Different sperm whale ‘dialects’ detected on separate sides of the Mediterranean | Whales

From “Hello” to “G’day,” English – like other languages ​​– is rich in dialects. Now researchers have found that sperm whales on different sides of the Mediterranean show similar differences in their vocalizations.

Sperm whales communicate vocally using short click sequences called codas. But the rhythmic pattern of these clicks, known as dialects, can vary between different matriarchal groups.

More importantly, a group of sperm whales can only associate with another group if they share the same dialect and therefore belong to the same “vocal clan”.

Co-author of the new study, Dr. from the University of St Andrews. “Polish is used to create social structures for these animals to cooperate in,” Luke Rendell said, noting similarities in how humans might be more comfortable conversing with someone who looks like them.

Now Rendell and his colleagues say they have discovered two distinct dialects among Mediterranean sperm whales; A small, endangered population of a few thousand individuals thought to have first entered these waters approximately 20,000 years ago.

What’s more, they say this finding offers new insight into how sperm whale dialects emerged.

Writing in the journal Proceedings of the Royal Society BThe team notes that genetic studies have previously suggested that Mediterranean sperm whales were isolated from other sperm whales. There are also signs that mating between those living in the western and eastern Mediterranean basins is limited, although individuals have been seen moving between the two.

In the new study, researchers analyzed hydrophone recordings of Mediterranean sperm whale groups made over 112 days between 2003 and 2021. These have been recorded around the Hellenic Trench near Greece in the eastern Mediterranean and around the Balearic Islands off the coast of Spain in the western basin.

While the team found that some codas were largely confined to the eastern or western groups, most sperm whale codas in both regions contained four clicks.

However, whales in the western Mediterranean basin preferred the 3+1 coda, which involves three clicks at regular intervals followed by a longer pause followed by another click, while whales in the eastern basin tended to use a faster version. However, there was a transition, with sperm whales in the eastern basin occasionally producing the western dialect.

Rendell said the findings show that sperm whales first settled in the western basin of the Mediterranean before spreading eastward and developing a dialect more quickly.

“The whales in the east remember the old ways, but they move on and clearly have a slightly different version of the same thing.” [general type of coda]but they improved it a little; “They changed it,” he said.

Rendell added that the results not only show that the process of dialect formation is slow, but also that it requires a level of isolation between populations; This situation, stated by the authors, is also important in the cultural evolution of human languages ​​and bird song dialects.

“This is the first example where we can look at a snapshot and think: ‘Oh, this seems to tell us how new dialects emerge,'” Rendell said. “We knew there were different dialects, but we never saw or had any clues as to their origin. And here we see that a group of sperm whales that separated from the main population are now starting to change their dialect as well.”