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// Workers AI · dad joke modeWhat did the spitting cobra say? "You're venom-ous to my ego.

From Wikipedia, the free encyclopedia
(Redirected from Spitting cobras)
Schematic comparison between sections of non-spitting cobra fangs (left) and spitting (right).
1: Section of the whole fang in the sagittal plane.
2: Horizontal section through the fang at the discharge orifice.
3: Frontal view of the discharge orifices.
Juvenile red spitting cobra, Naja pallida
Red spitting cobra

The term "spitting cobra" is commonly used to refer to several species of cobra that can intentionally, defensively shoot their venom directly from their fangs. This substance has two functions, with the first being as venom that can be absorbed via the victim’s eyes, mouth, or nose (or any mucous membrane or existing wound), and secondly as a toxungen, which can be sprayed on the target surface. Their ability to target and shoot venom is used in several different ways, self-defense being the most common instance.[1] Studies have shown that the targets (at which the cobras shoot) are far from random; rather, spitting cobras consciously take aim, directing their spray to the eyes and face of an aggressor with 90% accuracy.[2] In a remarkable case of convergent evolution, the individual cobra species evolved the ability to spit venom independently.[3]

Overview

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An alert, ready to attack Mandalay spitting cobra (Naja mandalayensis)
Handling of Naja siamensis, using full-face protection

Venomous snakes use venom as both a defensive and predatory mechanism, which includes the spitting cobras. Spitting cobras belong to the Elapidae, which comprises the cobras, mambas, coral snakes, kraits, taipans, death adders, and sea snakes.[4]

Spitting cobras typically inhabit dry savanna and semi-arid environments, particularly the hotter, open areas of sub-Saharan Africa.[4] They use venom primarily as a means of defense: spitting cobras have the ability to project venom several metres away from its location, and to accurately target the face of a potential threat.[1] The cobras can measure and adjust the venom dosage being delivered, based on the size and relative distance of their target, in order to ensure the highest envenomation potential possible.[5]

A 2021 study showed that the evolution of spitting in three cobra lineages, which are Hemachatus along with some African and Asian Naja species, corresponds to the separation of the human and chimpanzee evolutionary lineages in Africa and the arrival of Homo erectus in Asia. The authors therefore hypothesize that the arrival of bipedal, tool-using primates may have triggered the evolution of spitting in cobras.[6]

Toxicity

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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.[7][8] 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 origins roughly correlating with the evolution and/or arrival of early hominins.[6]

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.[9] 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 behaviour.[10][11] When cornered, some species "spit" their toxungen as far as 2 m (6.6 ft).[7]

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. Spitting cobras evolved higher pain-inducing venom through increased phospholipase A2 levels, which potentiate the pain-inducing action of the cytotoxins present in most cobra venoms.[6]

While spitting is typically their primary form of defense, all spitting cobras are still able to envenomate by biting. Bites are their primary method of killing prey, and delivers more venom than spitting, which is a purely antipredatory behavior.[12]

Species

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African cobras:

Asian cobras:

The following cladogram follows the analysis of Lee (2016), with the spitting taxa bolded:[7]

Additionally, some of the Viperidae have been reported to spit occasionally.[example needed][13]

Notes

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  1. 1 2 3 Not a “true spitting cobra”; although these species have the ability to “eject” venom, they rarely do so.

