Humpback Whales Sing Different Songs Every Few Years

Humpback whales (Megaptera novaeangliae) go through a "cultural revolution" of sorts once every few years, trading their old song for something simpler and fresher. Now, thanks to a study recently published in the Proceedings of the Royal Society B, scientists think they know how these "revolutions" take place.

The purpose of a male humpback's song is still a mystery to scientists. It may be a mating call or a form of man-to-man bonding, or it may be something else altogether – we just don't know. But we do know that it is highly complex, that all whales sing the same song, and that it goes through a cycle, getting a little more complex every year. At least, that is, until there is a "revolution," which turns the dial back to zero and restarts the entire process. 

Jenny Allen, a marine biologist at the University of Queensland in Australia, and colleagues spent 13 years between 2002 and 2014 collecting and analyzing the songs of 95 humpback whale singers. In total, they amassed 412 individual song cycles, investigating the songs’ length, repetitiveness, and variation to determine how complex each was.

The team noticed small changes made to the chorus every year. The result of which meant the songs slowly became longer and more complex, possibly due to embellishments made by individual whales hoping to make the tune their own. However, whenever there was a "cultural revolution," the new song would always be less complicated than the one it replaced. 

Why this simplicity? The researchers aren't so sure but offer up a couple of suggestions. It may come down to a preference – the simpler it is, the easier it is for individuals to add their own twist to the song. But it might instead reveal a limit on a whale's ability to learn. It may be that it is just too difficult for whales to learn a song that is any more sophisticated. 

Hopefully, this is a question future research will be able to settle but, in the meantime, Allen and her team hope this study can contribute to our understanding of how human culture spreads and develops over the years. 

"Humpback whale song is one of the best examples of animal culture [scientists] have," Allen told Discover. Humpbacks extend their culture (or, in this case, their songs) from population to population in a way that has only been witnessed in humans.

"If we can understand what drives the development of culture across animal species, we might be able to clarify what drove it to develop to such a complex extreme in humans."