Editing Squirrel (section)

== Characteristics ==
[[File:Sciurus carolinensis -British Columbia, Canada-8.jpg|left|thumb|Reaching out for food on a garden bird feeder, this squirrel can rotate its hind feet, allowing it to descend a tree headfirst.]]
[[File:Ratufa skull.JPG|thumb|left|Skull of an [[Oriental giant squirrel]] (genus ''Ratufa'')—note the classic [[sciuromorphous]] shape of the anterior [[zygomatic arch|zygomatic]] region.]]

Squirrels are generally small animals, ranging in size from the [[African pygmy squirrel]] and [[least pygmy squirrel]] at {{cvt|10-14|cm}} in total length and just {{cvt|12-26|g}} in weight,<ref name=Kingdon1997>{{cite book | author=Kingdon, J. | author-link=Jonathan Kingdon | year=1997 | title=The Kingdon Guide to African Mammals | publisher=Academic Press Limited, London | isbn=0-12-408355-2 | url-access=registration | url=https://archive.org/details/kingdonfieldguid00jona }}</ref><ref name=Payne1998>{{cite book| author1=Payne, J. | author2=C.F. Francis | year=1998 | title=A Field Guide to the Mammals of Borneo | page=243 | publisher=The Sabah Society | edition=3 | isbn=967-99947-1-6 }}</ref> to the [[Bhutan giant flying squirrel]] at up to {{cvt|1.27|m}} in total length,<ref name=Choudhury2002>{{cite journal | author=Choudhury, A. | year=2002 | title=Petaurista nobilis singhei: First record in India and a note on its taxonomy | journal=The Journal of the Bombay Natural History Society | volume=99 | issue=1 | pages=30–34 }}</ref> and several [[marmot]] species, which can weigh {{cvt|8|kg}} or more.<ref name=Krystufek2013>{{cite journal | author1=Kryštufek, B. | author2=B. Vohralík | year=2013 | title=Taxonomic revision of the Palaearctic rodents (Rodentia). Part 2. Sciuridae: Urocitellus, Marmota and Sciurotamias | journal=Lynx, N. S. (Praha) | volume=44 | pages=27–138 }}</ref><ref name=Armitage2002>{{cite book | author1=Armitage, K.B. | author2=Blumstein, D.T. | year=2002 | chapter=Body-mass diversity in marmots. Holarctic marmots as a factor of biodiversity | editor1=K.B. Armitage | editor2=V.Yu. Rumiantsev | title=Holarctic Marmots as a Factor of Biodiversity | publisher=ABF Publishing House | pages=22–32 }}</ref> Squirrels typically have slender bodies with long, bushy tails and large eyes. In general, their [[fur]] is soft and silky, though much thicker in some species than others. The coat color of squirrels is highly variable between—and often even within—species.<ref>[http://www.wildlifeonline.me.uk/squirrels.html Tree Squirrels], ''Wildlife Online'', 23 November 2010.</ref>

In most squirrel species, the hind limbs are longer than the forelimbs, while all species have either four or five toes on each foot. The feet, which include an often poorly developed [[thumb]], have soft pads on the undersides<ref name=EoM>Milton (1984)</ref> and versatile, sturdy [[claw]]s for grasping and [[tree climbing|climbing]].<ref>{{cite web|url=http://animals.howstuffworks.com/mammals/squirrel-info.htm|title=Rodents|date=22 April 2008|publisher=How Stuff Works|access-date=30 December 2016}}</ref> [[Tree squirrels]], unlike most mammals, can descend a tree headfirst. They do so by rotating their ankles 180 degrees, enabling the hind feet to point backward and thus grip the tree bark from the opposite direction.<ref>{{cite book|last1=Thorington|first1=Richard W.|last2=Koprowski|first2=John L.|last3=Steele|first3=Michael A.|last4=Whatton|first4=James F.|year=2012|page=8|title=Squirrels of the World|publisher=Johns Hopkins University Press|isbn=978-1-4214-0469-1}}</ref>

=== Head ===
As their large eyes indicate, squirrels have excellent [[Visual perception|vision]], which is especially important for the tree-dwelling species. Many also have a good sense of [[somatosensory system|touch]], with [[whiskers|vibrissae]] on their limbs as well as their heads.<ref name=EoM />

The teeth of sciurids follow the typical rodent pattern, with large [[incisor]]s (for gnawing) that grow throughout life, and cheek teeth (for grinding) that are set back behind a wide gap, or [[diastema]]. The typical [[dentition|dental formula]] for sciurids is {{DentalFormula|upper=1.0.1.3|lower=1.0.1.3}}.<ref>''The Beginning of the Age of Mammals'' Kenneth D. Rose (2006) {{ISBN|978-0-801-88472-6}} p. 326</ref>

=== Tail ===
The purposes of squirrels' tails, to benefit the squirrel, include:<ref>{{Cite web|url=http://www.nutsaboutsquirrels.com/1695/why-do-squirrels-have-bushy-tails/|title=Why do squirrels have bushy tails? &#124; Nuts About Squirrels}}</ref>

* To keep rain, wind, or cold off itself.
* To cool off when hot, by pumping more blood through its tail.
* As a counterbalance when jumping about in trees
* As a [[parachute]] when jumping.
* To signal with.

The hairs from squirrel tails are prized in [[fly fishing]] when tying [[fishing flies]].<ref>{{Cite web |last=Genova |first=Cosmo |date=2022-01-11 |title=How to Preserve a Squirrel Pelt For Fly Tying |url=https://www.fieldandstream.com/fishing/preserve-squirrel-pelt-fly-tying/ |access-date=2024-06-01 |website=Field & Stream |language=en-US}}</ref> Squirrel hair is very fine, making it better for tying fishing flies.<ref>{{Cite book |last=Valla |first=Mike |url=https://books.google.com/books?id=0AVDDQAAQBAJ&dq=%22squirrel+tail%22+%22guard+hair%22&pg=PA45 |title=Tying and Fishing Bucktails and Other Hair Wings: Atlantic Salmon Flies to Steelhead Flies |date=2016-09-05 |publisher=Rowman & Littlefield |isbn=978-0-8117-6532-9 |language=en}}</ref>

When the squirrel sits upright, its tail folded up its back may stop predators looking from behind from seeing the characteristic shape of a small mammal.