View source for Arctic ground squirrel

{{Short description|Species of rodent}}
{{Speciesbox
| image = Spermophilus parryii (eating mushroom).jpg
| status = LC
| status_system = IUCN3.1
| status_ref = <ref name="iucn status 12 November 2021">{{cite iucn |author=Cassola, F. |date=2016 |title=''Urocitellus parryii'' |volume=2016 |page=e.T20488A22262403 |doi=10.2305/IUCN.UK.2016-3.RLTS.T20488A22262403.en |access-date=12 November 2021}}</ref>
| genus = Urocitellus
| species = parryii
| authority = [[John Richardson (naturalist)|Richardson]], 1825
| synonyms = ''Spermophilus parryii''
| subdivision_ranks = Subspecies
| subdivision = 10 ssp., see [[#Subspecies|text]]
| range_map = Spermophilus parryii map.svg
}}

The '''Arctic ground squirrel''' ('''''Urocitellus parryii''''') ([[Inuktitut]]: ''ᓯᒃᓯᒃ, siksik'')<ref>{{Cite web|url=https://tusaalanga.ca/|title=Welcome to Tusaalanga {{!}} Inuktut Tusaalanga|website=tusaalanga.ca|access-date=2019-02-22}}</ref> is a [[species]] of [[ground squirrel]] in the squirrel family [[Squirrel|Sciuridae]] that is native to the [[Arctic]] and [[Subarctic]] regions of the [[Northern Hemisphere]], mainly in [[North America]] and [[Asia]]. For some people in [[Alaska]], particularly around the [[Aleutian Islands]], the [[Rodent|rodents]] are known as "parka" squirrels, likely due to their [[Fur|pelts]] being used for the ruff on [[Parka|parkas]] and other cold-weather clothing.<ref>[https://books.google.com/books?id=wRvFBAAAQBAJ&dq=Arctic+ground+squirrel+hood+edging&pg=PA77 Antarctica and the Arctic Circle: A Geographic Encyclopedia of the Earth's Polar Regions]</ref>

==Taxonomy==
Subspecies listed alphabetically.<ref>[https://www.departments.bucknell.edu/biology/resources/msw3/browse.asp?id=12401055 ''Urocitellus parryii''], MSW3</ref>
*''U. p. ablusus'' <small>Osgood, 1903</small>  
*''U. p. kennicottii'' <small>Ross, 1861</small> – [[Utqiagvik, Alaska|Barrow]] ground squirrel ([[Arctic Alaska|Northern Alaska]], N. [[Yukon]] and N. [[Northwest Territories]])
*''U. p. kodiacensis'' <small>Ross, 1861</small> – [[Kodiak Island]] ground squirrel
*''U. p. leucostictus'' <small>Brandt, 1844</small>   
*''U. p. lyratus'' <small>Hall and Gilmore, 1932 –</small> [[St. Lawrence Island]] ground squirrel
*''U. p. nebulicola'' <small>Osgood, 1903</small> – [[Shumagin Islands]] ground squirrel ([[Aleutians East Borough, Alaska|Aleutians East Borough]]; islands of [[Koniuji Island|Koniuji]], [[Korovin Island|Korovin]], [[Nagai Island|Nagai]], [[Popof Island|Popof]], [[Simeonof Wilderness|Simeonof]], [[Unga Island|Unga]])<ref>{{Cite web |title=Urocitellus parryii nebulicola {{!}} NatureServe Explorer |url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.103326/Urocitellus_parryii_nebulicola }}</ref>
*''U. p. osgoodi'' <small>Merriam, 1900</small>  – Osgood's Arctic ground squirrel (south of the [[Brooks Range]] in Alaska, near [[Fort Yukon, Alaska|Fort Yukon]] and [[Circle, Alaska|Circle]])<ref>{{Cite web |title=Urocitellus parryii osgoodi {{!}} NatureServe Explorer |url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.104767/Urocitellus_parryii_osgoodi }}</ref>
*''U. p. parryii'' <small>Richardson, 1825</small>  
*''U. p. plesius'' <small>Osgood, 1900</small>  
*''U. p. stejnegeri'' <small>J. A. Allen, 1903</small>   

==Description==
The Arctic ground squirrel typically has a beige-tan pelage with a lightly spotted backside. Similar to the related [[prairie dog]], it has a shorter face than the typical [[Arboreal locomotion|arboreal]] squirrels–due to its lifestyle of burrowing–as well as smaller ears, with a dark tail and white markings around the eyes. 

