Sperm whales 'learn social dialects'

A new study suggests that social learning, rather than genetic transmission, explains how sperm whales cohere into distinct "clans".
A new study suggests that social learning, rather than genetic transmission, explains how sperm whales cohere into distinct "clans".PHOTO: GETTY IMAGES

PARIS • Sperm whales create social cliques based on a shared dialect of vocal clicks - evidence that humans are not alone in having a culture, according to new research.

Combining data gleaned from decades of field observation and computer models, the study published on Tuesday suggests social learning, rather than genetic transmission, explains how the whales cohere into distinct "clans".

Scientists have long known that sperm whales, living in stable communities - composed mainly of females and calves - communicate using patterns of vocal clicks, called codas. They have also determined that these highly intelligent creatures, boasting the largest brains in the animal kingdom, interact most frequently with other whales using a shared dialect.

"It is quite rare to find groups of animals of the same species, in the same area, with unique behaviours," said lead author Mauricio Canto, a biology professor at Dalhousie University in Halifax, Canada.

"What we didn't know was how these different sperm whale 'dialects' evolved," Prof Canto said.

It might be chance variations, or genetically imprinted patterns passed along to offspring.

But Prof Canto suspected it was something else: whales learning directly from their peers, especially those closest to them.

To test his theory, Prof Canto and his colleagues fed 30 years of field work, on sperm whales living near the Galapagos Islands, into data-crunching computers.

The researchers devised 20 different scenarios that might generate codas - based on genetics, learning and random improvisation - and then let each virtual whale population evolve over thousands of years.

The results, published in Nature Communications, all pointed in the same direction: The formation of whale communities with a common dialect was rooted in "behaviour that is socially learnt and shared with a subset of the population".

As it turns out, this is also one definition - albeit, a broad one - of culture, thought by many to be a unique and defining characteristic of the human species.

Over the last 15 years, another kind of "culture war" has pitted experts, notably anthropologists, against a small but growing band of biologists on the question of whether whales, dolphins, great apes, elephants and some song birds could be said to have culture.

"We do not suggest that animal cultures are the same as the diverse, symbolic and cumulative human cultures," Prof Cantor said.

"But like us, animals can discover new things, learn and copy things from each other, and pass along this information over generations."


A version of this article appeared in the print edition of The Straits Times on September 10, 2015, with the headline 'Sperm whales 'learn social dialects''. Print Edition | Subscribe