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{{Short description|Common name for snakes of the genus Thamnophis}}
{{Hatnote|The article is about North American garter snakes. For the unrelated venomous snakes of Africa also called garter snakes, see ''[[Elapsoidea]]''.}}
{{Automatic taxobox
| name = Garter snake
| image = Thamnophis sirtalis sirtalis Wooster.jpg
| image_caption = The [[eastern garter snake]]<br />(''Thamnophis sirtalis sirtalis'')
| taxon = Thamnophis
| authority = [[Leopold Fitzinger|Fitzinger]], 1843
| synonyms = ''Atomarchus'', ''Chilopoma'', ''Eutaenia'', ''Eutainia'', ''Phamnovis'', ''Prymnomiodon'', ''Stypocemus'', ''Tropidonote'', ''Tropidonotus''
| synonyms_ref =<ref>[[Albert Hazen Wright|Wright AH]], Wright AA (1957). ''Handbook of Snakes of the United States and Canada''. Ithaca and London: Comstock Publishing Associates, a division of Cornell University Press. 1,105 pp. (in 2 volumes). (''Thamnophis'', p. 755).</ref>
| subdivision_ranks = Species
| subdivision = 35, see [[#Species and subspecies|text]]
| range_map = Thamnophis_range.png
| range_map_caption = ''Thamnophis'' distribution
}}

'''Garter snake''' is the [[common name]] for small to medium-sized [[snake]]s 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 north to [[Costa Rica]] in the south.

With about 37 recognized species and 52 subspecies,<ref>{{Cite web |title=Thamnophis {{!}} COL |url=https://www.catalogueoflife.org/data/taxon/CF7NJ |access-date=2025-08-07 |website=www.catalogueoflife.org}}</ref> garter snakes are highly variable in appearance; generally, they have large round eyes with rounded pupils, a slender build, [[keeled scales]] (appearing 'raised'), and a pattern of longitudinal stripes that may or may not include spots (although some have no stripes at all). Certain subspecies have stripes of blue, yellow, or red, mixed with black tops and beige-tan underbelly markings. They also vary significantly in total length, from {{cvt|18|to|51|in|cm}}.

With no real consensus on the classification of the species of ''Thamnophis'', disagreements between [[Taxonomy (biology)|taxonomists]] and disputed sources (such as field guides) are common. One area of debate, for example, is whether or not two specific types of snake are separate species, or [[subspecies]] of the same. Garter snakes are closely related to the genus ''[[Nerodia]]'' (water snakes), with some species having been moved back and forth between genera.

As garter snakes may retain toxins from their amphibian prey in their liver, they are one of the few species of snakes in the world that can be both venomous and poisonous.

== Taxonomy ==
The first garter snake to be scientifically described was the [[eastern garter snake]] (now ''Thamnophis sirtalis sirtalis''), by zoologist and taxonomist [[Carl Linnaeus]] in 1758.  The genus ''Thamnophis'' was described by [[Leopold Fitzinger]] in 1843 as the genus for the garter snakes and ribbon snakes.<ref>{{Cite web|url=https://www.itis.gov/servlet/SingleRpt/SingleRpt?search_topic=TSN&search_value=174133#null|title=ITIS Standard Report Page: Thamnophis|website=www.itis.gov|access-date=2019-07-06}}</ref> Many snakes previously identified as their own genera or species have been reclassified as species or subspecies in ''Thamnophis''. The [[Reptile Database]] currently recognised 37 species in the genus, some with several subspecies.<ref>{{cite taxon|reptileDB|title=Species in genus ''Thamnophis'' |url=https://reptile-database.reptarium.cz/advanced_search?genus=Thamnophis&exact%5B0%5D=genus&submit=Search |access-date=1 July 2024}}</ref>

== Distribution and habitat ==
Native to [[North America|North]] and [[Central America]], [[species]] in the genus ''Thamnophis'' can be found in all of the [[Contiguous United States|lower 48 United States]], and all of the Canadian provinces. They are found from the [[subarctic]] plains of west-central [[Canada]] east through [[Ontario]] and [[Quebec]]; from [[Atlantic Canada]] and south to [[Florida]], across the southern and central U.S. into the arid regions of the southwest and [[Mexico]], [[Guatemala]] and south to the neotropics and [[Costa Rica]].<ref>{{Cite web |title=Genus Thamnophis - taxonomy & distribution / RepFocus |url=https://repfocus.dk/Thamnophis.html |access-date=2025-08-07 |website=repfocus.dk}}</ref>

