A 400-pound wall of pure muscle wrapped in a surprisingly gentle soul—until you threaten its family. The silverback gorilla can bench-press an estimated 1,800 pounds and possesses grip strength capable of crushing a crocodile's skull with its bare hands. Pound for pound one of the strongest animals on Earth, and smart enough to learn sign language while doing it.

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.