- Mammals’ bodies outpaced their brains right after the dinosaurs died. According to the analyses of mammal skulls from creatures that lived shortly after the dinosaur mass extinction, for at least 10 million years after the dinosaurs disappeared, mammals got a lot brawnier but not brainier. https://www.sciencenews.org/article/mammal-big-bodies-small-brains-dinosaur-extinction-fossils 5 comments science