Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears
BACKGROUND: Despite centuries of research, debate remains on the scaling of metabolic rate to mass especially for intraspecific cases. The high variation of body mass within brown bears presents a unique opportunity to study the intraspecific effects of body mass on physiological variables. The ampl...
Published in: | Frontiers in Zoology |
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BioMed Central
2023
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Online Access: | http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10433566/ http://www.ncbi.nlm.nih.gov/pubmed/37587452 https://doi.org/10.1186/s12983-023-00501-3 |
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Research Evans, Alina L. Fuchs, Boris Singh, Navinder J. Thiel, Alexandra Giroud, Sylvain Blanc, Stephane Laske, Timothy G. Frobert, Ole Friebe, Andrea Swenson, Jon E. Arnemo, Jon M. Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
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Research |
description |
BACKGROUND: Despite centuries of research, debate remains on the scaling of metabolic rate to mass especially for intraspecific cases. The high variation of body mass within brown bears presents a unique opportunity to study the intraspecific effects of body mass on physiological variables. The amplitude of metabolic rate reduction in hibernators is dependent on body mass of the species. Small hibernators have high metabolic rates when euthermic but experience a drastic decrease in body temperature during torpor, which is necessary to reach a very low metabolic rate. Conversely, large hibernators, such as the brown bear (Ursus arctos), show a moderate decrease in temperature during hibernation, thought to be related to the bear’s large size. We studied body mass, abdominal body temperature, heart rate, and accelerometer-derived activity from 63 free-ranging brown bears (1–15 years old, 15–233 kg). We tested for relationships between body mass and body temperature, heart rate, and hibernation duration. RESULTS: The smallest individuals maintained lower body temperatures during hibernation, hibernated longer, and ended hibernation later than large bears. Unlike body temperature, winter heart rates were not associated with body mass. In summer, the opposite pattern was found, with smaller individuals having higher body temperature and daytime heart rates. Body mass was associated with body temperature in the winter hypometabolic state, even in a large hibernating mammal. Smaller bears, which are known to have higher thermal conductance, reached lower body temperatures during hibernation. During summer, smaller bears had higher body temperatures and daytime heart rates, a phenomenon not previously documented within a single mammalian species. CONCLUSION: We conclude that the smallest bears hibernated more deeply and longer than large bears, likely from a combined effect of basic thermodynamics, the higher need for energy savings, and a lower cost of warming up a smaller body. SUPPLEMENTARY INFORMATION: The online ... |
format |
Text |
author |
Evans, Alina L. Fuchs, Boris Singh, Navinder J. Thiel, Alexandra Giroud, Sylvain Blanc, Stephane Laske, Timothy G. Frobert, Ole Friebe, Andrea Swenson, Jon E. Arnemo, Jon M. |
author_facet |
Evans, Alina L. Fuchs, Boris Singh, Navinder J. Thiel, Alexandra Giroud, Sylvain Blanc, Stephane Laske, Timothy G. Frobert, Ole Friebe, Andrea Swenson, Jon E. Arnemo, Jon M. |
author_sort |
Evans, Alina L. |
title |
Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
title_short |
Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
title_full |
Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
title_fullStr |
Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
title_full_unstemmed |
Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
title_sort |
body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears |
publisher |
BioMed Central |
publishDate |
2023 |
url |
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10433566/ http://www.ncbi.nlm.nih.gov/pubmed/37587452 https://doi.org/10.1186/s12983-023-00501-3 |
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Ursus arctos |
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Ursus arctos |
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Front Zool |
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http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10433566/ http://www.ncbi.nlm.nih.gov/pubmed/37587452 http://dx.doi.org/10.1186/s12983-023-00501-3 |
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© BioMed Central Ltd., part of Springer Nature 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data. |
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https://doi.org/10.1186/s12983-023-00501-3 |
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Frontiers in Zoology |
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20 |
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1 |
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1776204469482029056 |
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ftpubmed:oai:pubmedcentral.nih.gov:10433566 2023-09-05T13:23:55+02:00 Body mass is associated with hibernation length, body temperature, and heart rate in free-ranging brown bears Evans, Alina L. Fuchs, Boris Singh, Navinder J. Thiel, Alexandra Giroud, Sylvain Blanc, Stephane Laske, Timothy G. Frobert, Ole Friebe, Andrea Swenson, Jon E. Arnemo, Jon M. 2023-08-17 http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10433566/ http://www.ncbi.nlm.nih.gov/pubmed/37587452 https://doi.org/10.1186/s12983-023-00501-3 en eng BioMed Central http://www.ncbi.nlm.nih.gov/pmc/articles/PMC10433566/ http://www.ncbi.nlm.nih.gov/pubmed/37587452 http://dx.doi.org/10.1186/s12983-023-00501-3 © BioMed Central Ltd., part of Springer Nature 2023 https://creativecommons.org/licenses/by/4.0/Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) . The Creative Commons Public Domain Dedication waiver (http://creativecommons.org/publicdomain/zero/1.0/ (https://creativecommons.org/publicdomain/zero/1.0/) ) applies to the data made available in this article, unless otherwise stated in a credit line to the data. Front Zool Research Text 2023 ftpubmed https://doi.org/10.1186/s12983-023-00501-3 2023-08-20T01:12:32Z BACKGROUND: Despite centuries of research, debate remains on the scaling of metabolic rate to mass especially for intraspecific cases. The high variation of body mass within brown bears presents a unique opportunity to study the intraspecific effects of body mass on physiological variables. The amplitude of metabolic rate reduction in hibernators is dependent on body mass of the species. Small hibernators have high metabolic rates when euthermic but experience a drastic decrease in body temperature during torpor, which is necessary to reach a very low metabolic rate. Conversely, large hibernators, such as the brown bear (Ursus arctos), show a moderate decrease in temperature during hibernation, thought to be related to the bear’s large size. We studied body mass, abdominal body temperature, heart rate, and accelerometer-derived activity from 63 free-ranging brown bears (1–15 years old, 15–233 kg). We tested for relationships between body mass and body temperature, heart rate, and hibernation duration. RESULTS: The smallest individuals maintained lower body temperatures during hibernation, hibernated longer, and ended hibernation later than large bears. Unlike body temperature, winter heart rates were not associated with body mass. In summer, the opposite pattern was found, with smaller individuals having higher body temperature and daytime heart rates. Body mass was associated with body temperature in the winter hypometabolic state, even in a large hibernating mammal. Smaller bears, which are known to have higher thermal conductance, reached lower body temperatures during hibernation. During summer, smaller bears had higher body temperatures and daytime heart rates, a phenomenon not previously documented within a single mammalian species. CONCLUSION: We conclude that the smallest bears hibernated more deeply and longer than large bears, likely from a combined effect of basic thermodynamics, the higher need for energy savings, and a lower cost of warming up a smaller body. SUPPLEMENTARY INFORMATION: The online ... Text Ursus arctos PubMed Central (PMC) Frontiers in Zoology 20 1 |