It seems unfairly menacing that a snake that can literally "stand up" and look a full-grown person in the eye would also be among the most venomous on the planet, but that describes the famous king cobra.King cobras can reach 18 feet (5.5 meters) in length, making them the longest of all venomous snakes. When confronted, they can raise up to one-third of their bodies straight off the ground and still move forward to attack. They will also flare out their iconic hoods and emit a bone-chilling hiss that sounds almost like a growling dog.Their venom is not the most potent among venomous snakes, but the amount of neurotoxin they can deliver in a single bite—up to two-tenths of a fluid ounce (seven milliliters)—is enough to kill 20 people, or even an elephant. Fortunately, king cobras are shy and will avoid humans whenever possible, but they are fiercely aggressive when cornered.King cobras live mainly in the rain forests and plains of India, southern China, and Southeast Asia, and their coloring can vary greatly from region to region. They are comfortable in the trees, on land, and in water, feeding mainly on other snakes, venomous and nonvenomous. They will also eat lizards, eggs, and small mammals.They are the only snakes in the world that build nests for their eggs, which they guard ferociously until the hatchlings emerge.King cobras may be best known as the species of choice for the snake charmers of South Asia. Although cobras can hear, they are actually deaf to ambient noises, sensing ground vibrations instead. The charmer's flute entices the cobra by its shape and movement, not by the music it emits.