Scientists were stunned when they first heard Bonnie whistle. The 30-year-old female orangutan at the Smithsonian National Zoo had never been taught to whistle, but she figured out the trick all by herself back in the 1980s, according to her caretakers. That makes her the first documented case of a primate spontaneously mimicking the sounds of another species—in this case, humans.
Though she can’t carry a tune, Bonnie seems to enjoy whistling and will usually happily comply when asked to do it. You can even watch her whistle on Youtube. The researchers, who published a paper on Bonnie in the journal Primates [subscription required], say she also taught another orangutan, Indah, how to whistle. Bonnie and Indah dispel the theory that orangutan vocalizations are only involuntary reactions to stimuli, and are mainly determined by evolutionary factors.
Instead, whistling orangutans suggest that orangutans can learn and teach each other new vocalizations. This would explain why separate populations of orangutans in the wild seem to maintain different repertoires of sounds—which can include screams, grumbles, barks, raspberries, and kiss squeaks.
Research on Bonnie may shed some light on the evolution of human speech. Too bad primates just don’t have the same vocal chords as we do. But imagine if they did—what would they say? Although scientists have already managed to have monkeys control prosthetic limbs using brain-machine interfaces. Maybe with the addition of a voice synthesizer we could eventually hear an orangutan speak.
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Image: flickr / AZAdam