]]'' – pygmy flying squirrels, [[Borneo]] and the [[Malay Peninsula]]
*** [[Lesser pygmy flying squirrel]], ''Petaurillus emiliae''
*** [[Hose's pygmy flying squirrel]], ''Petaurillus hosei''
*** [[Selangor pygmy flying squirrel]], ''Petaurillus kinlochii''
** Genus ''[[Petinomys]]'', [[Southeast Asia]]
*** [[Basilan flying squirrel]], ''Petinomys crinitus''
*** [[Travancore flying squirrel]], ''Petinomys fuscocapillus''
*** [[Whiskered flying squirrel]], ''Petinomys genibarbis''
*** [[Hagen's flying squirrel]], ''Petinomys hageni''
*** [[Siberut flying squirrel]], ''Petinomys lugens''
*** [[Mindanao flying squirrel]], ''Petinomys mindanensis''
*** [[Arrow flying squirrel]], ''Petinomys sagitta''
*** [[Temminck's flying squirrel]], ''Petinomys setosus''
*** [[Vordermann's flying squirrel]], ''Petinomys vordermanni''
** Genus ''[[Priapomys]]'', western [[Yunnan]] in [[China]] and adjoining regions of [[Myanmar]]
*** [[Himalayan large-eared flying squirrel]], ''P. leonardi''<ref>{{Cite journal|last1=Li|first1=Quan|last2=Cheng|first2=Feng|last3=Jackson|first3=Stephen M.|last4=Helgen|first4=Kristofer M.|last5=Song|first5=Wen-Yu|last6=Liu|first6=Shao-Ying|last7=Sanamxay|first7=Daosavanh|last8=Li|first8=Song|last9=Li|first9=Fei|last10=Xiong|first10=Yun|last11=Sun|first11=Jun|date=2021-07-18|title=Phylogenetic and morphological significance of an overlooked flying squirrel (Pteromyini, Rodentia) from the eastern Himalayas with the description of a new genus|journal=Zoological Research|language=en|volume=42|issue=4|pages=389–400|doi=10.24272/j.issn.2095-8137.2021.039|issn=2095-8137|pmc=8317177|pmid=34047079}}</ref>
* Subtribe [[Pteromyina]]
** Genus ''[[Aeretes]]'', northeastern [[China]]
*** [[Groove-toothed flying squirrel|Groove-toothed flying squirrel (North Chinese flying squirrel)]], ''Aeretes melanopterus''
** Genus ''[[Aeromys]]'' – large black flying squirrels, [[Thailand]] to [[Borneo]]
*** [[Black flying squirrel]], ''Aeromys tephromelas''
*** [[Thomas's flying squirrel]], ''Aeromys thomasi''
** Genus ''[[Belomys]]'', Southeast Asia
*** [[Hairy-footed flying squirrel]], ''Belomys pearsonii''
** Genus ''[[Biswamoyopterus]]'', northeastern [[India]] to southern [[China]] and southeast Asia
*** [[Namdapha flying squirrel]], ''Biswamoyopterus biswasi''
*** [[Laotian giant flying squirrel]], ''Biswamoyopterus laoensis''
*** [[Mount Gaoligong flying squirrel]] ''Biswamoyopterus gaoligongensis''
** Genus ''[[Eupetaurus]]'', [[Pakistan]] to [[China]]; rare
*** [[Western woolly flying squirrel]], ''Eupetaurus cinereus''
*** [[Yunnan woolly flying squirrel]], ''Eupetaurus nivamons''
*** [[Tibetan woolly flying squirrel]], ''Eupetaurus tibetensis''
** Genus ''[[Petaurista]]'' - giant flying squirrels, Southeast and East Asia
*** [[Red and white giant flying squirrel]], ''Petaurista alborufus''
*** [[Spotted giant flying squirrel]], ''Petaurista elegans''
*** [[Hodgson's giant flying squirrel]], ''Petaurista magnificus''
*** [[Bhutan giant flying squirrel]], ''Petaurista nobilis''
*** [[Indian giant flying squirrel]], ''Petaurista philippensis''
*** [[Chinese giant flying squirrel]], ''Petaurista xanthotis''
*** [[Japanese giant flying squirrel]], ''Petaurista leucogenys''
*** [[Red giant flying squirrel]], ''Petaurista petaurista''
*** [[Mechuka giant flying squirrel]], ''Petaurista mechukaensis''
*** [[Mishmi Hills giant flying squirrel]], ''Petaurista mishmiensis''
*** [[Mebo giant flying squirrel]], ''Petaurista siangensis''
** Genus ''[[Old World flying squirrel|Pteromys]]'' – Old World flying squirrels, [[Finland]] to [[Japan]]
*** [[Siberian flying squirrel]], ''Pteromys volans''
*** [[Japanese dwarf flying squirrel]], ''Pteromys momonga''
** Genus ''[[Pteromyscus]]'', southern [[Thailand]] to [[Borneo]]
*** [[Smoky flying squirrel]], ''Pteromyscus pulverulentus''
** Genus ''[[Trogopterus]]'', [[China]]
*** [[Complex-toothed flying squirrel]], ''Trogopterus xanthipes''

