Venomous snake
3887502
222475994
2008-06-29T15:22:16Z
Jwinius
141528
[[WP:UNDO|Undid]] revision 222466939 by [[Special:Contributions/206.126.209.43|206.126.209.43]] ([[User talk:206.126.209.43|talk]]) to remove link to hobbyist site.
A '''venomous snake''' is a [[snake]] that uses modified saliva, [[snake venom|venom]], usually delivered through highly specialized teeth such as hollow fangs, for the purpose of [[prey]] immobilization and self-defense. In contrast, non-venomous species either [[constriction|constrict]] their [[prey]], or simply overpower it with their jaws.
Venomous snakes include several [[family (biology)|families]] of snakes and do not form a single [[taxonomic classification|taxonomic]] group. This 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 [[pseudogene]]s) 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.
Venomous snakes are often said to be poisonous, although this is not the correct term, as [[venom]]s and [[poison]]s 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.<ref name="Kla97">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.</ref>
Many other snakes, such as [[Boidae|boas]] and [[Pythonidae|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.
==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:
<br/><br/>
{|cellspacing=0 cellpadding=2 align="center" border=1 style="border-collapse: collapse;"
!bgcolor="#f0f0f0" style="width:30%"|Family
!bgcolor="#f0f0f0"|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)
|[[Naja|Cobras]], [[Micrurus|coral snakes]], [[Bungarus|kraits]], [[Dendroaspis|mambas]], [[sea snake]]s, sea kraits and Australian elapids.
|-
|[[Viperidae]] (viperids)
|[[Viperinae|True vipers]] and [[Crotalinae|pit vipers]], including [[Crotalus|rattlesnakes]].
|-
|}
==References==
{{Reflist}}
[[Category:Snakes]]
[[Category:Venomous animals]]
[[cs:Jedovatí hadi]]
[[de:Giftschlangen]]
[[ja:毒蛇]]
[[nn:Giftslange]]
[[zh:毒蛇]]
==External Links==
*[http://www.fda.gov/Fdac/features/995_snakes.html For goodness snakes] Treating and Preventing Venomous Bites.
*[http://www.venomoussnakes.net Venomous Snakes] Pictures, videos and description of the most venomous snakes in the world.