Fossil evidence tells us that like most other reptiles and birds the dinosaurs built nests and laid eggs. Layer upon layer of fossilised nests in the Gobi Desert suggest that the dinosaurs returned to the same nesting sites year after year. Nests, young helpless chicks and caring parents all are images that we find familiar and comforting. It reassures us that even a creature as strange and alien as a dinosaur was capable of the nurturing, social behaviour that we find so reassuring and essential in our own lives. There is also the vexed question of whether dinosaurs were cold or warm blooded.
Reptiles are cold but birds are warm blooded.
But perhaps the greatest mystery of all is how they became extinct. Whatever killed them must have been catastrophic. A highly successful group of animals that roamed the Earth for over 150 million years, more than seventy times longer than humans, were wiped off the surface of the planet forever. It may have been small but the Eoraptor had razor sharp teeth. A whole branch of scientific study has grown up around the study of dinosaur fossils.