The American bullfrog spends winter months, or even intermittent cold spells, in a state called torpor. The bullfrog becomes sluggish and inactive but its body functions do not slow to the same point as hibernating animals achieve.
Some frogs live high on mountain slopes or in the frigid north.
During winter, a frog’s body temperature falls and its metabolism drops. Its heart may even stop beating!
Many frogs dig into mud or deep holes to escape killing frost, but some practice controlled freezing. They produce excess sugars or starches to prevent damage to sensitive tissues while the remaining water in their bodies turns to ice.
The North American wood frog, with a range extending far into the Alaskan tundra, can survive with 65% of the water in its body frozen!
