I think a better question is this:
What if there was no mass extinction that killed the dinosaurs?
It's possible that an intelligent dinosaur would have developed tens of millions of years before mammals had a chance to evolve. If that was the case dinosaurs I think it's very likely that dinosaurs would have evolved into humanoids with advanced intelligence and eventually create civilization. Could they have maintained their civilization for millions of years to still be around today? I don't know. In tens of millions of years humans will either have destroyed themselves or left earth for other planets. Maybe dinosaurs didn't go extinct. Maybe the left Earth millions of years ago.
BTW: Doctor Who starts up again today on BBC America!
