It's a mystery that has stumped scientists and submariners for 50 years: strange, duck-like sounds thumping through icy Antarctic waters. The source, which submariners deemed the "bio-duck," remained a puzzle -- until today.
In a study published in Biology Letters, marine biologists unveiled the creatures behind the quack. The "bio-duck" is neither fowl nor fish, it turns out, but something quite a bit bigger: minke whales.
In this audio clip, the "bio-duck" sound can be heard near the end, just before the whale splashes.
Biologist Denise Risch tells Science News that it's unclear what the bio-duck vocalizations mean. Very little is known about minke whales, she says, but researchers can now use this call to shed light on the species' population size and habitat.
For the whales, this discovery comes at a critical time. As the researchers point out, minke whales are the target of "lethal sampling efforts" -- Japan's pseudoscientific cull of this species. But minke whales aren't without their defenders, from the marine biologists to Sea Shepherd, all keeping a watchful eye on the Antarctic.