Every few years, humpback whales go through a “cultural revolution” and ditch their old song for a newer one.
The reason for the change — and why they sing at all — remains a mystery, but a study published in the journal Proceedings of the Royal Society analyzes the cyclical nature of the shifting songs sang by male humpback whales during the breeding season.
From 2002 to 2014, researchers examined the songs of male humpback whales as they passed the coast of Queensland, Australia, during their migration, the study says. Specifically, researchers studied 95 singing whales and 412 song cycles, looking for various themes and complexities that develop over time, as noted by Science Magazine.
They found that humpback whales from eastern Australia seemed to learn a new song from the whales from western Australia — and then began to add their own unique riffs to the song as the music slowly evolves.
The song would then be shared from group to group of humpback whales across the South Pacific, the study says.
Each group of humpback whales has its own song pattern they adhere to, the study says, but it changes “gradually each year.”
It’s not known why the male whales add their own unique flare to the song, but lead study author Jenny Allen, a marine biologist at the University of Queensland, has one theory, according to Discovery Magazine.
“Since all the males in a population sing the same song,” she told the magazine, “small changes might be an opportunity to stand out from the crowd.”
Over the years, the humpback whales continue to add new wrinkles to the music as it grows longer and more complex, the study notes. But at a certain point, one group of whales ditches that song in favor of a shorter and simpler tune, which they then spread to other groups of whales as they migrate throughout the ocean, according to the study’s findings.
The study’s authors dubbed that a “cultural revolution.”
It’s not known why they ditch the song for something more simplistic, although the researchers wrote in their study that it could be a sign that the humpback whales had reached the end of their “social learning capacity” and had to revert back to something easier to remember.
Finding an answer to that mystery, Allen said, could help humans learn about ourselves, too.
“Humpback whale song is one of the best examples of animal culture [scientists] have,” Allen told Discovery Magazine. “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.”
Another study found that humpback whales stop singing when a passenger-cargo ship passes near them and makes noise. The study’s authors theorized that the sound of the ship might be stressful to the whales, thus causing them to grow silent.