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Viper

2025-10-13T11:14:27Z

2001:4479:700:1500:50E6:FAB1:2F63:A4E6: Minor fixes to this section

{{Short description|Family of snakes}}
{{other uses}}
{{ref improve|date=August 2023}}
{{Use dmy dates|date=June 2021}}
{{Automatic taxobox
| fossil_range = {{Fossil range|47|0}} [[Eocene]]–Present <ref>{{Cite journal |last1=Wüster |first1=Wolfgang |last2=Peppin |first2=Lindsay |last3=Pook |first3=Catharine E. |last4=Walker |first4=Daniel E. |date=2008-11-01 |title=A nesting of vipers: Phylogeny and historical biogeography of the Viperidae (Squamata: Serpentes) |url=https://www.sciencedirect.com/science/article/abs/pii/S1055790308004211 |journal=Molecular Phylogenetics and Evolution |volume=49 |issue=2 |pages=445–459 |doi=10.1016/j.ympev.2008.08.019 |pmid=18804544 |bibcode=2008MolPE..49..445W |issn=1055-7903|url-access=subscription }}</ref>
| image = Viperidae-01.jpg
| image_caption =
| taxon = Viperidae
| authority = [[Nicolaus Michael Oppel|Oppel]], 1811
| synonyms = * Viperae Laurenti, 1768
* Viperini Oppel, 1811
* Viperidae Gray, 1825
| synonyms_ref = <ref name="McD99">McDiarmid RW, Campbell JA, Touré T. 1999. Snake Species of the World: A Taxonomic and Geographic Reference, vol. 1. Herpetologists' League. {{ISBN|1-893777-00-6}} (series). {{ISBN|1-893777-01-4}} (volume).</ref>
}}

'''Vipers''' are [[snake]]s in the family '''Viperidae''', found in most parts of the world, except for [[Antarctica]], [[Australia]],<ref>{{cite web |url=https://www.csiro.au/en/news/all/articles/2019/may/are-australian-snakes-really-the-most-dangerous-in-the-world |title=Are Australian snakes really the most dangerous in the world? |last=Fender-Barnett |first=Arli |publisher=[[CSIRO]] |date=2019-05-27 |archiveurl=https://web.archive.org/web/20231209003148/https://www.csiro.au/en/news/all/articles/2019/may/are-australian-snakes-really-the-most-dangerous-in-the-world |archivedate=2023-12-09 |quote=Yes, we have some scary snakes in Australia but none are close to what’s happening in tropical parts of Asia, Africa and South America – they have a group of snakes called Vipers (which we don’t have, phew!). }}</ref> [[Hawaii]], [[Madagascar]], [[Ireland]], and various other isolated islands. All vipers are [[venomous snake|venomous]], and have long (relative to non-vipers), hinged [[fang]]s that permit deep [[envenomation]] of their prey.<ref name="snakesuntamed">{{cite web|title=Viperids|website=Snakesuntamed.webr.ly|url=http://snakesuntamed.webr.ly/viperids|access-date=8 January 2015|archive-date=8 January 2015|archive-url=https://web.archive.org/web/20150108213717/http://snakesuntamed.webr.ly/viperids|url-status=dead}}</ref> Three subfamilies are currently recognized.<ref name="ITIS">{{ITIS |id=174294 |taxon=Viperidae |access-date=10 August 2006}}</ref> They are also known as '''viperids'''. The name "viper" is derived from the Latin word ''vipera'', -''ae'', also meaning viper, possibly from ''vivus'' ("living") and ''parere'' ("to beget"), referring to the trait [[viviparity]] (giving live birth) common in vipers like most of the species of [[Boidae]].<ref>Gotch AF. 1986. Reptiles – Their Latin Names Explained. Poole, UK: Blandford Press. 176 pp. {{ISBN|
0-7137-1704-1}}.</ref> The earliest known vipers are believed to have diverged from the rest of the clade [[Caenophidia]] in the early Eocene.<ref>{{Cite journal |last1=Wüster |first1=Wolfgang |last2=Peppin |first2=Lindsay |last3=Pook |first3=Catharine E. |last4=Walker |first4=Daniel E. |date=2008-11-01 |title=A nesting of vipers: Phylogeny and historical biogeography of the Viperidae (Squamata: Serpentes) |url=https://www.sciencedirect.com/science/article/abs/pii/S1055790308004211 |journal=Molecular Phylogenetics and Evolution |volume=49 |issue=2 |pages=445–459 |doi=10.1016/j.ympev.2008.08.019 |pmid=18804544 |bibcode=2008MolPE..49..445W |issn=1055-7903|url-access=subscription }}</ref>

==Description==
[[File:Crotalus skull.jpg|thumb|226px|A [[Crotalus|rattlesnake]] skull, showing the long fangs used to inject venom]]

