What was this?

These mysterious sounds reminded people of spaceship sounds in science fiction movies, but it turns out that the truth is much more ordinary. Biotwang is actually the call of Bryde’s whales (Balaenoptera edeni). According to researchers, this is how animals can call each other. A study on this has already been published in the journal Frontiers in Marine Science.

Scientists first detected the unusual sounds in 2014, when they used underwater gliders to conduct an acoustic survey of the Mariana Trench, the world’s deepest ocean trench, which lies 2,400 kilometers south of Japan and has a maximum depth of 10,935 meters.

Sounds captured by scientists: video

Sound can be divided into two distinct parts:

• The first is the low, growling sound that echoes deep within.
• The second is a high-frequency, metallic ringing that researchers have compared to the sounds of spaceships in the movies “Star Trek” and “Star Wars.”

At first, these sounds puzzled scientists. But in 2016, researchers found that the biotwang was most likely the call of large whales, such as blue whales (Balaenoptera musculus) or humpback whales (Megaptera novaeangliae), but it didn’t match any known whale calls.

In a new report, scientists were finally able to prove that these sounds are made by Bryde’s whales, thanks in part to new artificial intelligence (AI) tools. More than 200,000 hours of audio recordings featuring various sounds of the ocean were sifted through.

When researchers spotted 10 marine mammals swimming near the Mariana Islands and recorded nine of them making distinctive sounds, they suspected Bryde’s whales were behind the biological broadcast.

Once is a coincidence. Twice is a coincidence. Nine times exactly Bryde’s whale,
— the study’s lead author, Anne Allen, an oceanographer with the National Oceanographic and Atmospheric Administration (NOAA) Pacific Islands Fisheries Science Center, told the journal.

But to definitively prove that these were Bryde’s whales, the team needed to match the nature of the sounds to the species’ migration patterns, which meant sorting through years of audio recordings made by tracking stations in and around the Mariana Islands.

They sped up this process with artificial intelligence, converting biotwang into images known as spectrograms that can be easily distinguished from other sounds using a machine learning algorithm.

The data also showed an increase in noise in 2016, when rising ocean temperatures caused by the El Niño phenomenon led to an increase in Bryde’s whales visiting the area.

It’s still unclear why these cries sound so strange, but researchers have an idea why they’re made: it’s how animals signal their location and find other members of their group.