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. Individuals of some species of spitting cobras make hissing exhalations or lunging movements of their heads when "spitting", and it has been argued that such actions assist in propelling the venom, but research does not support the hypothesis that they play any major functional part except possibly enhancing the threatening effect of the behaviour. 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 cytotoxic effects, along with more typical neurotoxic effects of other cobra species.
Species of the spitting cobras
- Naja ashei
- Naja katiensis
- Naja mossambica
- Naja nigricincta
- Naja nigricollis
- Naja nubiae
- Naja pallida
Other spitting species
Some nonspitting cobras and vipers have been noted to spit occasionally. Certain predominantly Asian cobras have the spitting tendency. 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.
- Young, B. A.; Dunlap, K.; Koenig, K.; Singer, M. (September 2004). "The buccal buckle: The functional morphology of venom spitting in cobras". Journal of Experimental Biology 207 (20): 3483–3494. doi:10.1242/jeb.01170. PMID 15339944.
- Berthé, Ruben Andres. Spitting behaviour and fang morphology of spitting cobras. Doctoral thesis, Rheinischen Friedrich-Wilhelms-Universität, Bonn, April 2011.
- Rasmussen, Sara; Young, B.; Krimm, Heather (September 1995). "On the 'spitting' behaviour in cobras (Serpentes: Elapidae)". Journal of Zoology 237 (1): 27–35. doi:10.1111/j.1469-7998.1995.tb02743.x.
- Wüster, Wolfgang; Thorpe, Roger S. (December 1992). "Dentitional phenomena in cobras revisited: Spitting and fang structure in the Asiatic species of Naja (Serpentes: Elapidae)". Herpetologica 48 (4): 424–434. JSTOR 3892862.
- Greene, Harry W. (1997) Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley and Los Angeles, California.
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