Over 64 years ago, the ocean quacked. Specifically, sailors aboard an Oberon-class submarine in 1960 detected a series of short, odd noises that resembled an agitated waterfowl. But they weren’t the only people to hear the sounds. In the ensuing decades, multiple instances of the strange audio—nicknamed the “Bio-Duck”—were documented, particularly in the waters surrounding Australia and Antarctica, including a soundscape analysis of the South Fiji Basin in 1982. And while the jury is still out on the quack’s exact culprit–or culprits–there’s a new theory. According to experts, what researchers have described as one of the “largest still unresolved mysteries of the Southern Ocean” may be a conversation between underwater inhabitants.
According to Ross Chapman, a professor emeritus of ocean acoustics at Canada’s University of Victoria, the Bio-Duck sounds may very well come from some kind of animal.
“The sound was so repeatable, we couldn’t believe at first that it was biological,” Chapman said in a statement ahead of this year’s annual Meeting of the Acoustical Society of America. “But in talking to other colleagues in Australia about the data, we discovered that a similar sound was heard quite often in other regions around New Zealand and Australia.”
Chapman wasn’t there for the 1982 Bio-Duck detection, but he began studying the audio in 1986. Since then, the field of ocean acoustics has evolved considerably, allowing scientists better means to study and interpret the noises.
“You have to understand that this type of study of ocean noise was in its infancy in those days,” said Chapman. Focusing on Bio-Duck, however, helped further their understanding of ocean bioacoustics. “As it turned out, we learned something new about sound in the ocean every day as we looked further into the data—it was really an exciting time for us.”
In the case of 1982’s Bio-Duck detection, researchers used what’s known as an acoustic antenna, which includes multiple hydrophones towed behind a ship as it trawls the waters. The antenna’s calibration allows users to hone in on specific directions and better pinpoint the origins of underwater sounds. After reviewing the audio files, Chapman and colleagues are confident Bio-Duck events are almost certainly biological in nature.
“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.
[Related: A lone dolphin has been yelling into Baltic Sea for years.]
It’s still unclear the exact species making all those quacks, although many experts theorize they come from the Antarctic Minke whale—or, more accurately, whales.
“We discovered that there were usually several different speakers at different places in the ocean, and all of them [were] making these sounds,” said Chapman. “The most amazing thing was that when one speaker was talking, the others were quiet, as though they were listening. Then the first speaker would stop talking and listen to responses from others.”
But even if the Bio-Quack mystery is one day solved for good, the question will always linger as to what those chatty mammals were talking about back in 1982.
“Maybe they were talking about dinner, maybe it was parents talking to children, or maybe they were simply commenting on that crazy ship that kept going back and forth towing that long string behind it,” said Chapman.
