Sperm whales in the Mediterranean communicate in two different 'dialects'

A new study reveals distinct vocal differences between eastern and western populations of sperm whales in the Mediterranean. Western whales produce slower click sequences called 'codas,' while eastern ones use faster and different rhythm patterns.

Scraper SystemJune 29, 2026, 08:44 PM

Sperm whales in the Mediterranean communicate in two different 'dialects'

'Cultural' divide between east and west

Sperm whales living in the depths of the Mediterranean exhibit two distinct dialects in the click sequences known as 'codas' that they use to communicate with each other. According to the study published in the journal "Proceedings of the Royal Society B," the sound patterns of whales living around the Balearic Islands off the coast of Spain in the western Mediterranean are clearly distinct from those of whales living in the Hellenic Trench near Greece in the eastern Mediterranean.

Taylor Hersch, a postdoctoral researcher at the University of Bristol and lead author of the study, said in a statement to Al Jazeera, "Previous studies suggested that the '3+1' coda type, consisting of three rapid clicks followed by a pause and then a fourth click, was dominant among sperm whales in the Mediterranean." Hersch added, "However, the new study showed that this picture is simpler than reality; the same pattern is not performed in the same way everywhere."

Scientists analyzed over 5,000 sound recordings

As part of the research, 5,291 coda sounds recorded over 112 days between 2003 and 2021 were analyzed. It was determined that the western whales produced the '3+1' pattern at a slower tempo, accompanied by '2+1' type codas. The eastern whales, on the other hand, use a much faster version, called '3++1', and a distinctive coda type consisting of eight clicks with gradually increasing intervals.

The research team emphasizes that this difference is significant because it shows that Mediterranean sperm whales are not a single vocal community as previously thought. Although it is a small and isolated population, it is understood that a cultural diversity between east and west has begun to emerge or has already become distinct within this group.

Only eastern ones speak the western 'language'

One of the most striking findings of the study concerns the direction of vocal exchange. It was observed that some eastern groups occasionally used the slower western codas, but western groups almost never used the fast eastern codas. This asymmetric situation led researchers to the hypothesis that the slower western dialect might be older, and the faster eastern dialect emerged later, after sperm whales spread into the Mediterranean via the Strait of Gibraltar.

Animal behavior experts compare this to the formation of dialects in birds or isolated human communities. Although isolation sometimes reduces diversity, it can also open the door for new patterns to emerge, transmitted through social learning independent of genes.

The research has some limitations due to the lack of sufficient sound recordings from the central Mediterranean. The question of how the shallow waters stretching between Sicily, Sicily, and Tunisia act as a barrier between the two basins, and whether other sound patterns exist in the intervening region, remains unanswered for now. Completing the sound map is of great importance for the conservation of this isolated population, which is classified as endangered on the International Union for Conservation of Nature (IUCN) Red List and is thought to number no more than a few thousand.

Sperm whales in the Mediterranean communicate in two different 'dialects'