Abstract
Arctic ground squirrels overwinter in hibernacula with average temperatures of -8°C and minimum temperatures to -26°C, conditions that are extremely cold compared to those reported for other hibernators. During torpor, metabolic rate of arctic ground squirrels rises proportionally with decreases in ambient temperature (Ta) below 0°C while core body temperature (Tb) remains constant. At Ta > 0°C, metabolic rate remains minimal and relatively constant while Tb increases to > 12°C, implying temperature-independent inhibition of metabolism. Maximum torpor bout length is greatest at Ta near 0°C and shortens as Ta is either decreased or increased, giving support to both metabolic rate- and body temperature-linked hypotheses of what constrains torpor duration in mammals. Brain temperature, if it increases as Ta decreases below 0°C, may ultimately influence torpor duration in arctic ground squirrels.
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Barnes, B.M., Buck, C.L. (2000). Hibernation in the Extreme: Burrow and Body Temperatures, Metabolism, and Limits to Torpor Bout Length in Arctic Ground Squirrels. In: Heldmaier, G., Klingenspor, M. (eds) Life in the Cold. Springer, Berlin, Heidelberg. https://doi.org/10.1007/978-3-662-04162-8_7
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DOI: https://doi.org/10.1007/978-3-662-04162-8_7
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