Since the birth of paleontology, scientists have hotly debated whether dinosaurs were cold- or warm-blooded. It's been commonly suggested that warm-bloodedness was an avian innovation, something birds developed that their ancient dino relatives like Sue the T. rex did not. Traditional methods and tools like histology and scanning electron microscopes have hinted that this might not actually be true, but a new field of molecular paleobiology is giving us definitive answers. Watch us slice, dissolve, and shoot a laser at some of the Field Museum's coolest fossils to prove that dinosaurs weren't actually as cold-blooded as we once thought.