Book challenges ideas about why whales sing

University at Buffalo professor Eduardo Mercado III challenges the long-held scientific consensus that whales sing as a courtship display.
Mercado’s new book “Why Whales Sing?” proposes an alternative explanation: whales use their songs to explore and scan their surroundings, effectively using sound as sonar.
The sonar hypothesis directly opposes the reproductive hypothesis, which suggests that whales sing to attract mates, but Mercado argues that there is no evidence to support this theory.
Mercado’s research has been met with resistance from other whale experts in the past, but he persevered and continues to gather evidence that supports his sonar hypothesis.
Mercado believes that scientific progress often requires challenging established ideas, citing Max Planck’s quote “science progresses one funeral at a time,” and is eager to see the reproductive hypothesis put to rest.

A humpback whale swims through deep blue water.

Eduardo Mercado III, a University at Buffalo professor of psychology and an expert on whale song, wasn’t impressed as a young researcher in the 1990s when he first heard humpbacks singing.

Mercado is a cognitive scientist and a 2023 fellow of the Guggenheim Foundation. He knows how certain sounds, such as whale song, can release neurochemicals in listeners that produce feelings of pleasure, accounting, in part, for why the songs appeal to so many people. Mercado, at least initially, didn’t include himself among the enchanted.

That lackluster first impression soon became a driven scientific curiosity when Mercado encountered a few pages of text in a book discussing echolocation that caused him to think differently and more deeply about singing whales.

He has since published years’ worth of innovative research on whale song in leading journals, producing a body of work that upends more than 50 years of established science on the singing behavior of humpback whales, most of which concludes that whales sing as a courtship display, like songbirds, or peacocks spreading their tail feathers to attract a mate.

Not so, according to Mercado.

His new book, Why Whales Sing? (Johns Hopkins University Press, 2025), available November 4, is a persuasive and accessible explanation that challenges the scientific consensus while introducing its readers to previously unimagined and fascinating dimensions of whale behavior.

“What I’m arguing in this book is that singing whales aren’t performing, they’re exploring,” he explains. “They’re not ‘singing’ to serenade a potential mate but are instead vocally scanning to ‘see’ what’s going on for miles around them, using their songs as a kind of sonar.

“Whales see with song.”

This type of auditory scene analysis by whales is known as the sonar hypothesis, which directly opposes the nearly universally embraced reproductive hypothesis.

“In my mind, singing humpback whales are like submerged megaspiders laying out an acoustic web all around them,” he says. “The evidence needed to support the reproductive hypothesis just isn’t there.”

Researchers in the 1970s first proposed that some sounds produced by humpbacks might be used for echolocation, but their songs were nevertheless related to reproductive fitness. Those observations were ignored. Since whale song sounded nothing like the clicks used by dolphins, Earth’s most prominent underwater echolocators, scientists didn’t see the songs as sonar.

Mercado thought otherwise, and he has emerged as the leading and most diligent researcher exploring the sonar hypothesis. His book has been 20 years in the making. His first two attempts to interest a publisher failed, mainly because other whale experts opposed the publication of his revolutionary findings. But multiple studies on the topic created enough momentum to counteract critics’ complaints.

“Thirty years ago, when I first proposed that whale songs might be sonar, I was verbally stoned by many whale researchers for suggesting the possibility,” says Mercado. “I attempted to abandon the topic but failed because new evidence kept popping up indicating that singing humpbacks are echolocating.”

Evidence like the amount of interest female whales show in singing males. Mercado says it’s “essentially none.” In fact, females tend to actively avoid singers. In addition, contrary to male behavior in the courtship displays of other animals, singing males have no problem with other males approaching them. Singers rarely react aggressively to these “intruders” and sometimes swim off with them.

“I feel like the early scientific consensus that whale songs are love songs was a rush to judgment, like how people once portrayed gorillas as blood thirsty before more detailed observations revealed that they lived in peaceful families,” says Mercado.

Mercado says many novel scientific ideas, like evolution through natural selection, have at first been dismissed, but that has only served to encourage his continued work in the field of whale song.

“I think Max Planck got it right when he suggested science progresses one funeral at a time,” says Mercado. “And it’s time to put the reproductive hypothesis to rest.”

Source: University at Buffalo

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Q. Who is Eduardo Mercado III and what is his background?

A. Eduardo Mercado III is a University at Buffalo professor of psychology and a cognitive scientist, and he has been a fellow of the Guggenheim Foundation.

Q. What was Mercado’s initial impression of whale song when he first heard it in the 1990s?

A. Mercado wasn’t impressed as a young researcher in the 1990s when he first heard humpbacks singing, finding it lacking.

Q. Why did Mercado become interested in whale song again after his initial encounter with a book about echolocation?

A. Mercado’s interest was sparked by a few pages of text discussing echolocation that made him think differently and more deeply about singing whales.

Q. What is the main argument presented in Mercado’s new book, “Why Whales Sing?”?

A. Mercado argues that singing whales are not performing or serenading a potential mate, but rather exploring their surroundings using their songs as a kind of sonar.

Q. What is known as the sonar hypothesis, and how does it relate to whale behavior?

A. The sonar hypothesis suggests that whales use their songs to scan their environment, essentially “seeing” with sound, which directly opposes the widely accepted reproductive hypothesis.

Q. Why did Mercado’s initial proposal of the sonar hypothesis in the 1970s receive criticism from other whale researchers?

A. Other whale experts opposed Mercado’s findings because they didn’t fit with the established scientific consensus that whale songs were related to reproductive fitness.

Q. What evidence supports the sonar hypothesis, according to Mercado?

A. Evidence includes the fact that female whales show little interest in singing males and tend to avoid them, as well as the behavior of singing males towards other males.

Q. How does Mercado’s perspective on whale song compare to the traditional view that it is a courtship display?

A. Mercado believes that the traditional view was a “rush to judgment” and that his findings support the idea that whales are using their songs for echolocation, not just attracting mates.

Q. What advice does Mercado have for scientists who may be hesitant to challenge established theories?

A. Mercado says that science progresses one funeral at a time, implying that even seemingly unpopular ideas can eventually gain acceptance and contribute to our understanding of the world.