Monday, June 1, 2009

The Animal Communication Project: FROG CALLS

Ever wonder what all the croaking is about when you hear Frogs communicating? You knew those "ribbits" had a story to tell. Here it is:

From the Animal Communication Project...

The concave-eared torrent frog (Amolops tormotus) produces and responds to ultrasonic calls.

   "As dusk falls over a swampy pond, the chorus begins. First one frog croaks, a little hesitantly. Soon another joins in. Suddenly the pond resonates with the voices of dozens of male frogs, each signaling his species, availability and qualifications as a father.

Two populations of the same species, separated geographically—a highway running through a swamp, for example—develop dialects, slight differences in their calls. In most species, only males call, though the female midwife toad out shouts her mate. A sudden foreign sound silences them one and all. But soon a single voice starts again, followed by another and another.

The sound of a pond full of frogs can reach deafening levels, far out of proportion to the tiny bodies producing the sound. An air sac on the floor of the frog’s mouth enables it to do two remarkable things. First, when it’s expanded, the sac acts as a resonator, like the hollow body of a violin. Second, by forcing air into the sac from the lungs, then back into the lungs, a frog can croak continuously, even under water. The loudest frogs breed in temporary ponds. When the water’s available, the males muster mates quickly, for all frogs lay eggs only in water, and the tadpoles must grow legs before the temporary ponds dry up.

Click here for the rest of the story.

Photo © 2006 Albert S. Feng

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