Unusually close encounters with dwarf minke whales have allowed marine biologists for the first time to record sounds produced by this elusive animal--including one noise unlike that made by any other whale. The eavesdropping is already helping researchers study the animals' movements and behavior.
Biologists have recently learned that orcas jabber in local dialects, and humpbacks sing long complex songs that change through time (ScienceNOW, 29 November 2000). But the vocalizations of the less known minke whales have remained enigmatic. Only one type of sound had ever been definitely attributed to a minke, and the dwarf minke of Australia's Great Barrier Reef was virtually unknown. Then, in 1996, an Australian ecotourist company informed University of California, Santa Cruz, marine biologist Daniel Costa that a group of dwarf minkes regularly congregates around its boat, the Undersea Explorer, coming within meters of snorkelers. Costa and his graduate student Jason Gedamke wasted no time heading down under.
As they recorded the whales with a hydrophone at point-blank range, Gedamke sometimes heard a bizarre sound. "I was just stunned," he says. The sound is completely distinct from other whale calls, says Gedamke, who describes it as mechanical, "like beating on an oil drum," kind of a "bub-bub-BOING!" The sound is complex and regularly repeated, like a song. Gedamke, Costa, and the boat company's scientist, Andy Dunstan, published their findings in the June issue of the Journal of the Acoustical Society of America. Now that Gedamke has catalogued this sound and many other noises from the minke whale group, he can acoustically track distant whales at sea. How the minkes produce their sounds is unknown, however, as is their meaning.
The study "opens up a whole new area of interest and possibilities," says whale researcher Christopher Clark of Cornell University in Ithaca, New York. Researchers can now "look through the keyhole at the life of this animal and see how sound functions in its lifestyle," Clark says. The study also refutes claims by Norwegian and Japanese whale hunters that hunting is necessary for scientific reasons, Clark argues: "This research shows that you can study these animals better alive than dead."
Jason Gedamke's Web page, with whale sounds and pictures
Info on minke whales and ecotourist/research trips aimed at studying them, from Undersea Explorer
More sound files
Chris Clark's whale communication research at Cornell