Once upon a time our ancestors climbed down out of the trees and ventured into the dry savanna. They might have a good view of the area standing on two legs, but they were at a hopeless disadvantage when it came to speed, agility and power. The biped's bare hands were no match for giant fangs and razor-sharp claws, or for the superior strength and the killer instinct of the natives. And yet it was possible to find ways to overcome slowness and lack of power.