Are we the smartest creatures on the planet? Maybe. We certainly have abstract language down and we use it quite effectively to coordinate our actions. But our brains function like mammal brains, and they don’t seem to have any characteristic that we can definitively say is important, and we are the top. We certainly don’t have the biggest brains. A sperm whale’s brain is six times the size of ours. In fact, from a certain point of view, you can argue that humans aren’t actually intelligent. If the goal of a living system is to perpetuate itself, and we are, as some believe, living in a way that is not sustainable, then could you argue that collectively we are not an intelligent species?