All viperids have a pair of relatively long [[Solenoglypha#Solenoglyph|solenoglyphous]] (hollow) fangs that are used to inject [[venom]] from glands located towards the rear of the upper jaws, just behind the eyes. Each of the two fangs is at the front of the mouth on a short [[maxilla]]ry bone that can rotate back and forth. When not in use, the fangs fold back against the roof of the mouth and are enclosed in a membranous sheath. This rotating mechanism allows for very long fangs to be contained in a relatively small mouth. The left and right fangs can be rotated together or independently. During a strike, the mouth can open nearly 180° and the maxilla rotates forward, erecting the fangs as late as possible so that the fangs do not become damaged, as they are brittle. The jaws close upon impact and the muscular sheaths encapsulating the venom glands contract, injecting the venom as the fangs penetrate the target. This action is very fast; in defensive strikes, it will be more a stab than a bite. Viperids use this mechanism primarily for immobilization and digestion of prey. Pre-digestion occurs as the venom contains [[protease]]s, which degrade tissues. Secondarily, it is used for self defense, though in cases with nonprey, such as humans, they may give a [[dry bite]] (not inject any venom). A dry bite allows the snake to conserve its precious reserve of venom, because once it has been depleted, time is needed to replenish it, leaving the snake vulnerable. In addition to being able to deliver dry bites, vipers can inject larger quantities of venom into larger prey targets, and smaller amounts into small prey. This causes the ideal amount of predigestion for the lowest amount of venom.

Almost all vipers have [[keeled scales]], a stocky build with a short tail, and a triangle-shaped head distinct from the neck, owing to the location of the venom glands. The great majority have vertically elliptical, or slit-shaped, [[pupil]]s that can open wide to cover most of the eye or close almost completely, which helps them to see in a wide range of light levels. Typically, vipers are nocturnal and [[Ambush predator|ambush their prey]].
[[File:Arabian Horned viper.jpg|left|thumb|Arabian Horned Viper from Arabian Peninsula]]
Compared to many other snakes, vipers often appear rather sluggish. Most are [[Ovoviviparity|ovoviviparous]]: the eggs are retained inside the mother's body, and the young emerge living. However, a few lay eggs in nests. Typically, the number of young in a clutch remains constant, but as the weight of the mother increases, larger eggs are produced, yielding larger young.

==Geographic range==
[[File:Vipera berus in Finland.jpg|thumb|right|''[[Vipera berus]]'' pictured in [[Laukaa|Laukaa, Finland]], in May 2020]]
Viperid snakes are found in the Americas, Africa, Eurasia, and South Asia. In the Americas, they are native from south of [[48th parallel north|48°N]]. In the [[Old World]], viperids are located everywhere except [[Siberia]], Ireland, and north of the Arctic Circle save for in Norway and Sweden.<ref name="McD99"/> Wild viperids are not found in [[Australia]]. The [[Vipera berus|common adder]], a viperid, is the only venomous snake found in [[Great Britain]].

==Venom==
Viperid venoms typically contain an abundance of [[protein]]-degrading enzymes, called [[Protease|proteases]], that produce symptoms such as pain, strong local swelling and [[necrosis]], blood loss from cardiovascular damage complicated by [[coagulopathy]], and disruption of the blood-clotting system. Also being vasculotoxic in nature, viperine venom causes vascular [[Endothelium|endothelial]] damage and [[hemolysis]]. Death is usually caused by collapse in blood pressure. This is in contrast to [[elapid]] venoms, which generally contain [[neurotoxin]]s that disable muscle contraction and cause paralysis. Death from elapid bites usually results from [[Asphyxia|asphyxiation]] because the diaphragm can no longer contract, but this rule does not always apply; some elapid bites include [[proteolytic]] symptoms typical of viperid bites, while some viperid bites produce [[Neurotoxicity|neurotoxic]] symptoms.<ref name="snakesuntamed"/>

Proteolytic venom is also dual-purpose: first, it is used for defense and to immobilize prey, as with neurotoxic venoms; second, many of the venom's enzymes have a digestive function, breaking down molecules such as [[lipid]]s, [[nucleic acid]]s, and proteins.<ref name="Slo00">{{cite journal|author=Slowinski, Joe|date=2000|url=http://www.calacademy.org/calwild/2000spring/stories/venoms.html|title=Striking Beauties: Venomous Snakes|journal=California Wild|volume=53|issue=2 |archive-url=https://web.archive.org/web/20041013052652/http://www.calacademy.org/calwild/2000spring/stories/venoms.html |archive-date=13 October 2004}}</ref> This is an important adaptation, as many vipers have inefficient digestive systems.<ref name="Smi04">{{cite web|author=Smith, SA|date=2004|url=http://www.dnr.state.md.us/wildlife/ssss_snakes.asp|title=Did Someone Say... SSSSnakes?|publisher=Maryland Dept. of Natural Resources|access-date=2 December 2006|archive-date=21 July 2006|archive-url=https://web.archive.org/web/20060721184723/http://www.dnr.state.md.us/wildlife/ssss_snakes.asp|url-status=dead}}</ref>

Due to the nature of proteolytic venom, a viperid bite is often a very painful experience and should always be taken seriously, though it may not necessarily prove fatal. Even with prompt and proper treatment, a bite can still result in a permanent [[scar]], and in the worst cases, the affected limb may even have to be [[amputation|amputated]]. A victim's fate is impossible to predict, as this depends on many factors, including the species and size of the snake involved, how much venom was injected (if any), and the size and condition of the patient before being bitten. Viper bite victims may also be [[allergy|allergic]] to the venom or the [[antivenom]].

