For decades, researchers have been stumped by a mysterious quacking sound emanating from the Southern Ocean. Now, they may have the answer.

To their astonishment, the whales made the mysterious quacking sound, though researchers still aren’t sure what the purpose of the sound is.

First described by submariners in the 1960s, the strangely repetitious quacking sound in the Southern Ocean earned the nickname “bio-duck,” and researchers first recorded the phenomenon in ...

“We discovered that the data contained a gold mine of new information about many kinds of sound in the ocean, including sounds from marine mammals,” he explained.