That's a Joo lie. They were actually experimenting on joos and turned 6 Gorillian of them into dinosaurs that they were going to train to help terraform the moon so men could live among the stars. But all the dinosaurs wanted to do was eat all the valuables they could find. So the Nazis created a time machine and sent them all into the far distant past to protect the rest of the world. Unfortunately those dinos evolved into the modern Joo and thus the Nazis unknowingly created the very problem they were trying to save the world from. Unintended consequences.