===Behavior===
These snakes can decide how much venom to inject depending on the circumstances. The most important determinant of venom expenditure is generally the size of the snake; larger specimens can deliver much more venom. The species is also important, since some are likely to inject more venom than others, may have more venom available, strike more accurately, or deliver a number of bites in a short time. In predatory bites, factors that influence the amount of venom injected include the size of the prey, the species of prey, and whether the prey item is held or released. The need to label prey for chemosensory relocation after a bite and release may also play a role. In defensive bites, the amount of venom injected may be determined by the size or species of the predator (or antagonist), as well as the assessed level of threat, although larger assailants and higher threat levels may not necessarily lead to larger amounts of venom being injected.<ref name="Hay02">Hayes WK, Herbert SS, Rehling GC, Gennaro JF. 2002. Factors that influence venom expenditure in viperids and other snake species during predatory and defensive contexts. ''In'' Schuett GW, Höggren M, Douglas ME, Greene HW. 2002. Biology of the Vipers. Eagle Mountain Publishing, LC. 580 pp. 16 plates. {{ISBN|0-9720154-0-X}}.</ref>

===Prey tracking===
[[File:(Westliche Diamantklapperschlange) Crotalus atrox.jpg|thumb|right|The western diamondback rattlesnake ''[[Crotalus atrox]]'', the venom of which contains proteins allowing the snake to track down bitten prey]]
[[Hemotoxin|Hemotoxic]] venom takes more time than neurotoxic venom to immobilize prey, so viperid snakes need to track down prey animals after they have been bitten,<ref name="Hay02"/> in a process known as "prey relocalization". Vipers are able to do this via certain proteins contained in their venom. This important adaptation allowed [[Rattlesnake|rattlesnakes]] to evolve the strike-and-release bite mechanism, which provided a huge benefit to snakes by minimizing contact with potentially dangerous prey animals.<ref name=Saviolaetal2013/> This adaptation, then, requires the snake to track down the bitten animal to eat it, in an environment full of other animals of the same species. [[Western diamondback rattlesnake|Western diamondback rattlesnakes]] respond more actively to mouse carcasses that have been injected with crude rattlesnake venom. When the various components of the venom were separated out, the snakes responded to mice injected with two kinds of [[disintegrin]]s, which are responsible for allowing the snakes to track down their prey.<ref name=Saviolaetal2013>{{cite journal| last1 = Saviola| first1 = A.J.| last2 = Chiszar | first2 = D.| last3 = Busch| first3 = C. | last4 = Mackessy| first4 = S.P.| year = 2013| title = Molecular basis for prey relocation in viperid snakes| journal = BMC Biology| volume = 11 | pages = 20| doi =10.1186/1741-7007-11-20| pmid = 23452837| pmc = 3635877| doi-access = free}}</ref>

==Subfamilies==
{| class="wikitable"
! Subfamily<ref name="ITIS"/>
! Taxon author<ref name="ITIS"/>
! Genera<ref name="ITIS"/>
! Common name
! Geographic range<ref name="McD99"/>
|-
|[[Azemiopinae]]
|Liem, Marx & Rabb, 1971
|align="center"|1
|Fea's vipers
|style="width:40%"|[[Myanmar]], southeastern [[Tibet]] across [[South China]] ([[Fujian]], [[Guangxi]], [[Jiangxi]], [[Guizhou]], [[Sichuan]], [[Yunnan]], [[Zhejiang]]) to [[Northern Vietnam]]
|-
|[[Crotalinae]]
|[[Nicolaus Michael Oppel|Oppel]], 1811
|align="center"|22
|Pit vipers
|In the [[Old World]] from [[Eastern Europe]] eastward through [[Asia]] to [[Japan]], [[Taiwan]], [[Indonesia]], [[Peninsular India]] and [[Sri Lanka]]; in the [[New World]] from southern [[Canada]] southward through [[Mexico]] and [[Central America]] to [[southern South America]]
|-
|[[Viperinae]]
|Oppel, 1811
|align="center"|13
|True or pitless vipers
|[[Europe]], Asia, and Africa
|-
|}
[[Type genus]] = ''[[Vipera]]'' Laurenti, 1768<ref name="McD99"/>

