Bonnie is an orangutan who has learned how to whistle from humans. Article plus video here.

The 140-pound (63.5-kilometer) orangutan at the National Zoo in Washington, D.C., has been whistling for about two decades.

Now a new study suggests that the sounds she makes could hold clues about the origins of human language.

“The assumption is that someone was whistling and she probably picked it up from them,” said animal keeper and study co-auther Erin Stromberg.

Lisa Stevens, the zoo’s curator for great apes and giant pandas, said the key point is that the orangutan was not trained to whistle.

While orangutans can be taught new sounds with extensive training, Bonnie is the first indication that the animals can independently pick up the sounds from other species.

“It’s something she spontaneously developed,” Stevens said. “It wasn’t a trick.”

How does this relate to human language? Some linguists are interested in how language might have arisen in primates. In particular, Michael Arbib’s ‘Mirror Hypothesis‘ suggests that the ability to recognise and imitate the actions of others (both gestures and vocalisation) may have played a key role. Communication prepared the evolving brain for more complex cognition, and more complex cognition led to more involved communication.

With that in mind, it’s interesting that an ape would be able to imitate such an oral (if not vocal) behaviour. I was kind of surprised, however, that an orangutan was doing the imitating. As I remember, orangutans are rather solitary, and communication is social behaviour. Evidently the wiring for this kind of imitation goes pretty deep.