Wood frogs can survive with most of their body water frozen.
Why this sounds fake
A frozen vertebrate sounds dead because ice, no heartbeat, and no breathing usually mean irreversible damage.
For most vertebrates, freezing is catastrophic because ice damages tissues and pulls water out of cells. Wood frogs avoid that usual ending. During winter freezing, much of their body water can turn into extracellular ice while protective glucose and urea help keep cells from collapsing. Their heartbeat and breathing can stop during the frozen state, then return after thawing. This is not cartoon immortality, and the cells are not full of sharp internal ice. The surprise is more disciplined: a vertebrate can temporarily pause visible signs of life and restart because its chemistry controls where freezing happens.
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