For a long time paleontologists have studied the bones and teeth of dinosaurs they once thought that the tissue or proteins could only survive for four million years. scientist say that they have found dinosaur collagen. The Lufengosaurus walked on two legs instead of four. it was a plant eater. They thought that tissue would be long gone by now but a study in 2015 said that they had found red blood cels in a carnivoris dinosaurs claw