Figure 39.6 Frozen Frogs Wood frogs (Rana sylvatica) live in the northeastern United States, across most of Canada, and up into northern Alaska. They freeze solid in the winter and survive. During the fall and early winter, urea and glucose accumulate in the frogs’ cells and act as intracellular cryoprotectants (like antifreeze in your car radiator). Also, much intracellular water is redistributed to the extracellular fluid, which can freeze without damaging cells.