Adder

{{Short description|Species of venomous snake}} {{Other uses}} {{Use dmy dates|date=July 2020}} {{Speciesbox | image = Common European viper (Vipera berus) female Pieniny.jpg | image_caption = Female, Slovakia | image_alt = | status = LC | status_system = IUCN3.1 | status_ref = <ref name="IUCN">{{cite iucn |author=Munkhbayar, K. |author2= Rustamov, A |author3= Orlov, N.L. |author4= Jelić, D. |author5= Meyer, A. |author6= Borczyk, B. |author7= Joger, U. |author8= Tomović, L. |author9= Cheylan, M. |author10= Corti, C. |author11= Crnobrnja-Isailović, J. |author12= Vogrin, M. |author13= Sá-Sousa, P. |author14= Pleguezuelos, J. |author15= Sterijovski, B. |author16= Westerström, A. |author17= Schmidt, B. |author18= Sindaco, R. |author19= Borkin, L. |author20= Milto, K. |author21= Nuridjanov, D. |name-list-style=amp |year= 2021 |title= ''Vipera berus'' |article-number= e.T47756146A743903 |doi=10.2305/IUCN.UK.2021-3.RLTS.T47756146A743903.en |access-date=8 August 2023}}</ref> | genus = Vipera | species = berus | authority = (Linnaeus, 1758) | range_map = Vipera berus distribution.svg | synonyms = {{collapsible list| title=Species synonymy| * [''Coluber''] ''berus'' Linnaeus, 1758 * [''Coluber''] ''Chersea'' Linnaeus, 1758 * ''Coluber prester'' Linnaeus, 1761 * ''Coluber vipera Anglorum'' Laurenti, 1768 * ''Coluber Melanis'' Pallas, 1771 * ''Coluber Scytha'' Pallas, 1773 * ''C''[''oluber'']. ''Scytha'' — Bonnaterre, 1790 * ''Vipera melanis'' — Sonnini & Latreille, 1801 * ''Vipera berus'' — Daudin, 1803 * ''Vipera chersea'' — Daudin, 1803 * ''Vipera prester'' — Daudin, 1803 * [''Coluber''] ''Caeruleus'' Sheppard, 1804 * ''Vipera communis'' Leach, 1817 * ''Coluber chersea'' var. ''marasso'' Pollini, 1818 * [''Pelias''] ''berus'' — Merrem, 1820 * [''Vipera''] ''marasso'' — Sette, 1821 * ''Vipera limnaea'' Bendiscioli, 1826 * ''Vipera trilamina'' Millet, 1828 * [''Pelias''] ''Chersea'' — Wagler, 1830 * ''Vipera torva'' Lenz, 1832 * ''Pelias dorsalis'' Gray, 1842 * ''V''[''ipera'']. ''Prester'' var. ''gagatina'' Freyer, 1842 * ''Echidnoides trilamina'' — Mauduyt, 1844 * ''Vipera Pelias'' Soubeiran, 1855 * ''Pelias berus'' var. ''Prester'' — Günther, 1858 * ''Pelias berus'' var. ''Chersea'' — Günther, 1858 * ''P''[''elias berus'']. Var. ''dorsalis'' — Cope, 1860 * ''P''[''elias berus'']. Var. ''niger'' Cope, 1860 * ''V''[''ipera'']. (''Pelias'') ''berus'' — Jan, 1863 * ''V''[''ipera'']. (''Pelias'') ''berus'' var. ''prester'' — Jan, 1863 * ''V''[''ipera'']. (''Pelias'') ''berus'' var. ''lymnaea'' — Jan, 1863 * ''Pelias Chersea'' — Erber, 1863 * ''Pelias berus'' — Erber, 1863 * ''Vipera berus'' var. ''prester'' — Jan & Sordelli, 1874 * ''Vipera berus'' [''berus''] — Boettger, 1889 * [''Vipera berus''] var. ''montana'' Méhelÿ, 1893 * ''Vipera berus'' — Boulenger, 1896 * ''Pelias berus lugubris'' Kashehenko, 1902 * ''Vipera berus pelias'' — Chabanaud, 1923 * [''Vipera'' (''Pelias'') ''berus''] forma ''brunneomarcata'' A.F. Reuss, 1923 * [''Vipera'' (''Pelias'') ''berus''] forma ''luteoalba'' A.F. Reuss, 1923 * [''Vipera'' (''Pelias'') ''berus''] forma ''ochracea asymmetrica'' A.F. Reuss, 1923 * [''Vipera'' (''Pelias'') ''berus''] ''rudolphi-marchica'' A.F. Reuss, 1924 * [''Vipera'' (''Pelias'') ''berus''] forma ''bilineata'' A.F. Reuss, 1924 * ''Vipera'' (''Pelias'') ''berus'' forma ''chersea-splendens'' A.F. Reuss, 1925 * ''Vipera'' (''Pelias'') ''berus'' forma ''ochracea-splendens'' A.F. Reuss, 1925 * ''Vipera'' (''Pelias'') ''berus'' forma ''rutila'' A.F. Reuss, 1925 * ''Vipera'' (''Pelias'') ''berus'' forma ''punctata'' A.F. Reuss, 1925 * ''Coluber sachalinensis continentalis'' Nikolski, 1927 * ''P''[''elias'']. ''sudetica'' A.F. Reuss, 1927 (''nomen nudum'') * ''V''[''ipera'']. ''berus marchici'' A.F. Reuss, 1927 * ''Vipera berus rudolphi'' A.F. Reuss, 1927 (''nomen nudum'') * ''Vipera berus berus'' — Mertens & L. Müller, 1928 * [''Pelias''] ''elberfeldi'' A.F. Reuss, 1929 * ''Pelias rudolphi'' — A.F. Reuss, 1930 * ''Pelias schöttleri'' A.F. Reuss, 1930 * ''P''[''elias'']. ''tyrolensis'' A.F. Reuss, 1930 * ''Pelias schreiberi'' A.F. Reuss, 1930 * ''Pelias flavescens'' A.F. Reuss, 1930 (''nomen nudum'') * ''Pelias subalpina'' A.F. Reuss, 1930 (''nomen nudum'') * ''Pelias neglecta'' A.F. Reuss, 1932 * ''Vipera berus sphagnosa'' Krassawzef, 1932 * ''Pelias occidentalis'' A.F. Reuss, 1933 * ''Pelias occidentalis oldesloensis'' A.F. Reuss, 1933 (''nomen nudum'') * ''Pelias occidentalis orbensis'' A.F. Reuss, 1933 (''nomen nudum'') * ''Pelias sudetica'' forma ''steinii'' A.F. Reuss, 1935 (''nomen nudum'') * ''Vipera marchici'' — A.F. Reuss, 1935 * ''Pelias sudetica steinii'' forma ''emarcata'' A.F. Reuss, 1937 (''nomen illegitimum'') * ''Vipera'' (''Vipera'') ''berus berus'' — Obst, 1983 * ''Vipera berus'' forma ''brunneomarcata'' — Golay et al., 1993 * ''Vipera berus'' forma ''ochracea-asymmetrica'' — Golay et al., 1993 * ''Vipera berus'' forma ''luteoalba'' — Golay et al., 1993 * ''Pelias schoettleri'' — Golay et al., 1993 * ''Coluber coeruleus'' — Golay et al., 1993 * ''Vipera berus'' — Golay et al., 1993 }} | synonyms_ref = <ref name="McD99">McDiarmid RW, Campbell JA, Touré TA (1999). ''Snake Species of the World: A Taxonomic and Geographic Reference, Volume 1''. Washington, District of Columbia: Herpetologists' League. {{ISBN|1-893777-00-6}} (series). {{ISBN|1-893777-01-4}} (volume).</ref> }}

