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.

scholarly journals BODY TEMPERATURE AND ACTIVITY PATTERNS IN FREE-LIVING ARCTIC GROUND SQUIRRELS

2005 ◽  
Vol 86 (2) ◽  
pp. 314-322 ◽  
Author(s):  
Ryan A. Long ◽  
Timothy J. Martin ◽  
Brian M. Barnes
Keyword(s):  
Body Temperature ◽  
Activity Patterns ◽  
Ground Squirrels ◽  
Free Living ◽  
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

scholarly journals Circannual Rhythm in Body Temperature, Torpor, and Sensitivity to A1 Adenosine Receptor Agonist in Arctic Ground Squirrels

2013 ◽  
Vol 28 (3) ◽  
pp. 201-207 ◽  
Author(s):  
Jasmine M. Olson ◽  
Tulasi R. Jinka ◽  
Lindy K. Larson ◽  
Jeffrey J. Danielson ◽  
Jeanette T. Moore ◽  
...  
Keyword(s):  
Body Temperature ◽  
Adenosine Receptor ◽  
Receptor Agonist ◽  
Ground Squirrels ◽  
Circannual Rhythm ◽  
A1 Adenosine Receptor ◽  
Adenosine Receptor Agonist ◽  
Arctic Ground Squirrels

Metabolic Rate and Prehibernation Fattening in Free-Living Arctic Ground Squirrels

2013 ◽  
Vol 86 (5) ◽  
pp. 515-527 ◽  
Author(s):  
Michael J. Sheriff ◽  
Robert W. Fridinger ◽  
øivind Tøien ◽  
Brian M. Barnes ◽  
C. Loren Buck
Keyword(s):  
Metabolic Rate ◽  
Ground Squirrels ◽  
Free Living ◽  
Arctic Ground Squirrels

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
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