Underwater recordings reveal that, depending on whether they live in the eastern or western Mediterranean, sperm whales do not have the same repertoire of clicks to communicate with members of their group. Those of the East would have modified the dialect of the West by accelerating it.
An international team has just highlighted two dialects among sperm whales (Physeter macrocephalus) depending on whether cetaceans live in the east or western Mediterranean. Obtained through the analysis of underwater records made over a period of one hundred and twelve days between 2003 and 2021, the results are detailed in an article publiced on June 24 in Proceedings of the Royal Society B.
Sperm whales communicate by making series of a few clicks, called « codas ».« The sperm whales of the western Mediterranean favor a 3 + 1 format coda, composed of three regular clicks followed by a long pause, then a last click. Those in the East, on the other hand, tend to use a faster version, » reports The Guardian.
A dialect derived from the other
The fact that sperm whales share the same repertoire of codas is a structuring factor of society. Luke Rendell, a biologist at the University of Saint-Andrews, Scotland, and co-author of the new study, reminds the British newspaper that humans are also more inclined to engage in conversation with individuals who share the same language.
According to the researchers, the dialect of the oriental sperm whales would have evolved from that of their Western congeners: sperm whales, present in Mediterranean waters 20,000 years ago, would have first established themselves in the West, around the Balearic Islands, before a small group conquered the East.
“Easten cetaceans remember the good old days, but they continue on their way and they use a slightly different version of what is clearly a common coda. They made it evolve, » says Luke Rendell.
source : courrier international
