Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living 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...
Published in: | Biology Letters |
---|---|
Main Authors: | , , |
Format: | Article in Journal/Newspaper |
Language: | English |
Published: |
The Royal Society
2011
|
Subjects: | |
Online Access: | http://dx.doi.org/10.1098/rsbl.2011.0435 https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2011.0435 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2011.0435 |
id |
crroyalsociety:10.1098/rsbl.2011.0435 |
---|---|
record_format |
openpolar |
spelling |
crroyalsociety:10.1098/rsbl.2011.0435 2024-09-09T19:20:24+00:00 Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels Williams, Cory T. Barnes, Brian M. Buck, C. Loren 2011 http://dx.doi.org/10.1098/rsbl.2011.0435 https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2011.0435 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2011.0435 en eng The Royal Society https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ Biology Letters volume 8, issue 1, page 31-34 ISSN 1744-9561 1744-957X journal-article 2011 crroyalsociety https://doi.org/10.1098/rsbl.2011.0435 2024-08-12T04:27:37Z 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. Article in Journal/Newspaper Arctic midnight sun The Royal Society Arctic Burrows ENVELOPE(163.650,163.650,-74.300,-74.300) Biology Letters 8 1 31 34 |
institution |
Open Polar |
collection |
The Royal Society |
op_collection_id |
crroyalsociety |
language |
English |
description |
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. |
format |
Article in Journal/Newspaper |
author |
Williams, Cory T. Barnes, Brian M. Buck, C. Loren |
spellingShingle |
Williams, Cory T. Barnes, Brian M. Buck, C. Loren Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
author_facet |
Williams, Cory T. Barnes, Brian M. Buck, C. Loren |
author_sort |
Williams, Cory T. |
title |
Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
title_short |
Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
title_full |
Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
title_fullStr |
Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
title_full_unstemmed |
Daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
title_sort |
daily body temperature rhythms persist under the midnight sun but are absent during hibernation in free-living arctic ground squirrels |
publisher |
The Royal Society |
publishDate |
2011 |
url |
http://dx.doi.org/10.1098/rsbl.2011.0435 https://royalsocietypublishing.org/doi/pdf/10.1098/rsbl.2011.0435 https://royalsocietypublishing.org/doi/full-xml/10.1098/rsbl.2011.0435 |
long_lat |
ENVELOPE(163.650,163.650,-74.300,-74.300) |
geographic |
Arctic Burrows |
geographic_facet |
Arctic Burrows |
genre |
Arctic midnight sun |
genre_facet |
Arctic midnight sun |
op_source |
Biology Letters volume 8, issue 1, page 31-34 ISSN 1744-9561 1744-957X |
op_rights |
https://royalsociety.org/journals/ethics-policies/data-sharing-mining/ |
op_doi |
https://doi.org/10.1098/rsbl.2011.0435 |
container_title |
Biology Letters |
container_volume |
8 |
container_issue |
1 |
container_start_page |
31 |
op_container_end_page |
34 |
_version_ |
1809760533157511168 |