Unchanged for 200 million years because evolution couldn't improve the design, the saltwater crocodile is a 2,200-pound ambush predator with the strongest bite ever measured in the animal kingdom. Its death roll can dismember prey in seconds, and it can lurk motionless for hours before exploding from the water at terrifying speed. Dinosaurs went extinct; this thing didn't.

Don't let the pudgy appearance fool you—the hippopotamus is widely considered the most dangerous large animal in Africa, killing more humans annually than lions, leopards, and crocodiles combined. Its massive jaws open to a terrifying 180-degree angle and generate 1,800 PSI of bite force through foot-long canine teeth. At 4,000 pounds, it can outrun most humans on land and is absurdly agile in water.