Killer whales (Orcinus orca) possess the ability to engage in cross-species vocal learning, according to a University of San Diego study.

The researchers found that these whales socialized with bottlenose dolphins, they produced sounds that closely matched their social partners.

Humans, bats, some birds and cetaceans including whales and dolphins among others can also imitate new sounds like barks, gobbles and shrieks - the ability, known as, vocal learning. The finding suggests that vocal imitation may ease social interactions in cetaceans.

"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. There needs to be some experimental proof so you can say how well they learn and what context promotes learning," said Hubbs-SeaWorld Research Institute senior research scientist Dr. Ann Bowles in a press release.

For the study, the researchers compared old recordings of vocalizations patterns of killer whales that had been held with bottlenose dolphins to those of killer whales in same-species groups. The comparison was conducted to determine the degree to which killer whales learned vocalization patterns from dolphins.

The researchers found that killer whales that had been confined with dolphins for several years emitted sounds that closely matched with that of the dolphins'. For example, they generated more clicks and whistles and fewer pulsed calls. Plus, one killer whale living with dolphins learned how to create a chirp sequence that humans had previously taught the latter mammals.

"It's important to understand how they acquire [their vocalization patterns], and lifelong, to what degree they can change it, because there are a number of different [cetacean] populations on the decline right now," said Bowles. "And where killer whales go, we can expect other small whale species to go-it's a broader question."

The finding is published in The Journal of the Acoustical Society of America.