Do we know the origin of the dragon figure in mythology? Is it possible that some ancient people unearthed a dinosaur fossil, and made up a story around it?
I recently provided a couple of answers to this question. You may want to have a look at this and this. Given those answers, let me know if you have any questions.
If I don't provide my user name, I'll get scolded by a bot: /u/itsallfolklore.