The Natricinae are a

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end botanical subfamily names with "-oideae", and zo ...

of colubroid

snakes Snakes are elongated Limbless vertebrate, limbless reptiles of the suborder Serpentes (). Cladistically Squamata, squamates, snakes are ectothermic, amniote vertebrates covered in overlapping Scale (zoology), scales much like other members of ...

, sometimes referred to as a

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

(Natricidae). The subfamily comprises 36

genera Genus (; : genera ) is a taxonomic rank above species and below family as used in the biological classification of living and fossil organisms as well as viruses. In binomial nomenclature, the genus name forms the first part of the binomial s ...

. Members include many very common snake

species A species () is often defined as the largest group of organisms in which any two individuals of the appropriate sexes or mating types can produce fertile offspring, typically by sexual reproduction. It is the basic unit of Taxonomy (biology), ...

, such as the European grass snakes, and the North American water snakes and

garter snake Garter snake is the common name for small to medium-sized snakes belonging to the genus ''Thamnophis'' in the Family (biology), family Colubridae. They are native to North America, North and Central America, ranging from central Canada in the no ...

s. Some Old World members of the subfamily are known as keelbacks, because their

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales. Campbell JA, Lamar WW (2004). ''The Venomous Reptiles of the Western Hemisphere''. Ithaca and London: Comstock Publis ...

exhibit strong keeling. Natricine snakes are found in

Africa Africa is the world's second-largest and second-most populous continent after Asia. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 20% of Earth's land area and 6% of its total surfac ...

Asia Asia ( , ) is the largest continent in the world by both land area and population. It covers an area of more than 44 million square kilometres, about 30% of Earth's total land area and 8% of Earth's total surface area. The continent, which ...

Europe Europe is a continent located entirely in the Northern Hemisphere and mostly in the Eastern Hemisphere. It is bordered by the Arctic Ocean to the north, the Atlantic Ocean to the west, the Mediterranean Sea to the south, and Asia to the east ...

North America North America is a continent in the Northern Hemisphere, Northern and Western Hemisphere, Western hemispheres. North America is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South Ameri ...

, and

Central America Central America is a subregion of North America. Its political boundaries are defined as bordering Mexico to the north, Colombia to the southeast, the Caribbean to the east, and the Pacific Ocean to the southwest. Central America is usually ...

as far south as

Costa Rica Costa Rica, officially the Republic of Costa Rica, is a country in Central America. It borders Nicaragua to the north, the Caribbean Sea to the northeast, Panama to the southeast, and the Pacific Ocean to the southwest, as well as Maritime bo ...

. A single species, ''

Tropidonophis mairii ''Tropidonophis mairii'', also known commonly as Mair's keelback,. www.reptile-database.org. the common keelback, and the freshwater snake, is a species of colubrid snake in the subfamily Natricinae. The species is native to Australasia. Etymol ...

'', reaches

Australia Australia, officially the Commonwealth of Australia, is a country comprising mainland Australia, the mainland of the Australia (continent), Australian continent, the island of Tasmania and list of islands of Australia, numerous smaller isl ...

. 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

amphibian Amphibians are ectothermic, anamniote, anamniotic, tetrapod, four-limbed vertebrate animals that constitute the class (biology), class Amphibia. In its broadest sense, it is a paraphyletic group encompassing all Tetrapod, tetrapods, but excl ...

s, although a few are semi

fossorial A fossorial animal () is one that is adapted to digging and which lives primarily (but not solely) underground. Examples of fossorial vertebrates are Mole (animal), moles, badgers, naked mole-rats, meerkats, armadillos, wombats, and mole salamand ...

leaf-litter Plant litter (also leaf litter, tree litter, soil litter, litterfall, or duff) is dead plant material (such as leaves, bark, needles, twigs, and cladodes) that has fallen to the ground. This detritus or dead organic material and its constituent ...

snakes that feed on

invertebrate Invertebrates are animals that neither develop nor retain a vertebral column (commonly known as a ''spine'' or ''backbone''), which evolved from the notochord. It is a paraphyletic grouping including all animals excluding the chordata, chordate s ...

s. Most species are harmless to humans, but a few (e.g., '' Thamnophis sirtalis'', ''

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

'') are capable of inflicting bites that can result in local, non-life-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. The best-known species is '' Rhabdophis ...

'' ('' 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

The Natricinae are recognised as a sister group of the

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

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

*'' Afronatrix'' *''

Amphiesma Amphiesma is a genus of snakes in the subfamily Natricinae of the family Colubridae. Species in the genus ''Amphiesma'' are found across Asia. Species * ''Amphiesma stolatum'' (Linnaeus, 1758 Events January–March * January 1 ...

