A cobra is any of several highly poisonous snakes in the family Elapidae, including mambas, coral snakes, kraits, and true cobras. It can expand its neck ribs to form a characteristic hood. Found primarily in Africa and Asia, cobras are the favorite of snake charmers and feed on rats, toads, and small birds. The king cobra (Ophiophagus hannah) reaches 5.5 meters (18.5 feet) in length, and is the largest venomous snake in the world. The Indian cobra (Naja naja) with the spectacle-like markings on its hood, frequents houses at night to search for rats and is responsible for the deaths of several thousand people a year. Some African species have forward-facing fangs and can spit venom into a victim's eyes from more than 2 meters (7 feet), causing temporary or permanent blindness.