Researchers have finally identified the source of mysterious noises coming from the deepest ocean trench. The odd sounds, described as "biotwang" noises, sound a bit like sci-fi starships, and are actually whale calls from Bryde's whales (Balaenoptera edeni). The whales may use the calls to locate one another like a giant game of Marco Polo, researchers say.
Scientists first detected the unusual noises in 2014 while using underwater gliders to carry out an acoustic survey of the Mariana Trench — the world's deepest ocean trench, which spans more than 1,500 miles (2,400 kilometers) south of Japan and has a maximum depth of 35,876 feet (10,935 meters).
