Calling may be winding down in many parts of the state, but hearing the sleigh bell-like sound of hundreds of these wetland-loving frogs is a sure sign that spring has sprung. The spring peeper (pseudacris crucifer) is easy to identify with an “x” on its back, and their color ranges from dark to light brown. Being only about an inch in size, it’s amazing their chorus can carry for a quarter of a mile. That is why finding a peeper at night with a flashlight is not an easy challenge, even when nearby and peeping quite loudly.
Why do peepers peep? Each male is calling for females and defending its tiny territory. The familiar single but repeated peep is his announcement to the females. If a male territory is invaded by a rival male, he will make a short, trilling, aggressive call. To make their calls, peepers close their nostrils and mouths and squeeze their lungs, which causes the vocal sac (see photo) in the throat to inflate like a balloon. The peeping sound happens as air leaves the lungs, passes over the vocal cords and into the vocal sac.
Peepers can survive being frozen! As temperatures dip below 32 degrees, these frogs start producing their own “antifreeze” to help preserve the most essential organs. Up to 70% of the frog’s body can freeze and the heart stops pumping. Scientists still aren’t sure how frozen frogs can wake up again.
