In the 1960s, submariners patrolling the Southern Oceans around Antarctica heard a sound they had never heard before. Since it sounded a little like an underwater duck, they tagged the sound “bio-duck”. Over the years, bio-duck has been recorded many times but the source was never positively identified. Here is a recorded sample of bio-duck (recording credit: NOAA)
In February 2013, researchers attached acoustic tags to two Antarctic minke whales to monitor the sounds they make and hear while the whales were going about their daily lives. This was the first time anyone successfully tagged a minke whale and it wasn’t long before bio-duck showed up. Bio-duck is the sound Antarctic minke whales make before and during feeding dives. The analysis of the acoustic recordings was published in Biology Letters on April 23, 2014.
Now that researchers know what bio-duck belongs to, they are already using historical data to learn more about the minke whales. One item that was not known was that some minke whales spend the winter under the ice shelf. Minke whales are often seen in more Northern latitudes during the winter months and it was surprising to find some stay in the colder South. You can find out more about minke whales from the NOAA Fisheries website.