Hibernation and seasonal fasting in bears: the energetic costs and consequences for polar bears
TL;DR
Bears lose 15-30% of pre-hibernation body mass during hibernation
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This paper quantified the energetic costs of bear hibernation and the fitness consequences of different reserve levels. The finding that bears lose 15-30% of pre-hibernation body mass provides the empirical basis for reserve calculations. The emergence energy surge calculation (15-20% additional) comes from analyzing this data.
Key Findings from Robbins et al. (2012)
- Bears lose 15-30% of pre-hibernation body mass during hibernation
- Hyperphagia involves consuming up to 20,000 calories daily (10x normal)
- Minimum entry weight thresholds determine survival probability
- Emergence requires significant additional energy beyond dormancy burn
- Bears gain 3-4 pounds per day during hyperphagia
- Total weight gain of 150-200 pounds over 8-10 weeks
- 15-25% of consumed calories lost as heat during fat synthesis
- Hibernation requires approximately 525,000 calories of stored fat
Used in 2 chapters
See how this research informs the book's frameworks:
Quantified energetic costs of bear hibernation - 15-30% mass loss plus 15-20% emergence surge provides empirical basis for reserve calculations.
See energetic requirements →Quantifies fat accumulation rates during hyperphagia and consumption rates during dormancy - 150-200 pound weight gain over 8-10 weeks.
See storage economics →