Garter snakes are not originally native to the eastern Canadian island of [[Newfoundland (island)|Newfoundland]], but have been breeding there in the wild and gradually spreading since at least 2010. It is unknown how they reached the island, probably accidentally via [[hay]] shipments or as escaped pets.<ref>CBC News, "[https://www.cbc.ca/news/canada/newfoundland-labrador/snakes-newfoundland-research-invasive-species-1.7242649 Think there aren't any snakes in Newfoundland? Think again]", June 25, 2024. Accessed on June 27, 2024.</ref><ref>Nature Conservancy Canada, "[https://www.natureconservancy.ca/en/where-we-work/newfoundland-and-labrador/stories/snakes-saints-and-sightings.html#:~:text=The%20first%20confirmed%20report%20of,John's. Snakes, saints and sightings: What you can do to help uncover the mystery of gartersnakes in Newfoundland]". Accessed on June 27, 2024.</ref>

Their wide distribution is due to their varied diets and adaptability to different habitats, with varying proximity to water.<ref>{{Cite web |title=Thamnophis Fitzinger, 1843 |url=https://www.gbif.org/species/144104407 |access-date=2025-08-07 |website=www.gbif.org |language=en}}</ref> However, in the western part of North America these snakes are more aquatic than in the eastern portion. Garter snakes live in a variety of habitats, including forests, woodlands, fields, grasslands and lawns, but never far from water, often an adjacent wetland, stream or pond. This reflects the fact that amphibians are a large part of their diet. Garter snakes are often found near small ponds with tall weeds.<ref name=":0">{{Cite book |last=Rossman |first=Douglas Athon |url=https://books.google.com/books?id=n2rW7E8_uJoC&q=more+aquatic |title=The Garter Snakes: Evolution and Ecology |date=1996 |publisher=University of Oklahoma Press |isbn=978-0-8061-2820-7 |language=en |access-date=2025-08-06}}</ref>

==Behavior==
[[File:Garter snake tooth.jpg|left|thumb|The posterior tooth of a garter snake]]
Garter snakes have complex [[Pheromone|pheromonal]] communication systems. They can find other snakes by following their pheromone-scented trails. Male and female skin pheromones are so different as to be immediately distinguishable. However, male garter snakes sometimes produce both male and female pheromones. During the mating season, this ability fools other males into attempting to mate with them. This causes the transfer of heat to them in [[kleptothermy]], which is an advantage immediately after [[hibernation]], allowing them to become more active.<ref>{{cite journal | last1 = Shine | first1 = R | author-link = Richard Shine | last2 = Phillips | first2 = B | last3 = Waye | first3 = H | last4 = LeMaster | first4 = M | last5 = Mason | first5 = RT | year = 2001 | title = Benefits of female mimicry to snakes | journal = Nature | volume = 414 | issue = 6861| page = 267 | doi = 10.1038/35104687 | pmid = 11713516 | bibcode = 2001Natur.414..267S | s2cid = 205023381 | doi-access = free }}</ref> Male snakes giving off both male and female pheromones have been shown to garner more copulations than normal males in the [[mating ball]]s that form at the den when females enter the mating melee. A snake hatch can include as many as 57 young.<ref>{{Cite web|url=https://www.fairfaxcounty.gov/soil-water-conservation/garter-snakes-gardeners-best-friend|title=Garter Snakes: A Gardener's Best Friend &#124; Northern Virginia Soil and Water Conservation District|website=www.fairfaxcounty.gov}}</ref>

Garter snakes use the [[vomeronasal organ]] to communicate via pheromones through tongue flicking, which gathers chemical cues in the environment. Upon entering the [[Lumen (anatomy)|lumen]] of the organ, the chemical molecules will come into contact with the sensory cells, which are attached to the neurosensory epithelium of the vomeronasal organ.<ref name=":0" />

