Bonnie, a 30-year old female orangutan living at the Smithsonian National Zoological Park in Washington D.C., began whistling on hearing the sound made by her care-taker. This caught scientists’ attention because it was long argued that orangutans have no voluntary control over their vocals and that their sounds are purely emotional – more like a response to stimuli like predators.

I think humans are the evolutionary dead end not orangutans. Party! More whistling!