Yeah, so the idea of something such as a "dinosaur" did not even occur to anyone until the early 1800's. How could the writers of the Bible have written about something that wasn't even a known concept at the time in which they were writing? ;-) They wrote about stuff they could relate to, and stuff which they thought was important enough to merit writing about.

They did mention something about a dragon, in that Satan was referred to as a dragon in some passage. The prevalence of dragon myths in old legends in many parts of the world is an interesting phenomenon, given that the dragon seems to combine features of legged reptiles, snakes, and birds. It also is normally said to "breathe fire".

Perhaps the dragon legends had some kind of conscious or subconscious link to the dinosaurs that once inhabited the Earth. Then again, maybe not. I doubt that anyone will ever be able to figure it out.