References

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  1. 1 2 Westhoff, G.; Tzschätzsch, K.; Bleckmann, H. (October 2005). "The spitting behavior of two species of spitting cobras". Journal of Comparative Physiology A. 191 (10): 873–881. doi:10.1007/s00359-005-0010-8. ISSN 0340-7594. PMID 16007458. S2CID 39976553.
  2. ↑ Charles Q. Choi (2010-05-28). "Secret to Spitting Cobra's Deadly Accurate Aim Revealed". livescience.com. Retrieved 2025-03-16.
  3. ↑ "Spitting cobras' venom evolved to inflict pain". www.science.org. Retrieved 2025-03-16.
  4. 1 2 Hus, Konrad; Buczkowicz, Justyna; Petrilla, Vladimír; Petrillová, Monika; Łyskowski, Andrzej; Legáth, Jaroslav; Bocian, Aleksandra (2018-03-08). "First Look at the Venom of Naja ashei". Molecules. 23 (3): 609. doi:10.3390/molecules23030609. ISSN 1420-3049. PMC 6017371. PMID 29518026.
  5. ↑ Berthé, Ruben Andres; de Pury, Stéphanie; Bleckmann, Horst; Westhoff, Guido (2009-08-01). "Spitting cobras adjust their venom distribution to target distance". Journal of Comparative Physiology A. 195 (8): 753–757. doi:10.1007/s00359-009-0451-6. ISSN 1432-1351. PMID 19462171. S2CID 26202435.
  6. 1 2 3 Kazandjian, T. D.; Petras, D.; Robinson, S. D.; van Thiel, J.; Greene, H. W.; Arbuckle, K.; Barlow, A.; Carter, D. A.; Wouters, R. M.; Whiteley, G.; Wagstaff, S. C.; Arias, A. S.; Albulescu, L.-O.; Plettenberg Laing, A.; Hall, C.; Heap, A.; Penrhyn-Lowe, S.; McCabe, C. V.; Ainsworth, S.; da Silva, R. R.; Dorrestein, P. C.; Richardson, M. K.; Gutiérrez, J. M.; Calvete, J. J.; Harrison, R. A.; Vetter, I.; Undheim, E. A. B.; Wüster, W.; Casewell, N. R. (2021). "Convergent evolution of pain-inducing defensive venom components in spitting cobras" (PDF). Science. 371 (6527): 386–390. Bibcode:2021Sci...371..386K. doi:10.1126/science.abb9303. ISSN 0036-8075. PMC 7610493. PMID 33479150.
  7. 1 2 3 Panagides, Nadya; Jackson, Timothy; Ikonomopoulou, Maria; Arbuckle, Kevin; Pretzler, Rudolf; Yang, Daryl; Ali, Syed; Koludarov, Ivan; Dobson, James; Sanker, Brittany; Asselin, Angelique; Santana, Renan; Hendrikx, Iwan; Van Der Ploeg, Harold; Tai-a-Pin, Jeremie; Van Den Bergh, Romilly; Kerkkamp, Harald; Vonk, Freek; Naude, Arno; Strydom, Morné; Jacobsz, Louis; Dunstan, Nathan; Jaeger, Marc; Hodgson, Wayne; Miles, John; Fry, Bryan (13 March 2017). "How the Cobra Got Its Flesh-Eating Venom: Cytotoxicity as a Defensive Innovation and Its Co-Evolution with Hooding, Aposematic Marking, and Spitting". Toxins. 9 (3): 103. doi:10.3390/toxins9030103. PMC 5371858. PMID 28335411.
  8. ↑ Leslie, Mitch (2021-01-21). "Spitting cobras' venom evolved to inflict pain". Science. doi:10.1126/science.abg6859. ISSN 0036-8075. S2CID 234134648.
  9. ↑ 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. Bibcode:2004JExpB.207.3483Y. doi:10.1242/jeb.01170. PMID 15339944.
  10. ↑ Berthé, Ruben Andres. Spitting behaviour and fang morphology of spitting cobras. Doctoral thesis, Rheinischen Friedrich-Wilhelms-Universität, Bonn, April 2011.
  11. ↑ 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.
  12. ↑ Hayes, William K.; Herbert, Shelton S.; Harrison, James R.; Wiley, Kristen L. (September 2008). "Spitting versus Biting: Differential Venom Gland Contraction Regulates Venom Expenditure in the Black-Necked Spitting Cobra, Naja nigricollis nigricollis". Journal of Herpetology. 42 (3): 453–460. doi:10.1670/07-076.1. ISSN 0022-1511. S2CID 86154588.
  13. ↑ Wüster, Wolfgang; Thorpe, Roger S. (December 1992). "Dentitional phenomena in cobras revisited: Spitting and fang structure in the Asiatic species of Naja (Serpentes: Elapidae)" (PDF). Herpetologica. 48 (4): 424–434. JSTOR 3892862.[dead link]
  • Greene, Harry W. (1997) Snakes: The Evolution of Mystery in Nature. University of California Press, Berkeley and Los Angeles, California.
[edit]
  • 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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