Hearing a parrot mimicking human speech is nothing new, but hearing a whale mimicking the sound of humans talking will definitely surprise you.

Back in the year of 1984, a diver at the National Marine Mammal Foundation in San Diego emerged from the whale tank, and said, "Who told me to get out?" It was later determined that the sound "out" was uttered by a captive beluga whale named NOC; rather than a human being.

Researchers later found that chatting between whales in the tank sounded largely like two people conversating far away.

Comparison of recordings of NOC to human speech revealed that the rhythm of the whale's sound indeed matched that of human beings. The researchers were surprised to find that the whale's pitch, clicks and whistles were largely similar to that of humans.

NOC uttered those human speech-like sounds by making tweaks in the pressures in his nasal cavity and broadening a pair of vibrating lip-like structures in his blowhole.

Researchers are of the view that the whale's close proximity to human beings let it to listen to and imitate human speech.

The research appears in the recent issue of journal Current Biology.