Biology
The Metabolic Costs of Endothermy in Small Mammals: The Shrew Paradox
Quick fact
Some shrews have resting heart rates exceeding 1,000 beats per minute, and they can die of starvation within hours if they cannot find food. This extreme physiology highlights the paradox of endothermy in the smallest mammals: maintaining a constant high body temperature demands a disproportionately huge energy intake.
Why this is interesting
A shrew weighs only a few grams, but it must eat its own body weight in food every single day just to stay alive; what drives this frantic pace, and what does it reveal about the true cost of being warm-blooded?