Click ... click ... click-click-click. That’s the sound of a sperm whale in the eastern Caribbean.
Click-click-click-click-click. That’s a sperm whale that lives in the same place, but in a different social group.
Shane Gero and his team have discovered that each sperm whale social group in the region has its own clicking pattern, or dialect. (Also see "Whales With Caribbean Accents and Other Animal Dialects.")
What's more, each sperm whale that Gero observed socializes exclusively with other sperm whales that have the same accent.
The finding strengthens the idea that sperm whales throughout the world have different cultures, just like people. "It’s like how my Canadian passport tells you a little bit about who I am. I like hockey and I put maple syrup on everything," says Gero, a behavioral ecologist and founder of the Dominica Sperm Whale Project.
"The main way we identify these different cultures is their dialects,” he says.
Listen to Caribbean sperm whales vocalizing.
For a new study, Gero and colleagues analyzed 11 social sperm whale units, or clans, by recording their voices and observing their actions.
Scientists already knew that sperm whales in the Pacific Ocean have vocal clans, but this is the evidence of such clans in the Atlantic Ocean, according to the study, published recently in Royal Society Open Science.
Richard Connor, a dolphin and whale expert at the University of Massachusetts, Dartmouth, believes that these behavioral and vocal differences started as random variations that eventually developed into part of a clan’s culture. (Related: "Sperm Whales' Language Reveals Hints of Culture.")
“You could think of it as random error in learning,” says Connor, who wasn't involved in the study.
“But once those differences are there, that becomes a sort of membership tag.”
And communicating as a group likely helps them hunt more efficiently, the experts say.
“It’s probable that these groups travel in different areas and they track habitats, which includes … prey,” said Sarah Mesnick, an expert on sperm whale social structure at the Southwest Fisheries Science Center in California. (Also see "Rare Video Captures Sperm Whale in Deep Sea.")
“They know those areas. They transmit that information socially through the groups.”
The ongoing research into sperm whale culture suggests there's more at stake for the species, which still faces threats due to climate change and buildup of toxic metals, Gero adds.
That's because if one sperm whale clan goes extinct, that’s it: All that tradition and ancient wisdom specific to their niche is lost.