Our brains are the product of millions of years of evolution. Scientists would very much like to know how some of the most ancient brains functioned and evolved over time, but that’s obviously not possible, owing to the complete lack of primordial brains to work with. As a good consolation prize, however, scientists can work with crocodiles—an animal that originated more than 200 million years ago, barely changing over the eons. Accordingly, scientists can study crocodiles to understand at which point certain brain structures and behaviors first emerged.