Images: Are Whales 'Shouting' to be Heard?
Scientists use a long pole to attach temporary recording devices called “D-tags” to the backs of right whales. The tags record the whales’ calls and the background noise around them, as well as the animals’ movements. (Photo by Doug Nowacek)
Susan Parks (holding a D-tage) analyzed recordings of North Atlantic right whale calls and found that the calls became louder when the level of noise in the whales’ underwater environment grew louder. Parks earned her Ph.D. in 2003 from the MIT/WHOI Joint Program and is now on the faculty at Pennsylvania State University. (Photo by Kelly Slivka, Whale Center New England)
WHOI biologist Peter Tyack, left, and acoustic engineer Mark Johnson developed D-tags, which have provided an invaluable means for scientists to learn about what whales hear, "say," and do.
(Photo by Tom Kleindinst, Woods Hole Oceanographic Institution)
The population of North Atlantic right whales is lower than 400, and a noisier environment, from shipping and other human-made sounds, could affect the whales’ ability to communicate, find mates, and reproduce. Having to call louder could affect the whales in other ways as well. Calling louder takes more energy. It might also distort the meaning of the call—that is, what it sounds like to other whales. (Photo by Doug Nowacek)