Here is an excellent radio piece to capture your imagination. A man in the Navy listening for subs caught a frequency he didn't recognize. A marine biologist identified it as a whale, but the sound was all wrong. No other whale made that sound, which meant that, when he called out, no other whales responded. Ever. Year after year. The story has captured the minds of poets, scientists, a filmmaker, and plenty of everyday people. This link here also offers the back story behind the piece. Namely, how do you make a radio story about a whale who sings at a frequency too low for most radios to play? Enjoy.