These Wild Lemurs Sing Just Like Opera Stars, Widening Their Mouths as They Hit the High Notes, Study Suggests

Scientists suspect this musical trait arose independently in humans and indris, which split from a common ancestor some 74 million years ago. Today, the lemurs make loud, haunting calls to communicate with one another in the dense forests of eastern Madagascar

Sarah Kuta | Daily Correspondent

October 2, 2026 10:34 a.m.

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Professional singers are trained to subtly change the shape of their mouths and throats to make their voices louder and more resonant. This technique, known as formant tuning, can be especially useful for hitting very high notes: Sopranos, for example, typically open their mouths wider as they climb a musical scale, a technique that helps them amplify their voices without straining their vocal cords.

Now, new research suggests wild lemurs do the exact same thing. This ability, described in a paper published September 21 in the journal PLOS Computational Biology, likely helps the animals communicate over long distances in their dense forest habitat.

“While we may think of ourselves as the only ‘sopranos’ capable of producing such complex songs, there is another extraordinary singer in the forest, one that is singing, communicating and simply trying to survive,” study co-author Chiara De Gregorio, a primatologist at the University of Warwick in England, tells Reuters’ Marta Serafinko.

The new study focuses on the indri, the only known species of lemur that sings. These primates live in the tropical rainforests of eastern Madagascar, where they use vocalizations primarily to maintain their territorial spacing.

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“Through singing, they say, ‘Oh, we are here, we are occupying this territory,’” lead author Filippo Carugati, a biologist at the University of Turin in Italy, tells the New York Times’ Taylor Mitchell Brown and Cynthia Silva. “So [it starts] like a battle … in which they sing and they respond and there is the other group singing again. And so maybe they can sing for an hour in these long battles. And sometimes it ends with a physical battle.”

They also sometimes sing when they’re reunited with their companions, which Carugati likens to our “Marco! Polo!” call and response. Their haunting songs sound like something between “a wail and a siren,” Carugati tells Reuters, with highly structured patterns of rising and falling notes.

In the study, researchers analyzed 83 video recordings of 19 wild indris in Madagascar’s Maromizaha forest and Mitsinjo reserve. They used motion-tracking technology to denote the position of their upper and lower lips frame by frame in the footage, which they then compared with the audio of the creatures singing.

The shapes of the animals’ mouths corresponded with their pitches “very robustly,” Carugati tells Reuters. More specifically, the researchers found that as the indris sang higher frequencies, they opened their mouths wider—just like professional singers do. This likely helps amplify the animals’ calls, a helpful adaptation for communicating in an environment filled with thick vegetation.

“Indris rely on long-distance song to hold territory in dense rainforest, so anything that increases how far and how clearly that signal carries has a real, plausible benefit,” Carugati tells ABC News’ Matthew Glasser.

Humans and indris are both primates, but their lineages split from a common ancestor some 74 million years ago. Although the two species may use the same technique today, researchers suspect this adaptation arose independently in each animal, a phenomenon known as convergent evolution. They ultimately evolved the same strategy because “they’re facing the same kind of problem,” Carugati tells ABC News. “In this case, the shared problem is how to send an acoustic signal over a long distance.”

The findings add indris to a growing list of animals—including grasshopper mice, gibbons and gray wolves—known to adjust their vocal tracts to optimize their communication.

But widening their mouths to amplify higher-frequency sounds isn’t the only musical trait indris share with humans. A study published in 2021 found that indris also have rhythm, singing in the same patterns often used in human tunes. Similarly, scientists think rhythm evolved independently in the two species.

“It’s so close to human music—it’s quite astonishing,” Andrea Ravignani, a cognitive biologist at Sapienza University of Rome who co-authored the 2021 study, told the New York Times’ Sam Jones.

The findings add to scientists’ understanding of these unique singing primates—and they suspect there’s even more to learn. But time may be running out for indris, which are critically endangered.

Researchers don’t know exactly how many individuals remain in the wild, but their best guess is somewhere between 1,000 and 10,000. The species is declining because of hunting, climate change and deforestation, with Madagascar losing 44 percent of its natural forest cover between 1953 and 2014. Habitat loss has been particularly hard on the animals, because it has “severely fragmented” the population and made it more difficult for them to reproduce, according to the nonprofit Lemur Conservation Network.

De Gregorio hopes the new study will help raise awareness about indris and their precarious future.

“Unlike many other species, they have so far proved extremely difficult to maintain and reproduce in captivity,” she tells Reuters. “Their survival ultimately depends on protecting them in the wild.”

Sarah Kuta is a writer and editor based in Longmont, Colorado. She covers history, science, travel, food and beverage, sustainability, economics and other topics.