The Mechuka, Mishmi Hills, and Mebo giant flying squirrels were discovered in the northeastern state of India of Arunachal Pradesh in the late 2000s.<ref>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.</ref><ref>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.</ref><ref>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.</ref> 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.<ref>{{Cite journal|last1=Casanovas-Vilar|first1=Isaac|last2=Garcia-Porta|first2=Joan|last3=Fortuny|first3=Josep|last4=Sanisidro|first4=Óscar|last5=Prieto|first5=Jérôme|last6=Querejeta|first6=Marina|last7=Llácer|first7=Sergio|last8=Robles|first8=Josep M|last9=Bernardini|first9=Federico|last10=Alba|first10=David M|date=2018-10-09|title=Oldest skeleton of a fossil flying squirrel casts new light on the phylogeny of the group|journal=eLife|volume=7|pages=e39270|doi=10.7554/eLife.39270|pmid=30296996|issn=2050-084X|pmc=6177260 |doi-access=free }}</ref>
* ''[[Miopetaurista]]''
** ''[[Miopetaurista crusafonti]]''
** ''[[Miopetaurista dehmi]]''
** ''[[Miopetaurista diescalidus]]''
** ''[[Miopetaurista gaillardi]]''
** ''[[Miopetaurista gibberosa]]''
** ''[[Miopetaurista lappi]]''
** ''[[Miopetaurista neogrivensis]]''
** ''[[Miopetaurista thaleri]]''
** ''[[Miopetaurista tobieni]]''
* ''[[Pliopetaurista]]''
** ''[[Pliopetaurista kollmanni]]'' Daxner-Höck, 2004<ref name="Daxner-Höck 2004" />
* ''[[Neopetes]]''<ref name="Daxner-Höck 2004">Daxner-Höck G. (2004). "Flying Squirrels (Pteromyinae, Mammalia) from the Upper Miocene of Austria". ''[[Annalen des Naturhistorischen Museums in Wien]]'' '''106A''': 387–423. [http://www.biologiezentrum.at/pdf_frei_remote/ANNA_106A_0387-0423.pdf PDF].</ref>
** ''[[Neopetes hoeckarum]]'' (De Bruijn, 1998)
** ''[[Neopetes macedoniensis]]'' (Bouwens and De Bruijn, 1986)
** ''[[Neopetes debruijni]]'' (Reumer & Hoek Ostende, 2003)

==Life cycles==
[[File:Gliding flying squirrel.jpg|thumb|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 [[tree snake]]s, [[raccoon]]s, [[owl]]s, [[marten]]s, [[fisher (animal)|fisher]]s, [[coyote]]s, [[bobcat]]s, and [[feral cats]].<ref name=squirrel/> 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]],<ref>{{cite journal | last=Thorington | first=R.W Jr. |author2=Pitassy, D. |author3=Jansa, S.A. |year=2002 |title=Phylogenies of Flying Squirrels (Pteromyinae) |journal=Journal of Mammalian Evolution |volume=9 |issue=1–2 |pages=99–135 |url=http://www.tc.umn.edu/~jansa003/PDFs/Thorington.etal.02.pdf |archive-url=https://web.archive.org/web/20110611111147/http://www.tc.umn.edu/~jansa003/PDFs/Thorington.etal.02.pdf |url-status=dead |archive-date=2011-06-11 |access-date=2009-07-14 |doi=10.1023/A:1021335912016 |s2cid=12443674 }}</ref> since they are not adept at escaping birds of prey that hunt during the daytime.<ref name=squirrel/> 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.{{Citation needed|date=April 2010}}