If disturbed, a garter snake may coil and strike, but it typically hides its head and flails its tail. These snakes will also discharge a malodorous, musky-scented secretion from a gland near the [[cloaca]]. This secretion from North American garter snakes contains seven highly odoriferous volatile components: [[Acetic acid|acetic]], [[Propanoic acid|propanoic]], [[2-methylpropanoic acid|2-methylpropanoic]], [[Butanoic acid|butanoic]], and [[3-Methylbutanoic acid|3-methylbutanoic]] acids; and [[trimethylamine]], and [[2-Piperidinone|2-piperidone]].<ref>{{cite journal | last1 = Wood | first1 = William F. | last2 = Parker | first2 = Joshua M. | last3 = Weldon | first3 = Paul J. | year = 1995 | title = Volatile Components in Scent Gland Secretions of Garter Snakes (Thamnophis sp.) | journal = J. Chemical Ecology | volume = 21 | issue = 2 | pages = 213–219 | doi=10.1007/BF02036652| pmid = 24234020 | bibcode = 1995JCEco..21..213W }}</ref> They often use these techniques to escape when ensnared by a predator. They will also slither into the water to escape a predator on land. [[Hawks]], [[crow]]s, [[egret]]s, [[heron]]s, [[Crane (bird)|crane]]s, [[raccoon]]s, [[otter]]s and other snake species (such as [[coral snake]]s and [[kingsnake]]s) will eat garter snakes, with even [[shrew]]s and [[frog]]s eating the juveniles.
[[File:Garter Snake Scales.tif|thumb|Close up of the scales on the back of the common garter snake]]
Being [[heterothermic]], like all [[reptile]]s, garter snakes bask in the sun to regulate their body temperature. During [[brumate|brumation]] (the reptile equivalent of hibernation), garter snakes typically occupy large communal sites called [[Hibernaculum (zoology)|hibernacula]]. These snakes will migrate large distances to [[brumate]].<ref name=":0" />

=== Social behavior ===
A long-term study by the [[Ontario Ministry of Transportation]] has shed light on the social behavior of Butler's garter snakes. The study, conducted in a 250-hectare area near [[Windsor, Ontario|Windsor, Canada]], tracked over 3,000 individual snakes over a 12-year period. The findings challenge previous assumptions about solitary snake behavior and suggest that these snakes form social groups and communities. The study revealed that Butler's garter snakes do not wander randomly but instead tend to associate with specific groups of snakes. These groups typically consist of three to four individuals, with some larger groups reaching up to 46 snakes.<ref>{{cite news |last=Howlett |first=Joseph |url=https://www.science.org/content/article/garter-snakes-make-friends-organize-their-society-around-females |title=Garter snakes make friends, organize their society around females |work=[[Science (journal)|Science]] |date=2023-12-15 |access-date=2023-12-19 }}</ref><ref>{{Cite journal |last1=Skinner |first1=Morgan |last2=Miller |first2=Noam |date=2020-04-15 |title=Aggregation and social interaction in garter snakes (Thamnophis sirtalis sirtalis) |journal=Behavioral Ecology and Sociobiology |language=en |volume=74 |issue=5 |page=51 |doi=10.1007/s00265-020-2827-0 |bibcode=2020BEcoS..74...51S |issn=1432-0762}}</ref>

===Diet===
[[File:Garter swallowing frog.jpg|left|thumb|Eating a frog]]
Garter snakes, like all snakes, are carnivorous. Their diet consists of almost any creature they are capable of overpowering: [[slug]]s, [[earthworm]]s ([[Lumbricus terrestris|nightcrawlers]], as [[Eisenia fetida|redworms]] are toxic to garter snakes), [[leech]]es, [[lizard]]s, [[amphibian]]s (including [[frog]] eggs), <!--[[toads]], covered under 'amphibians'--> [[minnow]]s, and [[rodent]]s. When living near water, they eat other aquatic animals. The [[Thamnophis saurita|ribbon snake]] (''Thamnophis saurita'') in particular favors [[frog]]s (including [[tadpole]]s), readily eating them despite their strong chemical defenses. Food is swallowed whole. Garter snakes often adapt to eating whatever they can find and whenever they can find it because food can be either scarce or abundant. Although they feed mostly on live [[animal]]s they will sometimes eat eggs.<ref>{{Cite web |title=Garter Snake Care Sheet |url=http://www.thamnophis.com/index.php?page=caresheet |publisher=Thamnophis.com |access-date=2013-08-26 |archive-date=2023-04-30 |archive-url=https://web.archive.org/web/20230430072358/http://www.thamnophis.com/index.php?page=caresheet }}</ref>
{{Clear}}

