In the rain and snow, a hush seems to fall over the neighborhoods. The leaves aren’t there to rustle in the breezes, and the stray cats and little squirrels hide away. The people, too, are huddled in their dens, curled up in some quiet corner.
There’s one particular critter who hides especially well: the spring peeper. These frogs are native to Missouri, and they’re strange creatures. They snuggle into winter shelters of leaf piles, logs, and tree trunks, and won’t make a sound all winter. Along with a handful of other frog species, the spring peeper survives winter by going completely dormant–and even freezing through.
During their frozen slumber, the spring peeper is saved only by glycogen, a natural sugar in the frogs’ blood that acts as an antifreeze. This is just enough to keep ice crystals from forming in their vital organs. Its breath and heart have slowed to an almost undetectable rate, and the energy needed to keep these systems running at all comes from the same sugar. It ferments in their bodies and provides just enough energy to keep them alive.
The spring peeper runs out of glycogen stores right around the time that the first hint of warmth creeps into the air. So in the last days of winter, the spring peeper will miraculously thaw and awaken like the pet project of some mad scientist. This is where it gets its name: in that season of uncertainty, halfway between winter and spring, it emerges from its slumber and utters its call—a sequence of short peeps. The call of the spring peeper is said to be a sure sign that winter is relinquishing its bitter grip, and spring is on the way.
In the meantime, they sleep alongside the warmblooded hibernators in their shelters, waiting. And we wonder at a tiny frog who, for all our strength and smarts and stamina, would outlast us on a cold winter night.