Today’s frog is a very cool customer, the only frogs found north of the Arctic Circle. Wood Frog is the common name of Lithobates sylvaticus, the amphibian formerly known as Rana sylvatica. In winter, as much as 35-45% of their bodies can freeze. Ice crystals form beneath the skin and interspersed among the body’s skeletal muscles. The frog’s breathing, blood flow, and heart beat cease when they freeze. Special proteins prevent intracellular freezing and dehydration. Now is that cool, or what?