===Venom===
Garter snakes were long thought to be non-[[Venom|venomous]], but discoveries in the early 2000s revealed that they produce a neurotoxic venom.<ref>{{cite news| url=https://www.nytimes.com/2005/04/05/science/05veno.html | work=The New York Times | first=Carl | last=Zimmer | title=Open Wide: Decoding the Secrets of Venom | date=April 5, 2005}}</ref> Despite this, garter snakes cannot seriously injure or kill humans with the small amounts of comparatively mild venom they produce and they also lack an effective means of delivering it. In a few cases, some swelling and bruising has been reported.<ref name=warm/> They do have enlarged teeth in the back of their mouths<ref>{{cite journal | last1 = Wright | first1 = Debra L. | last2 = Kardong | first2 = Kenneth V. | last3 = Bentley | first3 = David L. | year = 1979 | title = The Functional Anatomy of the Teeth of the Western Terrestrial Garter Snake, ''Thamnophis elegans''. | journal = Herpetologica | volume = 35 | issue = 3| pages = 223–228 | jstor = 3891690 }}</ref> but their gums are significantly larger and the secretions of their [[Duvernoy's gland]] are only mildly toxic.<ref name=warm>{{cite magazine|last=Smith|first=Michael|date=September 2001|title=Duverney's Glands and "Warm" Herping|url=http://www.anapsid.org/duvernoygland.html|magazine=Cross Timbers Herpetologist|publisher=Dallas-Fort Worth Herpetological Society|via=Melissa Kaplan's Herp Care Collection }}</ref><ref>{{cite web|url=http://www.onlinenevada.org/articles/garter-snakes|title=Garter Snakes|last=de Queiroz|first=Alan|date=September 27, 2010|website=Online Nevada Encyclopedia|publisher=Nevada Humanities|access-date=December 29, 2016|archive-date=February 18, 2017|archive-url=https://web.archive.org/web/20170218214427/http://www.onlinenevada.org/articles/garter-snakes}}</ref>

Evidence suggests that garter snake and [[newt]] populations share an evolutionary link in their [[tetrodotoxin]] resistance levels, implying [[co-evolution]] between predator and prey.<ref>{{cite journal | last1 = Williams | first1 = Becky L. | last2 = Brodie | first2 = Edmund D. Jr. | last3 = Brodie | first3 = Edmund D. III | year = 2003 | title = Coevolution of Deadly Toxins and Predator Resistance: Self-Assessment of Resistance by Garter Snakes Leads to Behavioral Rejection of Toxic Newt Prey | journal = Herpetologica | volume = 59 | issue = 2| pages = 155–163 | doi = 10.1655/0018-0831(2003)059[0155:codtap]2.0.co;2 | s2cid = 18028592 }}</ref> Garter snakes feeding on toxic newts can also retain those toxins in their liver for weeks, making those snakes poisonous as well as venomous.<ref>{{cite journal|last1=Williams|first1=Becky L.|last2=Brodie|first2=Edmund D. Jr.|last3=Brodie|first3=Edmund D. III|year=2004|title=A resistant predator and its toxic prey: persistence of newt toxin leads to poisonous (not venomous) snakes|journal=Journal of Chemical Ecology|volume=30|issue=10|pages=1901–1919|doi=10.1023/B:JOEC.0000045585.77875.09|pmid=15609827|bibcode=2004JCEco..30.1901W |s2cid=14274035}}</ref>

==Conservation status==
[[File:Mating ball of garter snakes.jpg|thumb|left|A mating ball]]
[[File:Gartersnake2128.JPG|thumb|A young garter snake]]
Despite the decline in their population from collection as pets (especially in the more northerly regions, in which large groups are collected at hibernation),<ref>{{cite web |url=http://www.biokids.umich.edu/critters/Thamnophis_sirtalis/#conservation_status |title=''Thamnophis sirtalis ''|author=Zimmerman R|year=2013|website=Kids' Inquiry of Diverse Species |publisher=Animal Diversity Web |access-date= November 5, 2016}}</ref> pollution of aquatic areas, and the introduction of [[American bullfrog]]s as potential predators, garter snakes are still some of the most commonly found reptiles in much of their ranges. The San Francisco garter snake (''[[Thamnophis sirtalis tetrataenia]]''), however, has been on the endangered list since 1969. Predation by [[crayfish]] has also been responsible for the decline of the [[narrow-headed garter snake]] (''Thamnophis rufipunctatus'').<ref name=IUCN>{{cite iucn|author=Hammerson GA|title=''Thamnophis rufipunctatus ''|volume=2007|article-number=e.T63990A12727179|year=2007|doi=10.2305/IUCN.UK.2007.RLTS.T63990A12727179.en}}</ref> Many breeders have bred all species of garter snakes, making it a popular breed.
{{Clear}}

