Wood frogs freeze their bodies. Nikola SolicTo survive the winter, up to 60 percent of Alaskan wood frogs' bodies freeze solid. This allows them to survive temperatures as low as -80 degrees Fahrenheit. To achieve this semi-frozen state, the frogs build up high concentrations of glucose (up to 10 times the normal amount) in their organs and tissues. The sugar solutes act as "cryoprotectants," preventing their cells from shrinking or dying.

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