Spitting cobra

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Juvenile red spitting cobra, Naja pallida
Red spitting cobra

A spitting cobra is one of several species of cobras that have the ability to eject venom from their fangs when defending themselves against predators. The sprayed venom is harmless to intact skin. However, it can cause permanent blindness if introduced to the eye and left untreated (causing chemosis and corneal swelling).

The venom sprays out in distinctive geometric patterns, using muscular contractions upon the venom glands. These muscles squeeze the glands and force the venom out through forward-facing holes at the tips of the fangs.[1] The explanation that a large gust of air is expelled from the lung to propel the venom forward has been proven wrong.[2] When cornered, some species can "spit" their venom a distance as great as 2 m (6.6 ft). While spitting is typically their primary form of defense, all spitting cobras are capable of delivering venom through a bite, as well. Most species' venom exhibit significant hemotoxic effects, along with more typical neurotoxic effects of other cobra species.

Contents

[edit] Species of the spitting cobras

African:

Asiatic:

[edit] Other spitting species

Some nonspitting cobras and vipers have been noted to spit occasionally. Certain predominantly Asian cobras have the spitting tendency.[3] The rinkhals (Hemachatus haemachatus) is another elapid species, which, while not belonging to the cobra genus Naja, is closely related and is capable of spitting venom.

Several viper species (notably the Mangshan pitviper) have been reported to "fling" or even spit venom forward in a spray when threatened. These sprays are often very consistent.

[edit] References

  1. ^ Young, BA, Dunlap, K, Koenig, K and Singer, M (2004) The buccal buckle: the functional morphology of venom spitting in cobras. The Journal of Experimental Biology, 207: 3483–3494
  2. ^ Rasmussen, S, Young, B and Krimm H (1995) On the 'spitting' behaviour of cobras. Journal of Zoology, 237: 27–35
  3. ^ Wüster, W and Thorpe, RS (1992) Dentitional phenomena in cobras revisited: Spitting and fang structure in the Asiatic species of Naja (Serpentes: Elapidae). Herpetologica, 48: 424–434
  • Greene, Harry W. (1997) Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley and Los Angeles, California.

[edit] External links

  • Video of an African red spitting cobra spraying its venom
  • Video of an African red spitting cobra feeding
  • Discovery News 'Spitting Cobras' Sharp-Shooting Secrets"
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