== Sensory organs ==

=== Heat-sensing pits ===
[[Pit viper]]s have specialized sensory organs near the nostrils called heat-sensing pits.<ref name=":0">{{Cite journal|last1=Bullock|first1=T.H.|last2=Diecke|first2=F.P.J.|date=1956|title=Properties of an Infrared Receptor|journal=Journal of Physiology|volume=134|issue=1|pages=47–87|doi=10.1113/jphysiol.1956.sp005624|pmid=13377311|pmc=1359182}}</ref> The location of this organ is unique to pit vipers. These pits have the ability to detect [[thermal radiation]] emitted by [[Warm-blooded|warm-blooded animals]], helping them better understand their environment.<ref>{{Cite journal|last=Lynn|first=W. Gardner|date=1931|title=The Structure and Function of the Facial Pits of Pit Vipers|journal=American Journal of Anatomy|volume=49|pages=97–139|doi=10.1002/aja.1000490105}}</ref> Internally [[Vomeronasal organ|the organ]] forms a small pit lined with membranes, external and internal, attached to the [[trigeminal nerve]].<ref name=":0" /><ref>{{Cite journal|last=Newman|first=Eric A.|date=1982|title=The Infrared "Vision" of Snakes|journal=Scientific American|volume=243|issue=3|pages=116–127|doi=10.1038/scientificamerican0382-116|bibcode=1982SciAm.246c.116N}}</ref> [[Infrared light]] signals the internal membranes, which in turn signal the trigeminal nerve and send the infrared signals to the brain, where they are overlaid onto the visual image created by the eyes.<ref>{{Cite journal|last1=Gracheva|first1=Elena O.|last2=Ingolia|first2=Nicolas T.|last3=Kelly|first3=Yvonne M.|last4=Cordero-Morales|first4=Julio F.|last5=Hollopeter|first5=Gunther|last6=Chesler|first6=Alexander T.|last7=Sanchez|first7=Elda E.|last8=Perez|first8=John C.|last9=Weissman|first9=Johnathan S.|year=2010|title=Molecular Basis of Infrared Detection by Snakes|journal=Nature|volume=464|issue=7291|pages=1006–1011|doi=10.1038/nature08943|pmid=20228791|pmc=2855400|bibcode=2010Natur.464.1006G}}</ref>

==Taxonomy==
Whether family Viperidae is attributed to Oppel (1811), as opposed to Laurenti (1768) or Gray (1825), is subject to some interpretation. The consensus among leading experts, though, is that Laurenti used ''viperae'' as the [[plural]] of ''vipera'' (Latin for "viper", "adder", or "snake") and did not intend for it to indicate a family group taxon. Rather, it is attributed to Oppel, based on his Viperini as a distinct family group name, despite the fact that Gray was the first to use the form Viperinae.<ref name="McD99"/>

==See also==
* [[List of snakes]], overview of all snake families and genera
* [[Snakebite]]

==References==
{{Reflist}}

==Further reading==
{{Refbegin}}

* Gray JE. 1825. A synopsis of the genera of reptiles and Amphibia, with a description of some new species. [[Annals of Philosophy]], new ser., 10: 193–217.
* Laurenti JN. 1768. Specimen Medicum, Exhibens Synopsin Reptilium Emendatam cum Experimentis circa Venena et antidota reptilium Austriacorum. J.T. de Trattnern, Wien.
* Oppel M. 1811. Mémoire sur la classification des reptiles. Ordre II. Reptiles à écailles. Section II. Ophidiens. Annales du Musée National d'Histoire Naturelle, Paris 16: 254–295, 376–393.

{{Refend}}

==External links==
{{Commons|Viperidae}}
* {{NRDB family|page=viperidae.php|family=Viperidae|date=3 November|year=2008}}
* {{Cite AmCyc|wstitle=Viper}}
* {{Cite NSRW|wstitle=Viper|short=x}}
* [http://snake-facts.weebly.com/pit-vipers.html Pit vipers]

{{Snake families}}
{{Taxonbar|from=Q163656}}
{{Authority control}}

[[Category:Viperidae| ]]
[[Category:Snake families]]
[[Category:Taxa named by Nicolaus Michael Oppel]]

Bothrops atrox

2025-10-13T11:13:02Z

2001:4479:700:1500:50E6:FAB1:2F63:A4E6: /* Description */ minor fixes to this section

