The mystery of a duck-like quacking sound, dubbed "bio-duck", which baffled scientists for 50 years now has finally been solved.
The bizarre quacking sound was detected to be coming from the chatters of the Antarctic minke whale.
"It's a repetitive signal [ranging from 50 to 300 Hertz] with a slight downsweep that happens, typically every two or three or four seconds," co-author of the new study Dr Nick Gales, Chief Scientists in the Australian Antarctic Division, told ABC.
The bio-duck sound which was observed to be prevalent in Antarctic waters during winters implied that minke whales live under waters even when covered with ice. The quacking sound off Western Australia also implied that whales migrate to lower latitudes.
Denise Risch, lead researcher, from the US National Oceanic and Atmospheric Administration (Noaa) Northeast Fisheries Science Center in Massachusetts told BBC that their evidence was derived by attaching acoustic recorders to two marine mammals. The recorders showed that the minke whales were the ones making the noise.
"It was either the animal carrying the tag or a close-by animal of the same species producing the sound."
The researchers have yet to detect at what particular time or for what particular reason these minke whales produce the sound. All they have observed was that the whales produce the sound before taking deep dives to eat.
Dr Risch said that the team plans to conduct more researches involving the minke whales.
"Identifying their sounds will allow us to use passive acoustic monitoring to study this species.That can give us the timing of their migration - the exact timing of when the animals appear in Antarctic waters and when they leave again - so we can learn about migratory patterns, about their relative abundance in different areas and their movement patterns between the areas."
Furthermore, acoustic recorders will be used in the future to count the abundance of other marine mammals and how they behave underwater.
"A large part of ocean science now uses acoustics for any animals that are making noise because we can discriminate between different populations of animals on the basis of sound and their seasonal occurrence and absence from places, as well as a whole lot of behaviours," Gales added.
Their recent findings are published in the Royal Society journal Biology Letters.