The Double Double Life of Amphibians

By The Old Farmer's Almanac
Sep 21, 2017
Spring peeper HGW frogs

Spring Peeper

Jessica Crabtree


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Every year, the wood frog comes back from the dead. Not in the sense that it appears again after a long absence. In the most literal one: an inanimate, mostly frozen object, which has ceased to function, is suddenly resuscitated into being.

How does a wood frog make it through a frigid northern winter? No fur like the bear, no feathers like the owl, no warm blood of the squirrel, cozy in its nest. No burrow deep in the mud, where the box turtle’s pulse slows to one beat every few minutes. And no shivering like the man on his spring log, listening to the wood frogs wake up. The frogs haven’t shivered all winter: their defense against the cold is having no defenses.

Wood Frogs In Amplexus
Photo by Priya Nanjappa, USGS

Wood frogs (Lithobates sylvaticus) are native to much of the northeastern U.S. and most of Canada, west to Alaska. They endure sub-zero temperatures by going sub-zero themselves, shutting down almost all bodily functions. More than half of the frog’s blood and other liquids may turn to solid ice for weeks at a time. The frog’s urea acts as a kind of antifreeze to prevent permanent damage to body structures. By raising levels of glucose more than a hundredfold, individual cells keep themselves from breaking down internally, each one a kind of pilot light within a cold stove.

Wood Frog Embryos
Photo by Mark Roth, USGS

As the weather warms, the stove warms, too. Just a couple weeks after the thawing of the ponds, the edges get loud with a chorus of newly awakened voices. The sound of many wood frogs singing at once is like small-town gossip passed through a synthesizer: all the tones of articulate expression are there, but without the words. Thoreau called the wood frog “the very voice of the weather”:

The weather, what is it but the temperament of the earth? and he is wholly of the earth, sensitive as its skin in which he lives and of which he is a part.
(March 24, 1859)

Spring peepers (Pseudacris crucifer) are the other frogs to declare the end of the winter. By contrast to the wood frog’s, a peeper’s voice is a shrill, piercing alarm clock that you can’t send back to sleep. Males can produce a clear note of well over 100 decibels—at close range, not too different in sound or intensity from a fire alarm going off in your kitchen. Multiply this by the hundreds or even thousands of individuals calling in a single marsh, and lo and behold, your woods have become about as soothing as the inside of a jet engine. The air is shredded. It breaks on all sides with the force of a riled-up ocean wave.

Spring Peeper
Photo by Chris Brown, USGS

Confronted with such a sound, we can keep our distance, or put our hands over our ears. But how does a peeper, right in the thick of it, avoid blowing out its eardrum? The tympanum, the membrane that transmits sound to the frog’s inner ear, is thin enough to rupture, but it’s actually anchored by tissue to the animal’s lungs. Scientists have suggested that the deafening vibrations of the marsh are diffused throughout the frog’s body, the way a building funnels the force of a strong wind into its foundations. At 3.5 grams, a frog is fragile architecture, but it holds up. Its whole body is quaking. The air inside its lungs is already turbulent, even before it gets pumped out into sound. Each frog’s call is ashiver with the riot of his neighbor’s.  

The term “frog chorus” has ancient, literal origins. The playwright Aristophanes won first prize at the festival of Dionysus, four hundred and five years before the birth of Christ, for his Frogs, a comedy in which Dionysus himself appears on stage. The god is trying to make his way across Lake Acheron to pay a visit to the Underworld. His purpose is to bring back from the dead the playwright Euripides, who, as the best of the tragic playwrights, will bring glory to him, patron god of the theater. As Dionysus goes, he is mocked by a raucous army of frogs, which sing:


Spring Peeper Tadpole
Photo by Jeromi Hefner, USGS

Who knows something about death? Who knows how to come back and tell us about it? Who knows how to fill their lungs with the temperament of the earth and express it? Stop rowing—look no further. After just a few verses, Dionysus finds himself singing along:


Spring Peeper In Song
Photo by Brian M. Glorioso, USGS

About This Blog

Field Notes From the Woods, written by Henry Walters, shares observations and ruminations on plants, wildlife, weather, and other facets of nature. Henry Walters is a naturalist, a teacher, and a falconer. He lives and writes in a cabin in southern New Hampshire on a 1,700-acre tract of conservation land, of which he acts as steward. His poems, essays, and translations have appeared or are forthcoming in a number of print publications, including The Old Farmer’s Almanac.

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I find the songs of the woodfrogs and spring peepers most beautiful. They sing spring awake,they sing a different song to celebrate rain and yet another chorus to warn of intruders,and it gets more intense if they are predators.

I live in upstste NY and we

I live in upstste NY and we hear the spring peepers every year, especially near the woods and ponds. I love their sound. Spring is finally here and the sounds of nature are back.

I totally enjoy everything

I totally enjoy everything about The Farmers Almanac!

I live in n.w. Wisconsin and

I live in n.w. Wisconsin and this is one of my favorite sounds of the spring. They are all around us, we call them the spring peepers. We know the season has officially arrived and they sing me to sleep at night. I know some people think they are just noisy, but to me, it's a symphony.

What about the bright lime

What about the bright lime green frogs we have in the south? Would like to know more about them, also?

You're likely thinking of the

You're likely thinking of the Green Treefrog (Hyla cinerea), which ranges in color, but can be a striking lime-green. They often hang out near porch-lights, hunting insects that are attracted to the light. I love this frog's voice--it reminds me of an old-fashioned bicycle horn. The most amazing thing is the frog's habitat--as you might expect from the name, it spends most of its life in trees. One of our coolest frogs, without a doubt.


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