Sperm Whales Living in the Eastern Mediterranean Sea Seem to Have Developed a Distinct Dialect From Those in the West

All Mediterranean sperm whales were thought to be part of one cultural group, identifiable by a unique pattern of clicks, or a coda. But sound recordings suggest that eastern creatures use a sped-up version of the western whales’ coda

Sarah Kuta | Daily Correspondent

July 8, 2026 10:00 a.m.

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From Southern drawls to Irish brogues, humans can sound very different while speaking the same language. It turns out that some whales might have similar regional variations in their vocalizations, too.

Sperm whales living in different parts of the Mediterranean Sea appear to have their own distinct dialects, according to a study published in June in the journal Proceedings of the Royal Society B: Biological Sciences. The findings could offer new insights into the development and evolution of language among non-human animals.

Sperm whales are large, toothed marine mammals that inhabit all the world’s oceans. They can weigh up to 45 U.S. tons and measure up to 52 feet long, with their massive heads accounting for roughly a third of their overall body length. When they’re hungry, these behemoth creatures can dive up to 2,000 feet below the surface in search of squid, skates, sharks and deep-dwelling fish.

As they swim around together, these highly social animals communicate by making a series of rapid clicks known as a “coda.” The pattern of clicks is usually unique to each specific cultural group, used exclusively by members of the same social unit—like a vocal signature.

Scientists think that about 20,000 years ago, a group of intrepid sperm whales swam into the Strait of Gibraltar and entered the Mediterranean Sea, where they’ve remained ever since. The individuals living in the Mediterranean rarely leave the sea—and other sperm whales don’t often enter the area—so they’re considered a genetically distinct subpopulation. The group is considered endangered, with an estimated 250 to 2,500 mature individuals remaining.

“I’ve always thought of them as the weirdos of the sperm whale world,” study co-author Taylor Hersh, a biologist at the University of Bristol in England, tells Live Science’s Chris Simms.

For years, scientists thought all the individuals living in the sea belonged to the same cultural group, which used a specific coda called the “3+1”—three clicks and a pause, followed by a fourth click.

But Hersh and colleagues recently gained a more nuanced understanding of the subpopulation’s language. After analyzing 5,291 codas recorded between 2003 and 2021, the scientists determined that whales living on opposite sides of the Mediterranean use distinct dialects.

The whales living in the western Mediterranean, near Spain’s Balearic Islands, produce the typical 3+1 coda, which researchers have dubbed the western dialect. But those living in the eastern part of the sea, near the Hellenic Trench off Crete, Greece, seem to have adopted a faster version of 3+1, which the researchers call the eastern dialect.

The western whales “religiously” used the western dialect, Hersh tells Live Science. And most of the time, the eastern whales stuck to their eastern dialect. But in four recordings, researchers heard the eastern sperm whales use the western dialect, which suggests that they can switch between dialects.

The findings make sense, given that researchers suspect sperm whales entered the Mediterranean from the west and made their way east over time.

“The whales in the east remember the old ways, but they’re moving on, and they’ve got a slightly different version of what is clearly the same [general type of coda], but they’ve evolved it a little bit; they’ve changed it,” study co-author Luke Rendell, a biologist at the University of St. Andrews in Scotland, tells the Guardian’s Nicola Davis.

For now, the team doesn’t know why the eastern whales adopted their own variation of the 3+1 coda, nor why they sometimes switch between the two. One possibility is that the vocalizations of the eastern whales are still evolving, and that their current dialect represents a “sort of midway phase,” Ellen Jacobs, a marine biologist at Aarhus University in Denmark who was not involved with the study, tells Live Science.

“Changes in the rhythm might be a very feasible and meaningful way for coda signals to start to diverge,” she says, adding that the process might be similar to how the phrase “How do you do?” was sped up and shortened to “howdy.”

Sperm whales have long lifespans—they can live up to around 60 years—so researchers suspect the eastern dialect formed slowly, possibly over hundreds or thousands of years. This means that while humans living near the Mediterranean Sea were developing their own languages and customs, the local sperm whales were “also passing down their vocal traditions from one generation to the next,” says study co-author Txema Brotons, a biologist with the Tursiops Association, a group working to study and protect cetaceans, in a statement.

“This finding reminds us that the cultural history of the Mediterranean does not belong exclusively to humans,” says Brotons. “The Mediterranean is … a space of shared cultural diversity, where the evolution of human culture and animal culture has coexisted for thousands of years.”

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