How can a wood frog survive freezing?
A seasonal survival strategy allows parts of a small amphibian’s body to freeze without fatal damage.
Winter brings an extraordinary pause
Wood frogs live in northern forests where winter temperatures drop well below freezing. During the coldest periods, ice can form in spaces outside many of their cells, and normal activities such as breathing and heartbeat may become temporarily undetectable. When warmer weather returns, the frogs can thaw and resume normal activity.
Protecting the inside of cells
Ice crystals forming inside a living cell can damage its membranes and internal structures. Wood frogs reduce this danger by accumulating protective substances, including glucose and urea, that help limit dehydration and injury. Freezing is controlled rather than harmless: how fast a frog cools and how cold it becomes still matter.
A specialised adaptation, not a superpower
The wood frog is adapted to seasonal conditions in its particular habitat. Its survival does not mean that all frogs can be placed in a freezer and revived. Scientists study this ability because it illustrates how animals manage water, temperature and cellular stress. The broader lesson is that surviving extreme environments often depends on biochemical preparation long before the extreme arrives.
External references are provided for exploration; Curio Hour’s explanation is written separately.