The new records indicate behavior that is much more varied and extreme than scientists expected for this species, says Simone Baumann-Pickering, a marine mammal biologist at the Scripps Institution of Oceanography in La Jolla, California. One exceptional whale dove to 9,816 feet (2,992 meters), while a second stayed down for 138 minutes.
Scientists and the U.S. Navy are especially interested in these whales because sonar activity has stranded individuals on beaches in the Mediterranean Sea, the Canary Islands, and the Bahamas, says Greg Schorr, a research biologist with the Cascadia Research Collective in Olympia, Washington. (See “U.S. Navy Wins Dispute Over Sonar, Whales.”)
So far, no such strandings have occurred in southern California—the site of a Navy sonar testing area—he adds.
The new study, conducted in that testing area and published today in the journal PLOS ONE, is the first long-term look at the diving behavior of these animals.