==Species and subspecies==

Arranged alphabetically by scientific name:
{| class="wikitable sortable"
|-
! Image !! Name !! Subspecies !! Distribution
|-
|
|''[[Thamnophis ahumadai]]'' {{small|[[Christoph I. Grünwald|C. Grünwald]], [[María del Carmen G. Mendoza-Portilla|Mendoza-Portilla]], [[André J. Grünwald|A. Grünwald]], [[Carlos E. Montaño-Ruvalcaba|Montaño-Ruvalcaba]], [[Hector Franz-Chávez|Franz-Chávez]], [[Uri Omar García-Vázquez|García-Vázquez]], & [[Jacobo Reyes-Velasco|Reyes-Velasco]], 2024 }}<ref>{{Cite journal |last1=Grünwald |first1=Christoph I. |last2=Mendoza-Portilla |first2=María del Carmen G. |last3=Grünwald |first3=André J. |last4=Montaño-Ruvalcaba |first4=Carlos |last5=Franz-Chávez |first5=Héctor |last6=García-Vázquez |first6=Uri O. |last7=Reyes-Velasco |first7=Jacobo |date=2024-06-26 |title=A new species of Thamnophis (Serpentes, Colubridae) from Jalisco, Mexico, with a discussion on the phylogeny, taxonomy, and distribution of snakes related to Thamnophis scalaris |url=https://herpetozoa.pensoft.net/article/122213/ |journal=Herpetozoa |language=en |volume=37 |pages=157–179 |doi=10.3897/herpetozoa.37.e122213 |doi-access=free |issn=2682-955X}}</ref>
|
|Jalisco Mountain, Mexico
|-
|[[File:Thamnophis atratus (1).jpg|120px]] || [[Aquatic garter snake]], ''[[Thamnophis atratus]]'' {{small|([[Robert Kennicott|Kennicott]], 1860) }} ||
* [[Santa Cruz garter snake]], ''T. a. atratus'' {{small|(Kennicott, 1860)}}
* [[Oregon garter snake]], ''T. a. hydrophilus'' {{small|[[Henry Sheldon Fitch|Fitch]], 1936}}
* [[Diablo Range garter snake]], ''T. a. zaxanthus'' {{small|[[Jeff Boundy|Boundy]], 1999}}
||  coast of Oregon and California.
|-
| || [[Bogert's garter snake]], ''[[Thamnophis bogerti]]'' {{small| [[Douglas A. Rossman|Rossman]] & [[Frank T. Burbrink|Burbrink]], 2005 }} ||

|| Oaxaca, Mexico
|-
| || [[Shorthead garter snake]], ''[[Thamnophis brachystoma]]'' {{small| ([[Edward Drinker Cope|Cope]], 1892)}} ||

||  northwestern Pennsylvania and southwestern New York.
|-
|[[File:Thamnophis butleri.jpg|120px]] || [[Butler's garter snake]], ''[[Thamnophis butleri]]'' {{small|(Cope, 1889) }} ||

||  northwestern Ohio, northeastern Indiana, the eastern portion of the Lower Peninsula of Michigan, and the adjacent extreme southern tip of Ontario, Canada.
|-
| ||[[Goldenhead garter snake]], ''[[Thamnophis chrysocephalus]] '' {{small| (Cope, 1885)}} ||

|| Mexico.
|-
| || [[Conant's garter snake]], ''[[Thamnophis conanti]]'' {{small|Rossman & Burbrink, 2005 }} ||

||  Puebla and Veracruz, Mexico.
|-
| ||[[Cope's mountain meadow snake]], ''[[Thamnophis copei]]'' {{small|[[Alfredo Dugès|Dugès]], 1879}} ||

|| Mexico.
|-
|[[File:Sierra garter snake handled.jpg|120px]] || [[Sierra garter snake]], ''[[Thamnophis couchii]]'' {{small|(Kennicott, 1859) }} ||

