Robert T. Bakker
In the 1960s, paleontologist John Ostrom began work on the theropod "Deinonychus". His findings, which were expanded upon by his student Robert T. Bakker, contributed to the Dinosaur Renaissance, a revolution in the study of dinosaurs. Of particular importance were a reevaluation of the origin of birds that showed them to be closely related to coelurosaurian dinosaurs, reappraisal of dinosaur physiology that suggested they were not the sluggish cold-blooded animals that they had long been assumed to be, and a recognition that dinosaurs formed a natural group.