Hibernation in the Extreme: Burrow and Body Temperatures, Metabolism, and Limits to Torpor Bout Length in Arctic Ground Squirrels

摘要: Arctic ground squirrels overwinter in hibernacula with average temperatures of -8°C and minimum to -26°C, conditions that are extremely cold compared those reported for other hibernators. During torpor, metabolic rate arctic rises proportionally decreases ambient temperature (Ta) below 0°C while core body (Tb) remains constant. At Ta > 0°C, minimal relatively constant Tb increases 12°C, implying temperature-independent inhibition metabolism. Maximum torpor bout length is greatest at near shortens as either decreased or increased, giving support both rate- temperature-linked hypotheses what constrains duration mammals. Brain temperature, if it may ultimately influence squirrels.