What quacks like a duck, but doesn’t look or swim like one? (Hint: It’s probably not a duck.) That’s the enigma researchers have been mulling over since the 1960s, when submariners first reported a strange noise emanating from the Antarctic Ocean. Some two decades later, scientists recorded the unidentifiable sounds while conducting an experiment in the Pacific’s South Fiji Basin.
And now we’re one step closer to solving the puzzle. On Nov. 21, New Zealand researchers announced they believe the source of those head-scratching noises, described as four short bursts resembling a quack, is definitely biological — and what’s more, the noisy creatures seem to be talking to each other.
“We discovered that there were usually several different speakers at different places in the ocean, and all of them making these sounds,” University of Victoria researcher and underwater acoustic expert Ross Chapman said in a press release. “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.”
To gather the 1982 data that led to this epiphany, scientists towed an acoustic antenna behind their ship. The antenna carried an array of hydrophones, devices similar to microphones that gather acoustic signals from different directions underwater and translate them into measurable sounds.
But the question still remains: What’s doing the quacking? The theory with the most chatter behind it points to Antarctic minke whales, an idea strengthened by the fact that these noises are mainly heard during winter — the only time the animals vocalize — and supported by a 2014 study that analyzed data from acoustic recordings tags. These mammals are known for their singing, much like their minke whale cousins in other seas, which produce a variety of spirited sounds like grunts, thumps, and “boings.”
“Our results solve the mystery” of the quacks, the 2014 study claims. However, the recently reported research from New Zealand can’t conclusively say the recordings came from cetaceans.
For now, the unknown animals are still largely called by their original nickname from the ’60s: bio-ducks. Some lore has even taken the nature of these mysterious creatures a step further, dubbing them UFOs, fish, or the ever-vague “oceanographic phenomenon.”
The other case that has yet to be closed here? What exactly the biological entities were discussing. “It’s always been an unanswered issue in my mind,” Chapman said in the press release. “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.” We’re betting it’s the latter.
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