|| California and Oregon in the United States
|-
|[[File:Thamnophis cyrtopsis ocellatus.jpg|120px]] || Blackneck garter snake, ''[[Thamnophis cyrtopsis]]'' {{small| (Kennicott, 1860)}} ||
* Western blackneck garter snake, ''T. c. cyrtopsis'' {{small|(Kennicott, 1860)}}
* Eastern blackneck garter snake, ''T. c. ocellatus'' {{small|(Cope, 1880)}}
* Tropical blackneck garter snake, ''T. c. collaris'' {{small|([[Giorgio Jan|Jan]], 1863)}}
|| southwestern United States, Mexico and Guatemala
|-
|[[File:Coast Garter Snake.jpg|120px]] ||[[Western terrestrial garter snake]], ''[[Thamnophis elegans]]'' {{small|([[Spencer Fullerton Baird|Baird]] & [[Charles Frédéric Girard|Girard]], 1853) }} ||
* [[Arizona]] garter snake, ''T. e. arizonae'' {{small|[[Wilmer W. Tanner|W. Tanner]] & [[Charles Herbert Lowe|Lowe]], 1989}}
* Mountain garter snake, ''T. e. elegans'' {{small|(Baird & Girard, 1853)}}
* [[Sierra San Pedro Mártir|San Pedro Mártir]] garter snake, ''T. e. hueyi'' {{small|[[John Van Denburgh|Van Denburgh]] & [[Joseph Richard Slevin|Slevin]], 1923}}
* Coastal garter snake, ''T. e. terrestris'' {{small|[[Wade Fox|Fox]], 1951}}
* Wandering garter snake, ''T. e. vagrans'' {{small|(Baird & Girard, 1853)}}
* Upper Basin garter snake, ''T. e. vascotanneri'' {{small|W. Tanner & Lowe, 1989}}
||central British Columbia, central Alberta, and southwestern Manitoba in Canada, central United States
|-
|[[File:Thamnophis eques1.jpg|120px]] || [[Mexican garter snake]], ''[[Thamnophis eques]]'' {{small|([[:fr:Adolph Reuss|Reuss]], 1834) }} ||
* Mexican garter snake, ''T. e. eques'' {{small|(Reuss, 1834)}}
* Laguna Totolcingo garter snake, ''T. e. carmenensis'' {{small|[[Roger Conant (herpetologist)|Conant]], 2003}}
* ''T. e. cuitzeoensis'' {{small|Conant, 2003}}
* ''T. e. diluvialis'' {{small|Conant, 2003}}
* ''T. e. insperatus'' {{small|Conant, 2003}}
* Northern Mexican garter snake, ''T. e. megalops'' {{small|(Kennicott, 1860)}}
* ''T. e. obscurus'' {{small|Conant, 2003}}
* ''T. e. patzcuaroensis'' {{small|Conant, 2003}}
* ''T. e. scotti'' {{small|Conant, 2003}}
* ''T. e. virgatenuis'' {{small|Conant, 1963}}
|| Mexico and in the United States (Arizona and New Mexico).
|-
|[[File:Thamnophis errans.jpg|120px]] || [[Mexican wandering garter snake]], ''[[Thamnophis errans]]'' {{small| [[Hobart Muir Smith|H. M. Smith]], 1942}} ||

||  Chihuahua, Durango, Jalisco, Nayarit, and Zacatecas States of Mexico. 
|-
| || [[Montane garter snake]], ''[[Thamnophis exsul]]'' {{small|Rossman, 1969 }} ||

|| Mexico.
|-
| ||[[Fox's mountain meadow snake]], ''[[Thamnophis foxi]]'' {{small|[[Douglas A. Rossman|Rossman]] & [[Richard M. Blaney|Blaney]], 1968}} ||

|| Mexico.
|-
| || [[Highland garter snake]], ''[[Thamnophis fulvus]]'' {{small| ([[Marie Firmin Bocourt|Bocourt]], 1893)}} ||

||Mexico, Guatemala, Honduras and El Salvador.
|-
|[[File:Giant Garter Snake 1.jpg|120px]] || [[Giant garter snake]], ''[[Thamnophis gigas]]'' {{small| [[Henry Sheldon Fitch|Fitch]], 1940}} ||

|| central California.
|-
| || [[Godman's garter snake]],<ref>Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). ''The Eponym Dictionary of Reptiles''. Baltimore: Johns Hopkins University Press. xiii + 296 pp. {{ISBN|978-1-4214-0135-5}}. (''Thamnophis godmani'', p. 102).</ref> ''[[Thamnophis godmani]]'' {{small|([[Albert Günther|Günther]], 1894) }} ||

|| southern Mexico
|-
|[[File:Thamnophis hammondii 02.jpg|120px]] || [[Two-striped garter snake]], ''[[Thamnophis hammondii]]'' {{small|(Kennicott, 1860) }} ||

||  central California to Baja California, Mexico
|-
| || Liner's garter snake, ''[[Thamnophis lineri]]''<ref>[http://reptile-database.reptarium.cz/species?genus=Thamnophis&species=lineri&search_param=%28%28genus%3D%27Thamnophis%27%29%29 ''Thamnophis lineri'']. The Reptile Database. http://www.reptile-database.org.</ref> {{small|Rossman & Burbrink, 2005 }} ||