During the brief [[Midnight sun|boreal summer]], Arctic ground squirrels undergo an annual [[Moulting|molting]] (coat shedding/re-growth) cycle in preparation for the onset of colder weather; this is seen in other Arctic species, as well, such as the white winter coat of the [[Arctic fox]], [[Arctic hare|Arctic]] and [[Snowshoe hare|snowshoe hares]], [[Stoat|ermine]] (stoat), and even some birds, such as the [[rock ptarmigan]]. Summer coats include reddish and yellow colorations along the cheeks and sides of the body; in the fall, these red patches are shed and replaced by a more silvery color. The lighter coloration in winter helps the ground squirrels to camouflage against the often snow-white ground and better evade predators, such as [[Snowy owl|snowy owls]] or foxes. The average length of an Arctic ground squirrel is approximately {{convert|39|cm|abbr=on}}. Since Arctic ground squirrels undergo drastic seasonal changes in body mass, it is difficult to give an average mass;<ref>{{cite journal|last=Buck|first=C.L.|author2=Barnes, B.M.|title=Annual cycle of body composition and hibernation in free-living arctic ground squirrels|journal=Journal of Mammalogy|year=1999|volume=80|issue=2|pages=430–442|doi=10.2307/1383291|jstor=1383291|doi-access=}}</ref> adult females are close to {{convert|750|g|abbr=on}}, while males may weigh nearly {{convert|100|g|abbr=on}} heavier.<ref name="ADW" />

==Distribution and habitat==
The Arctic ground squirrel can be found in parts of western [[Northern Canada]], from the [[Arctic Circle]] to the [[Yukon]], northern [[British Columbia]] and the [[Northwest Territories]]; west into [[Alaska]], the [[Aleutian Islands]] archipelago, and across to the [[Russian Far East]] ([[Siberia]]), including the [[Kamchatka Peninsula]].<ref name="iucn status 12 November 2021" /> The [[St. Lawrence Island]] subspecies (''U. p. lyratus'') of Arctic ground squirrel is found on its namesake island in the [[Bering Sea]]; the Kodiak Island subspecies (''U. p. kodiacensis'') is found on the [[Alaska Peninsula]], namely [[Kodiak Island|Kodiak]].

The Arctic ground squirrel has evolved with and is found on the North American Arctic [[tundra]]; depending on the subspecies, its preferred habitats are typically hillside or mountain slopes, [[Riparian zone|riparian]] areas (such as river flats, banks or lake shores) or tundra ridges. Arctic ground squirrels prefer to live in sandy soil due to its ease of manipulation for burrowing, and its superior drainage as opposed to richer soils.<ref>Nadler C, Hopkins RS (1976). Patterns of evolution and migration in the arctic ground squirrel, ''Spermophilus parryii'' (Richardson). [Internet]. Chicago (ZL) U.S.A.: Department of Medicine, Northwestern University Medical School, and the University of Kansas, Lawrence (KS) U.S.A.: Museum of Natural History and Department of Systematics and Ecology; [updated 1976 Oct 20; cited 2013 Nov 10]. Available from: http://www.nrcresearchpress.com/doi/pdf/10.1139/z77-097.</ref> Arctic ground squirrels make shallow tunnels and burrows in locations where the [[permafrost]] will not prevent them from digging.<ref>{{cite web |title=BBC Nature - Arctic ground squirrel videos, news and facts |url=https://www.bbc.co.uk/nature/life/Arctic_Ground_Squirrel |publisher=[[BBC Earth]] |access-date=6 November 2013}}</ref> The more southerly subspecies typically inhabit open meadows and open tundra habitats.<ref name=ADW>[http://animaldiversity.ummz.umich.edu/site/accounts/information/Spermophilus_parryii.html Animal Diversity Web]</ref>

