Evolutionary biologist Arkhat Abzhanov of Harvard University noted an apparent resemblance between the skulls of juvenile dinosaurs and adult birds and decided to do a more comprehensive study. With graduate student Bhart-Anjan Bhullar, he used CT scanners to examine dozens of skulls, including modern birds, theropods — the dinosaurs most closely related to birds — and earlier dinosaur species. By identifying various landmarks on the skulls, they were able to track how the skull shapes had changed over the years.
