What does anybody need a brain for? Brains are energetically expensive to make and to use, and susceptible to making mistakes. Accordingly, not learning, i.e. sticking to an innate or random strategy, is often the best thing to do. Still, humans and other animals display sophisticated learning and cognition. Recent research shows that each animal has specific learning abilities and lacks others according to its environment and evolutionary history. Understanding what different brains are used for can help us understand why they evolved.