What was that? For decades, mysterious sounds have been recorded from the ocean that have absolutely stumped scientists.
While some remain a mystery, this week, researchers determined that an odd noise known as the "bio-duck" was emitted by an Antarctic minke whale.
Denise Risch of Integrated Statistics and her colleagues explain in the journal Biology Letters that the Donald Duck-type sound is produced by Antarctic minke whales, which they tagged and recorded at Wilhelmina Bay, off the western Antarctic Peninsula.
"For decades, the bio-duck sound has been recorded in the Southern Ocean, but the animal producing it has remained a mystery," said Risch.
The bio-duck sound is often picked up by hydrophones positioned under the ice of Antarctica.