text: who were the dinosaurs? hint: not "what" were the dinosaurs?  see question "where does oil really come from?" for additional clue. simple answer:  dinosaurs apart from being prehistoric lizards were the recipe for a lot of the oil and coal that exists underground in the earth as well as under seas and swamps.   that's why coal and oil are refered to as "fossil fuels" because petroleum, oil, and coal are all comprised of previous dead organisms such as animals and plants (and of course the dinosaurs).  i hope this answered your question and helps.