[potsandpans]

there's really no saying. mammals have been around for ~180 million years, so ~112 million before the mass extinction. The dinosaurs were on earth for about 165 million years.

Given the relative quickness that intelligence exploded in later hominids, who knows. we could know about some gibbon analog in the dinosaurs right now, that given just a little longer could've made it to human levels of intelligence.