The spring peeper

StoryImage( ‘/Images/Story//Auto-img-11763118633751.jpg’, ”, ‘The spring peeper – Pseudacris crucifer, shown here at nearly twice its actual size, is readily identified by the “X” that marks its back. It is found throughout the eastern United States and southeastern Canada.‘);
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This little frog has been making itself heard since the beginning of March.

Rarely more than an inch long, the spring peeper produces one of the loudest voices you’ll hear each spring, much earlier than most other frogs, toads or crickets. The high peeping and twilling of this nocturnal frog can be heard on mild evenings, even while patches of snow remain on the ground. As the season warms, more and more peepers join the chorus, until their calls blend into a cacophony sounding oddly like waves of jingling glass bells.

Spring peepers can also be heard during the daytime when the skies are heavily overcast or when it is raining. By late summer, they’ve stopped calling, and the night is overtaken by sounds of crickets and other insects. Then, as the chill of fall sets in, these frogs again begin to sing.

They’re most common in woody areas around wetlands and ponds, but they may also be heard in urban areas if a source of water is not too far away. Even small temporary spring pools are enough to sustain a population of these frogs. Chances are, however, that you’ll never actually see any spring peepers. They’re too small and too well camouflaged in the shrubs and trees where they spend most of their time.

The peeper’s early spring emergence comes from a special winter strategy employed by various species of frogs: they can survive freezing. Freeze-tolerant frogs have adapted to winter by saturating their organs with sugar-rich blood when temperatures drop. The sugars act as antifreeze. As the water in their hollow body cavities freezes, the sugary solution in their cells remains a slushy liquid. Their hearts stop beating, their lungs quit, and vital functions cease. Even after their bodies have chilled to sub-freezing, these frogs can come back to life as soon as they’re warmed.

After spending winter in shallow piles of leaf litter or under bark, they’re among the first hibernators to receive the benefit of warm, thawing sunlight.

The males do the calling, and, in the spring, the purpose of peeping is to attract females. After mating, females locate the nearest water source and deposit up to 1,000 eggs. The young tadpoles feed on microbes and plant matter, selecting larger prey such as insect larvae as they grow. They mature into adults by mid-summer, but it may take as long as three years before they’re ready to breed.

from the April 11-17, 2007, issue

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