Percentage of hours Niche Mapper predicted panting would be required for polar bears to maintain a minimum metabolic rate during different fasting scenarios.

Bears of different body lengths and initial body condition (poor, average, excellent) were modeled with a target metabolic rate of 2.66*mass0.78 W (adapted from [26]) for every hour of the day during the fast. Panting was initiated if Niche Mapper could not reach a heat balance with a metabolic rate of at least 95% of the target metabolic rate.The different fast scenarios are as follows:a120 day fast beginning July 29; 1977–2006 temperatures; no shade available.b180 day fast beginning June 11; 1977–2006 temperatures; no shade available.c180 day fast beginning June 11; +3°C temperatures; no shade available.d180 day fast beginning June 11; 1977–2006 temperatures, shade available.e180 day fast beginning June 11, +3°C temperatures; shade available.