As cold-blooded creatures, wood frogs were susceptible to frigid temperatures and could freeze completely solid, to the point that their hearts stopped completely. And yet, the frog has evolved in such a way that glycogen continues to break down into glucose, which acts a bit like nature’s antifreeze. They can remain frozen and immobilized for weeks, but when the weather finally begins to warm, the wood frog blinks and its heart starts back up; there’s a quick breath, and the frog hops away in search of its mate, as if God had merely hit the pause button.
