A cobra produces its characteristic hood by spreading specialized neck ribs and the skin between them.
When threatened, many cobras raise the front part of the body and expand the neck into a broad hood. The display makes the snake appear larger and more conspicuous, helping discourage predators or other threats. It is a defensive signal rather than a separate body part or a rigid structure.
The name cobra is used for several venomous elapid snakes, especially species in the genus Naja. Not every snake called a cobra belongs to Naja: the king cobra, for example, belongs to the separate genus Ophiophagus. Some cobras also have distinctive hood markings, while others show a relatively plain hood.
Cobras are found across Africa and Asia, with related hooded elapids occurring elsewhere. Their venom varies among species and may affect nerves, muscles, or tissues. The hood itself is not evidence of a particular venom type; it is primarily a visual defensive adaptation.