A spitting cobra is any of several species of cobras that can defensively spray a toxic secretion from their fangs. This secretion functions as both a venom (that can be injected via a wound) and a toxungen (that can be sprayed on the target surface). Venom The spat toxungen is generally harmless on intact mammalian skin (although contact can result in delayed blistering of the area), but can cause permanent blindness if introduced to the eye; if left untreated it may cause chemosis and corneal swelling. The toxungen sprays out in distinctive geometric patterns when muscles squeeze the glands to squirt it out through forward-facing holes near the tips of the fangs. Individuals of some species of spitting cobras make hissing exhalations/lunging movements of their heads when "spitting", and such actions may 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 behavior. When cornered, some species "spit" their toxungen as far as . While spitting is typically their primary form of defense, all spitting cobras also can deliver their toxin as a venom by biting. Most spitting cobras' venom/toxungen is significantly cytotoxic, apart from the neurotoxic and cardiotoxic effects typical of other cobra species. The ability to spit likely evolved in cobras three times independently through convergent evolution. In each of these three events, the venom convergently evolved to be more effective at creating pain in mammals to serve as a better deterrent, with each of the three evolutions roughly correlating with the evolution and/or arrival of early hominins. Species ‡: Not a “true spitting cobra”, although these species have the ability to “eject” venom, they rarely do so and when they do use this defense, it is exceptionally rare. African cobras: Naja ashei Naja katiensis Naja mossambica Naja nigricincta Naja nigricincta woodi Naja nigricollis Naja nubiae Naja pallida Asian cobras: Naja atra ‡ Naja kaouthia ‡ Naja sagittifera ‡ Naja mandalayensis Naja philippinensis Naja samarensis Naja siamensis Naja sputatrix Naja sumatrana Spitting snakes in other families: Hemachatus haemachatus Some of the Viperidae have been reported to spit occasionally. References Greene, Harry W. (1997) Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley and Los Angeles, California. External links Video of an African red spitting cobra spraying its venom Video of an African red spitting cobra feeding Discovery News