||  Mexico. 
|-
|[[File:Thamnophis marcianus.jpg|120px]] || [[Checkered garter snake]], ''[[Thamnophis marcianus]]'' {{small| (Baird & Girard, 1853)}} ||
* ''T. m. marcianus'' {{small|(Baird & Girard, 1853)}}
* ''T. m. praeocularis'' {{small|(Bocourt, 1892)}}
* ''T. m. bovalli'' {{small|(Dunn, 1940)}}
|| southwestern United States, Mexico, and Central America.
|-
|[[File:Blackbelly Garter Snake imported from iNaturalist photo 162669277 on 15 November 2021.jpg|120px]] || [[Blackbelly garter snake]], ''[[Thamnophis melanogaster]]'' {{small| ([[Wilhelm Peters|Peters]], 1864)}} ||
* [[Gray blackbelly garter snake]], ''T. m. canescens'' {{small|H.M. Smith, 1942}}
* [[Chihuahuan blackbelly garter snake]], ''T. m. chihuahuanensis'' {{small|W. Tanner, 1959}}
* [[Lined blackbelly garter snake]], ''T. m. linearis'' {{small|H.M. Smith, [[C. William Nixon|Nixon]] & [[Philip Wayne Smith|P.W. Smith]], 1950}}
* [[Mexican blackbelly garter snake]], ''T. m. melanogaster'' {{small|([[Wilhelm Peters|W. Peters]], 1864)}}
|| Mexico.
|-
||| [[Tamaulipan montane garter snake]], ''[[Thamnophis mendax]]'' {{small|[[Charles F. Walker|Walker]], 1955 }} ||

||Mexico.
|-
||| [[Southern Durango spotted garter snake]], ''[[Thamnophis nigronuchalis]]'' {{small|Thompson, 1957}} ||

||  Durango, Mexico.
|-
|[[File:Thamnophis ordinoides 071616 A.jpg|120px]] || [[Northwestern garter snake]], ''[[Thamnophis ordinoides]]'' {{small| (Baird & Girard, 1852)}} ||

|| California, Oregon, and Washington; in Canada, it is found in British Columbia
|-
| || [[Tepalcatepec Valley garter snake]], ''[[Thamnophis postremus]]'' {{small| [[Hobart Muir Smith|Smith]], 1942}} ||

||  Mexico. 
|-
|[[File:Thamnophis proximus rubrilineatus.jpg|120px]] || Western ribbon snake, ''[[Thamnophis proximus]]'' {{small| ([[Thomas Say|Say]], 1823)}} ||
* [[Chiapas]] Highlands ribbon snake, ''T. p. alpinus'' {{small|Rossman, 1963}}
* Arid land ribbon snake, ''T. p. diabolicus'' {{small|Rossman, 1963}}
* Gulf Coast ribbon snake, ''T. p. orarius'' {{small|Rossman, 1963}}
* Orangestripe ribbon snake or western ribbon snake ''T. p. proximus'' {{small|(Say, 1823)}}
* [[Thamnophis proximus rubrilineatus|Redstripe ribbon snake]], ''T. p. rubrilineatus'' {{small|Rossman, 1963}}
* Mexican ribbon snake, ''T. p. rutiloris'' {{small|(Cope, 1885)}}
||  western United States, Mexico, and Central America
|-
|[[File:Thamnophis pulchrilatus4.jpg|120px]] || [[Yellow-throated garter snake]], ''[[Thamnophis pulchrilatus]]'' {{small|([[Edward Drinker Cope|Cope]], 1885) }} ||

|| Mexico.
|-
|[[File:Thamnophis-radix.JPG|120px]] || [[Plains garter snake]], ''[[Thamnophis radix]]'' {{small|(Baird & Girard, 1853) }} ||

|| central United States as far north as Canada and as far south as Texas.
|-
| || [[Rossman's garter snake]], ''[[Thamnophis rossmani]]'' {{small|Conant, 2000 }} ||

|| Mexico.
|-
| || [[Narrow-headed garter snake]], ''[[Thamnophis rufipunctatus]]'' {{small|(Cope, 1875) }} ||

