In a surprising discovery, it has been revealed that killer whales can copy human speech and can mimic words like "hello" and "bye bye".
A killer whale named Wikie has started "talking" human language.
High-pitched, eerie and yet distinct, the sound of a voice calling the name "Amy" is unmistakable.
"The results reported here show that killer whales have evolved the ability to control sound production and qualify as open-ended vocal learners", the scientists conclude.
Although mimicking human sounds is hard for mammals, whales can seemingly learn to reproduce them by hearing.
"The evidence that killer whales can show vocal learning provides us with a missing piece of understanding about their lives in the wild", Rendell wrote.
Researchers say she might even be able to hold basic conversations with humans in the future.
A new experiment was carried out in which Wikie was trained in a way that she could understand the signal when she had to mimic and her trainer invited and gave her 11 new sounds like howling of a wolf, elephant call and a creaking door. They sometimes even attempt to communicate with other species: scientists have observed killer whales mimicking the sounds of bottlenose dolphins and sea lion barks.
In the wild, different killer whale groups demonstrate unique vocal "dialects", and they have been documented copying noises made by other species. In fact, an African grey parrot recently garnered headlines by mimicking human speech so accurately that the bird was referenced in a murder trial, allegedly for speaking what may have been its owner's last words before the man was killed.
Wikie copied a trainer at Marineland Aquarium in Antibes, France.
"Yes, it's conceivable ... if you have labels, descriptions of what things are", he said. The female orca, who was born in captivity and has two sons, learned to copy sounds and words.
Though the recordings are not ideal, they are recognizable, including when she says, "Amy", the name of her trainer.
To determine whether the original sounds and Wikie's versions matched, the researchers asked human judges to decide, and then ran computer algorithms to provide a more objective assessment of the similarities.
While the sounds were all made and copied when the animals' heads were out of the water, Call said the study shed light on orca behaviour.
Dr Irene Pepperberg, an expert in parrot cognition at Harvard University, also described the study as exciting, but said: "A stronger test would have been whether the various sounds produced could be correctly classified by humans without the models present for comparison".