Venomous snake
Venomous snake is any of a large and diverse number of snakes that is able to deliver venom (modified saliva) into another organism, typically for purposes of capturing prey or self-defense. Venom normally is delivered by means of a bite, using highly specialized teeth such as hollow fangs, while a poisonous organism involves ingestion of the animal or contracting the poisonous agent through the skin. Whereas venomous snakes use venom to immobilize prey, non-venomous species either constrict their prey, or simply overpower it with their jaws.
Venomous snakes include several families of snakes and do not form a single taxonomic group.
Overview
Venomous snakes are often said to be poisonous, although this is not the correct term, as venoms and poisons are different. Poisons can be absorbed by the body, such as through the skin or digestive system, while venoms must first be introduced directly into tissues or the blood stream through mechanical means. It is, for example, therefore harmless to drink snake venom as long as there are no lacerations inside the mouth or digestive tract.[1]
Many other snakes, such as boas and pythons may not be venomous, but their bites should be attended to medically. Their teeth may be long and sharp, capable of inflicting lacerations, with bites often introducing mouth bacteria and shed teeth into the wound.
The fact that venomous snakes are spread over several families has been interpreted to mean that venom in snakes originated more than once as the result of convergent evolution. Evidence has recently been presented for the Toxicofera hypothesis however; if correct, venom was present (in small amounts) in the ancestor of all snakes (as well as several lizard families) as 'toxic saliva' and evolved to extremes in those snake families normally classified as venomous by parallel evolution. The Toxicofera hypothesis further implies that 'non-venomous' snake lineages have either lost the ability to produce venom (but may still have lingering venom pseudogenes) or actually do produce venom in small quantities, likely sufficient to assist in small prey capture, but not normally cause harm to humans if bitten.
Families of venomous snakes
Over 600 species are known to be venomous — about a quarter of all snake species. The following groups of snakes can be aggressive and inflict dangerous, even potentially lethal bites:
| Family | Description |
|---|---|
| Atractaspididae (atractaspidids) | Burrowing asps, mole vipers, stilleto snakes. |
| Colubridae (colubrids) | Most are harmless, but others have toxic saliva and at least five species, including the boomslang (Dispholidus typus), have caused human fatalities. |
| Elapidae (elapids) | Cobras, coral snakes, kraits, mambas, sea snakes, sea kraits and Australian elapids. |
| Viperidae (viperids) | True vipers and pit vipers, including rattlesnakes. |
ReferencesISBN links support NWE through referral fees
- ↑ Klauber LM. 1997. Rattlesnakes: Their Habitats, Life Histories, and Influence on Mankind. Second Edition. First published in 1956, 1972. University of California Press, Berkeley. ISBN 0-520-21056-5.
External Links
- For goodness snakes Treating and Preventing Venomous Bites.
- Venomous Snakes Pictures, videos and description of the most venomous snakes in the world.
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