An Animal version of Deadliest Warrior?

Ok I remember watching a show once and it was really good but its not on and i have no idea what it was called. Two sides had a different animal like one had hippo the other alligator in one episode. They would calculate the force m etc. and build a robot version. Then like in Deadliest Warrior they would "act out" what would happen if the two animals met. I remember that the Hippo bit the gator in half.