Meet Bonnie, the Smithsonian National Zoo's very own whistling orangutan. She got some attention recently when a paper published in Primates described her as the first ever case of a primate imitating a sound—a whistle—from another species—human—without being trained to do so.
"It seems like she heard people whistle and without being rewarded for it picked it up on her own," says one of her caretakers, Erin Stromberg, who has worked for the National Zoo for over six years. "It is louder when you’re right in front of her, and she can go from either sucking in or blowing out to make the whistle. So she’s actually quite good at it."
The behavior was first noticed back in the late 1980s, and was even picked up by another orangutan that has since passed on, but has only now been recorded. And the study, conducted in conjunction with the Great Ape Trust of Iowa, explored the phenomenon even further. Stromberg and another caretaker prompted Bonnie with short or long and one or two whistles to see if she would mimic the different sounds, and she did. "They never cease to amaze me with their intelligence," says Stromberg, of the orangutans.