Cobra

The hood is a warning display, not a hunting tool. When a cobra feels threatened it lifts the front third of its body off the ground and swings a series of long, hinged ribs in its neck outward and forward, which stretches the loose skin there into a broad flat disc. This makes the snake look much larger and more dangerous, and in many species shows off bold eyespots or bands on the back of the hood. The message is to leave it alone, since a cobra would rather not waste venom, which takes time and energy to replace, on an animal too big to eat. If the bluff fails, the bite follows.

Some can, and it is a genuine spray rather than true spitting. The spitting cobras have fang openings that face forward rather than down, and by squeezing the venom glands with the mouth slightly open they fire twin jets of venom that break into a fine mist, accurately aimed at the face of a large attacker from up to about 2.5 metres. On skin the venom does little, but in the eyes it causes severe pain and inflammation and can scar the cornea and cause blindness if not washed out quickly with plenty of water or any bland liquid. Only a subset of African and Asian cobras spit; the king cobra and Indian cobra do not.

Potentially deadly, but very treatable with modern care. Cobra venom is mainly neurotoxic, blocking the chemical signal from nerve to muscle, so a serious bite brings drooping eyelids, difficulty swallowing and speaking, and finally paralysis of the breathing muscles, which can kill within hours if untreated. Cobras cause a large share of the snakebite deaths in Africa and Asia, mostly among farmers and children in rural areas with poor access to hospitals. Where antivenom and the ability to support breathing are available, the great majority of bite victims survive. Some cobra bites also cause serious local tissue death around the wound.

Cobra is a common name rather than a scientific group, applied to several only distantly related snakes that share the habit of rearing and hooding when alarmed. Most true cobras are stout, medium to large snakes in the family Elapidae, the same family as mambas, coral snakes, and sea snakes, all of which have short fixed front fangs and mostly neurotoxic venom. This sets them apart from vipers, which have long folding fangs and mostly tissue-destroying venom, and from the harmless constrictors. The king cobra is not a true cobra at all but a close relative that grew large and specialised in eating other snakes.