Off the coast of Crete, a population of sperm whales has been quietly composing its own linguistic evolution—for at least 20,000 years. Now, researchers at the University of St. Andrews have captured that process in action, documenting how these endangered whales develop new vocal dialects while retaining memories of the old ones.
The study, published in Proceedings of the Royal Society B, analyzed two decades of acoustic recordings from sperm whales in the Mediterranean Sea. What they found upended an earlier assumption: scientists had believed all Mediterranean whales belonged to a single vocal clan, identified by a distinctive pattern of clicks called the '3+1' coda—three clicks followed by a pause, then a fourth. But the new research reveals that whales living in the eastern Mediterranean, particularly around the Hellenic Trench centered off Crete, have developed a faster version of this call.
"These findings paint a picture of the history of sperm whales living in the Mediterranean, consistent with a progressive occupation from west to east, ending with the development of a distinctive dialect in the animals living in the east," said lead author Dr. Taylor Hersh of the University of Bristol.
The discovery becomes even more remarkable when considering what the whales do on certain days: some groups "go retro," producing the slower western form of the coda alongside their new faster dialect. This suggests the whales carry both linguistic traditions in their cultural memory, switching between them depending on context—a flexibility researchers call striking evidence of cultural complexity.
"The new dialect is clearly a modified version of the presumably ancestral slow 3+1 and that groups in the east also clearly remember that dialect as they have these 'throwback' days," Hersh said.
The Mediterranean sperm whale population, estimated at a few thousand individuals, has been genetically isolated from ocean-dwelling relatives for thousands of years. Scientists believe the whales first entered the Mediterranean around 20,000 years ago, spreading from Gibraltar to establish populations throughout the sea. Today, the population faces serious threats from fishery entanglement and ship strikes, leading to its endangered status.
For Dr. Luke Rendell of the University of St. Andrews, who coordinated the study, the findings connect the whales' cultural evolution to a broader story. "The Mediterranean has been the cradle of significant aspects of human cultural evolution from ancient Greece onwards," he said. "Over that entire period, sperm whale culture has also been evolving."
Dr. Alexandros Frantzis of the Pelagos Cetacean Research Institute, who helped discover the eastern Mediterranean population three decades ago, called the research "one of the most interesting publications in which we have participated." Added Dr. Txema Brotons of Spain's Asociación Tursiops: "This finding reminds us that the cultural history of the Mediterranean does not belong exclusively to humans."
As scientists continue to decode the mysteries of sperm whale communication, they say understanding these cultural dialects could ultimately aid conservation efforts—by revealing how these animals identify and connect with one another across their fragmented Mediterranean home.