Sounds are the main communication method used in mating games as a threat warning and for spatial orientation (for example, in the case of bats).
It is widely accepted that sounds play the main role on land and are hardly used in marine life. However, it is not true. A good example is the blue whale, the largest oceanic mammal, that can produce sounds at up to 189 dB. But what is the animal that makes the loudest sounds taking into account its body mass?
This species is called Leocratides kimuraorum. This hesionid polychaete has been recently found on the east coast of Honshu Island in Japan. It can make sounds up to 157 dB, which is quite amazing considering its body length of just 3 cm!
Leocratides kimuraorum sounds like clattering. The sounds serve to intimidate enemies. It was quite easy to make them produce their sounds: the minute the scientists put two worms next to each other, they started squabbling.