The undisputed king of the African savanna, the lion commands respect with a bone-crushing bite force and claws that can shred steel-drum lids. Hunting in coordinated prides, a male lion's 550-pound frame and thunderous roar can be heard from five miles away. Few animals dare challenge this apex predator on its home turf.

The largest land carnivore on Earth, the polar bear is a 1,500-pound Arctic killing machine perfectly engineered for sub-zero survival. Its paw swipe can decapitate a seal in one motion, and it can smell prey from 20 miles away across frozen tundra. Evolution looked at the grizzly bear and said 'what if we made it bigger, meaner, and gave it a fur coat rated to negative 50?'