In Aesop's fable "The Crow and the Pitcher," a parched crow discovers a pitcher holding water. The liquid is pooled at the bottom of the vessel where the crow can't reach it. So in typical Aesopian fashion, the crow comes up with the idea to drop pebbles into the water one by one, making the liquid rise to the top and allowing the bird to quench its thirst. The moral of the story: "Little by little does the trick." Scientists from New Zealand recently brought the fable to life. They put New Caledonian crows to the test with vessels of various shapes and sizes. In most instances, crows were able to manipulate the water level to a height that allowed them to reach a morsel of food that was floating on top, they report this week in PLOS One. The same task—known as the Aesop's fable paradigm—has been given to children as a cognitive test. Sarah Jelbert, a PhD student in psychology at Auckland University and the study's lead scientist, wanted to test out the limits to the crows...