From flying squirrels to grizzly bears, and from torpid turtles to insects with antifreeze, the animal kingdom relies on some staggering evolutionary innovations to survive winter. Unlike their human counterparts, who must alter the environment to accommodate physical limitations, animals are adaptable to an amazing range of conditions. Examining everything from food sources in the extremely barren winter land-scape to the chemical composition that allows certain creatures to survive, Heinrich's Winter World awakens the largely undiscovered mysteries by which nature sustains herself through winter's harsh, cruel exigencies.