'''''Vipera berus''''', commonly known as the '''common European adder'''<ref name="Mal03">Mallow D, Ludwig D, Nilson G (2003). ''True Vipers: Natural History and Toxinology of Old World Vipers''. Malabar, Florida: Krieger Publishing Company. {{ISBN|0-89464-877-2}}.</ref> and the '''common European viper''',<ref name="Sti74">Stidworthy J (1974). ''Snakes of the World''. New York: Grosset & Dunlap Inc. 160 pp. {{ISBN|0-448-11856-4}}.</ref> is a species of venomous snake in the family Viperidae. The species is extremely widespread, and thus can be found throughout much of Europe, and as far as East Asia.<ref name="McD99"/> There are three recognised subspecies.

Known by a host of common names including '''common adder''' and '''common viper''', the adder has been the subject of much folklore in Britain and other European countries.<ref name="HCT">{{cite web |url=http://www.crislis.co.uk/adder/folklore.htm |title=Everyday Adders – the Adder in Folklore |website=The Herpetological Conservation Trust |access-date=7 February 2010 |archive-url=https://web.archive.org/web/20091003133453/http://www.crislis.co.uk/adder/folklore.htm |archive-date=3 October 2009 }}</ref> It is not regarded as especially dangerous;<ref name="Mal03"/>{{page needed|date=August 2022}} the snake is not aggressive and usually bites only when really provoked, stepped on, or picked up. Bites can be very painful, but are rarely fatal.<ref name="War05">{{cite journal|author=Warrell, David A.|pmid=16308385|year=2005 |title=Treatment of bites by adders and exotic venomous snakes |volume=331|issue=7527 |pages=1244–1247|doi=10.1136/bmj.331.7527.1244|pmc=1289323 |journal=British Medical Journal}}</ref> The specific name, ''berus'', is Neo-Latin and was at one time used to refer to a snake, possibly the grass snake, ''Natrix natrix''.<ref name="Got">Gotch, Arthur Frederick (1986). ''Reptiles: Their Latin Names Explained''. Poole, UK: Blandford Press. 176 pp. {{ISBN|0-7137-1704-1}}.</ref>

The common adder is found in different terrains, habitat complexity being essential for different aspects of its behaviour. It feeds on small mammals, birds, lizards, and amphibians, and in some cases on spiders, worms, and insects. The common adder, like most other vipers, is ovoviviparous, giving birth to live young.<ref>{{cite journal |last1=Owens |first1=JB |last2=Wüster |first2=W |last3=Mulley |first3=J |title=The genome sequence of the common adder, Vipera berus (Linnaeus, 1758) |version=2 |work=Wellcome Open Res 2025, 10:11 |url=https://doi.org/10.12688/wellcomeopenres.23470.2}}</ref> Females breed once every two or three years and litters are usually born in late summer to early autumn in the Northern Hemisphere. Litters range in size from three to 20 with young staying with their mothers for a few days. Adults grow to a total length (including tail) of {{convert|60|to|90|cm|in|abbr=on}} and a mass of {{convert|50|to|180|g|oz|abbr=on}}{{Citation needed span|text= |date=January 2020|reason=}}. Three subspecies are recognised, including the nominate subspecies, ''Vipera berus berus'', described here.<ref name="ITIS">{{ITIS|id=634988 |taxon=''Vipera berus'' |access-date = 15 August 2006}}</ref> The snake is not considered to be threatened, though it is protected in some countries.

