(NEWSER) – A mysterious quacking noise in the ocean that has baffled scientists for decades has finally been identified, researchers say. Acoustic recorders placed on Antarctic minke whales have produced what NOAA experts say is "conclusive evidence" that the sound is their chatter, the BBC reports. The sound was dubbed the "bio-duck" when it was first picked up by sonar operators on submarines in the '60s. It's since been heard in the Southern Ocean around Antarctica and western Australia, typically in winter and spring. Still a mystery: why the whales make the sound. Researchers did note, though, that the vocalizations were always recorded when the whales were close to the surface, before making deep dives to eat.
After 50 Years, Mysterious Ocean Quack Identified - 'Bio-duck' is actually minke whale