{{Short description|Species of snake}}
{{Speciesbox
| image = Bothrops atrox 113840233.jpg
| image_caption = ''Bothrops atrox'': Note the [[Pit viper|sensory pit]], the [[pupil]] of the eye, and the [[Snake scale|keeled scales]]. This colour variant was photographed in [[Ecuador]].
| status = LC
| status_system = IUCN3.1
| status_ref = <ref>{{cite iucn |author=Gutiérrez-Cárdenas, P. |author2=Caicedo, J.R. |author3=Rivas, G. |author4=Murphy, J. |year=2021 |title=''Bothrops atrox'' |volume=2021 |article-number=e.T44582135A44582154 |doi=10.2305/IUCN.UK.2021-3.RLTS.T44582135A44582154.en |access-date=16 January 2023}}</ref>
| genus = Bothrops
| species = atrox
| authority = ([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]])
| synonyms = *''Coluber atrox'' Linnaeus, 1758
*[''Coluber''] ''ambiguus'' [[Johann Friedrich Gmelin|Gmelin]], 1788
*''Vipera Weigeli'' [[François Marie Daudin|Daudin]], 1803
*''Cophias holocericeus'' [[Prince Maximilian of Wied-Neuwied|Wied-Neuwied]], 1821
*''Trigonoceph''[''alus'']. ''atrox'' – [[Heinrich Rudolf Schinz|Schinz]], 1822
*''Vipera atrox Weigelii'' – Schinz, 1822
*''Trigonoceph''[''alus'']. ''holocericeus'' – Schinz, 1822
*''Bothrops furia'' [[Johann Georg Wagler|Wagler]], 1824
*''Bothrops tessellatus'' Wagler, 1824
*''Craspedocephalus atrox'' – [[Leopold Fitzinger|Fitzinger]], 1826
*''Craspedocephalus Weigelii'' – Fitzinger, 1826
*[''Bothrops''] ''atrox'' – Wagler, 1830
*[''Bothrops''] ''ambiguus'' – Wagler, 1830
*''T''[''rigonocephalus'']. ''atrox'' – [[Hermann Schlegel|Schlegel]], 1837
*''Trigonocephalus Colombiensis'' [[Edward Hallowell (herpetologist)|Hallowell]], 1845
*''Bothrops affinis'' [[John Edward Gray|Gray]], 1849
*''Bothrops atrox'' var. ''tessellatus'' – [[Giorgio Jan|Jan]] & Sordelli, 1875
*''Lachesis atrox'' – [[George Albert Boulenger|Boulenger]], 1896
*''Botrhops atrox'' – [[Adrián Recinos|Recinos]], 1913
*''B''[''othrops'']. ''Neuvoiedii Venezuelenzi'' Briceño Rossi, 1934
*''Trimeresurus atrox'' – [[Karl Patterson Schmidt|Schmidt]] & Walker, 1943
*''Bothrops atrox atrox'' – [[:fr:Alphonse Richard Hoge|Hoge]], 1952
*''Bothrops colombiensis'' – Hoge, 1966
*''Bothrops atrox colombiensis'' – Gubensk, Turk & Drujan, 1978
*''Bothrops isabelae'' Sandner-Montilla, 1979
*''Bothrops lanceolatus aidae'' Sandner-Montilla, 1981
*''B''[''othrops'']. ''atrox aidae'' – [[Paulo Vanzolini|Vanzolini]], 1986
*''Bothrops lanceolatus nacaritae'' Sandner-Montilla, 1990<ref name=McD99>McDiarmid RW, [[Jonathan A. Campbell|Campbell JA]], Touré T. 1999. ''Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1''. Herpetologists' League. 511 pp. {{ISBN|1-893777-00-6}} (series). {{ISBN|1-893777-01-4}} (volume).</ref>
}}

'''''Bothrops atrox''''' — also known as the '''common lancehead''', '''''fer-de-lance''''', '''''barba amarilla''''',<ref name="C&L04">Campbell JA, Lamar WW. 2004. ''The Venomous Reptiles of the Western Hemisphere''. Comstock Publishing Associates, Ithaca and London. 870 pp. 1500 plates. {{ISBN|0-8014-4141-2}}</ref> and '''''mapepire balsain''''' — is a highly [[venom]]ous [[pit viper]] [[species]] found in the tropical lowlands of northern [[South America]] east of the [[Andes]], as well as the [[Caribbean]] island of [[Trinidad]].<ref name=McD99/> No subspecies are currently recognized.<ref name=ITIS>{{ITIS|id=634854| taxon = Bothrops atrox |access-date=6 November 2006}}</ref>

==Taxonomy==
The common lancehead was one of the many [[Amphibia in the 10th edition of Systema Naturae|reptile and amphibian]] species described by [[Carl Linnaeus]] in the landmark 1758 [[10th edition of Systema Naturae|10th edition]] of his ''[[Systema Naturae]]'', where it was given the binomial name ''Coluber atrox''.<ref>{{cite book |last= Linnaeus |first=Carl |author-link= Carl Linnaeus |title= Systema Naturae per Regna Tria Naturae, Secundum Classes, Ordines, Genera, Species, cum Characteribus, Differentiis, Synonymis, Locis |publisher= (Laurentii Salvii) |location= [[Stockholm|Holmiae]] |volume= I |edition= 10th revised |language= la |year= 1758 |page=222 | url=https://www.biodiversitylibrary.org/page/727133}}</ref> The [[Taxonomy (biology)|taxonomy]] of this species is controversial; it may include ''[[Bothrops leucurus|B. leucurus]]'' and ''[[Bothrops moojeni|B. moojeni]]'', and some of its populations are sometimes said to be separate species. ''[[Bothrops asper|B. asper]]'' was formerly included in this species, but most authorities now consider it distinct.

==Names==
Common names include lancehead, ''fer-de-lance'', ''barba amarilla'', and ''mapepire balsain'', among others.<ref name="C&L04"/>

