The king cobra (Ophiophagus Hannah) is the world's longest venomous snake, with a length up to 5.6 m (18.5 ft). 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. Despite the word "cobra" in its name, this snake is not a member of Naja ("true cobras") but belongs to its own genus. The king cobra is considered to be a very dangerous snake.
There are 270 different types of Cobras and their relatives, including Taipans, Adders, Mambas, and many sea snakes including Kraits, and they all have short fangs and are all extremely poisonous.
The skin of this snake is olive-green, tan, or black, and it has faint, pale yellow cross bands down the length of the body. The belly is cream or pale yellow, and the scales are smooth. Juveniles are shiny black with narrow yellow bands (can be mistaken for a banded krait, but readily identified with its expandable hood). The head of a mature snake can be quite massive and bulky in appearance, though like all snakes, they can expand their jaws to swallow large prey items. It has proteroglyph dentition, meaning it has two short, fixed fangs in the front of the mouth which channel venom into the prey like hypodermic needles. The male is larger and thicker than the female. The average lifespan of a wild king cobra is about 20 years.
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.
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. King cobras are able to hunt throughout the day, although it is rarely seen at night, leading most herpetologists to classify it as a diurnal species.
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.