The Mariana Trench, a massive rift stretching from Japan to Australia, contains the deepest sections of the world’s oceans. Despite decades of research and even manned missions to the bottom of the trench, researchers are still discovering new species every year but still have barely scratched the surface. Now, scientists think a mysterious sound coming from the trench in the last few years is a previously unknown call from a dwarf minke whale.
An acoustic monitor at the Trench recorded an unknown five-part call coming from the ocean depths, according to a press release. The sound typically lasts between 2.5 and 3.5 seconds swinging between deep 38-hertz moans and 8,000- hertz squeals. Researchers have dubbed the unidentified sound the Western Pacific Biotwang.
According to ScienceAlert, the acoustic monitoring buoy recorded the sound many times between the fall of 2014 and the spring of 2015 within the Mariana Trench Marine National Monument.
While not confirmed, researchers believe it is probably a new vocalization from a dwarf minke whale. “It’s very distinct, with all these crazy parts,” Sharon Nieukirk, senior faculty research assistant in marine bioacoustics at Oregon State, who helped analyze the call, says in the release. “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.”
Parts of the new call are actually similar to another unique call recorded near Australia, reports ScienceAlert, which researchers have dubbed the Star Wars call because it sounds like the movie franchise’s laser blasters. “The complex structure of the Western Pacific Biotwang sound, the frequency sweep, and the metallic nature of the final part of this call are all very similar to characteristics of dwarf minke whale Star Wars calls,” the team writes in a paper appearing in The Journal of the Acoustical Society of America.
Neukirk points out, however, that there is one problem with that idea: Baleen whale calls are typically related to mating, but the Biotwang was heard throughout the year. “If it’s a mating call, why are we getting it year round? That’s a mystery,” she says in the press release. “We need to determine how often the call occurs in summer versus winter, and how widely this call is really distributed.”
It’s not the first time a whale has thrown the scientific community for a loop. In the 1960s, scientists began recording a sound called “Bio-duck” in areas of the Southern Ocean, reports Tanya Lewis at LiveScience. The quacking was so repetitive that researchers at first thought it must be mechanical, coming from a submarine or other human source. It wasn’t until 2013 that researchers tagged two minke whales with acoustic microphones. To their astonishment, the whales made the mysterious quacking sound, though researchers still aren’t sure what the purpose of the sound is.
More research may also solve the mystery of the Biotwang, but the ocean is full of other head-scratchers like the beeping coming from the ocean floor in Arctic Canada and The Bloop, a massive low frequency sound recorded in 1997 which could have been an ice shelf breaking up—or a Kraken emerging from its thousand-year slumber.