Once you know the shape of the melanosomes in a fossil, you can learn all sorts of things about the animal. For example, some dinosaurs with fearsome reputations were incredibly showy. "Many of the close relatives of Velociraptor — you know, that was chasing the kids around in the kitchen [in "Jurassic Park"]?" Vinther said. "First of all, that was covered in feathers. It was really bird-like, not like this naked thing that we see there. But furthermore, most of the relatives that we looked at that were close to it, they were iridescent. So they would have had a...