Dinosaurs are enemies and characters that appeared in the original Spyro series, though one, Dino-Rang appears in Skylanders. Few of the notable enemies from the Classic games are, Ripto and his Riptocs, as well as other dinosaur enemies from various worlds. It was noted by Spyro in Spyro: Enter the Dragonfly that dinosaurs and magic don't mix, which is why Ripto never fully properly used his magic.
Population
It is unknown how big the population is, but Ripto managed to create an army.