In the pitch-black of the Arctic winter, as the freezing winds whip across the surface of the frozen sea, beneath the ice you might just catch the whispers of jazz emanating from the frigid depths. But this is no aquatic Louis Armstrong or Miles Davis, instead, it is the ever-shifting melody of the enigmatic bowhead whale (Balaena mysticetus).
The Arctic whales have been found to produce surprising vocals throughout the entire winter season. What is most impressive about these whale calls, however, is the diversity that is unmatched by any other whale, and possibly any other mammal. The only other cetacean known to sing such complex songs are humpback whales, but theirs has a structure and form that is seemingly absent in the bowheads.
“If humpback whale song is like classical music, bowheads are jazz,” explained Kate Stafford, lead author of the study published in the journal Biology Letters. “The sound is more freeform.”
By dropping hydrophones into the waters off the eastern coast of Greenland, the researchers found that after the Arctic is plunged into darkness for six months of the year, the whales' concert begins, and seemingly doesn’t stop again until the Sun reappears above the horizon. They found that for 24 hours from November until April, the bowhead whales sang to their heart's content.
From the offset, this was a good sign. One of the reasons that the bowhead whale is so under studied is that they were hunted extensively. When whaling really kicked off in the 18th century, the massive cetaceans were prime targets due largely to their size but also the fact that their range was so close to the main whaling nations of North America and Northern Europe.
The continual tunes of the whales picked up in this study showed that there is a healthy population of the bowheads – perhaps around 200 of them – in this region. But by listening in on the whales over a period of years, the researchers were blown away for another reason.
Over the course of four winter seasons, the whales sang a total of 184 songs. What was amazing was that all of these were unique. “Not only were there never any song types repeated between years, but each season had a new set of songs,” said Stafford.
The lack of knowledge on bowheads means that many questions about them remain completely unanswered. It is assumed that it's the males making jazz, but we don’t even know if the individuals keep the same songs for their life, or mix them up, or if the calls are for the benefit of the females or other males. Stafford hopes to answer some of these questions by continuing to eavesdrop on the improv-loving whales.