===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.<ref>{{cite journal|last=Studelska |first=Rebecca. |year=1997 |title=Northern Flying Squirrels |url=http://www.northern.edu/natsource/MAMMALS/Northe1.htm |publisher=Northern State University |access-date=2009-09-14 |url-status=dead |archive-url=https://web.archive.org/web/20080219220147/http://www.northern.edu/natsource/MAMMALS/Northe1.htm |archive-date=February 19, 2008 }}</ref>

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 they are capable of independent survival.<ref>{{cite journal |last=Patterson. |first=Robert |year=2009 |title=Life Cycle |url=http://www.flyingsquirrels.com/lifecycle.html |access-date=2009-09-14 |url-status=dead |archive-url=https://web.archive.org/web/20090130014623/http://www.flyingsquirrels.com/lifecycle.html |archive-date=2009-01-30 }}</ref>

===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.<ref name=squirrel/><ref>{{cite journal |last=North |first=M. |author2=Trappe, J. |author3=Franklin, J. |year=1995 |title=Standing crop and animal consumption of fungal sporocarps in Pacific Northwest forests |journal=Ecology |volume=78 |issue=5 |pages=1543–1554 |url=http://www.plantsciences.ucdavis.edu/affiliates/north/Publications/Standing%20crop%20and%20animal%20consumption%20of%20fungal.pdf |archive-url=https://web.archive.org/web/20100610103643/http://www.plantsciences.ucdavis.edu/affiliates/north/Publications/Standing%20crop%20and%20animal%20consumption%20of%20fungal.pdf |url-status=dead |archive-date=2010-06-10 |access-date=2009-07-14 |doi=10.1890/0012-9658(1997)078[1543:SCAACO]2.0.CO;2 |s2cid=86779270 }}</ref><ref name=siberian/> Many gliders have specialized diets and there is evidence to believe that gliders may be able to take advantage of scattered protein deficient food.<ref name="Byrnes 2011 991–1001">{{cite journal|last=Byrnes|first=G.|author2=A.J. Spence|title=Ecological and biomechanical insights into the evolution of gliding in mammals|journal=Integrative and Comparative Biology|year=2011|volume=51|issue=6|pages=991–1001|doi=10.1093/icb/icr069|pmid=21719434|doi-access=free}}</ref> Additionally, gliding is a fast form of locomotion and by reducing travel time between patches, they can increase the amount of foraging time.<ref name="Byrnes 2011 991–1001"/>

==See also==
{{portal|Mammals}}
* [[Anomalure]], aka: scaly-tailed squirrel
* [[Flying and gliding animals]]
* [[Gliding possum]]

==References==
{{Reflist|35em}}

==Further reading==
* Thorington, R. W. Jr. and R. S. Hoffman. 2005. Family Sciuridae. pp.&nbsp;754–818 in ''Mammal Species of the World a Taxonomic and Geographic Reference''. D. E. Wilson and D. M. Reeder eds. Johns Hopkins University Press, Baltimore.
* {{Cite EB1911|wstitle=Flying-squirrel}}

==External links==
{{Commons category|Pteromyini}}
{{Wikispecies|Pteromyini}}
* [https://www.nwf.org/Educational-Resources/Wildlife-Guide/Mammals/Flying-Squirrels Flying Squirrels, National Wildlife Foundation]
* [http://animaldiversity.ummz.umich.edu/site/accounts/classification/Pteromyinae.html Animal Diversity Web: Pteromyinae], classification

{{S. Sciurinae2 nav}}

{{Taxonbar|from=Q9490}}
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{{DEFAULTSORT:Flying Squirrel}}
[[Category:Flying squirrels| ]]
[[Category:Gliding animals]]
[[Category:Extant Rupelian first appearances]]
[[Category:Taxa named by Johann Friedrich von Brandt]]