'' *''

Amphiesmoides ''Amphiesmoides'' is a genus of snake in the subfamily Natricinae of the family Colubridae. The genus contains the sole species ''Amphiesmoides ornaticeps''. Commonly known as Werner's ornate snake or the white-eyed keelback, it is native to Sout ...

'' *'' Anoplohydrus'' *''

Aspidura ''Aspidura'' is a genus of snakes in the subfamily Natricinae of the Family (biology), Family Colubridae. The genus is Endemism, endemic to island of Sri Lanka. Member species are Common name, commonly known as rough-sided snakes, except for ''A ...

'' *''

Atretium ''Atretium schistosum'', also known commonly as the split keelback and the olive keelback wart snake, is a species of snake in the subfamily Natricinae of the family Colubridae. The species, which is the sole species in the genus ''Atretium'', ...

'' *''

Blythia ''Blythia'' is a genus of snakes in the subfamily Natricinae of the family Colubridae of the superfamily Colubroidea. The genus, which contains two recognized species, is native to South Asia and Southeast Asia.. Etymology The genus ''Blythia' ...

'' www.reptile-database.org. *'' 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 asperri ...

'' *'' Haldea'' *''

Hebius ''Hebius'' is a genus of snakes in the Family (biology), family Colubridae.. Geographic range The genus ''Hebius'' is Endemism, endemic to Asia.Guo et al. Taxonomy All of the member species of the genus ''Hebius'' were formerly placed in the ge ...

'' *'' Helophis'' *''

Herpetoreas ''Herpetoreas'' is a genus of snakes in the subfamily Natricinae of the Family (biology), family Colubridae. The genus is Endemism, endemic to South Asia. Species The genus ''Herpetoreas'' contains the following 7 species, which are recognized a ...

'' *''

Hydrablabes ''Hydrablabes'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. The genus contains two species. Geographic range Both species of the genus ''Hydrablabes'' are endemic to Borneo. Species The following two species are r ...

'' *'' Hydraethiops'' *''

Iguanognathus The spatula-toothed snake (''Iguanognathus werneri'') is a species of snake in the Family (biology), family Colubridae. The species is Endemism, endemic to Indonesia. Etymology The Specific name (zoology), specific name, ''werneri'', is in honor ...

'' *'' Isanophis'' *''

Limnophis ''Limnophis'' is a genus of snakes in the subfamily Natricinae of the Family (biology), family Colubridae. The genus contains three species. Geographic range Species of the genus ''Limnophis'' are Endemism, endemic to southern Africa. Species T ...

'' *'' Liodytes'' *'' Lycognathophis'' *'' Natriciteres'' *''

Natrix ''Natrix'' is a genus of Old World snakes found mainly 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 t ...

'' *''

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. Five of the species have recognized subspecies. Descript ...

'' *''

Opisthotropis ''Opisthotropis'' is a genus of snakes in the subfamily Natricinae of the Family (biology), family Colubridae. The genus is native to Southeast Asia and South China. Species The genus ''Opisthotropis'' contains the following 25 species which are ...

'' *''

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 ''Pseudagkistrodon'' is a monotypic genus of snake in the subfamily Natricinae of the family Colubridae. The sole species is ''Pseudagkistrodon rudis'', also known commonly as the red keelback, the false habu, and the false viper. It is found in ...

'' *'' 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'' – aquat ...

'' *'' Sahyadriophis'' *''

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 ''Sm ...

'' *''

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 Common name, commonly as slender snakes or worm-eating snakes, in the subfamily Natricinae of the Family (biology), family Colubridae. The genus is Endemism, endemic to Asia. Geographic range Species ...

'' *''

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. *'' Trim ...

'' *''

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 (biology), family Colubridae. www.reptile-database.org. Species The following 20 species are recognized as being valid. *''Tropidonophis aenigmaticus'' – East P ...

'' *''

Virginia Virginia, officially the Commonwealth of Virginia, is a U.S. state, state in the Southeastern United States, Southeastern and Mid-Atlantic (United States), Mid-Atlantic regions of the United States between the East Coast of the United States ...

'' *''

Xenochrophis ''Xenochrophis'' is a genus of snakes in the subfamily Natricinae of the Family (biology), family Colubridae. The genus is Endemism, endemic to Asia. Some members have been moved to the genus ''Fowlea''. Etymology The generic nomen ''Xenochrophi ...

Classification

Genera

References

Further reading