This post was written by Mollie Flanigan, GMC’s Land Stewardship Coordinator.
One of the things I look forward to and enjoy about spring is the chorus of the spring peepers. Spring peepers are Vermont’s smallest type of frog and they live around marsh wetlands throughout the state. They are best known for their call – the male frog makes a short, ascending whistle or a series of ascending peeps that are quite loud and extend throughout the spring season. They start about mid-March and extend through July, but they peak right around the beginning of May.
The way spring peepers get through our winter to be able to sing in the spring is fascinating. Along with four other types of frogs (wood frogs, Cope’s gray tree frogs, eastern gray tree frogs, and western chorus frogs), spring peepers enter a frozen state to survive the winter.
As temperatures drop and ice crystals start to form on the frog’s skin, its liver produces glucose, a kind of antifreeze circulated in its blood that prevents its cells from freezing and its tissues from dehydrating. As freezing continues, ice crystals form between the cells of the frog, but not within them. Eventually, the frog stops breathing, and its heart slows to a stop. The frog remains in this frozen state for the entire winter, even through occasional freeze-thaw cycles.
Once spring returns and the temperature climbs, the frog thaws, and its heart starts beating again. There are many things about this process that science has yet to discover, including what signals the heart to start beating again!
The chorus of the spring peepers is one of those things you can enjoy during mud season, listening on your morning walk or even just lying in bed.