Underwater Caller I.D. A computer program can determine which whale is clicking away. Humpback whales sing underwater.
Gray whales grunt while rooting about on the sea floor.
It's very regular. It's almost like a clock ticking. By recording these clicks and running them through a computer program, Dougherty can identify the individual whales that produced them. During a 1997-98 study, he spent time on a boat off the north coast of Norway, recording sperm whale clicks. We used random sets of 50 clicks for training and testing the program.