If there ever had been a dino civilisation how would science look for or understand signs that it existed?
Interestingly small mammals coexisted with dinos for a very long time and long before they evolved into cave men so maybe there isn’t evolution of a big brain isn’t inevitable.
https://bigthink.com/the-past/dinosaur-civilization/
https://ask.metafilter.com/268088/Would-there-be-any-way-of-knowing-if-dinosaurs-had-a-civilization