The Ravens understand the basic principles of hydrostatics; In the myth 'the thirsty Crow', Aesop describes how a clever bird cast pebbles in a half-full pitcher in order to raise the level and finally to be able to drink water. The legend was the basis for an IQ test in which a Crow New Caledonia (Corvus moneduloides), by researchers at the University of Auckland in New Zealand, they brought before a difficult problem.