Arctic ground squirrel

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Arctic ground squirrel
Spermophilus parryii (eating mushroom).jpg
Conservation status
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Subphylum: Vertebrata
Class: Mammalia
Order: Rodentia
Family: Sciuridae
Genus: Spermophilus
Species: S. parryii
Binomial name
Spermophilus parryii
Richardson, 1825
Subspecies

10 ssp., see text

Synonyms

Urocitellus parryii

The Arctic ground squirrel (Urocitellus parryii) is a species of ground squirrel native to the Arctic. People in Alaska, particularly around the Aleutians, refer to them as "Parka" (pronounced "par'kee") squirrels. probably because their pelt is good for making the fur edging on the hoods of Parka style jackets.[2]

Subspecies[edit]

Listed alphabetically.[3]

  • S. p. ablusus Osgood, 1903
  • S. p. kennicottii Ross, 1861 – Barrow ground squirrel (northern Alaska, northern Yukon, and northern Northwest Territories)
  • S. p. kodiacensis Ross, 1861
  • S. p. leucostictus Brandt, 1844
  • S. p. lyratus Hall and Gilmore, 1932
  • S. p. nebulicola Osgood, 1903
  • S. p. osgoodi Merriam, 1900
  • S. p. parryii Richardson, 1825
  • S. p. plesius Osgood, 1900
  • S. p. stejnegeri J. A. Allen, 1903

Background[edit]

20,000 year old Arctic ground squirrel mummy

The diurnal Arctic ground squirrel lives on the tundra and is prey to the Arctic Fox, the Red Fox, wolverine, lynx, the Grizzly Bear, and eagles. It is one of the few Arctic animals, along with their close relatives the marmots[4] and the un-related little brown bat that hibernate.[5] In the summer it forages for tundra plants, seeds, and fruit to increase body fat for its winter hibernation. By late summer the male arctic ground squirrel begins to store food in its burrow so that in the spring[6] it will have edible food until the new vegetation has grown. The burrows are lined with lichens, leaves, and muskox hair.

During hibernation, its brain drops to just above freezing, its core body temperature reaches temperatures down to -2.9°C[7] and its heart rate drops to ~1BPM. Peripheral, colonic, and blood temperatures become subzero..

Geographic range[edit]

The Arctic ground squirrel can be found in regions of Northern Canada ranging from the Arctic Circle to northern British Columbia, and down to the southern border of the Northwest Territories, as well as Alaska and Siberia.[1]

Habitat[edit]

The Arctic ground squirrel is native to the North American Arctic tundra, where its main habitats are on mountain slopes, river flats, banks, lakeshores and tundra ridges of the arctic tundra. Ground squirrels live in sandy soil due to easy digging and good drainage.[8] Arctic ground squirrels make shallow burrows in areas where the permafrost does not prevent them from digging.[9] The Arctic ground squirrel inhabits dry Arctic tundra and open meadows in the most southern habitats of this species.[10]

On tundra, Kugluktuk, Nunavut

Physical description[edit]

The Arctic ground squirrel has a beige and tan coat with a white-spotted back. This squirrel has a short face, small ears, a dark tail and white markings around its eyes. Arctic ground squirrels undergo a coat change from summer to winter. Summer coats include red/yellow colorations along the cheeks and sides of the animal. In fall, these red patches are replaced with silvery fur. The average length of an Arctic ground squirrel is approximately 39 cm (15 in). Since arctic ground squirrels undergo drastic seasonal changes in body mass, it is difficult[11] to give an average mass, but for adult females it is close to 750 g (26 oz), however, males generally are around 100 g (3.5 oz) heavier than females.[10]

Reproduction[edit]

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, 10 g (0.35 oz) hairless pups. After 6 weeks the pups are weaned and this is followed by rapid growth to prepare for the upcoming winter.[10]

Behaviour[edit]

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,[12] at which time it can reduce its body temperatures from 37 °C (99 °F) to as little as −3 °C (27 °F).[13] In the warmer months, the squirrel is active during the day time.

