In the animal kingdom, it's an evolutionary arms race between attack and defense. Nat Geo counts down the animals with the top 10 security systems. Buffalo surround their young, forming a barricade against the savannah's predators. Mess with them, and you'll wish you'd never been born. Surprisingly, the best defenses may be the simplest ones. Field fares, small birds, fight their enemies with their feces. And the most fearless animal of all, the honey badger, eats venomous snakes for breakfast.