SANTA CRUZ, CA--When Jason Gedamke and Daniel Costa first went to Australia to record the sounds of dwarf minke whales, people told them they were wasting their time. There were very few reports of minke whale vocalizations, and some experts believed the species rarely made any sounds at all. But according to Gedamke, a graduate student at the University of California, Santa Cruz, not only are minke whales vocal, their repertoire includes a loud and distinctive songlike sequence unlike any previously recorded whale sound.
"It's surprisingly loud and complex, and sounds like it's produced mechanically or synthetically," Gedamke said. "When I first heard it, I couldn't believe it came from a whale."
Neither could some whale experts he sent the recording to later, who suggested he check with the Australian Navy to find out if the noise was coming from their equipment. It turned out that Australian researchers had been hearing it for years and called it the "guitarfish" or "boingfish" sound, but had no idea what its source was. Gedamke calls it the "star-wars" vocalization; his logbook entry after first hearing the sound, which resembles a laser-gun sound effect, was simply "Star Wars!!??"
Gedamke and Costa, a professor of ecology and evolutionary biology at UC Santa Cruz, worked with Andy Dunstan, a scientist on the research and ecotourism vessel Undersea Explorer. They went to great lengths to demonstrate conclusively that the sound is made by dwarf minke whales. The researchers reported their findings in the June issue of the Journal of the Acoustic Society of America.
Their work was made easier by a remarkable population of dwarf minke whales that congregates from May to September on the northern part of Australia's Great Barrier Reef. These whales are unusually curious; when the Undersea Explorer stopped near them, they would approach to within a few yards and circle the boat and snorkeling observers for hours on end.