Sperm whale dialects differ between eastern and western Mediterranean
10 reported
Researchers have identified two distinct vocal dialects among sperm whales in the Mediterranean Sea, according to a study published in Proceedings of the Royal Society B. The study, led by Dr Luke Rendell of the University of St Andrews, analyzed hydrophone recordings of sperm whale groups made over 112 days between 2003 and 2021. Recordings were taken around the Hellenic Trench near Greece in the eastern Mediterranean and around the Balearic Islands off Spain in the western basin. Sperm whales communicate using sequences of short clicks called codas, and the rhythmic pattern of these clicks forms a dialect that differs between matriarchal groups. The researchers found that whales in the western basin favored a 3+1 coda pattern with three regularly spaced clicks followed by a longer pause and another click, while those in the eastern basin used a faster version of the same pattern. Some crossover was observed, with eastern basin whales occasionally producing the western dialect. Rendell stated the findings suggest sperm whales first established themselves in the western basin before spreading eastward and developing a faster dialect, marking the first time researchers have observed clues about how new sperm whale dialects originate.
What’s reported
Sperm whales communicate using sequences of short clicks called codas.
The rhythmic pattern of these clicks, known as the dialect, differs between matriarchal groups.
One group of sperm whales will only associate with another if they share the same dialect and belong to the same vocal clan.
The study analyzed hydrophone recordings made over 112 days between 2003 and 2021.
Recordings were taken around the Hellenic Trench near Greece (eastern Mediterranean) and around the Balearic Islands off Spain (western basin).
Most sperm whale codas in both areas involved four clicks.
Western basin whales favored a 3+1 coda pattern; eastern basin whales used a faster version.
Eastern basin whales occasionally produced the western dialect.
The Mediterranean sperm whale population is small and endangered, numbering a few thousand individuals.
Genetic studies have previously suggested Mediterranean sperm whales became isolated from other sperm whales about 20,000 years ago.
Key figures
Dr Luke Rendell, University of St Andrews, co-author of the study.
Sources: The Guardian
