Imagine the surprise among researchers when they discovered that what appeared to have been a human conversation near the beluga whale enclosure was actually the voice of the captive mammal. The accompanying audio clip is a sample of the whale’s mimicry of human speech, and it’s sure to inspire smiles, laughter, disbelief, or even awe among listeners.

The whale, named NOC (pictured, below right), lived at San Diego’s National Marine Mammal Foundation for 30 years before dying in 2007. The study was recently published in Current Biology under the title “Spontaneous human speech mimicry by a cetacean.”

Of that initial discovery in 1984, study co-author Sam Ridgeway, of the U.S. Navy Marine Mammal Program, told National Geographic: “You could hear there was a conversation, but you couldn’t make out what they were saying.”

The conversation was heard several times and the source remained a mystery until a human diver told researchers he had heard what sounded like a request to get out of the water. The voice turned out to be from NOC, which had formed the word “out” and repeated that word several times while the diver was in the water.

This began after NOC had spent seven years in captivity.

Researchers then embarked on their study, and recordings revealed that the white whale had learned to speak with human-like frequencies and rhythms.

In the wild, beluga whales are highly social and communicate in a language of clicks, whistles, and clangs.

However, they have been known to mimic other sounds.

As for captive belugas, this might not be the only evidence of one of the small whales attempting to mimic human speech.

About 15 years ago, staff at Vancouver Aquarium suggested that a 15-year-old beluga had uttered its name, “Lagosi.”

NOC lived among dolphins and socialized with two female belugas. His spontaneous mimicry of human voices subsided after about four years, when he became sexually mature.

The study concluded: “We do not claim that our whale was a good mimic compared to such well-known mimics as parrots or mynah birds. However, the sonic behavior we observed is an example of vocal learning by the white whale. It seems that NOC’s close association with humans played a role in how often he employed his human voice, as well as in its quality.”

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–Image showing NOC before his death in 2007 is courtesy of the U.S. Navy