Following our article on the various killer whale ecotypes, one reader asked whether killer whales of different ecotypes are able to communicate with each other, or if they had different “languages”.
In a marine environment with practically zero visibility, sound plays an essential role in the daily life of the killer whale, allowing it to roam the ocean, hunt its prey and interact with members of its own species. Calls, grunts, whistles, squeals, clicks: the killer whale has a vast vocal repertoire!
From one killer whale ecotype to another, the use of these sounds varies significantly. Since they evolve completely independently, do not consume the same resources and do not interbreed, these ecotypes have no necessity to come into contact with one another. In this context, each variety seems to have developed its own separate repertoire.
Some killer whale ecotypes live in isolated environments, which would easily explain their dissimilarities. But other ecotypes occasionally cross paths while maintaining a completely distinct mode of communication. This is the case for resident killer whales, Bigg’s killer whales and offshore killer whales. These three varieties all reside off the coast of British Columbia, in the Northeast Pacific.
When hunting, offshore killer whales are characterized by their silence, while one can hear a whole racket of “clicks” amongst the residents. This difference is readily explained: the former ecotype hunts marine mammals, which can hear the frequencies emitted by killer whales, while the latter feeds exclusively on fish, which cannot detect these frequencies. Each ecotype has therefore developed its own language adapted to its own diet and feeding techniques.
Eyes of the heart
Even within ecotypes, there are “acoustic clans” which have their own dialect, strictly used for communication purposes. For example, the resident population of the Pacific has matriarchal units of two or three individuals that share the same whistles and calls. Thanks to the latter, the killer whales are able to recognize their “loved ones” and occasionally communicate over long distances. These types of vocalizations provide social cohesion within the group, and, unlike clicks used for hunting, are not shared by the entire community.
According to researchers, the existence of such “acoustic clans” is the result of cultural transmission. Indeed, their dialect is not “innate”, but rather learned and transmitted from generation to generation or between members of the same clan.
The exception proves the rule
There is, however, one exception that transcends the cultural boundaries of killer whales. Research suggests that there is a so-called “universal” call, which is believed to be produced by all populations of Pacific killer whales. It is thought to be used to signify a form of sexual arousal, though researchers are still unsure of its role in social interactions.
Scientists compare this sound to expressions of emotion in humans: instinctively understood by everyone, regardless of language barriers. Unlike so-called “cultural” vocalizations transmitted between generations or individuals, this call is believed to be innate. It therefore appears that the question of culture vs. nature is not unique to humans!