scholarly journals Entraining to the polar day: circadian rhythms in arctic ground squirrels

2017 ◽  
Vol 220 (17) ◽  
pp. 3095-3102 ◽  
Author(s):  
Cory T. Williams ◽  
Brian M. Barnes ◽  
Lily Yan ◽  
C. Loren Buck
Keyword(s):  
Circadian Rhythms ◽  
Ground Squirrels ◽  
Polar Day ◽  
Arctic Ground Squirrels

Hibernation and Circadian Rhythms of Body Temperature in Free-Living Arctic Ground Squirrels

2012 ◽  
Vol 85 (4) ◽  
pp. 397-404 ◽  
Author(s):  
Cory T. Williams ◽  
Brian M. Barnes ◽  
Melanie Richter ◽  
C. Loren Buck
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Ground Squirrels ◽  
Free Living ◽  
Arctic Ground Squirrels

scholarly journals Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels

2011 ◽  
Vol 8 (1) ◽  
pp. 31-34 ◽  
Author(s):  
Cory T. Williams ◽  
Brian M. Barnes ◽  
C. Loren Buck
Keyword(s):  
Body Temperature ◽  
Circadian Rhythms ◽  
Ground Squirrels ◽  
The Arctic ◽  
Constant Light ◽  
Polar Regions ◽  
Free Living ◽  
Active Season ◽  
Temperature Rhythms ◽  
Arctic Ground Squirrels

In indigenous arctic reindeer and ptarmigan, circadian rhythms are not expressed during the constant light of summer or constant dark of winter, and it has been hypothesized that a seasonal absence of circadian rhythms is common to all vertebrate residents of polar regions. Here, we show that, while free-living arctic ground squirrels do not express circadian rhythms during the heterothermic and pre-emergent euthermic intervals of hibernation, they display entrained daily rhythms of body temperature ( T b ) throughout their active season, which includes six weeks of constant sun. In winter, ground squirrels are arrhythmic and regulate core body temperatures to within ±0.2°C for up to 18 days during steady-state torpor. In spring, after the use of torpor ends, male but not female ground squirrels, resume euthermic levels of T b in their dark burrows but remain arrhythmic for up to 27 days. However, once activity on the surface begins, both sexes exhibit robust 24 h cycles of body temperature. We suggest that persistence of nycthemeral rhythms through the polar summer enables ground squirrels to minimize thermoregulatory costs. However, the environmental cues (zeitgebers) used to entrain rhythms during the constant light of the arctic summer in these semi-fossorial rodents are unknown.

Seasonal loss and resumption of circadian rhythms in hibernating arctic ground squirrels

2017 ◽  
Vol 187 (5-6) ◽  
pp. 693-703 ◽  
Author(s):  
Cory T. Williams ◽  
Maya Radonich ◽  
Brian M. Barnes ◽  
C. Loren Buck
Keyword(s):  
Circadian Rhythms ◽  
Ground Squirrels ◽  
Arctic Ground Squirrels

scholarly journals Habitat selection by arctic ground squirrels (Spermophilus parryii)

2010 ◽  
Vol 91 (5) ◽  
pp. 1251-1260 ◽  
Author(s):  
Oliver E. Barker ◽  
Andrew E. Derocher
Keyword(s):  
Habitat Selection ◽  
Ground Squirrels ◽  
Spermophilus Parryii ◽  
Arctic Ground Squirrels

MAPKs are differentially modulated in arctic ground squirrels during hibernation

2005 ◽  
Vol 80 (6) ◽  
pp. 862-868 ◽  
Author(s):  
Xiongwei Zhu ◽  
Mark A. Smith ◽  
George Perry ◽  
Yang Wang ◽  
Austin P. Ross ◽  
...  
Keyword(s):  
Ground Squirrels ◽  
Arctic Ground Squirrels

scholarly journals Interrelationships Among Timing of Hibernation, Reproduction, and Warming Soil in Free-Living Female Arctic Ground Squirrels

2012 ◽  
pp. 63-72 ◽  
Author(s):  
Cory T. Williams ◽  
Michael J. Sheriff ◽  
Franziska Kohl ◽  
Brian M. Barnes ◽  
C. Loren Buck
Keyword(s):  
Ground Squirrels ◽  
Free Living ◽  
Arctic Ground Squirrels

Landscape-scale habitat associations of small mammals on the western coast of Hudson Bay

2021 ◽  
Author(s):  
Kevin Hawkshaw ◽  
Lee Foote ◽  
Alastair Franke
Keyword(s):  
Small Mammals ◽  
Vegetation Index ◽  
Normalized Difference Vegetation Index ◽  
Distance Sampling ◽  
Habitat Associations ◽  
Ground Squirrels ◽  
Suitable Habitat ◽  
Western Coast ◽  
Water Index ◽  
Arctic Ground Squirrels

Availability of suitable habitat affects the distribution and abundance of Arctic fauna, influencing how species respond to climate change and disturbance from resource extraction in the region. We surveyed Arctic ground squirrels (Urocitellus parryii Richardson, 1825) using distance sampling transects and concurrently counted microtine rodent burrows. Abundance of Arctic ground squirrels and microtine burrows was positively correlated with terrain ruggedness. Microtine burrows were more abundant inland and in areas with freshwater, while Arctic ground squirrels were more often found at low elevation without freshwater. Arctic ground squirrel abundance was positively related to the normalized difference water index, a proxy for vegetation water content, while microtine burrows were weakly correlated with the normalized difference vegetation index. Our study highlights the habitat associations of ecologically significant small mammals in an underrepresented Arctic study area.

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