Editing Squirrel (section)

=== Feeding ===
[[File:Squirrel, Manyara National Park, Tanzania (2010).jpg|thumb|right|Squirrel eating a fruit in [[Manyara National Park]], [[Tanzania]]]]
[[File:Squirrel in Seurasaari autumn.JPG|thumb|right|[[Red squirrel]] in the [[Seurasaari]] island in [[Helsinki]], [[Finland]]. The tame red squirrels on that island have become accustomed to humans thanks to their long-term feeding.<ref>Merja Laavola: Eläinten elintasosairaudet näkyvät Seurasaaressa. Vartti Etelä-Helsinki, Sanoma Kaupunkilehdet, 2010. (in Finnish)</ref>]]
[[File:Squirrel eating pumpkin seeds.webm|thumb|thumbtime=0|Squirrel retrieving and eating [[pumpkin]] seeds.]]

Because squirrels cannot digest [[cellulose]], they must rely on foods rich in [[protein]], [[carbohydrates]], and [[fat]]s. In [[temperate]] regions, early spring is the hardest time of year for squirrels because the nuts they [[Hoarding (animal behavior)|buried]] are beginning to sprout (and thus are no longer available to eat), while many of the usual food sources are not yet available. During these times, squirrels rely heavily on tree buds. Squirrels, being primarily [[herbivores]], eat a wide variety of plants, as well as [[nut (fruit)|nuts]], [[seed]]s, [[conifer cone]]s, [[fruit]]s, [[fungus|fungi]], and green [[vegetation]]. Some squirrels, however, also consume meat, especially when faced with hunger.<ref name="squirrels" /><ref>{{cite news |website=[[bbc.co.uk]] |access-date=13 July 2018 |url=http://news.bbc.co.uk/2/hi/4489792.stm |title=Russian squirrel pack 'kills dog' |date=1 December 2005}}</ref> Squirrels have been known to eat small [[bird]]s, young [[snake]]s, and smaller rodents, as well as [[bird egg]]s and [[insect]]s. Some [[tropical]] squirrel species have shifted almost entirely to a diet of insects.<ref>Richard W. Thorington, Katie Ferrell – [https://books.google.com/books?id=Y7cuEWCWpLMC&pg=PA75 ''Squirrels: the animal answer guide''], JHU Press, 2006, {{ISBN|0-8018-8402-0}}, {{ISBN|978-0-8018-8402-3}}, p. 75.</ref>

Squirrels, like [[pigeons]] and other fauna, are [[synanthropes]], in that they benefit and thrive from their interaction in human environments. This gradual process of successful interaction is called synurbanization, wherein squirrels lose their inherent fear of humans in an [[urban area|urban]] environment.<ref name="peim">{{cite journal |last1=Peiman |first1=Kathryn |title=Sublethal consequences of urban life for wild vertebrates |journal=Environmental Reviews |date=June 2016 |volume=24 |issue=4 |pages=416–425 |doi=10.1139/er-2016-0029|hdl=1807/74036 |hdl-access=free }}</ref> When squirrels were almost completely eradicated during the [[Industrial Revolution]] in [[New York City|New York]], they were later re-introduced to "entertain and remind" humans of nature. The squirrel blended into the urban environment so efficiently that when synanthropic behavior stops (i.e. people do not leave trash outside during particularly cold winters), they can become aggressive in their search for food.

Aggression and predatory behavior has been observed in various species of ground squirrels, in particular the [[thirteen-lined ground squirrel]].<ref>{{cite journal | last=Friggens | first=M. | title=Carnivory on Desert Cottontails by Texas Antelope Ground Squirrels | jstor=3672818 | journal=The Southwestern Naturalist | volume=47 | issue=1 | pages=132–133 | year=2002 | doi=10.2307/3672818| bibcode=2002SWNat..47..132F }}</ref> For example, Bernard Bailey, a scientist in the 1920s, observed a thirteen-lined ground squirrel preying upon a young [[chicken]].<ref>{{cite journal | last=Bailey | first=B. | title=Meat-eating propensities of some rodents of Minnesota | journal=Journal of Mammalogy | volume=4 | issue= 2| page=129 | year=1923 | doi = 10.1093/jmammal/4.2.129 }}</ref> Wistrand reported seeing this same species eating a freshly killed [[snake]].<ref>{{cite journal | last=Wistrand | first=E.H. | title=Predation on a Snake by ''Spermophilus tridecemlineatus'' | jstor=2424389 | journal=American Midland Naturalist | volume=88 | issue=2 | pages=511–512 | year=1972 | doi=10.2307/2424389}}</ref> There has also been at least one report of squirrels preying on atypical animals, such as an incident in 2005 where a pack of black squirrels killed and ate a large stray [[dog]] in [[Lazo, Russia]].<ref name="bbcn">{{cite news |title=Russian Squirrel Pack Kills Dog |url=http://news.bbc.co.uk/2/hi/4489792.stm |website=BBC News |date=December 2005 |access-date=7 August 2020}}</ref> Squirrel attacks on humans are exceedingly rare, but do occur.<ref name="bbc2">{{cite news |title=Cornwall squirrel 'pack' attacks boy, three |work=BBC News |date=14 July 2016 |url=https://www.bbc.com/news/uk-england-cornwall-36792959 |access-date=7 August 2020}}</ref><ref name="atl1">{{cite web |last1=Lafrance |first1=Adrienne |title=When Squirrels Attack – A cautionary tale |url=https://www.theatlantic.com/science/archive/2017/06/when-squirrels-attack/531129/ |website=The Atlantic |date=21 June 2017 |access-date=7 August 2020}}</ref>

Whitaker examined the stomachs of 139 thirteen-lined ground squirrels and found bird flesh in four of the specimens and the remains of a short-tailed [[shrew]] in one;<ref>{{cite journal | last=Whitaker | first=J.O. | title=Food and external parasites of ''Spermophilus tridecemlineatus'' in Vigo County, Indiana | jstor=1379067 | journal=Journal of Mammalogy | volume=53 | issue=3 | pages=644–648 | year=1972 | doi=10.2307/1379067}}</ref> Bradley, examining the stomachs of [[white-tailed antelope squirrel]]s, found at least 10% of his 609 specimens' stomachs contained some type of vertebrate, mostly [[lizard]]s and rodents.<ref>{{cite journal | last=Bradley | first=W. G. | title=Food habits of the antelope ground squirrel in southern Nevada | jstor=1377723 | journal=Journal of Mammalogy | volume=49 | issue=1 | pages=14–21 | doi=10.2307/1377723 | year=1968}}</ref> Morgart observed a white-tailed antelope squirrel capturing and eating a [[Perognathus flavus|silky pocket mouse]].<ref>{{cite journal | last=Morgart | first=J. R. | title=Carnivorous behavior by a white-tailed antelope ground squirrel ''Ammospermophilus leucurus'' | jstor=3670745 | journal=The Southwestern Naturalist | volume=30 | issue=2 | pages=304–305 | doi=10.2307/3670745 |date=May 1985| bibcode=1985SWNat..30..304M }}</ref>