Whale song remix: Study shows that humpbacks shift pitch when a neighbor joins in

BUFFALO, N.Y. – A humpback whale alters the pitch of its song when joined by a neighboring singer, a finding that opens a new chapter in the ongoing effort to understand whale song, some of the most structurally and acoustically complex vocal patterns produced by mammals.

“The status quo has been that humpbacks ignore one another when singing,” says Eduardo Mercado III, PhD, a professor emeritus of psychology in the University at Buffalo College of Arts and Sciences, and co-author of the new study exploring vocal interactions between pairs of humpbacks. “But our results suggest that humpbacks are listening to one another and changing pitch in reaction to a co-singer’s song.”

Mercado says the vocal interactions between humpbacks are much more sophisticated and dynamic than what has been previously observed in other mammals, even dolphins.

Reacting to a co-singer and altering song pitch requires great mental and vocal flexibility. Bats show some ability to adjust vocal pitches based on the sounds they hear from other bats. But humans, performing in choirs for instance, and now humpback whales, are the only mammals known to fine tune their voices while singing together. 

And the adjustments are contextual, with whales sometimes shifting the pitches of individual sounds up or down depending on how a second singer is vocalizing.

“Humpbacks seem to be able to do the same things we do, but in different contexts,” says Mercado, a 2023 fellow of the Guggenheim Foundation. “They’re listening quite intently and modifying songs in real time in ways that don’t seem to be by chance.”

Results of the study, led by Julia Hyland Bruno, PhD, assistant professor of biological sciences at the New Jersey Institute of Technology, are published in the most recent edition of the journal Animal Behaviour.

“Studying these vocal dynamics could help us understand how these mysterious animals perceive and explore their social world,” says Hyland Bruno.

In general, mammals vocalize in groups for two main reasons. One reason is to show off their physical prowess, such as when lions roar. A second reason, as is the case with some primates, is to vocalize collectively to show they are members of a group. But in those instances, the animals are simply increasing the intensity of their vocalizations or joining others who are already part of a chorus. They are not changing their sounds based on what they hear from others, like humpbacks.

“What humpbacks are doing is similar to what jazz musicians might do when reacting to what a bandmate is playing,” says Mercado. “It’s kind of a bizarre convergence. Why is this ability apparently limited to humans and humpbacks, among mammals?”

Why whales tweak their songs in reaction to hearing other singers remains a mystery.

That’s a question for further research. Mercado says the current study establishes that humpbacks can adjust pitch based on what they hear.

“This paper is a starting point, not an end point,” says Mercado. “Now that we know whales are doing this, we can study why they’re doing this.”