These freaky 'moans' were recorded deep beneath the sea

Mysterious sound
CC BY 2.0 tata_aka_T/Flickr

Scientists say the alien five-part call from the Mariana Trench is similar to the so-called 'Star Wars' sound.

Reaching staggering depths of 36,000 feet and more, the Mariana Trench is the deepest known part of the ocean and holds some of the world’s most intriguing secrets – but even at relatively shallower depths, mysteries prevail. Case in point, a curious audio recording collected by a team of scientists from Oregon State University’s Hatfield Marine Science Center.

Named the “Western Pacific Biotwang,” the sound is unusual for its complexity and wide frequency range. It could potentially be a previously unheard call of a baleen whale, though many questions remain.

“It’s very distinct, with all these crazy parts,” said Sharon Nieukirk, senior faculty research assistant in marine bioacoustics at Oregon State. “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.”

The researchers describe the sound, which lasts between 2.5 and 3.5 seconds, as a five-part call that “includes deep moans at frequencies as low as 38 hertz and a metallic finale that pushes as high as 8,000 hertz.” The Biotwang sounds something like the so-called “Star Wars” sound made by dwarf minke whales on the Great Barrier Reef (you can listen to both sounds in the video below).

Minke whales belong to the baleen whale family and make a variety of calls specific to the regions they live in – along with the Star Wars there are “boings” in the North Pacific and "low-frequency pulse trains" in the Atlantic.

“We don’t really know that much about minke whale distribution at low latitudes,” says Nieukirk, lead author of the study. “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.”

Nieukirk says that like the Star Wars call, the Biotwang has complex structure, frequency sweep and a metallic ending – thus making it logical that it could be coming from a minke whale. But they aren’t sure yet and mysteries ensue. For example, notes a press statement from OSU, “baleen whale calls are often related to mating and heard mainly during the winter, yet the Western Pacific Biotwang was recorded throughout the year.”

“If it’s a mating call, why are we getting it year round? That’s a mystery,” says Nieukirk. “We need to determine how often the call occurs in summer versus winter, and how widely this call is really distributed.”

“Now that we’ve published these data, we hope researchers can identify this call in past and future data, and ultimately we should be able to pin down the source of the sound,” Nieukirk continues. “More data are needed, including genetic, acoustic and visual identification of the source, to confirm the species and gain insight into how this sound is being used. Our hope is to mount an expedition to go out and do acoustic localization, find the animals, get biopsy samples and find out exactly what’s making the sound. It really is an amazing, weird sound, and good science will explain it.”

Tags: Oceans | Whales

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