Gedamke discovered the sound while on the research vessel Undersea Explorer at the Great Barrier Reef. He was on the boat to study a population of dwarf minke whales known for their remarkable curiosity.
The boat conducts dwarf minke whale research in addition to a "swim with whales" program for tourists. The whales call the reef home from May to September. They fearlessly approach and circle boatsand snorkelersfor hours on end.
"Snorkeling off the back of the Undersea Explorer is often like being in a fishbowl with up to 20 or more whales. Here, there, left, right, in front, in back, below. Everywhere you look sometimes you can see whales," Gedamke said.
To identify the source of the Stars Wars sound, Gedamke set out a series of underwater microphones, or hydrophones, on the reef to record the sounds.
At the same time, Gedamke spoke into a microphone to record the location of the whales he saw from the deck of the boat.
Back in the lab, he analyzed the recordings. Sound travels outward from where it is produced, so when a whale made a sound, it would arrive at the closest hydrophone first, then at the others, depending on their locations.
By carefully measuring when the sound arrived at each hydrophone, Gedamke was able to pinpoint where the noise originated. He then compared the location of the noise to his the locations of the whales he had observed from the deck of the boat.
"Often the acoustic location I calculated and the visual location I described matched. When they did a number of times, I could confidently say that the dwarf minke whale was the source of this very unusual sound," he said.
Gedamke speculated in 2001 that the dwarf minke whales make the noise as part of their mating behavior. "I still believe it's related to mating and have been able to find further support for this based on the work that followed," he said.
Mellinger said Gedamke's association of the dwarf minke whales with the Star Wars sound is allowing researchers to find the whales in the wild and conduct more intensive studies. For example, Mellinger said, researchers are learning about the whales' habitat use, movements, and population sizeall of which are important to know if the whales are to be protected.
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