A female orangutan named Bonnie from the National Zoo in Washington DC knows how to whistle and she does it because she can. Bonnie's whistling was documented by Great Ape Trust of Iowa early last December. Her self-taught talent shed new light on the evolution of speech, said Bonnie's keeper Erin Stromberg. "Sounds aren't necessarily all genetic ... they also can be behavioral or ecological, and they are also voluntary", Stromberg added. BBC picked up the story last Thursday.
Bonnie whistles because she feels like it, not because for potential food reward. Researchers thought that orangutans have a limited number of sounds that they can make, all are involuntary responses based on emotions or to avoid predators. Bonnie's whistling certainly changed this perception. It turns out that Bonnie's friend, Indah also knew how to whistle. Scientists believe that Indah learned how to whistle from Bonnie. Indah died in 2004.
Bonnie's vocal plasticity might be the answer for the evolution of speech in orangutans or even the great apes.
"Orangutan’s spontaneous whistling opens new chapter in study of evolution of speech". Click on the Great Ape Trust of Iowa website or the .pdf version to read more.