== Fossil record ==
The Arctic ground squirrel has an extensive [[Fossil|fossil record]] from the [[Pleistocene]]. During the [[Last Glacial Maximum]], it was abundant in areas such as the Klondike region where it is currently rare or absent.<ref>{{Cite journal |last1=Zazula |first1=Grant D. |last2=Froese |first2=Duane G. |last3=Elias |first3=Scott A. |last4=Kuzmina |first4=Svetlana |last5=Mathewes |first5=Rolf W. |date=April 2007 |title=Arctic ground squirrels of the mammoth-steppe: paleoecology of Late Pleistocene middens (∼24000–29450 14C yr BP), Yukon Territory, Canada |url=https://linkinghub.elsevier.com/retrieve/pii/S0277379106003404 |journal=[[Quaternary Science Reviews]] |language=en |volume=26 |issue=7–8 |pages=979–1003 |doi=10.1016/j.quascirev.2006.12.006 |access-date=12 August 2024 |via=Elsevier Science Direct|url-access=subscription }}</ref> Fossilised Arctic ground squirrel nests and caches have also been used for palaeoenvironmental reconstruction; ''Calamagrostis canadensis'', ''Carex albonigra,'' and ''Koeleria'' sp. are common in caches from Late Pleistocene Alaska, indicating the presence of an aerially extensive mammoth steppe ecosystem in the region at this time.<ref>{{Cite journal |last1=Gaglioti |first1=Benjamin V. |last2=Barnes |first2=Brian M. |last3=Zazula |first3=Grant D. |last4=Beaudoin |first4=Alwynne B. |last5=Wooller |first5=Matthew J. |date=November 2011 |title=Late Pleistocene paleoecology of arctic ground squirrel ( Urocitellus parryii ) caches and nests from Interior Alaska's mammoth steppe ecosystem, USA |url=https://www.cambridge.org/core/journals/quaternary-research/article/abs/late-pleistocene-paleoecology-of-arctic-ground-squirrel-urocitellus-parryii-caches-and-nests-from-interior-alaskas-mammoth-steppe-ecosystem-usa/982E275DBF56FE03ECBD13D6BB54C818 |journal=[[Quaternary Research]] |language=en |volume=76 |issue=3 |pages=373–382 |doi=10.1016/j.yqres.2011.08.004 |bibcode=2011QuRes..76..373G |issn=0033-5894 |access-date=27 August 2024 |via=Cambridge Core|url-access=subscription }}</ref>[[Image:Arctic ground squirrels, Nunavut.jpg|thumb|On tundra, [[Kugluktuk, Nunavut|Kugluktuk]], [[Nunavut]]]]

==Behaviour==
[[File:Squirrel Mummy.jpg|thumb|20,000-year-old Arctic ground squirrel mummy]]
The diurnal Arctic ground squirrel lives on the tundra, where it may fall prey to the Arctic and the [[red fox]], [[wolverine]], [[Canada lynx|Canada]] and [[Eurasian lynx]], [[brown bear]], snowy owls and [[eagle]]s. It is one of the few Arctic mammal species which [[Hibernation|hibernates]] in the winter, similarly to the [[little brown bat]] and the closely related [[marmot]].<ref>[http://www.wc.adfg.state.ak.us/index.cfm?adfg=wildlife_news.view_article&issue_id=48&articles_id=279 The Long Sleep: Which Animals Hibernate?]</ref> In the summer, it forages for [[tundra]] [[plant]]s, [[seed]]s, and [[fruit]] to increase [[Adipose tissue|body fat]] for its winter hibernation. By late summer, the male Arctic ground squirrel begins to store food in its cache so that, come springtime,<ref name="EnvironmentYukon">{{cite web |url=http://www.environmentyukon.gov.yk.ca/wildlifebiodiversity/mammals/agsquirrel.php |title=Arctic Ground Squirrel |publisher=Environment Yukon |date=3 March 2015 |access-date=17 May 2015 |archive-url=https://web.archive.org/web/20101229142406/http://www.environmentyukon.gov.yk.ca/wildlifebiodiversity/mammals/agsquirrel.php |archive-date=29 December 2010 |url-status=dead }}</ref> it will have a food source until the any new vegetation has grown. Their burrows are lined with [[lichen]]s, [[leaf|leaves]], [[Poaceae|grasses]], and [[muskox]] hair, amongst other animal fibers they may find.