The [[Spanish language|Spanish]] common name ''barba amarilla'' (yellow beard), an allusion to the pale-yellow chin color, is also used in [[English language|English]]. In [[Venezuela]], it is called ''mapanare''. In [[Colombia]], it is known as ''mapaná '' (Llanos of Vichada) and ''talla equis''. In [[Guyana]] and [[Suriname]], it is called ''labaria''<ref>{{cite web|title=Environmental Impact Assessment- Buddy's International Hotel |publisher=Cemco, Inc. |year=2006 |url=http://www.epaguyana.org/downloads/emd/buddys%20draft%20eia-final%20draft.pdf |archive-url=https://web.archive.org/web/20070810025850/http://www.epaguyana.org/downloads/emd/buddys%20draft%20eia-final%20draft.pdf |archive-date=2007-08-10 |page=47 |access-date=2006-11-10 }}</ref> or ''labarria''.<ref>{{cite web|title=Venomous Snakes of Guyana|publisher=Iwokrama International Centre for Rain Forest Conservation and Development|url=http://www.iwokrama.org/forest/snakes.htm|access-date=2006-11-10|archive-url=https://web.archive.org/web/20060928154926/http://www.iwokrama.org/forest/snakes.htm|archive-date=2006-09-28}} Includes a photograph.</ref> In [[Peru]], it is called ''aroani'' (Yagua), ''cascabel'' (juveniles), ''ihdóni'' (Bora), ''jergón'', ''jergona'', ''jergón de la selva'', ''macánchi'' (Alto Marañón), ''machacú'', ''marashar'' and ''nashipkit'' (Aguaruna names). The name ''jergón''<ref name="C&L04"/> is an allusion to the X-like markings of the color pattern. In [[Ecuador]] and [[Panama]], these markings have led to the snake simply being referred to as ''equis'' (the Spanish name of the letter 'x'). In Trinidad, it is known as ''mapepire balsain''.<ref>''Cote ce Cote la: Trinidad & Tobago Dictionary'', p. 75. John Mendes. (1986) Arima, Trinidad.</ref> In Bolivia, it is called ''Yoperojobobo''. In Brazil, the common names are ''jararaca''<ref>{{cite web|title=Fotos Serpentes |publisher=Herpetofauna|year=2015|url= http://www.herpetofauna.com.br/FotosSerpentes5.htm|access-date=2015-08-08}}</ref> or ''Jararaca-do-norte''. The name ''fer-de-lance'' comes from [[French language|French]], meaning, "head of a lance", "[[spear]]head", or literally "lance iron".<ref>"fer-de-lance, n., Etymology". Oxford English Dictionary, Oxford University Press, July 2023, <https://doi.org/10.1093/OED/1762061176></ref><ref>{{Cite web |title=Definition of fer-de-lance |url=https://www.merriam-webster.com/dictionary/fer-de-lance |access-date=2023-11-01 |website=[[Merriam Webster]] |publisher= |language=en}}</ref>

==Description==
A terrestrial species, adults usually grow to a total length 75–125 cm (about 30–50 inches) and are moderately heavy-bodied. Reports of the maximum size are not clear, as this species is often confused with ''[[Bothrops asper|B. asper]]''. Soini (1974) mentioned of a series of 80 specimens collected in northeastern Peru, the largest was a female of {{cvt|138.8|cm|ftin}}. The largest specimen measured by Campbell and Lamar (2004) was a female with a total length of {{cvt|162|cm|ftin}}.<ref name="C&L04"/>

The scalation includes 23–29 (usually 23–25) rows of [[dorsal scales]] at midbody, 169–214 and 177–214 [[ventral scales]] in males and females, respectively, 52–86 (usually 75 or fewer) [[subcaudal scales]] in males, which are usually divided, and 47–72 subcaudals in females. On the head, the [[rostral scale]] is about as high, or slightly higher, than it is wide. There are three to 11 (usually five to 9) [[keeled scales|keeled]] [[intersupraocular scales]], seven to 13 (usually eight to 11) [[sublabial scales]] and six to 9 (usually seven) [[supralabial scales]], the second of which is fused with the [[prelacunal]] to form a [[lacunolabial]].<ref name="C&L04"/>

[[File:Fer-de-Lance (Bothrops atrox) (39388290454).jpg|thumb|''Bothrops atrox" colour variant in French Guiana: Irrespective of colour, this underlying pattern of banding is typical of most populations.]]
The color pattern is highly variable, including a ground color that may be olive, brown, tan, gray, yellow, or (rarely) rusty. The body markings are highly variable, as is the degree of contrast; in some specimens, the pattern is very well defined, while in others, it may be virtually absent. In general, however, the body pattern consists of a series of dorsolateral blotches, rectangular or trapezoidal in shape, which extend from the first scale row to the middle of the back. These blotches may oppose or alternate across the midline, often fusing to form bands. They also have pale borders, which in some cases may be prominent, and may be invaded from below by tan or gray pigment, occasionally dividing them into pairs of ventrolateral spots. The belly may be white, cream, or yellowish gray, with an increasing amount of gray to black mottling posteriorly that may fade again under the tail. The head usually does not have any markings other than a moderately wide postocular stripe that runs from behind the eye back to the angle of the mouth. The irises are gold or bronze, with varying amounts of black reticulation, while the tongue is black.<ref name="C&L04"/>

==Distribution and habitat==
This species is found in the tropical lowlands of South America east of the Andes, including southeastern [[Colombia]], southern and eastern [[Venezuela]], the island of Trinidad (although some confusion exists regarding the taxonomical systematics of this population), [[Guyana]],<ref>{{cite journal|author=Cole, C.J.|author2=C.R. Townsend|author3=R.P. Reynolds|author4=R.D. MacCulloch|author5=A. Lathrop|name-list-style=amp|title=Amphibians and reptiles of Guyana, South America: Illustrated keys, annotated species accounts, and a biogeographic synopsis|journal=Proceedings of the Biological Society of Washington|date=2013|volume=125|issue=4|pages=317–620|doi=10.2988/0006-324x-125.4.317|s2cid=86665287}}</ref> [[Suriname]], [[French Guiana]], eastern [[Ecuador]], eastern [[Peru]], [[Panama]], northern [[Bolivia]], and the northern half of [[Brazil]].<ref name=McD99/> The [[Type locality (biology)|type locality]] is listed as "Asia", which is obviously a mistake. Schmidt and Walker (1943:295) proposed this be corrected to "Surinam".<ref name=McD99/>

