One of the biggest differences between humans and animals is the ability to understand the idea of "If I do X, Y might happen." New Caledonian crows seem to possess the intelligence to understand this "causal" concept. Why do crows have this ability? What does the crow know and what does it tell us about brain size, the evolution of intelligence, and just who is the smartest creature on the planet? In the latest addition to the Scientists in the Field...