With no place to go and no one to care for them, the became a real problem when they got smart as hell REALLY fast. They took over in a big way, their massive flying death-beasts were one thing, but it was the humanoid ones that really took the world by storm. They had gone through our technological infancy at light-speed, something about Reptilian reproduction with long life spans…. their brains were different, more focused.
The Dinos took earth, the sites of the fights are still there, burning and enclosed, they use them as entertainment, theme parks really.