Woo Frog is the common name given to Rana sylvatica. The Wood Frog has a broad North American distribution, extending from the Southern Appalachians to Boreal forests. As for other northern frogs hibernating close to the surface in soil and/or leaf litter, wood frogs are resistant to freezing. Liver glycogen is converted in large quantities to glucose, in response to ice formation in their tissues. Glucose acts as an antifreeze, inhibiting ice formation in and rupture of cells. If ice formation is confined to extracellular fluids, they can survive the winter.