Bonnie, a 30-year-old female orangutan living at the Smithsonian National Zoological Part in Washington, D.C., started doing something strange one day: she started whistling!
Scientists have long known that orangutans copy physical movements of humans, but Bonnie's whistling indicates that the learning capacities of orangutans and other great apes in the auditory domain might be more flexible than previously believed, Wich said. The behavior goes against the argument that orangutans have no control over their vocalizations and the sounds are purely emotional that is, an involuntary response to stimuli such as predators.
Bonnie appears to whistle for the sake of making a sound rather than to receive a food reward or some other incentive. If asked to whistle, she is likely to oblige, another indication to scientists that she makes the sound voluntarily.