During the mating season, males engage in male-male aggressive encounters for the mating rights.[14]

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.[10]

Food habits[edit]

This squirrel feeds on grasses, sedges, mushrooms, bog rushes, bilberries, willows, roots, stalks, leaves, leaf buds, flowers, catkins, and seeds. They will also eat insects, and occasionally they will even feed on carrion (such as mice, snowshoe hares and caribou) [15] as well as juvenile arctic ground squirrels.[16] Sometimes these squirrels carry food back to their den in their cheeks.[10]

Conservation[edit]

Although Environment Yukon has not estimated their population size, their conservation status is currently said to be “secure” (Environment Yukon 2013).[17] The Arctic ground squirrel is classified as Least Concern (LC) on the IUCN Red List (Arkive 2013).[18]

References[edit]

  1. ^ a b Linzey, A. V. (2008). Urocitellus parryii. In: IUCN 2008. IUCN Red List of Threatened Species. Retrieved 8 January 2009.
  2. ^ http://togiak.fws.gov/wildlife/squirrels.htm
  3. ^ Spermophilus parryii, MSW3
  4. ^ Alaska Marmot
  5. ^ The Long Sleep: Which Animals Hibernate?
  6. ^ Arctic Ground Squirrel, Environment Yukon
  7. ^ 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: Genomic analysis of miRNAs in an extreme mammalian hibernator, the Arctic Ground Squirrel. Physiological Genomics 42A:39-51. (2010)
  8. ^ Nadler C , Hopkins R S .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.
  9. ^ BBC Nature. Artic Ground Squirrel. [Internet]. [Cited November 6th 2013]. Available from: http://www.bbc.co.uk/nature/life/Arctic_Ground_Squirrel
  10. ^ a b c d e Animal Diversity Web
  11. ^ Buck, C.L.; Barnes, B.M. (1999). "Annual cycle of body composition and hibernation in free-living arctic ground squirrels". Journal of Mammology 80 (2): 430–442. doi:10.2307/1383291. 
  12. ^ Buck, C.L.; Breton, A.; Kohl, F.; Toien, O.; Barnes, B.M. (2008). "Overwinter body temperature patterns in free-living Arctic Ground Squirrels (Spermophilus parryii)". Hypometabolism in Animals: Hibernation, Torpor and Cryobiology: 317–326. 
  13. ^ Barnes, Brian M. (1989-06-30). "Freeze Avoidance in a Mammal: Body Temperatures Below 0°C in an Arctic Hibernator". Science (American Association for the Advancement of Science) 244: 1593–1595. doi:10.1126/science.2740905. PMID 2740905. Retrieved 2009-08-12. 
  14. ^ Buck, C.L.; Barnes, B.M. (2003). "Androgen in free-living arctic ground squirrels: seasonal changes and influence of staged male-male aggressive encounters". Hormones and Behavior (43): 318–326. 
  15. ^ Bernhardt, 2013. Canadian Biodiversity. [Internet]. Redpath Museum; McGill University; [Cited November 6th 2013]. Available from: http://canadianbiodiversity.mcgill.ca/english/species/mammals/mammalpages/spe_par.htm
  16. ^ McLean I G. 1983. Paternal behaviour and killing of young in Arctic ground squirrels. Animal Behaviour. [Internet]. [updated 1983 February; cited 2013 Nov 10] Volume 31 (Issue 1): Pages 32–44. Available from : http://www.sciencedirect.com.proxy1.library.mcgill.ca/science/article/pii/S0003347283801717#
  17. ^ Environment Yukon. 2013. Arctic Ground Squirrel (Spermophilus parryii ). [Internet]. [Cited November 7th 2013]. Available from: http://www.env.gov.yk.ca/animals-habitat/mammals/agsquirrel.php
  18. ^ Arkive, 2013. Arctic Ground Squirrel. [Internet]. [Cited November 7th 2013]. Available from: http://www.arkive.org/arctic-ground-squirrel/spermophilus-parryii/image-G78548.html

Further reading[edit]