The Cassowary is the only bird that made it to this list. Their kicks can rupture your organs and internal bleeding which can result in death. Also, they can claw you. Just imagine its claws going into you. Sure, protective parent owls clawing your eyes out and causing you to fall down a tree to your death (it has happened) are scary, but these birds are usually harmless unless you do something really stupid. While the vegetarian Cassowary (found in the rainforests of Australia and New Guinea) is usually a shy animal, and will try to avoid confrontations, males can be extremely aggressive at times, and zookeepers agree that cassowaries are among the most dangerous creatures to keep in a zoo. Listed by the Guinness World Records as the world’s most dangerous bird, the Cassowary has an enormous, dagger-like claw on the second toe of each foot. When confronted, it will leap into the air and kick its enemy, kung fu-style, using the deadly claws to cause serious injury. It can, literally, claw your guts out. And even if it doesn’t, the kick is mighty enough to rupture your internal organs and cause massive internal bleeding and death. Needless to say, you should never approach one of these birds, particularly if they are captive or protecting their chicks.