Not only are killer whales the largest of the dolphin family but they’re also recognized as one of the world’s largest powerful aquatic apex predators – but did you know they can speak?

Over time, orcas – also known as killer whales – have evolved to swim up to 40 miles a day, according to National Geographic. They can hunt on land and are actually in possession of the largest marine mammal brain.

Here’s something you may not know about orcas though – they can apparently copy basic human words like ‘hello’ and ‘bye bye’.

Orcas are one of the most intelligent marine mammals in the world (Wirestock/Getty Images)

Orcas mimicking human language

The recording is part of a 2018 study published in the journal Proceedings of the Royal Society B: Biological Sciences, which saw experts from Germany, Spain, the UK and Chile documenting how they discovered orcas could mimic human language.

Josep Call, a professor in evolutionary origins of mind at the University of St Andrews and co-author, explained the researchers initially wanted to see ‘how flexible a killer whale can be’ when it comes to copying sounds they’re not used to.

“We thought what would be really convincing is to present them with something that is not in their repertoire – and in this case ‘hello’ [is] not what a killer whale would say,” Call said, per The Guardian.

The team carried out the research by first training a 14-year-old orca named Wikie to copy three familiar orca sounds made by her three-year-old calf, then exposing her to five orca sounds she had never heard before.

The human sounds the orca was able to say

Finally, Wikie heard a human make three orca sounds, then six human sounds including the words ‘hello’, ‘Amy’, ‘ah ha’, ‘one, two’ and ‘bye bye’.

After listening to Wikie’s responses, the team found that the orca was able to quickly copy the sounds, including nailing two of the human utterances on the first attempt.

Recordings of Wikie capture her attempts to mimic the human speaking to her, and while admittedly some of the attempts sound like they’ve come from a terrifying goblin, others are eerily accurate.

Listeners have been left unnerved by the recordings, with one viewer commenting: “The hello sounded demonic.”

Wikie the whale succeeded in mimicking a number of human sounds (Abramson et. al/CBS News)

And another joked: “OK, that second hello was a little demonic. Was that really an orca, or the Devil speaking through a ghost box LOL The funniest and scariest thing EVER! That’s my day, can’t stop laughing my head off lol.”

But as demonic as the recordings might sound, other viewers have pointed out just how amazing it is to hear the whale mimic humans.

“This makes me tear up, the fact that we live in a such a beautiful world filled with wonderful creatures,” one person wrote.

While only one human sound given to Wikie – ‘hello’ – was correctly produced more than 50 percent of the time on subsequent trials, the findings offered the first evidence that orcas may be learning sounds by vocal imitation.

“This is something that could be the basis of the dialects we observe in the wild – it is plausible,” Call said.

Can orcas understand what these sounds mean?

Wikie’s responses are made even more impressive by the fact her vocal apparatus is so different to humans.

Call said: “Even though the morphology [of orcas] is so different, they can still produce a sound that comes close to what another species, in this case us, can produce.”

That being said, Call added: “We have no evidence that they understand what their ‘hello’ stands for.”

Though the research with Wikie has offered some initial insight, Call noted that more trials would need to be carried out with wild orcas to learn more about how they learn sounds.