User blog comment:BraveheartA7X/Resistance Universe/@comment-1839021-20100209211843/@comment-38.109.29.125-20130325194014

The Chimera were on the planet long before humans, therefore, they could not enslave them. It says they left when an object impacted Earth, 65 million yrs ago. This also presumably is the same one that killed the dinosaurs. Humans came about later.