When you are ready to hear a frog call click on "I'm Listening" - you will hear a frog call.
Click on the name of the frog you think is calling. If you are not sure, click on "clue" to get a hint.
If you're right, click on "I'm listening" again, to hear the next frog call.
All frog calls from CARCN Internet site, courtesy of Dr. David Green.