Where dinosaurs hot or cold bloodied?
The debate about whether dinosaurs were hot or cold-blooded is quite controversial. It used to be assumed that dinosaurs were cold-blooded like their reptile ancestors. Some paleontologists have recently argued that at least some dinosaurs were fast, active, competed against hot-blooded mammals, lived in cool areas, were related to birds, and therefore were endothermic (generating their own body heat, or hot-blooded).