==Taxonomy== There are three subspecies of ''V. berus'' that are recognised as being valid including the nominotypical subspecies. {| class="wikitable" !Subspecies<ref name="ITIS"/> !Taxon author<ref name="ITIS"/> !Common name !Geographic range |- |''V. b. berus'' |(Linnaeus, 1758) |Common European adder<ref name="Mal03"/>{{page needed|date=August 2022}} |style="width:40%"|Norway, Sweden, Bulgaria, Finland, Latvia, Estonia, Lithuania, France, Denmark, Germany, Austria, Switzerland, Northern Italy, Belgium, Netherlands, Great Britain, Poland, Croatia, Czech Republic, Slovakia, Slovenia, Hungary, Romania, Russia, Ukraine, Mongolia, Northwest China (north Xinjiang) |- |''V. b. bosniensis'' |Boettger, 1889 |Balkan cross adder<ref name="Ste71"/> |Balkan Peninsula |- |''V. b. sachalinensis'' |Zarevskij, 1917 |Sakhalin adder<ref name="Meh87"/> |Russian Far East (Amur Oblast, Primorsky Kray, Khabarovsk Kray, Sakhalin Island), North Korea, Northeast China (Jilin) |- |}

The subspecies ''V. b. bosniensis'' and ''V. b. sachalinensis'' have been regarded as full species in some recent publications.<ref name="Mal03"/>{{page needed|date=August 2022}}

The name 'adder' is derived from ''nædre'', an Old English word that meant snake in the older forms of many Germanic languages. It was commonly used in the Old English version of the Christian Scriptures for the devil and the serpent in the Book of Genesis.<ref name="HCT"/><ref name="Name">{{cite web |url=http://dictionary.reference.com/browse/adder |title=adder |work=Dictionary.com Unabridged |publisher=Random House, Inc. |access-date=7 February 2010}}</ref> In the 14th century, 'a nadder' in Middle English was rebracketed to 'an adder' (just as 'a napron' became 'an apron' and 'a ''nompere''{{'}} changed into 'an umpire').

In keeping with its wide distribution and familiarity through the ages, ''Vipera berus'' has a large number of common names in English, which include: :''Common European adder'',<ref name="Mal03"/>{{page needed|date=August 2022}} ''common European viper'',<ref name="Sti74"/> ''European viper'',<ref name="USN91">U.S. Navy (1991). ''Poisonous Snakes of the World''. New York: United States Government / Dover Publications Inc. 232 pp. {{ISBN|0-486-26629-X}}.</ref> ''northern viper'',<ref name="NRDB">{{NRDB species|genus=Vipera|species=berus |date=21 November|year=2007}}</ref> ''adder'', ''common adder'', ''crossed viper'', ''European adder'',<ref name="Meh87">Mehrtens JM (1987). ''Living Snakes of the World in Color''. New York: Sterling Publishers. 480 pp. {{ISBN|0-8069-6460-X}}.</ref> ''common viper'', ''European common viper'', ''cross adder'',<ref name="Ste71">Steward JW (1971). ''The Snakes of Europe''. Cranbury, New Jersey: Associated University Press (Fairleigh Dickinson University Press). 238 pp. LCCCN 77-163307. {{ISBN|0-8386-1023-4}}.</ref> or ''common cross adder''.<ref name="Bro73">Brown, John H. (1973). ''Toxicology and Pharmacology of Venoms from Poisonous Snakes''. Springfield, Illinois: Charles C. Thomas. 184 pp. LCCCN 73-229. {{ISBN|0-398-02808-7}}.</ref>

In Welsh, it is called ''gwiber'', a name derived from Latin ''vīpera''. In Denmark, Norway and Sweden, the snake is known as ''hugorm'', ''hoggorm'' and ''huggorm'', roughly translated as 'striking snake'. In Finland, it is known as ''kyykäärme'' or simply ''kyy'', in Estonia it is known as ''rästik'', while in Lithuania it is known as ''angis''. In Poland the snake is called ''żmija zygzakowata,'' which translates as 'zigzag viper', due to the pattern on its back.

==Description== Relatively thick-bodied, adults usually grow to {{convert|60|cm|in|abbr=on}} in total length (including tail), with an average of {{convert|55|cm|in|abbr=on}}.<ref name="Mal03"/>{{page needed|date=August 2022}} Maximum size varies by region. The largest, at over {{convert|90|cm|in|abbr=on}}, are found in Scandinavia; specimens of {{convert|104|cm|in|abbr=on}} have been observed there on two occasions. In France and Great Britain, the maximum size is {{convert|80|-|87|cm|in|abbr=on}}.<ref name="Mal03"/>{{page needed|date=August 2022}} Mass ranges from {{convert|50|g|oz|abbr=on}} to about {{convert|180|g|oz}}.<ref>{{cite journal |title=Is sperm really so cheap? Costs of reproduction in male adders,''Vipera berus''|doi=10.1098/rspb.1997.0065|jstor=50437|pmc=1688262|year=1997 |last1=Olsson |first1=M. |last2=Madsen |first2=T. |author2-link=species:Thomas Madsen |last3=Shine |first3=R. |author3-link=Richard Shine |journal=Proceedings of the Royal Society B: Biological Sciences |volume=264|issue=1380 |pages=455–459}} (includes chart showing range of male mass in one population)</ref><ref>{{cite journal|author1=Strugariu, Alexandru|author1-link=species:Alexandru Strugariu |author2=Zamfirescu, Ştefan R.|author3=Gherghel, Iulian |author3-link=species:Iulian Gherghel |title=First record of the adder (''Vipera berus berus'') in Argeș County (Southern Romania) |journal=Biharean Biologist|year=2009 |volume=3|issue=2 |page=164 |url=http://www.doaj.org/doaj?func=abstract&id=476009 |access-date=9 February 2013 |archive-url=https://web.archive.org/web/20131023061050/http://www.doaj.org/doaj?func=abstract&id=476009 |archive-date=23 October 2013 }} (gives example masses of females).</ref> left|thumb|alt=Shows the front parts of two common adders. One snake has the normal colour while the other has melanistic colour/pattern form. The head of the normal snake is enclosed in a half-coil of the melanistic form.|''V. berus'': normal and melanistic colour patterns The head is fairly large and distinct and its sides are almost flat and vertical. The edge of the snout is usually raised into a low ridge. Seen from above, the rostral scale is not visible, or only just. Immediately behind the rostral, there are two (rarely one) small scales.

Dorsally, there are usually five large plates: a squarish frontal (longer than wide, sometimes rectangular), two parietals (sometimes with a tiny scale between the frontal and the parietals), and two long and narrow supraoculars. The latter are large and distinct, each separated from the frontal by one to four small scales. The nostril is situated in a shallow depression within a large nasal scale.