Communication between squirrels is done through both vocal and physical means. When they meet, nose to nose contact is made or other body parts are pressed together. The "tsik-tsik" calls are made in response to threats and vary as between different predators. Deep guttural sounds are used to indicate land-based predators while short "band whistle" chatter indicates danger from the air.<ref name="ADW" />

=== Hibernation ===
The Arctic ground squirrel hibernates over winter from early August to late April in adult females and from late September to early April for adult males,<ref>{{cite journal|last=Buck|first=C.L.|author2=Breton, A.|author3=Kohl, F.|author4=Toien, O.|author5=Barnes, B.M.|title=Overwinter body temperature patterns in free-living Arctic Ground Squirrels (Spermophilus parryii)|journal=Hypometabolism in Animals: Hibernation, Torpor and Cryobiology|year=2008|pages=317–326}}</ref> at which time it can reduce its body temperatures from {{convert|37|C}} to as little as {{convert|-3|C}}.<ref>{{cite journal|last=Barnes |first=Brian M. |date=1989-06-30 |title=Freeze Avoidance in a Mammal: Body Temperatures Below 0°C in an Arctic Hibernator |journal=[[Science (journal)|Science]] |volume=244 |issue=4912 |pages=1593–1595 |publisher=[[American Association for the Advancement of Science]] |url=http://users.iab.uaf.edu/~brian_barnes/publications/1989barnes.pdf |access-date=2009-08-12 |pmid=2740905 |doi=10.1126/science.2740905 |url-status=dead |archive-url=https://web.archive.org/web/20081216233837/http://users.iab.uaf.edu/~brian_barnes/publications/1989barnes.pdf |archive-date=2008-12-16 }}</ref> During hibernation, its core body temperature reaches temperatures down to {{cvt|-2.9|C|F}}<ref>Liu Y, Hu W, Wang H, Lu M, Shao C, Menzel C, Yan Z, Ying L, Zhao S, Khaitovich P, Liu M, Chen W, Barnes BM, and Yan J: [http://mercury2.iab.uaf.edu/brian_barnes/publications/2010_Liu_etal.pdf Genomic analysis of miRNAs in an extreme mammalian hibernator, the Arctic Ground Squirrel. Physiological Genomics] {{webarchive |url=https://web.archive.org/web/20150402105238/http://mercury2.iab.uaf.edu/brian_barnes/publications/2010_Liu_etal.pdf |date=April 2, 2015 }} 42A:39-51. (2010)</ref> and its heart rate drops to about one beat per minute. [[Peripheral nervous system|Peripheral]], colonic, and blood temperatures become subzero. The best theory as to why the squirrel's blood doesn't freeze is that the animal is able to cleanse their bodies of [[ice nucleator]]s which are necessary for the development of ice crystals. In the absence of ice nucleators, body fluids can remain liquid while in supercooled state.  This process is being studied with the hope that mechanism present in arctic ground squirrels may provide a path for better preservation of human organs for transplant.<ref>{{Cite web|url=http://www.bbc.com/earth/story/20160308-how-one-squirrel-manages-to-survive-being-frozen|title=When your veins fill with ice|last=Asher|first=Claire|website=www.bbc.com|language=en|access-date=2019-05-02}}</ref> The connections between brain cells also wither away in this state. The damage should have resulted in death, but research on related species show that these connections regrow after waking up. In the warmer months, the squirrel is active during the day.

