Whales sing loud enough that their songs travel through the ocean, but knowing the mechanics behind that has been a mystery. Scientists now think they have an idea, and it’s something not seen in other animals: a specialised voice box. Experts say the discovery will direct future research into how whales communicate.

In a paper published in the journal Nature, Coen Elemans of the University of Southern Denmark and colleagues studied the voice boxes, or larynxes, from three dead, stranded whales—a humpback, minke and sei—all baleen whales.