The eye is relatively large, equal in size to or slightly larger than the nasal scale, but often smaller in females. Below the supraoculars, there are six to 13 small circumorbital scales, usually eight to 10. The temporal scales are smooth (rarely weakly keeled). There are 10–12 sublabials and six to 10 (usually eight or 9) supralabials. Of these, numbers 3 and 4 are the largest, while numbers 4 and 5 (rarely 3 and 4) are separated from the eye by a single row of small scales (sometimes two rows in alpine specimens).<ref name="Mal03" />

There are 21 rows of dorsal scales midbody (rarely 19, 20, 22, or 23). They are strongly keeled scales, except for those bordering the ventral scales. The scales appear to be loosely attached to the skin, with the lower rows becoming increasingly wider. Those closest to the ventral scales are twice as long as those along the midline. The number of ventral scales is 132–150 in males and 132–158 in females. The anal plate is single. The subcaudals are paired and number 32–46 in males and 23–38 in females.<ref name="Mal03"/>{{page needed|date=August 2022}}

This species exhibits significant variation in colouration. Light-coloured specimens are characterised by small, incomplete, dark crossbars on their backs, while darker specimens display faint or clear, darker brown markings. Melanistic individuals are completely black and lack any apparent dorsal pattern. However, most specimens have a zigzag pattern on their backs that extends along their entire bodies and tails. A distinctive dark V or X marking is usually present on the dorsal surface of the head. A dark streak runs from the eye to the neck and continues as a series of longitudinal spots along the flanks.<ref name="Mal03"/>{{page needed|date=August 2022}}

Unlike most snakes, the sexes of this species can often be distinguished by colour. Females are typically brown with dark brown markings, whereas males are a uniform grey with black markings. The base colour of males is often slightly lighter than that of females, which makes the black zigzag pattern stand out more. Melanistic individuals are often female.

==Distribution and habitat== thumb|alt=A common adder basking in the open upon loose moss litter with head resting upon its coil and facing away. The central part of its body is thick and it has probaby eaten recently.|''V. berus'' [[File:Vipera berus in Finland.jpg|thumb|''V. berus'' pictured in Laukaa, Finland]] ''Vipera berus'' has a wide range. It can be found across the Eurasian land-mass; from northwestern Europe (Great Britain, Belgium, Netherlands, Scandinavia, Germany, France) across southern Europe (Italy, Serbia, Albania, Croatia, Montenegro, Bosnia and Herzegovina, North Macedonia, Bulgaria, and northern Greece) and eastern Europe to north of the Arctic Circle, and Russia to the Pacific Ocean, Sakhalin Island, North Korea, northern Mongolia and northern China. It is found farther north than any other snake species.{{citation needed |date=November 2015}} The type locality was originally listed as 'Europa'. Mertens and Müller (1940) proposed restricting the type locality to Uppsala, Sweden<ref name="McD99"/> and it was eventually restricted to Berthåga, Uppsala by designation of a neotype by Krecsák & Wahlgren (2008).<ref>{{cite journal |author=Krecsák, László |author2=Wahlgren, Richard |title=A survey of the Linnaean type material of ''Coluber berus'', ''Coluber chersea'' and ''Coluber prester'' (Serpentes, Viperidae)|doi=10.1080/00222930802126888|year=2008 |journal=Journal of Natural History |volume=42|issue=35–36 |pages=2343–2377|bibcode=2008JNatH..42.2343K |s2cid=83947746|url=https://zenodo.org/record/5224014 }}</ref>

In several European countries, it is notable for being the only native venomous snake. It is also one of only three native British snake species. The other two, the barred grass snake and the smooth snake, are non-venomous.<ref name="ARKADD">{{cite web |url=http://www.arkive.org/adder/vipera-berus/ |archive-url=https://web.archive.org/web/20081107055335/http://www.arkive.org/adder/vipera-berus/ |archive-date=7 November 2008 |title=Adder (''Vipera berus'') |access-date=2 October 2015 |website=ARKive}}</ref>

Sufficient habitat complexity is crucial for this species to be present, in order to support its various behaviours—basking, foraging, and hibernation—as well as to offer some protection from predators and human disturbance.<ref name="Mal03"/>{{page needed|date=August 2022}} It is found in a variety of habitats, including: chalky downs, rocky hillsides, moors, sandy heaths, meadows, rough commons, woodland edges, sunny glades and clearings, scrubby slopes and hedgerows, rubbish tips, coastal dunes, and stone quarries. If dry ground is available nearby, it will venture into wetlands and may therefore be found on the banks of streams, lakes, and ponds.<ref name="Str79">Street, Donald (1979). ''The Reptiles of Northern and Central Europe''. London: B.T. Batsford Ltd. 272 pp. {{ISBN|0-7134-1374-3}}.</ref>

In much of southern Europe, such as southern France and northern Italy, it is found in either low-lying wetlands or at high altitudes. In the Swiss Alps, it may ascend to about {{convert|3000|m|ft|abbr=on}}. In Hungary and Russia, it avoids open steppeland; a habitat in which ''V. ursinii'' is more likely to occur. In Russia, however, it does occur in the forest steppe zone.<ref name="Str79"/>