===Diet===
This squirrel feeds on grasses, [[Cyperaceae|sedges]], mushrooms, bog rushes, [[Bilberry|bilberries]], [[willow]]s, roots, stalks, leaves, leaf buds, flowers, [[Amentotaxus|catkins]], and seeds. They will also eat insects and, occasionally, even supplement their diet with [[carrion]] (such as mice, [[snowshoe hare]]s and [[Reindeer|caribou]])<ref>{{cite web |author=Torsten Bernhardt |publisher=Canadian Biodiversity. Redpath Museum; McGill University |access-date=6 November 2013 |url=http://canadianbiodiversity.mcgill.ca/english/species/mammals/mammalpages/spe_par.htm |title=Canadian Biodiversity: Species: Mammals: Arctic Ground Squirrel |archive-url=https://web.archive.org/web/20130614222133/http://canadianbiodiversity.mcgill.ca/english/species/mammals/mammalpages/spe_par.htm |archive-date=14 June 2013 |url-status=dead }}</ref> as well as juvenile Arctic ground squirrels.<ref>{{cite journal |journal=[[Animal Behaviour (journal)|Animal Behaviour]] |title=Paternal behaviour and killing of young in Arctic ground squirrels |last1=McLean |first1=Ian G |year=1983 |volume=31 |issue=1 |pages=32–44 |doi=10.1016/S0003-3472(83)80171-7|s2cid=53147479 }}</ref> Sometimes these squirrels carry food back to their den in their cheeks.<ref name=ADW/>

===Reproduction===
During the mating season, males engage in male-male aggressive encounters for mating rights.<ref>{{cite journal|last=Buck|first=C.L.|author2=Barnes, B.M.|year=2003|title=Androgen in free-living arctic ground squirrels: seasonal changes and influence of staged male-male aggressive encounters|journal=Hormones and Behavior|volume=43|issue=2|pages=318–326|doi=10.1016/s0018-506x(02)00050-8|pmid=12694642|s2cid=37114468}}</ref>

Arctic ground squirrels live individually in burrow systems. Mating occurs between mid-April and mid-May (depending on [[latitude]]) after winter hibernation. Mating includes male-male competition for access to females, and litters are typically sired by multiple males. [[Gestation]] is approximately 25 days, and results in a litter of 5 to 10, {{convert|10|g|abbr=on}} hairless pups. After six weeks, the pups are weaned and this is followed by rapid growth to prepare for the upcoming winter.<ref name="ADW" />

==Conservation==
[[File:Arctic ground squirrel by Matt Henschen USFWS.jpg|thumb|Arctic ground squirrel in [[Alaska Maritime National Wildlife Refuge]]]]
Although Environment Yukon has not estimated their population size, their conservation status is currently said to be "secure" (Environment Yukon 2013).<ref name="EnvironmentYukon" />
The Arctic ground squirrel is classified as least concern (LC) on the IUCN Red List (Arkive 2013).<ref>Arkive, 2013. Arctic Ground Squirrel. [Internet]. [Cited November 7th 2013]. Available from: http://www.arkive.org/arctic-ground-squirrel/spermophilus-parryii/image-G78548.html {{Webarchive|url=https://web.archive.org/web/20131112040352/http://www.arkive.org/arctic-ground-squirrel/spermophilus-parryii/image-G78548.html |date=2013-11-12 }}</ref>

==References==
{{Reflist}}

==Further reading==
* Hall, E. Raymond (1981). ''The Mammals of North America.'' 2 volumes. Ronald Press.
* {{cite journal | last1 = Helgen | first1 = K. M. | last2 = Cole | first2 = F. R. | last3 = Helgen | first3 = L. E. | last4 = Wilson | first4 = D. E. | year = 2009 | title = Generic revision in the Holarctic ground squirrel genus ''Spermophilus'' | url =https://zenodo.org/record/895398 | journal = Journal of Mammalogy | volume = 90 | issue = 2| pages = 270–305 | doi=10.1644/07-mamm-a-309.1| doi-access = free }}
* 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.

==External links==
*{{Commons category-inline|Urocitellus parryii|Arctic ground squirrel}}
*{{Wikispecies-inline|Urocitellus parryii|Arctic ground squirrel}}

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[[Category:Urocitellus]]
[[Category:Mammals of the Arctic]]
[[Category:Arctic land animals]]
[[Category:Mammals described in 1825]]
[[Category:Mammals of Russia]]
[[Category:Mammals of Siberia]]
[[Category:Rodents of the United States]]
[[Category:Rodents of Canada]]
[[Category:Fauna of the Holarctic realm]]
[[Category:Taxa named by John Richardson (naturalist)]]