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Whales are among the great communicators of the animal world. They produce all sorts of sounds: squeaks, whistles and even epic arias worthy of an opera house.

And one whale in particular has apparently done something that's never been documented before: He imitated human speech.

The beluga, or white whale, is smallish as whales go and very cute, if you're into marine mammals. Belugas are called the "canaries of the sea" because they're very vocal.

These sounds are for things like echolocation, like bats use, or for basic communication, as in, "Hello, honey, I'm home."

But a white whale at San Diego's National Marine Mammal Foundation did something very different. NOC (pronounced Nocee), as he was called, lived in an enclosure in the San Diego Bay. Biologist Sam Ridgway was there one day when divers were swimming nearby. "This one diver surfaced next to the whale pen and said, 'Who told me to get out?' And the supervisor said, 'Nobody said anything.' "

A curious Ridgway started recording NOC. And what he heard was quite strange: It had the cadence and rhythm of human speech. No words were distinguishable, but the sounds were eerily "right." Ridgway laid out audiograms of NOC's chatter, and they showed that the rhythm and pitch were different from NOC's normal sounds: They were, in fact, very similar to human speech. NOC had lowered the pitch of his sounds several octaves below normal, into the range of human speech at 300-400 hertz.

Ridgway says there's no reason to think NOC understood speech; he was just mimicking humans he'd heard. From where? "I think it was from divers using underwater communication equipment," he says.

When NOC was mimicking humans, Ridgway looked inside the whale's nose. "He did an unusual thing that we had never seen before in any of these animals," Ridgway recalls, "which was, he overinflated the two large sacs that kind of collect air to make sound."

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