===Conservation status=== thumb|alt=An adult female adder found basking in the sun by Loch Shin, Sutherland in Scotland. She preferred to pose for a photograph rather than slither away.|''V. berus'' female In Great Britain, the killing, injuring, harming or selling of adders is illegal under the provisions of the Wildlife and Countryside Act 1981.<ref name="arkive">{{cite web |url=http://www.arkive.org/adder/vipera-berus/facts-and-status.html |archive-url=https://web.archive.org/web/20090711202421/http://www.arkive.org/adder/vipera-berus/facts-and-status.html |archive-date=11 July 2009 |title=Adder (''Vipera berus'') - facts and status |work=ARKive |access-date=7 February 2010 }} This ref cites Beebee T, & Griffiths R. (2000) [https://books.google.com/books?id=dgwaUAqmumYC ''Amphibians and Reptiles: a Natural History of the British Herpetofauna.''] London: Harper Collins Publishers Ltd. as the source.</ref> A similar situation exists in Norway under the {{ill|Viltloven|no}} (The Wildlife Act 1981)<ref>{{cite web |url=http://www.wwf.no/bibliotek/wwf_naturfakta/hoggorm/ |title=Hoggorm |website=WWF Norway |language=no}}</ref> and in Denmark (1981).<ref>{{cite web |title=Hugorm |url=http://mst.dk/natur-vand/natur/artsleksikon/krybdyr/hugorm/ |website=Ministry of Environment and Food of Denmark |publisher=Miljø- og Fødevareministeriet |access-date=27 June 2018 |archive-date=27 June 2018 |archive-url=https://web.archive.org/web/20180627091334/http://mst.dk/natur-vand/natur/artsleksikon/krybdyr/hugorm/ }}</ref> In Finland (Nature Conservation Act 9/2023) killing an adder is legal if it is not possible to capture and transfer it to another location<ref>{{Cite web |title=9/2023 English - Translation of Finnish acts |url=https://www.finlex.fi/en/laki/kaannokset/2023/en20230009 |access-date=2 June 2024 |website= |publisher=Ympäristöministeriö (Ministry of the Environment) |at=Chapter 8 Section 70}}{{dead link|date=May 2025|bot=medic}}{{cbignore|bot=medic}}</ref> and the same provision also applies in Sweden.<ref>{{Cite web |title=Artskyddsförordning (2007:845) |url=https://www.riksdagen.se/sv/dokument-och-lagar/dokument/svensk-forfattningssamling/artskyddsforordning-2007845_sfs-2007-845 |access-date=12 June 2024 |website= |publisher=Klimat- och näringslivsdepartementet |at=10 §}}</ref> The common viper is categorised as 'endangered' in Switzerland,<ref>Monney JC, Meyer A (2005). ''Rote Liste der gefährdeten Reptilien der Schweiz''. Hrsg. Bundesamt für Umwelt, Wald und Landschaft BUWAL, Bern und Koordinationsstelle für Amphibien- und Reptilienschutz der Schweiz, Bern. BUWAL-Reihe.</ref> and is also protected in some other countries in its range. It is also found in many protected areas.<ref name="IUCN"/>

This species is listed as protected (Appendix III) under the Berne Convention.<ref name="COE">{{cite web |url=https://rm.coe.int/168097eb57 |title=Convention on the Conservation of European Wildlife and Natural Habitats, Appendix III |date=19 September 1979 |website=Council of Europe |access-date=6 September 2021}}</ref>

The International Union for Conservation of Nature Red List of Threatened Species describes the conservation status as of 'least concern' in view of its wide distribution, presumed large population, broad range of habitats, and likely slow rate of decline though it acknowledges the population to be decreasing.<ref name="IUCNLC">{{cite book |url=https://portals.iucn.org/library/sites/library/files/documents/RL-2001-001-2nd.pdf |chapter=IV: The Categories |title=2001 IUCN Red List Categories and Criteria, version 3.1 |edition=2nd |date=2012 |publisher=International Union for Conservation of Nature |isbn=978-2-8317-1435-6 |access-date=14 February 2010}}</ref> Reduction in habitat for a variety of reasons, fragmentation of populations in Europe due to intense agriculture practices, and collection for the pet trade or for venom extraction have been recorded as major contributing factors for its decline.<ref name="IUCN"/> A citizen science based survey in the UK found evidence of extensive population declines in the UK, especially affecting smaller populations.<ref name=MTAC2019>{{cite journal |last1=Gardner |first1=Emma |last2=Julian |first2=Angela |last3=Monk |first3=Chris |last4=Baker |first4=John |title=Make the Adder Count: population trends from a citizen science survey of UK adders |journal=Herpetological Journal |date=2019 |volume=29 |pages=57–70 |doi=10.33256/hj29.1.5770 |s2cid=92204234 |url=https://centaur.reading.ac.uk/82357/1/MTAC.pdf|doi-access=free }}</ref> A combination of public pressure and disturbance, habitat fragmentation and poor habitat management were considered the most likely causes of the decline. The release of 47 million non-native pheasants and 10 million partridges each year by countryside estates has also been suggested to have a significant impact on adder populations across the UK, with the possibility the reptile could be extinct by 2032.<ref>{{Cite news |last=Milton |first=Nicholas |date=1 October 2020 |title=Game birds 'could wipe out adders in most of Britain within 12 years' |language=en-GB |work=The Guardian |url=https://www.theguardian.com/environment/2020/oct/01/adder-extinct-across-britain-snake-threat-game-birds-release |access-date=1 October 2020|issn=0261-3077}}</ref> {{clear|left}}

==Behaviour== thumb|alt=A slender adder lies in a half circle on the bare soil which has a few dried leaves. The black zig-zag pattern along the dorsal spine of the snake contrasts against the white borders forming a pattern resembling the teeth of an open zip. |''V. berus'' male This species is mainly diurnal, especially in the north of its range. Further south, it is said<ref>{{cite book |url=https://archive.org/details/snakesofeurope00boul |last=Boulenger |first=G.A. |author-link=George Albert Boulenger |date=1913 |title=Snakes of Europe |location=London |publisher=Methuen & Co |at=pp. xi + 269 (''Vipera berus'', pp. 230–239, Figure 35)}}</ref> to be active in the evening, and it may even be active at night during the summer months. It is predominantly a terrestrial species, though it is known to climb up banks and into low bushes in order to bask or search for prey.<ref name="Str79"/>

Adders are not usually aggressive and tend to be rather timid, biting only when they are cornered, alarmed, stepped on, or picked up. They will usually disappear in the undergrowth at the slightest hint of danger, but will return once all is quiet, often to the same spot. Occasionally, individual snakes will reveal their presence with a loud, sustained hiss, presumably to warn off potential aggressors. These are often pregnant females. When threatened, the front part the adder's body is drawn into an S-shape in preparation for a strike.<ref name="Str79"/>

