Sperm whales have different dialects that they adopt through social learning, scientists have discovered. The findings suggest sperm whale communication is the result of a process similar to those that generate human cultures.
Researchers led by the Dalhousie University in Canada published their findings in the journal Nature Communications. Sperm whales live in multi-level societies containing family groups that form part of larger clans. Within these clans, whales communicate using similar patterns of clicks – or codas.
The team used models created with an 18-year empirical study to show how each clan can be distinguished by similarities in the patterns of their vocal clicks, and that these differing dialects emerge as a result of social learning rather than genetic or cultural processes.
Study author Maurício Cantor and the team looked at social interactions and vocalisations of sperm whales near the Galapagos Islands to find out how these dialects might have emerged and simulated interactions between individuals. Their findings show the most likely way clans rose is by whales learning the vocalisations of other whales that behave similar to them.
Distinct clusters of individuals with similar acoustic repertoires, mirroring the empirical clans, emerge when whales learn preferentially the most common codas (conformism) from behaviourally similar individuals (homophily), they wrote. Cultural transmission seems key in the partitioning of sperm whales into sympatric clans.
By means of feedback between homophily and social influence, individuals who behave similarly preferentially associate and learn from one another, increasing their behavioural similarity. This process breeds relationships among like-minded individuals, and simultaneously tends to dissolve relationships between individuals with distinct behaviour.
