Different dialects emerge in sperm whale societies through cultural learning, finds a study in Nature Communications. The study suggests that processes similar to those underlying the formation of human cultures also operate in complex animal societies.>
As occurs in human societies, sperm whales live in multi-level groups, where individuals within family units group together into larger clans. Each clan can be distinguished by similarities in the pattern of their vocal 'click' repertoires, but it is not fully understood how different clans can emerge when there are no physical barriers separating groups in the ocean.
Mauricio Cantor and colleagues use a dataset accumulated over 18 years characterising the social interactions and vocalisations of sperm whales living near the Galapagos Islands to investigate the most likely way in which these vocal clans may have emerged. Using agent-based modelling to simulate interactions between individuals, they show that the most likely way in which these clans could have arisen is by whales preferentially learning the vocalisations of other whales that behave similarly to them.
The authors also find that other possible scenarios, such as genetic inheritance of call structures, or random fixation of call types among groups, cannot explain the patterns observed in the wild. This suggests that information flow within groups - for example, types of communicative signals - may be responsible for the emergence of clans and help maintain their cohesion.