This cold-adapted species hibernates in winter. In Great Britain, males hibernate for around 150 days and females for around 180 days. In northern Sweden, hibernation lasts 8–9 months. On mild winter days, they may emerge to bask in areas where the snow has melted, often travelling across snow in the process. Approximately 15% of adults and 30–40% of juveniles die during hibernation.<ref name="Mal03"/>{{page needed|date=August 2022}}

==Feeding== thumb|''V. berus'' female; head detail. Their diet mainly consists of small mammals, such as mice, rats, voles, and shrews, as well as lizards. They sometimes take slow worms, and even weasels (such as least weasels and possibly juvenile stoats) and moles. Adders also feed on amphibians, such as frogs, newts, and salamanders. Birds are also reported<ref name="Leighton">{{cite book |title=The Life-History of British Serpents and Their Local Distribution in the British Isles |last=Leighton |first=Gerald R. |year=1901 |publisher=Blackwood & Sons |location=Edinburgh & London |isbn=1-4446-3091-1 |page=84 |url=https://books.google.com/books?id=7i_8ZmymfMoC |access-date=8 February 2010}}</ref> to be consumed, especially nestlings and even eggs, for which they will climb into shrubbery and bushes. Generally, diet varies depending on locality.<ref name="Str79"/>

Juveniles will eat nestling mammals, small lizards and frogs as well as worms and spiders. One important dietary source for young adders is the alpine salamander (''Salamadra atra''). Because both species live at higher altitudes, ''S. atra'' could be a prevalent food source for adders, since there may be few other animals. One study suggests that alpine salamanders could consist of almost half of the adders' diets in some locations. They have been witnessed swallowing these salamanders in the early morning hours.<ref name=":0">{{Cite journal |last1=Anibaldi |first1=Claudio |last2=Luiselli |first2=Luca |author2-link=species:Luca Luiselli |last3=Capula |first3=Massimo |author3-link=species:Massimo Capula |date=1995 |title=The diet of juvenile adders, Vipera berus, in an alpine habitat |journal=Amphibia-Reptilia |volume=16 |issue=4 |pages=404–407 |doi=10.1163/156853895x00488 |issn=0173-5373}}</ref> Once they reach about {{convert|30|cm|ft|abbr=on}} in length, their diet begins to resemble that of the adults.<ref name="Mal03" />{{page needed|date=August 2022}}

==Reproduction== In Hungary, mating takes place during the last week of April, whereas in the north it occurs later, during the second week of May). Mating has also been observed in June and even in early October, but it is unclear whether any offspring result from autumn mating.<ref name="Mal03"/>{{page needed|date=August 2022}} Females often breed once every two years,<ref name="Str79"/> or even once every three years if the seasons are short and the climate is not conducive.<ref name="Mal03"/>{{page needed|date=August 2022}} [[File:Viperaberus1.jpg|thumb|alt=Closeup of snake coils with head resting on coil looking front and left. The gray dorsal scales on the thick coils are clearly seen as having prominent keels.| ''V. berus'' – showing strongly keeled scales on dorsal area.]] Males find females by following their scent trails, which can extend for hundreds of metres a day. If a female flees after being found, the male will pursue her. Courtship involves a synchronised display of a side-by-side 'flowing' movement, with the tongue flicking along the back and the tail being whipped excitedly. Pairs remain together for a day or two after mating. Males expel their rivals and engage in combat. This often begins with the aforementioned flowing behaviour before culminating in the dramatic 'adder dance'.<ref name="Mal03"/>{{page needed|date=August 2022}} In this act, males face each other, raising the front of their bodies vertically and making swaying movements and attempt to push each other to the ground. This sequence of actions is repeated until one of the two males becomes exhausted and withdraws to find another mate. Appleby (1971) notes that he has never seen an intruder win one of these contests, suggesting that the defender becomes so frustrated during the courtship that he refuses to accept defeat in pursuit of mating opportunities.<ref>Appleby, Leonard G. (1971). ''British Snakes''. London: J. Baker. 150 pp. {{ISBN|0-212-98393-8}}.</ref> There is no record of any biting taking place during these bouts.<ref name="Str79"/>

Females usually give birth in August or September, but sometimes as early as July, or as late as early October. Litters can range in size from three to 20. The young are usually born encased in a transparent sac, and must free themselves from it. Occasionally, they manage to break free from this membrane while still inside the mother.

Neonates measure {{convert|14|to|23|cm|in|abbr=on}} in total length (including tail), with an average total length of {{convert|17|cm|in|abbr=on}}. They are born with a fully functional venom apparatus and a reserve supply of yolk within their bodies. They shed their skin for the first time within a day or two. Females do not appear to take much interest in their offspring, but the young have been observed to remain near their mothers for several days after birth.<ref name="Str79" />

