The Natricinae are a subfamily of colubroid

snakes Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joi ...

, sometimes referred to as a family (Natricidae). The subfamily comprises 37

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

. Members include many very common snake species, such as the European grass snakes, and the North American water snakes and

garter snakes Garter snake is a common name for generally harmless, small to medium-sized snakes belonging to the genus ''Thamnophis'' in the family Colubridae. Native to North and Central America, species in the genus ''Thamnophis'' can be found from the sub ...

. Some Old World members of the subfamily are known as keelbacks, because their dorsal scales exhibit strong keeling. Natricine snakes are found in

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

Asia Asia (, ) is one of the world's most notable geographical regions, which is either considered a continent in its own right or a subcontinent of Eurasia, which shares the continental landmass of Afro-Eurasia with Africa. Asia covers an area ...

Europe Europe is a large peninsula conventionally considered a continent in its own right because of its great physical size and the weight of its history and traditions. Europe is also considered a Continent#Subcontinents, subcontinent of Eurasia ...

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

, and

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

as far south as

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

. A single species, '' Tropidonophis mairii'', reaches

Australia Australia, officially the Commonwealth of Australia, is a Sovereign state, sovereign country comprising the mainland of the Australia (continent), Australian continent, the island of Tasmania, and numerous List of islands of Australia, sma ...

. Although the highest diversity is in North America, the oldest members are in Asia and Africa, suggesting an Old World origin for the group. Most species are semiaquatic and feed on fish and amphibians, although a few are semifossorial or leaf-litter snakes that feed on invertebrates. Most species are harmless to humans, but a few (e.g., ''

Thamnophis sirtalis The common garter snake (''Thamnophis sirtalis'') is a species of thamnophis snake, in the natricine subfamily, which is indigenous to North America and found widely across the continent. Most common garter snakes have a pattern of yellow stri ...

'', ''

Thamnophis elegans The western terrestrial garter snake (''Thamnophis elegans'') is a western North American species of colubrid snake. At least five subspecies are currently recognized. Description Most western terrestrial garter snakes have a yellow, light orang ...

'') are capable of inflicting bites that can result in local, nonlife-threatening symptoms, and at least two members of the genus ''

Rhabdophis ''Rhabdophis'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. Species in the genus ''Rhabdophis'' are generally called keelback snakes, and are found primarily in Southeast Asia. Toxicity ''Rhabdophis'' is often thoug ...

'' ('' R. tigrinus'' and '' R. subminiatus'') are capable of inflicting life-threatening bites to humans, though they have only enlarged, ungrooved fangs in the back of the mouth. 364 pp. .

Classification

They are recognised as a sister group of the

Dipsadinae Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species. Dips ...

plus the

Pseudoxenodontinae Pseudoxenodontinae is a small subfamily of colubroid snakes, sometimes referred to as a family (Pseudoxenodontidae). They are found in southern and southeastern Asia, from northeast India to southern China (including Taiwan) and south into Indon ...

Genera

*''

Adelophis Adelophis is a genus of snakes in the family Colubridae. They are endemic to Mexico. Species * ''Adelophis copei'' Dugès, 1879 – Cope's mountain meadow snake * ''Adelophis foxi Fox's mountain meadow snake (''Thamnophis foxi'', meaning "Fo ...

'' *'' Afronatrix'' *''

Amphiesma Amphiesma is a genus of snakes in the family Colubridae. They are found across Asia. Species * '' Amphiesma stolatum'' (Linnaeus, 1758) – buff striped keelback * ''Amphiesma monticola ''Amphiesma monticola'', also known as the Wynad keel ...

'' *''

Amphiesmoides ''Amphiesmoides'' is a genus of snake in the family Colubridae that contains the sole species ''Amphiesmoides ornaticeps''. It is commonly known as Werner's ornate snake or white-eyed keelback. It is found in China and Vietnam Vietnam o ...

'' *''

Anoplohydrus ''Anoplohydrus'' is a genus of snakes in the family Natricidae that contains the sole species ''Anoplohydrus aemulans''. It is found on the island of Sumatra Sumatra is one of the Sunda Islands of western Indonesia. It is the largest isl ...

'' *''

Aspidura ''Aspidura'' is a genus of the Colubridae family of snakes that is endemic to island of Sri Lanka which is commonly known as rough-sided snake, and as මැඩිල්ලා (maedilla) in Sinhala. Black-spined snake which was once in the gen ...

