The whales in the east remember the old ways, but they're moving on
In the ancient basin of the Mediterranean, sperm whales on opposite shores have quietly grown apart in the way they speak to one another — eastern populations near Greece clicking faster than their western counterparts near Spain, and each group choosing to socialize only with those who share their tongue. Researchers from the University of St Andrews, publishing in the Proceedings of the Royal Society B, have captured what may be the first observable moment of dialect birth in these animals: a population in the slow, generational act of cultural divergence. The discovery places whales alongside humans and songbirds as creatures whose identities are shaped not only by genetics, but by what they learn and pass on.
- Scientists have long known that whale populations speak in different dialects — but how those dialects are born has remained one of cetology's quiet mysteries.
- Now, 112 days of hydrophone recordings spanning nearly two decades reveal eastern Mediterranean whales clicking faster than their western relatives, a measurable and consistent divergence rooted in geography.
- The stakes are social and existential: sperm whales refuse to associate with those outside their dialect, meaning vocal difference is not mere accent but the boundary between belonging and isolation.
- The Mediterranean population — genetically cut off from the wider sperm whale world for roughly 20,000 years — appears to have split internally, with the eastern group evolving a faster rhythm from a shared ancestral pattern.
- The finding reframes cetacean culture as something dynamic and ongoing, not fixed — these whales are not merely inheriting tradition but actively, if slowly, transforming it.
Sperm whales in the Mediterranean have developed distinct dialects on opposite sides of the sea — whales near Greece click differently than those near Spain, and these differences are not trivial. Sperm whales will only socialize with others who share their vocal pattern, making dialect the very currency of belonging. The clicks in question are called codas: short, rhythmic sequences that form the basis of sperm whale social life, enabling the bonds that allow them to hunt and survive together.
Dr. Luke Rendell of the University of St Andrews and colleagues published their findings in the Proceedings of the Royal Society B, drawing on hydrophone recordings gathered over 112 days between 2003 and 2021. They tracked two populations — one near the Hellenic Trench off Greece, another near the Balearic Islands off Spain. Both groups favored four-click codas, but the rhythm diverged: western whales preferred a 3+1 structure, three evenly spaced clicks followed by a pause and a final click, while eastern whales used a faster variation of the same idea. Some eastern whales occasionally produced the western pattern, suggesting the groups had not been entirely sealed off from one another — yet the divergence was real.
The Mediterranean sperm whale population, thought to have arrived some 20,000 years ago and since become genetically isolated from whales worldwide, had begun to drift apart internally. Rendell described the eastern dialect as an evolution of the original: the whales remember the old ways, but have moved on. What makes this significant is not merely that dialects differ, but that researchers could observe a population mid-divergence — a rare snapshot of cultural evolution in motion.
The parallel to human language and birdsong is deliberate: isolation drives innovation, and innovation repeated across generations becomes tradition. For sperm whales, whose social structures are complex enough to require dialect and whose communication is learned rather than innate, the Mediterranean offers a living laboratory for understanding how culture travels through time.
Sperm whales in the Mediterranean have developed distinct dialects on opposite sides of the sea, much the way English speakers from different regions might greet each other with "Howdy" or "G'day." Researchers analyzing underwater recordings have found that whales living near Greece click differently than those near Spain, and these vocal differences matter profoundly: whales will only socialize with others who speak their dialect. The clicks themselves—short, rhythmic sequences called codas—are how sperm whales form the social bonds that allow them to hunt and survive together.
Dr. Luke Rendell of the University of St Andrews and his colleagues published their findings in the Proceedings of the Royal Society B after analyzing hydrophone recordings collected over 112 days between 2003 and 2021. They monitored two populations: one near the Hellenic Trench off Greece in the eastern basin, another near the Balearic Islands off Spain in the west. What emerged was a portrait of two populations speaking related but distinctly different languages.
Both groups favored codas made of four clicks, but the rhythm differed. Western Mediterranean whales preferred a pattern of three evenly spaced clicks followed by a longer pause and then a single click—what researchers call a 3+1 structure. Eastern whales used a faster version of essentially the same idea. The distinction was consistent enough that it revealed something deeper: the eastern population appeared to be a branch that had split off and begun evolving its own way of speaking. Some eastern whales occasionally produced the western dialect, suggesting the populations had not been completely isolated, yet the divergence was real and measurable.
Rendell explained the finding as a window into how whale cultures actually form. The Mediterranean sperm whale population—a few thousand individuals thought to have arrived roughly 20,000 years ago—had become genetically isolated from other sperm whales worldwide. Within that isolation, the eastern and western groups had begun to drift apart vocally. "The whales in the east remember the old ways, but they're moving on and they've got a slightly different version," Rendell said, describing how the faster eastern dialect appeared to be an evolution of the original western pattern. The process was slow, requiring both time and some degree of separation between groups.
What makes this discovery significant is that it offers the first real glimpse into how new dialects emerge in sperm whales at all. Scientists had long known that different whale populations spoke different dialects—that much was established. But the mechanism, the origin story, remained opaque. Here, in the Mediterranean, researchers could observe a population in the act of linguistic change, a snapshot of cultural evolution unfolding. The finding parallels what happens in human languages and in birdsong: isolation drives innovation, and innovation, repeated across generations, becomes tradition.
The implications extend beyond cetacean biology. Understanding how sperm whales transmit culture—how knowledge and behavior pass from one generation to the next through learned vocalization—illuminates a form of intelligence that exists outside the human realm. These are animals with social structures complex enough to require dialect, with the capacity to learn and modify their communication over time. The Mediterranean whales, separated by geography and speaking in subtly different tongues, offer a rare opportunity to watch that process unfold.
Citas Notables
The dialect is used to form social structures, within which these animals will cooperate.— Dr. Luke Rendell, University of St Andrews
This is the first example we've got where we can look at a snapshot and think: 'Oh, this seems to be telling us about how new dialects come about.'— Dr. Luke Rendell
La Conversación del Hearth Otra perspectiva de la historia
Why does it matter that whales have dialects? Aren't they just making noise?
The dialect is the password to belonging. A sperm whale won't cooperate with another whale unless they share the same dialect. It's how they form the family groups that hunt together, raise calves together, survive together. Without the right accent, you're an outsider.
So these Mediterranean whales—they're isolated from the rest of the world's sperm whales?
Genetically, yes. They've been in the Mediterranean for about 20,000 years, cut off from the Atlantic populations. But what's fascinating is that even within that isolation, they're splitting into two distinct groups—east and west—and their dialects are diverging.
How do you know the eastern whales are newer, that they came later?
The pattern suggests it. The western dialect looks like the original. The eastern whales use a faster version of the same basic structure. It's as if they inherited the old way of speaking, then gradually sped it up, changed it slightly. Some eastern whales still use the western pattern occasionally, which shows the split is recent enough that the old way hasn't been completely forgotten.
Is this evolution happening right now, or did it happen in the past?
Both. The divergence happened over time, but we're observing it in the present. We're seeing a population frozen at a particular moment in its linguistic history—far enough along that the dialects are clearly distinct, but recent enough that we can still see the connection between them.
What does this tell us about how whale culture actually works?
That it's learned, not instinctive. That it changes. That isolation matters. A group of whales separated from the main population doesn't just keep speaking the old way forever—they modify it, adapt it, make it their own. That's culture. That's how traditions form and transform across generations.
Could this happen to human languages?
It already has. Every language we speak is a dialect that diverged from something else. The Mediterranean whales are showing us the mechanism in real time—how a single way of speaking becomes two, how isolation and time reshape communication into something new but recognizable.