Paleontologists don’t go looking for brains, and I’m not surprised. I once got to hold a fresh brain in my hands (it was at a medical school–nothing fishy, I promise), and I can vouch that they are marvelously delicate: a custard for thinking. When any vertebrate with a brain dies, be it human, turtle, or guppy, that fragile greasy clump of neurons is one of the first organs to vanish. Scientists must infer what ancient brains were like very often by examining the case that held it–that is, if they can find a relatively intact braincase.

In recent years, scientists have been able to get important clues about brains by scanning the brain cases. They can create virtual fossils in their