In an ancient Greek fable about the value of ingenuity, a thirsty crow raises the level of water in a pitcher by dropping in stones. Researchers who presented chimps with a similar problem to the one in the 2,000-year-old Aesop fable found that some of the animals were able to solve it by spitting water—and, in one, case, urinating—into a vessel to obtain an out-of-reach floating peanut. The urinating chimp was "spitting water into the tube, then got frustrated, so he started peeing and then he realized: 'Wait a minute, if I move in that direction, that fills up the tube,'" the lead researcher tells the BBC. The urine didn't stop the chimp from eating the peanut, the scientist noted.
A third of the chimps studied were able to obtain the peanut, a task which flummoxed all the gorillas studied. "I think it is quite impressive—I call it insightful behavior," the lead researcher says. The team presented human 4, 6, and 8-year-olds with a similar task, giving them watering cans. Only two of the 24 4-year-old children were able to complete the task. Ten of the 24 6-year-old kids managed it, and 14 of the 24 8-year-olds worked out that they needed to use the water. An earlier study found that all four crows presented with the quandary had no problem solving it.