An orangutan at Washington's National Zoo has pleased her caretakers with a unique skill—she's taken up whistling. Researchers have previously taught apes to do so, but Bonnie is different in that she started on her own, apparently by mimicking zookeepers, NPR reports. (She also imitates workers sweeping floors and wiping windows.) Aside from providing a little music, scientists say Bonnie's skill could help them study the evolution of human speech.
In tests, researchers found that Bonnie, who's 32, would imitate long or short whistles. "She was pretty good at following what I was doing," said one. "I think what makes it significant is that she decided to do it on her own. Something made her want to whistle, or at least try it out. And so to me, she was challenging herself to do something else."