The Secret Societies of Sperm Whales

How can we differentiate one sperm whale clan from another? The most clearly established distinctions by researchers are the vocal dialects that characterize each clan. Used notably for echolocating prey, the spermaceti organ in the enormous head of these marine giants also plays a role in communication.

A recent study by researcher Taylor A. Hersh demonstrates how certain codas are used as symbolic markers between clans. Cultural groups use symbolic markers to identify themselves. In humans, these markers could take the form of a tattoo or an anthem, while in sperm whales, clans are distinguished by their dialect. Indeed, each clan has identity codas that always follow a specific pattern. Thus, the codas seem to act as signals that enable sperm whales to identify the clan of origin of their peers. By listening and analyzing the patterns of these codas, seven different clans of sperm whales were identified in the Pacific Ocean. Identity codas also have an important place within a clan’s social structure. Using codas, a social unit can choose other units from within the same clan to form a group.

Sperm whales are marine mammals that can be observed around the globe. They can also be found in the St. Lawrence River. Given that the geographical range of a given clan can cover huge swaths of ocean – from Japan to Chile, for example – it is not uncommon for several clans to coexist in the same waters. Codas recorded in two clans sharing the same territory are more likely to have more pronounced differences in their patterns.

And where do males fit into all this? After all, sperm whales can sometimes be observed roaming the seas alone. While females stick together their whole lives, the Encyclopedia of Marine Mammals describes very different behaviour for males. Once they’ve acquired their cultural baggage from their mothers, they leave the family unit in which they grew up to join more loosely-knit groups composed solely of other young males. However, they later end up splitting off and migrating northward, alone, toward the colder waters of the globe. After they have reached sexual maturity, they seek out females with which to reproduce, but only linger for a few hours per social unit. Males are not shy about mating with females from other clans, as Whitehead mentions.