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The "Clickish" Culture of Sperm Whales
Deep-diving mammals' unique vocalizations hint at complex social learning

In a paper published Sept. 8 in the journal Nature Communications and covered extensively around the world, a group of researchers including Bren School postdoc Reniel Cabral, a marine population ecologist with expertise in modeling, describe how they used idiosyncratic vocal “clicks” emitted by sperm whales to gain insights into the animals’ complex multi-level societies. The team's findings suggest that processes similar to those that generate complex human cultures could be at play in non-human societies and create multilevel social structures in the wild. In other words, sperm whales may have culture.

Reniel Cabral

The researchers used 18 years of data gathered by a group led by principal investigator Hal Whitehead to determine that, while sperm whales’ ability to communicate via vocalized clicks — the loudest noises produced by any animal — is part of the mammals' genetic inheritance, the patterns in which they emit them are not. Further, they found, individuals in different sperm whale clans, which comprise hundreds of individuals, communicate by using patterns of clicks shared almost exclusively by individuals within that clan.

The study parallels studies from the 1990s demonstrating that different groups of chimpanzees that were isolated from each other showed cultural differences. For instance, various groups used blades of grass as a tool to get insects out of the ground, but different groups had learned to use the tool differently.

But there is an important difference between the chimp study and this new whale study. The chimp communities that learned to use the same tool differently were geographically separated from each other, leading scientists to conclude that such isolation led to the differences in learned behavior. The ocean, on the other hand, has no such barriers, and sperm whale clans often encounter each other and may swim together in large groups.

Sperm whales organize themselves into social units of about a dozen individuals, and those groups are part of larger clans that may comprise hundreds of individuals. In the Galápagos, for instance, a thousand sperm whales may be found swimming together in one area, a population that includes multiple clans.

Despite that extensive mingling, though, individual clans develop click patterns unique to their clan, and their calves then learn the sounds that are preferred by the group. This is perhaps the most significant finding of the study, for it suggests a higher or more subtle level of social learning.

"It's interesting to find key features of human culture in other, non-human societies," Cabral said.

Read the paper.

A sperm whale photographed in clear Caribbean waters