Despite the vast destruction of rain forests, it is among the most numerous and common of [[Crotalinae|pit vipers]] and is not endangered. In Trinidad, it prefers wet forests from sea level to {{cvt|940|m|ft|-1}}.<ref name=Her61>Herklots GAC. 1961. ''The Birds of Trinidad and Tobago''. Collins, London, p. 10.</ref> Along with ''[[Bothrops caribbaeus]]'' and ''[[Bothrops lanceolatus|B. lanceolatus]]'', it is one of three ''Bothrops'' species found in the [[West Indies]].

==Behavior==
Although generally [[terrestrial animal|terrestrial]], it is also an excellent swimmer and even climbs trees when necessary to reach prey. Generally [[nocturnal]], it may forage at any time of the day, though, if necessary. These snakes are also easily agitated.

==Feeding==
Their main diet includes mostly small mammals (such as rodents and opossums) and birds, but also frogs, lizards, smaller snakes, fish, crayfish, centipedes, and tarantulas.<ref name="sta.uwi.edu">{{cite web|url=https://sta.uwi.edu/fst/lifesciences/sites/default/files/lifesciences/images/Bothrops_atrox%20-%20Mapepire%20Balsain%20or%20Fer-de-Lance.pdf|title=''Bothrops atrox'' (Mapepire Balsain or Fer-de-Lance)|website=The Online Guide to the Animals of Trinidad and Tobago|access-date=17 March 2022|publisher= [[University of the West Indies|UWI]]}}</ref><ref name="animaldiversity.org">{{Cite web|url=https://animaldiversity.org/accounts/Bothrops_atrox/|title = ''Bothrops atrox'' (Barba Amarilla, Fer-de-Lance, common lancehead)|website=Animaldiversity.org}}</ref><ref name=Ecuador/><ref>Murphy, John. (1998). Amphibians and reptiles of Trinidad and Tobago / John C. Murphy. SERBIULA (sistema Librum 2.0). 1998. 10.2307/1447462.</ref> Larger prey is struck and released, after which it is tracked down by its scent trail.

==Reproduction==
''Bothrops atrox'' can give live birth to up to 80 offspring at once. Adults breed year-round. After mating, females with developing [[embryos]] travel in and out of sunlight to keep themselves and the embryos at a constant temperature. In [[equator]]ial regions, the gestation period is about three to four months, with an average of 60 young per litter. At birth, the young are about {{cvt|30|cm|in}} in total length, more brightly colored than adults, and have [[yellow]] or [[beige]] tails.

Three species of the Neotropical [[pit viper]] ''Bothrops atrox'' group were confirmed to undergo facultative [[parthenogenesis]] on the basis of captivity information and by the use of molecular markers (heterologous [[microsatellites]]).<ref name = Cubides-Cubillos2020>{{cite journal|author=Cubides-Cubillos SD|author2= Patané JSL|author3= Pereira da Silva KM|author4= Almeida-Santos SM|author5= Polydoro DS|author6= Galassi GG|author7= Travaglia Cardoso SR|author8= Silva MJJ|title= Evidence of facultative parthenogenesis in three Neotropical pitviper species of the ''Bothrops atrox'' group|journal= PeerJ|date= 18 November 2020|volume=8|article-number=e10097 |doi=10.7717/peerj.10097|doi-access= free|pmid=33240594|pmc= 7680053}}</ref> Infertile eggs, non-viable ova and malformed offspring were frequent in those cases.<ref name = Cubides-Cubillos2020/>

==Venom==
These snakes are known to search for [[rodents]] in [[Coffea|coffee]] and [[banana]] plantations. Workers there are often bitten by the snakes, which can lie camouflaged for hours, nearly undetectable, and strike with high speed.

