Orca whales can learn how to speak dolphin, according to a new study. This shows the marine animals, also known as killer whales, are one of the few that has ever been known to emulate other species.

The study examined 10 captive killer whales, three of which lived with bottlenose dolphins, and seven that lived with other orcas. The three animals who lived with dolphins communicated using a large number of whistles, buzzes and clicks, similar to sounds made by their smaller cousins. The study showed that the remaining seven whales continued to use pulses in their communications. Orca whales are capable of producing a wide range of sounds, which include clicks and whistles, in addition to pulses. Whales who live together in a pack develop unique variations, known to cetacean biologists as a 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. There needs to be some experimental proof so you can say how well they learn and what context promotes learning," Ann Bowles, senior research scientist at Hubbs-SeaWorld Research Institute, said.

The three orcas living with bottlenose dolphins provided researchers with the perfect opportunity to study how the animals reacted to the situation. Dolphins and orcas are capable of producing many of the same sounds, but usually do so in differing proportions. Investigators on the study compared recordings of each group of killer whales, allowing them to measure the degree to which cross-species vocalizations had been adopted by the larger marine mammals.

One killer whale learned a unique sequence of chirps from the dolphins, which was taught to them by one of their human caretakers.

Dolphins also possess similar skills to orcas, allowing them to mimic the sounds of whales and other wild animals.

Sounds made by members of most species are ingrained in the animal - they are unable to produce any vocalization except the range of call with which they were born. Other species known to learn from the sounds of other animals and mimic them include humans, bats, birds, elephants and seals.

Researchers believe killer whales may imitate dolphins in order to aid with social interactions. The ability also shows a high degree of neural plasticity - the ability to adapt brain circuits to new situations - in the animals.

"Killer whales seem to be really motivated to match the features of their social partners," Bowles told the press.

Discovery of killer whales imitating dolphins was profiled in the Journal of the Acoustical Society of America.