Orangutans try to communicate by gesturing in the same way as people do, researchers find.
In a series of sessions with captive female orangutans, Richard Byrne and his colleagues at the University of St. Andrews in Scotland offered individual animals a whole serving of a favorite food, a half serving, or a food that the apes didn't prefer. The scientists recorded signals that the animals made before food appeared, when it was offered, and after the food was given over.
"They have gestures that have more or less precise meanings," Byrne says. He notes that such abilities are often considered uniquely human.
"It's what orangutans do when they're thwarted that reveals what's in their minds," Byrne says.