A wood frog that survives freezing

The North American wood frog (Lithobates sylvaticus, also called Rana sylvatica) can survive freezing of a large fraction of its body water. Studies report roughly 65–70% of body water as mostly extracellular ice; during deep freezing, heartbeat, circulation, and breathing cease. The frog thaws and resumes physiological functions, but the percentage depends on population, conditions, and experimental protocol. It is not a precise universal threshold or a guarantee of health after any freezing event.