Washington: In a surprise finding, scientists have discovered that a white whale can make voices uncannily close to human speech.
During acoustic analysis of the mammal, researchers at the National Marine Mammal Foundation in California found the whale could imitate human speech.
Interestingly, whales are known to produce sounds in a manner that is wholly different from humans.
"Our observations suggest that the whale had to modify its vocal mechanics in order to make the speech-like sounds," said Sam Ridgway of the National Marine Mammal Foundation.
In 1984, Ridgway and others began to notice some unusual sounds in the vicinity of the whale and dolphin enclosure. As they describe it, it sounded as though two people were conversing in the distance, just out of range of their understanding.
The unusually familiar sounds were traced back to one white whale in particular only some time later when a diver surfaced from the whale enclosure to ask his colleagues an odd question: "Who told me to get out?"
Researchers identified a white whale called NOC behind it. NOC had lived among dolphins and other white whales and had often been in the presence of humans.
White whales or beluga whales are Arctic and sub-Arctic cetacean.
While there have been other anecdotal reports of whales sounding like humans before, but in this case Ridgway's team wanted to capture some real evidence.
They recorded the whale's sounds to reveal a rhythm similar to human speech and fundamental frequencies several octaves lower than typical whale sounds, much closer to that of the human voice.
"Whale voice prints were similar to human voice and unlike the whale's usual sounds. The sounds we heard were clearly an example of vocal learning by the white whale," Ridgway said.
Whales make sounds via their nasal tract, not in the larynx as humans do. To make those human-like sounds, NOC had to vary the pressure in his nasal tract while making other muscular adjustments and inflating the vestibular sac in his blowhole, the researchers found.
However, after 30 years at the National Marine Mammal Foundation, NOC passed away five years ago.
The details were published in journal Current Biology.
First Published: Tuesday, October 23, 2012, 15:40