Scientists have discovered that sperm whales living in the eastern Mediterranean Sea appear to have developed a distinct vocal dialect from those inhabiting the western part of the basin, offering fresh evidence that animal communication can evolve in ways similar to human language.
The findings, published in Proceedings of the Royal Society B, are based on nearly two decades of acoustic recordings collected across the Mediterranean.
Researchers analysed 5,291 "codas", rhythmic sequences of clicks that sperm whales use to communicate socially. For years, scientists believed all Mediterranean sperm whales belonged to a single cultural group identified by a characteristic "3+1" coda, consisting of three clicks followed by a pause and a fourth click. However, the latest analysis found that whales in the eastern Mediterranean, particularly near Greece's Hellenic Trench, produce a noticeably faster version of the same call than whales around Spain's Balearic Islands.
The study also revealed that while western whales consistently use the traditional dialect, eastern whales occasionally switch back to the western version. Researchers say this suggests the eastern population still retains knowledge of the older vocal pattern while gradually developing its own variation over time.
Scientists believe sperm whales first entered the Mediterranean through the Strait of Gibraltar around 20,000 years ago before spreading eastward. Because this population has remained largely isolated, its vocal traditions may have evolved independently across generations. The endangered Mediterranean population is estimated to include only a few hundred to a few thousand mature individuals.
Researchers say the findings provide rare insight into how culture and communication evolve in non-human species. They hope further studies will help explain why eastern whales developed a faster dialect and why they sometimes alternate between the two, potentially offering deeper clues into the evolution of animal language and social behaviour.
