The deep haunting tones of the world's largest animals, baleen whales, are iconic - but how the songs are produced has long been a mystery. Whales evolved from land dwelling mammals which vocalize by passing air through a structure called the larynx - a structure which also helps keep food from entering the respiratory system. However toothed whales like dolphins do not use their larynx to make sound, instead they have evolved a specialized organ in their nose. Now a team of researchers have discovered the structure used by baleen whales - a modified version of the larynx. Whales like Humpbacks and Blue whales are able to create powerful vocalizations but their anatomy also limits the frequency of the sounds they can make and depth at which they can sing. This leaves them unable to escape anthropogenic noise pollution which occur in the same range.
Article: Evolutionary novelties underlie sound production in baleen whales