The Alaska wood frog (Rana sylvatica) has an extraordinary ability to survive the winter: it can freeze a large part of its body and then fully thaw in spring. Falling temperatures trigger a massive production of glucose, which acts as a natural antifreeze and reduces the formation of harmful ice crystals inside cells. During the freezing period, up to about 65 % of its body water can solidify. At this time, breathing, heartbeat, blood circulation and brain activity cease, and metabolism comes n