'' *''

Atretium ''Atretium schistosum'', the split keelback or olive keelback wart snake, is a species of snake found in South Asia. It is a common and harmless watersnake. Distribution Found in Sri Lanka, India, Bangladesh and Nepal. In India it occurs in ...

'' *''

Blythia ''Blythia'' is a genus of snakes of the superfamily Colubroidea.. Species * ''Blythia hmuifang'' Vogel, Lalremsanga, & Vanlalhrima, 2017 - Mizoram ground snake * ''Blythia reticulata ''Blythia reticulata'', commonly known as Blyth's reticula ...

'' *'' Clonophis'' *''

Fowlea ''Fowlea'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. The genus is endemic to Asia. Species The following species are recognized as being valid.. The Reptile Database. www.reptile-database.org. *'' Fowlea aspe ...

'' *'' Haldea'' *''

Hebius ''Hebius'' is a genus of snakes in the family Colubridae.. Geographic range The genus ''Hebius'' is endemic to Asia.Guo et al. Taxonomy All of the member species of the genus ''Hebius'' were formerly placed in the genus ''Amphiesma'', but in 20 ...

'' *'' Helophis'' *''

Herpetoreas ''Herpetoreas'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. The genus is endemic to South Asia. Species The genus ''Herpetoreas'' contains the following 7 species, which are recognized as being valid. *'' Herpetore ...

'' *'' Hydrablabes'' *'' Hydraethiops'' *'' Iguanognathus'' *'' Isanophis'' *'' Limnophis'' *'' Liodytes'' *'' Lycognathophis'' *'' Natriciteres'' *''

Natrix ''Natrix'' is a genus of Old World snakes found across Eurasia (although the range of ''Natrix tessellata'' extends into Egypt and those of '' N. astreptophora'' and '' N. maura'' into north-west Africa) in the subfamily Natricinae of the famil ...

'' *''

Nerodia ''Nerodia'' is a genus of nonvenomous colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Description ''Nerodia'' species vary greatly, but all are ...

'' *''

Opisthotropis ''Opisthotropis'' is a genus of snakes in the family Colubridae. The genus is endemic to Southeast Asia and South China. Species The genus ''Opisthotropis'' contains the following 25 species which are recognized as being valid, listed alphabetic ...

'' *''

Paratapinophis ''Trimerodytes praemaxillaris'' is a species of snake in the subfamily Natricinae of the family Colubridae. It is also known commonly as Angel's mountain keelback, Angel's stream snake, and the brown stream snake. The species is endemic to South ...

'' *'' Pseudagkistrodon'' *'' Regina'' *''

'' *''

Rhabdops ''Rhabdops'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. The genus is endemic to the Western Ghats of India. Species The genus ''Rhabdops'' contains two recognized valid species: *'' Rhabdops aquaticus'' – aq ...

'' *''

Smithophis ''Smithophis'' is a genus of snakes in the subfamily Natricinae of the family Colubridae; the one species that was known prior to 2019 had been classified under the genus ''Rhabdops,'' but was removed in the process of erecting the new genus '' ...

'' *''

Storeria ''Storeria'' is a genus of snakes in the subfamily Natricinae of the Family (biology), family Colubridae. The genus is Endemism, endemic to North America and Central America. The genus consists of five species, four of which are known as brown ...

'' *'' Thamnophis'' *''

Trachischium ''Trachischium'' is a genus of snakes, known commonly as slender snakes or worm-eating snakes, in the subfamily Natricinae of the family Colubridae. The genus is endemic to Asia. Geographic range Species of the genus ''Trachischium'' are fou ...

'' *''

Trimerodytes ''Trimerodytes'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. The genus is endemic to East Asia and Southeast Asia. Species The genus ''Trimerodytes'' contains 7 species which are recognized as being valid. *''Trime ...

'' *''

Tropidoclonion ''Tropidoclonion'' is a genus of snake in the subfamily Natricinae of the Family (biology), family Colubridae. The genus is Monotypic taxon, monotypic, containing the sole species ''Tropidoclonion lineatum'', Common name, commonly known as the li ...

'' *''

Tropidonophis ''Tropidonophis'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. www.reptile-database.org. Species The following 20 species are recognized as being valid. *'' Tropidonophis aenigmaticus'' – East Papuan keelback, ...

'' *''

Virginia Virginia, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...

'' *''

Xenochrophis ''Xenochrophis'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. The genus is endemic to Asia. Some members have been moved to the genus Fowlea. Etymology The generic nomen of Xenochrophis is presumably derived from ...

Classification

Genera

References

Further reading