>>13634870Lot of assumptions you've made OP, firstly that Dinosaurs consist of some kind of monolithic category when it's actually a very diverse group shoehorned into a coinage in 1841 to describe certain types of fossils. While there are very few identified species of Dinosaurs (in the hundreds - many for which the only record is a single fossil!), it's probably only a fraction of a fraction of the total number of Dinosaur species that ever roamed the earth. After all, we haven't found the fossil of every dinosaur that ever lived, right?
Secondly that length of time has anything to do with it, the evolution of anatomically modern humans happened very quickly and very recently.
Also it's kinda like compound interest - once it accelerates it's like a rocket. Isn't he theory that early humans out-hunted and even out-sexed Neanderthals? Once a sufficiently 'smart' brain has evolved, it becomes a evolutionary arms race to keep up.
But the answer you're probably looking for is climatic. The earth was a lot hotter in the Jurassic period and rapidly and dramatically cooled. Humans are what biologists use to call a K-Species, we take a lot of time raising our young, we also don't have litters. The thing about K-species is you need a stable climactic environment. A lot of the advantages of human brains are social i.e. K-species traits that require lots of acculturation so they can cooperate to survive.
