Cobra
From Wikipedia, the free encyclopedia
A cobra (pronunciation ) is a venomous snake of family Elapidae, of several genera, but particularly Naja. (Non-cobra elapidae include the taipans, brown snakes, tiger snakes, fierce snakes, coral snakes, mambas, and sea snakes.) Cobras generally inhabit tropical and desert regions of Asia and Africa.
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[edit] Appearance and description
The cobra's most recognizable feature is its hood, a section of its neck which it can flatten outwards in a threat display. Note that most snakes can flatten their necks to some degree; cobras are only more adept. Cobras come in varying colors from black or dark brown to yellowish white. Elapidae cannot fold their fangs down, as Viperidae can, so their fangs are generally shorter. Most cobras are quite large, reaching on average 1.2–2.5 m (3.9-8.2 ft) long.
Cobra is the Portuguese (and old Galician) common name for a snake; it came from the late Latin word for "a snake": colobra (from the classical Latin coluber, colubra). When Portuguese navigators arrived on the coasts of Africa and South Asia in the 16th century, they named the cobra "cobra-capelo", or "hood-snake"; from this compound, the name entered Spanish, French, English, and other European languages.
They kill their prey by injecting a neurotoxin through their hollow fangs. The neurotoxin blocks the synaptic communication between the victim's neurons and muscles, thus stopping movement and muscle control.
The cobra's predators include the mongoose and some raptors.
[edit] Types of cobra
The following is far from a complete list.
The most common cobra is the Indian cobra or Spectacled cobra Naja naja, native to the Indian subcontinent and associated with snake charming there. The Black cobra, found in Pakistan and North India, is generally considered to be a sub-species.[citation needed]
The second most common cobra species is the Monocled cobra, Naja kaouthia, widespread in Asia.
In addition to a deadly bite, the Spitting cobra can incapacitate larger would-be predators by delivering venom to their eyes. While extremely irritating, it rarely causes lasting damage if washed out promptly
The King cobra is ophiophagous; it feeds almost entirely on other snakes, even venomous ones, although it sometimes preys on small rodents and birds. It will only attack humans if provoked or in other extreme circumstances that threaten its survival.If not treated, a king cobra's bite can kill a person in just half an hour. King Cobras may reach up to 5.2m (17.1ft) in length, making them the largest venomous snakes in the world.
[edit] Cobra venom
As with all elapids, the venom of cobras is highly neurotoxic and dangerous. Therefore, any cobra bite must be regarded as life-threatening and professional medical assistance should be immediately sought. Early symptoms of a bite include ptosis, diplopia , dysphagia, and dizziness, followed by progressive respiratory muscle weakness, ultimately requiring endotracheal intubation.
Standard treatment involves the use of antivenom. Additionally, it is possible to support bite victims via mechanical ventilation, using equipment of the type generally available at hospitals. Such support should be provided until the venom is metabolised and the victim can breathe unaided. If death occurs it takes place approximately 6 to 12 hours after the cobra bite. Cause of death is respiratory failure ie suffocation caused by complete paralysis of the diaphragm.
[edit] Rhythm
Indian snake charmers play a harmless trick on spectators. A cobra rises from its basket and sways in time with the music, apparently hypnotized. In fact, as far as the snake is concerned, the music is irrelevant - the cobra can't hear a thing. What prompts it to perform is the snake charmer's clever manipulation of the cobra's natural tendencies. When suddenly thrust into the open air from the darkness of the basket, the snake rises up and spreads its hood, its normal reaction to a threat. It sees the swaying pipe and mistakes it for another snake. That error, together with the charmer's movements in time with the music, holds the snake's attention. As the charmer moves the pipe, so the cobra bobs its head. That is the only way for the snake to follow the pipe's movements, because it cannot swivel its eyes.
[edit] Trivia
- The archaic term asp was used to describe many venomous snakes and the asp said to have been used by Cleopatra VII to commit suicide may have been an Egyptian cobra.
- In Vietnam, cobras are bottled in rice wine to produce snake wine, which is believed to possess medicinal properties.