One of the smartest dinosaurs was the Troodon, which was 6.5 feet long but had a brain-to-body ratio similar to that of a modern bird or mammal. The dumbest dinosaur was the stegosaurus, its brain was the size of a walnut and its body was the size of a van.
Scientists aren't clear on how long dinosaurs lived, but some speculate that they may have lived as long as 200 years. Also, contrary to what many people believe, paleontologists do not divide dinosaurs into the groups of herbivores and carnivores, but rather by their hip-bone structure. They are categorized as either saurischian, meaning lizard-hipped, or ornithischian, meaning bird-hipped. Saurischian dinosaurs, which included both carnivores and herbivores, had one hip bone pointing forward. Ornithischian dinosaurs were herbivores, and all their hip bones pointed backwards. Scientists believe that birds evolved from the saurischian dinosaurs, rather than their namesake.
Scientists also believe that not all dinosaurs were cold-blooded. They have a solid case arguing that some dinosaurs, specifically the smaller carnivores, may have been warm-blooded.
The early Chinese used their discovery of dinosaur teeth as proof for the existence of dragons. The first recorded dinosaur bone discovery was made in China around 3,500 years ago, long before people knew about dinosaurs.