A giant duck quacks in the ocean: scientists believe the mysterious sound resembles a "conversation of leviathans."

Decades ago, in 1960, people first heard a strange sound in the waters of Antarctica: a repetitive noise resembling the quacking of a massive duck. More than 60 years have passed since then, yet scientists are still searching for explanations behind this peculiar sound, as reported by Science Alert.

According to ocean scientist Ross Chapman from the University of Victoria in Canada, despite years of research, scientists still lack a complete answer. At the same time, researchers acknowledge that new studies analyzing the sounds of bio-ducks suggest that what they produce is actually a form of conversation.

Researchers discovered that several vocalizing individuals are located at different points in the ocean, all producing these sounds. What is particularly intriguing is that the sounds seem to resemble conversation: when one spoke, the others remained silent, as if listening. Then the first speaker would stop and listen to the responses of the others.

The world's oceans cover more than half of our planet's surface and are the least explored areas on Earth. The Earth's oceans are extremely vast and deep, making them challenging to study. It is often said that we know more about Mars than the ocean floor. Therefore, it is not surprising that there are things hidden beneath the waves that we have not seen, along with animal behaviors we cannot identify.

The mysterious sounds were first recorded in the waters of Antarctica and later off the western coast of Australia. For decades, scientists have tried to unravel this mystery and finally succeeded: it took just over 50 years and numerous tags for researchers to link the appearance of the strange sound to Antarctic minke whales (Balaenoptera bonaerensis) in 2014. Scientists analyzed tag recordings and found that the whales produced sounds similar to those of the bio-duck.

It seemed the mystery had been solved, but according to Chapman, it’s not that straightforward. Similar sounds have also been recorded in other oceans around the Earth and have not been associated with animal observations. Scientists believe that the sounds could have been made by minke whales, but it is also possible that they were produced by an entirely different whale.

Chapman and his colleagues have been studying the soundscape of the Southern Ocean since the 1980s when recordings showed that the bio-duck or its higher-frequency relative, the bio-goose, were heard throughout Australia and New Zealand. He and his colleagues determined that the sound must have originated from an animal.

Researchers note that initially, they could hardly believe the sound was biological. Scientists continued their work and literally learned something new about the ocean sound every day as they delved deeper into the data. The findings were fascinating.

Chapman points out that even if the mystery of the sound's origin is solved and it is indeed produced by minke whales, there remains an enigma. Firstly, scientists still do not know the purpose of these sounds. However, the team is confident that the nature of the recordings they and their colleagues managed to obtain indicates that it is a form of exchange or conversation. At the same time, the purpose of this conversation remains unclear.

Although we still do not know what exactly the whales were discussing, Chapman and his colleagues believe that further research may help unveil this secret.