{{Short description|Species of snake}} {{Speciesbox | image = Viperine water snake (Natrix maura).jpg | image_caption = Swimming, Spain | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 20 November 2021">{{cite iucn |author=Jose Antonio Mateo Miras, Marc Cheylan, M. Saïd Nouira, Ulrich Joger, Paulo Sá-Sousa, Valentin Pérez-Mellado, Benedikt Schmidt, Andreas Meyer, Roberto Sindaco, Antonio Romano, Iñigo Martínez-Solano |date=2009 |title=''Natrix maura'' |volume=2009 |article-number=e.T61538A12510365 |doi=10.2305/IUCN.UK.2009.RLTS.T61538A12510365.en |access-date=20 November 2021}}</ref> | genus = Natrix | species = maura | authority = (Linnaeus, 1758) | synonyms = *''Coluber maurus'' <br />{{small|Linnaeus, 1758}} *''Coluber viperinus'' <br />{{small|Sonnini & Latreille, 1802}} *''Tropidonotus viperinus'' <br />{{small|— Boulenger, 1893}} *''Natrix maura'' <br />{{small|— Arnold & Burton, 1978}} | range_map = Mapa Natrix maura.png | range_map_caption = Range map of Natrix maura }}

The '''viperine water snake''' or '''viperine snake''' ('''''Natrix maura''''') is a semiaquatic, fish-eating natricine water snake. Despite its common names, it is not a member of the subfamily Viperinae. It was given its common names due to exhibiting a dorsal colour pattern that superficially resembles that of sympatric adder species. In comparison to other ''Natrix'' species its head is also somewhat wider and more distinct from the neck. Like most members of the Natricinae it possesses a venom gland on each side of the upper jaw (Duvernoy's gland) that produces a mild venom that may play a role in swallowing or digestion. The gland is not associated with an enlarged specialized tooth and the venom has to be applied by chewing. The species usually does not bite as a means of defense, and the effect of a bite would be harmless to humans.

==Behaviour== The viperine snake looks like an adder and occasionally behaves like one. It is known to strike like an adder, but not to bite. It spends most of its time in water hunting fish, frogs and other aquatic animals. The species is diurnal.<ref name="uicnmed">[http://www.uicnmed.org/web2007/cd_rep_amp/materials/reptile_summery/natrix_maura.pdf UIcnmed.org]</ref>

== Fossil record == Fossils of the viperine snake are known from El Chaparral, a fossil site in Villaluenga del Rosario that dates back to the latter part of the Early Pleistocene.<ref>{{Cite journal |last=Sánchez-Bandera |first=Christian |last2=Blasco |first2=Rafael Marquina |last3=Bisbal-Chinesta |first3=Josep Francesc |last4=Fagoaga |first4=Ana |last5=Cáceres |first5=Isabel |last6=Gutiérrez |first6=José María |last7=Pacheco |first7=Francisco Giles |last8=López-García |first8=Juan Manuel |last9=Blain |first9=Hugues-Alexandre |date=9 June 2025 |title=Rainiest Spain: amphibians and reptiles from the late Early Pleistocene-age site of El Chaparral (Cádiz) |url=https://link.springer.com/article/10.1007/s12549-025-00656-3 |journal=Palaeobiodiversity and Palaeoenvironments |language=en |volume=105 |issue=2 |pages=377–400 |doi=10.1007/s12549-025-00656-3 |issn=1867-1594 |access-date=10 September 2025 |via=Springer Nature Link|url-access=subscription }}</ref>

==Geographic range== The viperine snake is found in southwestern Europe and northwestern Africa. Specifically, ''N. maura'' is found in the European countries of Portugal, Spain, Andorra, France, northwestern Italy, and Switzerland. It has spread to areas of England, as well{{Citation needed|date=September 2023}}. It is found in African countries of Morocco, northern Algeria, northwestern Libya, and northern to central Tunisia. It was introduced to Mallorca in the Baleares (not indicated on the distribution map).<ref name="uicnmed"/>

==Description==

''N. maura'' is grey, brown, or reddish dorsally, with a black zigzag vertebral stripe, and lateral series of black ocelli with yellow centers. The labials are yellow with black sutures. It has a diagonal dark band on each temple, and another behind it on each side of the neck. Ventrally, it is yellow or red, checkered with black, or all black. The strongly keeled dorsal scales are arranged in 21 rows. The ventrals are 147–160; the anal plate is divided; and the paired subcaudals number 47–72. Adults may attain a total length of 85&nbsp;cm (33 inches), with a tail 17&nbsp;cm (7 inches) long.<ref>Boulenger GA. 1893. ''Catalogue of the Snakes in the British Museum (Natural History). Volume I., Containing the Families ... Colubridæ Aglyphæ, part.'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xiii + 448 pp. + Plates I-XXVIII. (''Tropidonotus viperinus'', pp. 235–237).</ref>

==Habitat== The viperine snake is found in rivers and lakes, and has also been recorded from areas of brackish water.

==Invasion== The species is invasive on Mallorca.<ref name="Kraus-2015">{{cite journal | last=Kraus | first=Fred | title=Impacts from Invasive Reptiles and Amphibians | journal=Annual Review of Ecology, Evolution, and Systematics | publisher=Annual Reviews | volume=46 | issue=1 | date=2015-12-04 | issn=1543-592X | doi=10.1146/annurev-ecolsys-112414-054450 | pages=75–97}}</ref> ''N. maura'' predates on ''Pelophylax perezi'' among other prey on Mallorca. Research by Moore et al. 2004 suggests trophic subsidy provided by ''P. perezi'' is maintaining higher numbers of the invader than would otherwise occur.<ref name="Kraus-2015" /> ''N. maura'' has altered the behavior of Mallorcan prey. Moore et al. 2004 found that the higher numbers mentioned above are allowing the invader to exert such high pressure that prey species such as the Majorcan midwife toad (''Alytes muletensis'') have retreated entirely to habitats too steep for ''N. maura''.<ref name="Kraus-2015" />

==See also== * List of reptiles of Italy

==References== {{Reflist}}

==External links== * [http://www.euroherp.com/species/Natrix_maura/ Euroherp.com]

==Further reading== *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}}. (''Natrix maura'', pp.&nbsp;202–204 + Plate 37 + Map 115). *Linnaeus C. 1758. ''Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, locis. Tomus I. Editio Decima, Reformata.'' Stockholm: L. Salvius. 824 pp. (''Coluber maurus'', new species, p.&nbsp;219). (in Latin).

{{Taxonbar|from=Q1541871}} {{Authority control}}

{{DEFAULTSORT:Natrix Maura}} Category:Natrix Category:Snakes of Africa Category:Reptiles of North Africa Category:Reptiles of Europe Category:Reptiles described in 1758 Category:Animal taxa named by Carl Linnaeus

{{Natricinae-stub}}