==Venom== Adder venom is primarily proteolytic, haemotoxic, and cytotoxic,<ref name=":1">{{Cite journal |last=Latinović |first=Zorica |last2=Leonardi |first2=Adrijana |last3=Šribar |first3=Jernej |last4=Sajevic |first4=Tamara |last5=Žužek |first5=Monika C. |last6=Frangež |first6=Robert |last7=Halassy |first7=Beata |last8=Trampuš-Bakija |first8=Alenka |last9=Pungerčar |first9=Jože |last10=Križaj |first10=Igor |date=2016-09-02 |title=Venomics of Vipera berus berus to explain differences in pathology elicited by Vipera ammodytes ammodytes envenomation: Therapeutic implications |url=https://linkinghub.elsevier.com/retrieve/pii/S1874391916302597 |journal=Journal of Proteomics |language=en |volume=146 |pages=34–47 |doi=10.1016/j.jprot.2016.06.020}}</ref><ref name=":2">{{Cite journal |last=Di Nicola |first=Matteo R. |last2=Pontara |first2=Andrea |last3=Kass |first3=George E.N. |last4=Kramer |first4=Nynke I. |last5=Avella |first5=Ignazio |last6=Pampena |first6=Riccardo |last7=Mercuri |first7=Santo Raffaele |last8=Dorne |first8=Jean Lou C.M. |last9=Paolino |first9=Giovanni |date=2021-04-15 |title=Vipers of Major clinical relevance in Europe: Taxonomy, venom composition, toxicology and clinical management of human bites |url=https://linkinghub.elsevier.com/retrieve/pii/S0300483X21000470 |journal=Toxicology |language=en |volume=453 |article-number=152724 |doi=10.1016/j.tox.2021.152724}}</ref> although some populations may also have neurotoxic and neuromuscular effects.<ref>{{Cite journal |last=Malina |first=Tamás |last2=Krecsák |first2=László |last3=Westerström |first3=Alexander |last4=Szemán-Nagy |first4=Gábor |last5=Gyémánt |first5=Gyöngyi |last6=M-Hamvas |first6=Márta |last7=Rowan |first7=Edward G. |last8=Harvey |first8=Alan L. |last9=Warrell |first9=David A. |last10=Pál |first10=Balázs |last11=Rusznák |first11=Zoltán |last12=Vasas |first12=Gábor |date=2017-09-01 |title=Individual variability of venom from the European adder (Vipera berus berus) from one locality in Eastern Hungary |url=https://linkinghub.elsevier.com/retrieve/pii/S0041010117301848 |journal=Toxicon |language=en |volume=135 |pages=59–70 |doi=10.1016/j.toxicon.2017.06.004}}</ref> The venom is considered simpler than the related ''Vipera ammodytes,'' which could explain its comparatively mild effects and greater LD50.<ref name=":1" /> There is probably regional and individual variation in the venom composition of adders.<ref name=":2" />

Due to the rapid rate of human expansion throughout the range of this species, bites are relatively common. Domestic animals and livestock are frequent victims. In Great Britain, most cases occur between March and October. In Sweden, there are around 1,300 bites per year, with an estimated 12% of cases requiring hospitalisation.<ref name="Mal03" />{{page needed|date=August 2022}} At least eight different antivenoms are available against bites from this species.<ref name="MAVIN">{{cite web |url=http://www.toxinfo.org/antivenoms/indication/VIPERA_BERUS.html |title=''Vipera berus'' antivenoms |website=Munich AntiVenom INdex (MAVIN) |access-date=15 September 2006 |archive-url=https://web.archive.org/web/20190417204349/http://www.toxinfo.org/antivenoms/indication/VIPERA_BERUS.html |archive-date=2019-04-17}}</ref>

Mallow et al. (2003) describe the toxicity of the venom as being relatively low compared to that of other viper species. They cite Minton (1974) who reported the {{LD50}} values for mice to be 0.55 mg/kg IV, 0.80 mg/kg IP and 6.45 mg/kg SC. For comparison, one test found that the minimum lethal dose of venom for a guinea pig was 40–67 mg, whereas only 1.7 mg was necessary when ''Daboia russelii'' venom was used.<ref name="Mal03"/>{{page needed|date=August 2022}} Brown (1973) gives a higher subcutaneous LD50 range of 1.0–4.0 mg/kg.<ref name="Bro73"/> All agree that the venom yield is low. Minton (1974) mentions 10–18 mg for specimens {{convert|48|–|62|cm|in|round=0.5|abbr=on}} in length,<ref name="Mal03"/>{{page needed|date=August 2022}} while Brown (1973) lists only 6 mg.<ref name="Bro73"/>

Relatively speaking, bites from this species are not highly dangerous.<ref name="Mal03" />{{page needed|date=August 2022}} In Britain, there were only 14 known fatalities between 1876 and 2005—the last of which was a five-year-old child in 1975<ref name="War05" />—and one near-fatal bite on a 39-year-old woman in Essex in 1998.<ref name="War05" /> An 82-year-old woman died following a bite in Germany in 2004, although it is unclear whether her death was due to the effects of the venom,<ref>{{cite web |url=http://www.ggiz-erfurt.de/aktuelles/akt_press_04_juli_kreuzotter_ostsee.htm |title=''Giftschlangen: Tod durch Kreuzotterbiss?'' |trans-title=Venomous snakes: death from adder bite? |date=May 4, 2004 |website=Gemeinsames Giftinformationszentrum Erfurt |language=de |access-date=6 September 2021 |archive-url=https://web.archive.org/web/20110721140222/http://www.ggiz-erfurt.de/aktuelles/akt_press_04_juli_kreuzotter_ostsee.htm |archive-date=July 21, 2011}}</ref> and a 52-year-old male died in Sweden after failing to seek treatment in 2023<ref>{{cite web |last1=Mittendorf and Windskog |title=Anaphylaxis as probable cause of death in a rare case of fatal Vipera berus bite |url=https://link.springer.com/article/10.1007/s12024-023-00776-2 |website=Springer Nature Link |publisher=Images in Forensics |access-date=6 January 2026}}</ref>. A 44-year-old British man was left seriously ill after he was bitten by an adder in the Dalby Forest, Yorkshire, in 2014.<ref>{{cite news |url=https://www.yorkshirepost.co.uk/news/dont-pick-snakes-warn-officials-after-man-bitten-yorkshire-forest-1837117 |title=Don't pick up snakes warn officials after man is bitten in Yorkshire forest |date=7 August 2014 |newspaper=The Yorkshire Post |access-date=6 September 2021}}</ref> Even so, professional medical help should always be sought as soon as possible after any bite.<ref>{{Cite web |last=McKillop |first=Ann |date=April 2021 |title=Advice on Adder Bites |url=https://firstaidtrainingcooperative.co.uk/advice-on-adder-bites-2/ |website=First Aid Training Co-operative}}</ref> Very occasionally bites can be life-threatening, particularly in small children, while adults may experience discomfort and disability long after the bite.<ref name="War05" /> The length of recovery varies, but may take up to a year.<ref name="Mal03" />{{page needed|date=August 2022}}<ref>{{cite news |url=https://www.aftenposten.no/norge/i/dd2W2X/rekordmange-bitt-av-hoggorm |title=''Rekordmange bitt av hoggorm'' |trans-title=Record number of bites from vipers |author= |date=9 July 2018 |newspaper=Aftenposten |language=no |access-date=11 June 2021}}</ref>