Their venom is hemorrhagic, damaging the vascular endothelium and consuming coagulation factors in a mechanism known as [[venom-induced consumption coagulopathy]].<ref>{{cite journal|author=Larreche S|author2= Mion G |author3= Goyffon M. |title=Haemostasis disorders caused by snake venoms|journal= Ann Fr Anesth Reanim. |year=2008|volume=27|issue=4|pages=302–309|doi= 10.1016/j.annfar.2008.02.009 |pmid= 18420371 }}</ref> As a result, clotting assays such as [[prothrombin time]] and [[aPTT]] will be highly disturbed. Spontaneous recovery from coagulopathy is seen 14 to 30 hours after bite according to a study performed in French Guiana. A Mexican polyvalent antivenom was tested, but had no effect on it.<ref>{{cite journal|author=Heckmann X|author2= Lambert V|author3= Mion G|author4= Ehrhardt A|author5= Marty C|author6= Perotti F|display-authors= et al|title= Failure of a Mexican antivenom on recovery from snakebite-related coagulopathy in French Guiana|journal= Clinical Toxicology|date=1 July 2020|volume= 59|issue= 3|pages=193–199 |doi=10.1080/15563650.2020.1786108|pmid= 32609546}}</ref> ''B. atrox'' venom can result in several systemic and local symptoms, such as severe bleeding, kidney failure, abnormal clotting, blisters, and necrosis.<ref>{{cite thesis|url=https://tede.ufam.edu.br/bitstream/tede/6252/5/Disserta%C3%A7%C3%A3o_%20Marissa%20B.%20Anjos.pdf|title=Avaliação do efeito do veneno de Bothrops atrox sobre baços de camundongos tratados com o extrato de Bellucia dichotoma Cong.: um estudo estereológico|date=September 2017|publisher=Tede.ufam.edu.br|access-date=17 March 2022|author=Marissa B. Anjos|degree=Masters}}</ref> The bite can also result in hemorrhage in the central nervous system, which leads to sequelae and even death. In a case reported in the Brazilian Amazon, symptoms such as pain and [[ecchymoses]], [[headaches]], [[nausea]], [[vomiting]], [[diarrhea]], [[hypertension]], and blood incoagulability were reported, the patient died of [[stroke]], even after administration of the antivenom.<ref>{{Cite journal|last1=Silva de Oliveira|first1=Sâmella|last2=Freitas-de-Sousa|first2=Luciana Aparecida|last3=Alves|first3=Eliane Campos|last4=de Lima Ferreira|first4=Luiz Carlos|last5=da Silva|first5=Iran Mendonça|last6=de Lacerda|first6=Marcus Vinícius Guimarães|last7=Fan|first7=Hui Wen|last8=Moura-da-Silva|first8=Ana Maria|last9=Monteiro|first9=Wuelton Marcelo|date=2017-11-01|title=Fatal stroke after Bothrops snakebite in the Amazonas state, Brazil: A case report |url=http://www.sciencedirect.com/science/article/pii/S0041010117302660|journal=Toxicon|language=en|volume=138|pages=102–106|doi=10.1016/j.toxicon.2017.08.021|pmid=28842354|bibcode=2017Txcn..138..102S |issn=0041-0101|url-access=subscription}}</ref> The common lancehead has an [[LD50|LD50]] of 1.1 to 4.9 mg/kg; the venom of juveniles is more inflammatory, lethal, and hemorrhagic, and kills more quickly than that of adults. People bitten by neonates are more likely to develop [[coagulopathy]].<ref name=Ecuador>{{Cite web|title=Common Lancehead (''Bothrops atrox'')|url=https://www.reptilesofecuador.com/bothrops_atrox.html|access-date=2022-01-26|website=Reptilesofecuador.com}}</ref>

Venom yield averages {{convert|124|mg}}, although it may be as much as {{convert|342|mg}}.{{citation needed|date=September 2020}} The enzyme reptilase (batroxobin), derived from this snake's venom, is used in modern medical laboratories to measure fibrinogen levels and blood coagulation capability. The test is considered to be a replacement for thrombin time, and is used when heparin is present in the sample. The enzyme is unaffected by heparin.<ref>{{Cite journal|pmid=458385|volume=17|issue=6|pages=369–372|last=Heimann |first=D|author2=V Wolf|author3=H Keller|title=[The use of reptilase for electrophoresis of heparinized plasma (author's transl)]|journal=Zeitschrift für klinische Chemie und klinische Biochemie |date=June 1979 }}</ref>

==References==
{{Reflist}}

==Further reading==
{{refbegin}}
*Hays WST, Conant Sheila. 2007. Biology and Impacts of Pacific Island Invasive Species. 1. A Worldwide Review of Effects of the Small Indian Mongoose, ''Herpestes javanicus'' (Carnivora: Herpestidae). Pacific Science '''61''' (1): 3–16.
*[[Carl Linnaeus|Linnaeus, C.]] 1758. ''Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I''. Tenth Edition. Holmiæ. Stockholm. 824 pp. (''Coluber atrox'', p. 222.)
*Mehrtens JM. 1987. ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. {{ISBN|0-8069-6460-X}}.
*[[Mark O'Shea (herpetologist)|O'Shea M]]. 2005. ''Venomous Snakes of the World''. Princeton, New Jersey: Princeton University Press. 160 pp. {{ISBN|0-691-12436-1}}.
{{refend}}

==External links==
{{Commons}}
* {{NRDB species|genus=Bothrops|species=atrox|date=28 November|year=2007}}

{{Bothrops}}

{{Taxonbar |from=Q900848}}

[[Category:Bothrops|atrox]]
[[Category:Snakes of the Caribbean]]
[[Category:Reptiles of Bolivia]]
[[Category:Snakes of Brazil]]
[[Category:Reptiles of Colombia]]
[[Category:Reptiles of Ecuador]]
[[Category:Reptiles of French Guiana]]
[[Category:Reptiles of Trinidad and Tobago]]
[[Category:Reptiles of Guyana]]
[[Category:Reptiles of Panama]]
[[Category:Reptiles of Peru]]
[[Category:Reptiles of Suriname]]
[[Category:Reptiles of Venezuela]]
[[Category:Reptiles described in 1758]]
[[Category:Animal taxa named by Carl Linnaeus]]