Dinosaurs often had the necessary features and indeed owed their superiority over the mammals for millions of years to having evolved them. Similar answers to evolutionary problems arise repeatedly. Convergence suggests that the solution of the problem of the evolution of intelligence in mammals and dinosaurs would yield similar features in both. By making deductions from convergence we can reveal otherwise unsuspected possibilities. Humans have many characteristics of aquatic animals, pointing to an extended period of partial submergence which could explain a gap of four million years in our fossil record.
Evolution can occur astonishingly quickly.
Intelligent dinosaurs could evolve, as Homo sapiens did, in a geologically short time. Because evolution and extinction were rapid they left few traces. Puzzles in old rocks could be remains of the dinosaurian civilization. Though this should be the most important evidence, it is poorly documented, having been glossed over or ignored by the experts. But even without it the circumstantial case remains strong.