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. (Read more chimpanzees stories.)