Large, fearsome, deadly, and now bilingual, orcas, or killer whales as they are commonly known, demonstrate an ability to reproduce the sounds dolphins use to communicate. The striking black-and-white marine mammal joins a short list of animals that possess the ability to imitate sounds and use them in appropriate social contexts, including humans, elephants, seals, bats, and birds.

This ability to imitate sounds and use them in social ways is called “vocal learning,” an ability that has been extensively studied in birds. Avian researchers have characterized vocal learning in songbirds to the level of identifying specific neural pathways. Similar investigations in large marine mammals is difficult and has been slow to arrive.

Researchers at the University of San Diego and the Hubbs-SeaWorld Research Institute found that when killer whales are socialized with bottlenose dolphins, they alter the types of sounds they make and end up closely matching their social partners. This is evidence that vocal imitation may facilitate social interactions in different cetacean (whale and dolphin) species.

Previous research has already shown that killer whales possess complex vocal repertoires consisting of clicks, whistles, and brief bursts of sound punctuated with silence, or “pulsed calls.” Acoustic features have been observed to vary by social groups whereby closely related or co-residing whales produce similar pulsed calls that are distinct for that group. Cetacean scientists refer to these group-specific vocalizations as dialect.

“There’s been an idea for a long time that killer whales learn their dialect, but it isn’t enough to say they all have different dialects so therefore they learn,” said Ann Bowles, senior author of the study. “There needs to be some experimental proof so you can say how well they learn and what context promotes learning.”

The results of the study were published this week in the Journal of the Acoustical Society of America.