May the Force free Willy.
“Star Wars” may take place in a galaxy far, far away, but here on Earth, scientists have discovered a species of whale that produces a sound that fans of the acclaimed franchise will find very familiar.
The only problem is that until recently, the scientists didn’t know where the sound was coming from.
The US Navy captured the sounds on tape while using “gliders” to monitor the ocean for cetacean species near the Mariana Islands Range Complex, a military training facility in the North Pacific.
The Navy’s gliders picked up the noises over the course of 37 dives between the fall of 2014 and the spring of 2015. They found that the calls usually came 5 or 6 minutes apart, and could be detected in different parts of the ocean, including in deep and shallow waters.
Researchers christened the sound the “Western Pacific Biotwang” and believe that the noises are coming from a new, still unidentified type of minke whale.
Meet the minke whale
Minkes are a variety of small baleen whale, a category that also includes humpback and blue whales. Baleens are carnivorous cetaceans and are known for their baleen plates, a built-in straining system that allows them to take in small fish and krill while filtering out seawater.
Minkes are also known for their range of regionally-specific calls; minke whales in the North Pacific produce noises that sound like “boings” whereas in the Atlantic, the calls are referred to as “pulse-trains.”
Minkes are one of the more mysterious breeds of whale, owing largely to the fact that they rarely travel up to the ocean’s surface and reside mainly in the high seas, where tracking them is difficult.
Identifying the sound
Scientists have already ruled out anthropogenic sources of noise, such as ships or airguns. They also do not believe that the noise is geophysical, or that it stems from low-frequency noises like wind or rain. Therefore, researchers conclude that the sounds must be biological; they believe the calls are similar in tone to those issued by dwarf minke whales.
In 2001, dwarf minke whale calls were captured on tape near Australia’s Great Barrier Reef. The researchers studying the whales dubbed the noise the “Star Wars” sound, as the call sounds eerily similar to the pulsing hum emitted by light sabers (scientists almost named the sound after Beethoven’s Fifth Symphony, a tribute to the call’s triple beat, followed by one long, held note).
The new research, published recently in The Journal of the Acoustical Society of America, describes the new sounds as “complex” and containing “both harmonics and amplitude modulation, followed by broad-frequency metallic-sounding sweeps up to 7.5 kHZ.”
What does this all mean?
Scientists believe they have enough information to reasonably conclude that a baleen whale produces the mysterious noise, but acknowledge that more research is required.
They’re most interested in understanding why the whales are making these calls; they believe that the sound might be a mating call, but baleen whales issue mating calls only in the winter and they’ve detected the Western Pacific Biotwang in other seasons.
Sharon Nieukirk — a bioacoustics research assistant at Oregon State University who worked on the study — is optimistic that her team will be able to definitively identify the strange noise: “Ultimately we should be able to pin down the source of the sound,” she says. “It really is an amazing, weird sound, and good science will explain it.”
Scientists, may the force be with you.