whistling ape

Recently, a keeper was walking past the great ape house at the Smithsonian National Zoo, in Washington DC, when he heard whistling coming from inside. Thinking that one of the zoo's visitors had infiltrated the restricted area, he hurried to investigate. It turned out not to be a person who was making the noise, but one of the ape house's long-time residents, Bonnie, a 30-year-old orangutan.Serge Wich and his colleagues at the Great Ape Trust in Des Moines, Iowa, think she copied it from the keepers and have been studying Bonnie's behaviour since she went public. She can't hold a tune, as such, and in the scientists' opinion she doesn't whistle for attention, or to ask for anything, but just to pass the time of day. "It appears that she does it for her own satisfaction," says Al Setka, a spokesman for the trust.