|Green Frog - inflated with air and ready to call|
When a Green Frog calls it produces a series of single notes that sound like someone plucking the same string of an out-of-tune guitar over and over again - "plunk plunk plunk". In the photo below you can see that the frog has inflated his vocal sacs and is calling. If you look closely, you can actually see the sound wave traveling across the surface of the water. Look along the frog's side and in the dark water at the bottom right of the photo for a series of concentric lines traveling away from the frog.
|Calling Green Frog - note the sound waves on the water's surface|
Nature is pretty awesome!