As if the deepest known part of the Earth’s ocean wasn’t already spooky enough, some mysterious sounds that fall somewhere in between a half-muted rawr and bad dubstep have been coming from the Mariana Trench and leaving scientists stumped.
But after months of speculation, a team of researchers at Oregon State believe they’ve finally discovered the source of the noises—a new type of baleen whale call that no one has ever heard before.
“It’s very distinct, with all these crazy parts,” Sharon Nieukirk, lead author on the study, said in a blog post on the university’s site. “The low-frequency moaning part is typical of baleen whales, and it’s that kind of twangy sound that makes it really unique. We don’t find many new baleen whale calls.”
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The sounds were recorded with passive acoustic ocean gliders, which are instruments that can travel autonomously for months at a time and dive up to 1,000 meters. The five-part call, now nicknamed the “Western Pacific Biotwang,” includes deep moans at frequencies as low as 38 hertz and a metallic finale that pushes as high as 8,000 hertz. Here’s a clip:
Researchers say the sounds most closely resemble those produced by dwarf minke whales on the Great Barrier Reef off the northeast coast of Australia, which are often referred to as the “Star Wars call.”
“We don’t really know that much about minke whale distribution at low latitudes,” Nieukirk said. “The species is the smallest of the baleen whales, doesn’t spend much time at the surface, has an inconspicuous blow, and often lives in areas where high seas make sighting difficult. But they call frequently, making them good candidates for acoustic studies.”
She says there are enough similarities that it could be coming from the minke whale, but many questions remain. For example, baleen whale calls are often related to mating and heard mainly during the winter, but these sounds were recorded during various parts of the year.
Read more about the study in the The Journal of the Acoustical Society of America.