Local symptoms include severe and immediate pain, followed by swelling and tingling after a few minutes, although this may take up to 30 minutes. Blisters containing blood are uncommon. The pain may then spread within a few hours, accompanied by tenderness and inflammation. Red lymphangitic lines and bruising may appear, and the entire limb can become swollen and bruised within 24 hours. The swelling may also spread to the trunk and, in children, the whole body. Necrosis and intracompartmental syndromes are very rare.<ref name="War05"/>

Systemic symptoms arising from anaphylaxis can be severe. These may manifest within five minutes of the bite, or can be delayed for several hours. These symptoms may include nausea, retching and vomiting, abdominal colic and diarrhoea, incontinence of urine and faeces, sweating, fever, vasoconstriction, tachycardia, lightheadedness, loss of consciousness, and even blindness,{{citation needed |date=May 2020}} shock, angioedema of the face, lips, gums, tongue, throat and epiglottis, urticaria and bronchospasm. If left untreated, these symptoms may persist or fluctuate for up to 48 hours.<ref name="War05"/> In severe cases, cardiovascular failure may occur.<ref name="Mal03"/>{{page needed|date=August 2022}}

==In culture and beliefs== It was once thought that adders were deaf, as referenced in Psalm 58 (v. 4), yet snake oil derived from adders was used as a cure for deafness and earaches. Females were also thought to swallow their young when threatened and regurgitate them unharmed later. It was further believed that they did not perish until sunset.<ref>{{cite book |last1=Simpson |first1=Jacqueline |last2=Roud |first2=Stephen |date=2000 |title=A Dictionary of English Folklore |chapter-url=https://books.google.com/books?id=iTcdvd1iRXsC&pg=PT13 |publisher=Oxford University Press |chapter=Entry for "Adder" |isbn=978-0-19-210019-1}}</ref> Remedies for adder "stings" included killing the snake responsible and rubbing the corpse or its fat on the wound, also holding a pigeon or chicken on the bite, or jumping over water. Adders were thought to be attracted to hazel trees and repelled by ash trees.<ref name="HCT"/>

The Druids believed that large, frenzied gatherings of adders took place in spring, at the centre of which was a polished rock called an adder stone or ''Glain Neidr'' in the Welsh language. These stones were said to have held supernatural powers.<ref name="HCT"/>

==References== {{Reflist}}

==Further reading== {{Refbegin}} *Ananjeva NB, Borkin LJ, Darevsky IS, Orlov NL (1998). [''Amphibians and Reptiles. Encyclopedia of Nature of Russia'']. Moscow: ABF. (in Russian). *Arnold EN, Burton JA (1978). ''A Field Guide to the Reptiles and Amphibians of Britain and Europe''. London: Collins. 272 pp. {{ISBN|0-00-219318-3}}. (''Vipera berus'', pp. 217–218 + Plate 39 + Map 122). *Boulenger GA (1896). ''Catalogue of the Snakes in the British Museum (Natural History). Volume III., Containing the...Viperidæ.'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiv + 727 pp. + Plates I.- XXV. (''Vipera berus'', pp. 476–481). *Goin CJ, Goin OB, Zug GR (1978). ''Introduction to Herpetology: Third Edition''. San Francisco: W.H. Freeman. xi + 378 pp. {{ISBN|0-7167-0020-4}}. (''Vipera berus'', pp. 122, 188, 334). *Jan G, Sordelli F (1874). ''Iconographie générale des Ophidiens: Quarante-cinquième Livraison.'' Paris: Baillière. Index + Plates I.- VI. (''Vipera berus'', Plate II, Figure 1; var. ''prester'', Plate II, Figures 2-4; var. ''concolor'', Plate II, Figure 5; var. ''lymnaea'', Plate II, Figure 6). *Joger U, Lenk P, Baran I, Böhme W, Ziegler, Heidrich P, Wink M (1997). "The phylogenetic position of ''Vipera barani'' and of ''Vipera nikolskii'' within the ''Vipera berus'' complex". ''Herpetologica Bonnensis'' 185-194. *Linnaeus C (1758). ''Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Tomus I. Editio Decima, Reformata.'' Stockholm: L. Salvius. 824 pp. (''Coluber berus'', p. 217). *Minton SA Jr. (1974). ''Venom Diseases''. Springfield, Illinois: CC Thomas Publ. 256 pp. {{ISBN|978-0-398-03051-3}}. *Morris PA (1948). ''Boy's Book of Snakes: How to Recognize and Understand Them''. A volume of the Humanizing Science Series, edited by Jaques Cattell. New York: Ronald Press. viii + 185 pp. (The common viper, ''Vipera berus'', pp. 154–155, 182). *{{cite journal |last1=Wüster |first1=Wolfgang |last2=Allum |first2=Christopher S. E. |last3=Bjargardóttir |first3=I. Birta |last4=Bailey |first4=Kimberley L. |last5=Dawson |first5=Karen J. |last6=Guenioui |first6=Jamel |last7=Lewis |first7=John |last8=McGurk |first8=Joe |last9=Moore |first9=Alix G. |last10=Niskanen |first10=Martti |last11=Pollard |first11=Christopher P. |author1-link=species:Wolfgang Wüster |title=Do aposematism and Batesian mimicry require bright colours? A test, using European viper markings |journal=Proceedings of the Royal Society of London. Series B: Biological Sciences |date=2004 |volume=271 |issue=1556 |pages=2495–2499 |doi=10.1098/rspb.2004.2894|pmid=15590601 |pmc=1691880 }} {{Refend}}

==External links== {| | {{Commons}} | {{Wikispecies|Vipera berus}} | {{Collier's Poster|Adder|year=1921}} |} {{Taxonbar|from=Q192056}} {{Authority control}}

Category:Vipera Category:Reptiles of Europe Category:Reptiles of East Asia Category:Reptiles of Russia Category:Fauna of Siberia Category:Arctic land animals Category:Aposematic species Category:Reptiles described in 1758 Category:Animal taxa named by Carl Linnaeus