|| Arizona and New Mexico, and in the Mexican states of Sonora, Chihuahua and Durango
|-
|[[File:EasternRibbonSnake.jpg|120px]] || [[Thamnophis saurita|Ribbon snake]], ''[[Thamnophis saurita]]'' {{small|([[Carl Linnaeus|Linnaeus]], 1766) }} ||
* [[Bluestripe ribbon snake]], ''T. s. nitae'' {{small|Rossman, 1963}}
* [[Southern ribbon snake]], ''T. s. sackenii'' {{small|(Kennicott, 1859)}}
* [[Thamnophis saurita saurita|Eastern ribbon snake]], ''T. s. saurita'' {{small|(Linnaeus, 1766)}}
* [[Thamnophis saurita septentrionalis|Northern ribbon snake]], ''T. s. septentrionalis'' {{small|Rossman, 1963}}
||  Eastern North America
|-
|[[File:Thamnophis scalaris.jpg|120px]] ||[[Longtail alpine garter snake]], ''[[Thamnophis scalaris]]'' {{small|(Cope, 1861) }} ||

|| Mexico.
|-
| || [[Short-tail Alpine garter snake|Short-tail alpine garter snake]], ''[[Thamnophis scaliger]]'' {{small|(Jan, 1863) }} ||

|| Mexico.
|-
|[[File:Thamnophis sirtalis annectens.jpg|120px]] || [[Common garter snake]], ''[[Thamnophis sirtalis]]'' {{small|([[Carl Linnaeus|Linnaeus]], [[10th edition of Systema Naturae|1758]]) }} ||
* [[Texas garter snake]], ''T. s. annectens'' {{small|[[Bryce C. Brown|Brown]], 1950}}
* [[Red-spotted garter snake]], ''T. s. concinnus'' {{small|([[Edward Hallowell (herpetologist)|Hallowell]], 1852)}}
* [[New Mexico garter snake]], ''T. s. dorsalis'' {{small|(Baird & Girard, 1853)}}
* [[valley garter snake]], ''T. s. fitchi'' {{small|Fox, 1951}}
* [[California red-sided garter snake]], ''T. s. infernalis'' {{small|([[Henri Marie Ducrotay de Blainville|Blainville]], 1835)}}
* ''T. s. lowei'' {{small|[[Wilmer W. Tanner|W. Tanner]], 1988}}
* [[Maritime garter snake]], ''T. s. pallidulus<!-- SPELLING SOURCE - http://reptile-database.reptarium.cz/species?genus=Thamnophis&species=sirtalis -->'' {{small|[[Glover Morrill Allen|Allen]], 1899}}
* Red-sided garter snake, ''T. s. parietalis'' {{small|(Say, 1823)}}
* [[Puget Sound]] garter snake, ''T. s. pickeringii'' {{small|(Baird & Girard, 1853)}}
* [[Blue-striped garter snake]], ''T. s. similis'' {{small|Rossman, 1965}}
* [[Eastern garter snake]], ''T. s. sirtalis'' {{small|([[Carl Linnaeus|Linnaeus]], 1758)}}
* [[Thamnophis sirtalis semifasciatus|Chicago garter snake]], ''T. s. semifasciatus'' {{small|(Cope, 1892)}}
* [[San Francisco garter snake]], ''T. s. tetrataenia'' {{small|(Cope, 1875)}}
|| North America
|-
| || [[Sumichrast's garter snake]], ''[[Thamnophis sumichrasti]]'' {{small|(Cope, 1866)}} ||

|| Mexico.
|-
|||[[Madrean narrow-headed garter snake]], ''[[Thamnophis unilabialis]]'' {{small| W. Tanner, 1985}} ||

||Mexico. 
|-
| || [[West Coast garter snake]], ''[[Thamnophis validus]]'' {{small|([[Robert Kennicott|Kennicott]], [[1860]]) }} ||
* [[Mexican Pacific Lowlands garter snake]], ''T. v. celaeno'' {{small|(Cope, 1860)}}
* ''T. v. isabellae'' {{small|(Conant, 1953)}}
* ''T. v. thamnophisoides'' {{small|(Conant, 1961)}}
* ''T. v. validus'' {{small|(Kennicott, 1860)}}
|| Mexico.
|-
|}

In the above list, a [[Binomial nomenclature|binomial authority]] or a [[Trinomen|trinomial authority]] in parentheses indicates that the species or subspecies was originally described in a genus other than ''Thamnophis''.

==See also==
{{Portal|snakes}}
* [[Narcisse Snake Dens]]
* [[List of snakes]], overview of all snake families and genera

==References==
{{Reflist}}

==Further reading==
* [[Roger Conant (herpetologist)|Conant R]] (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition''. Boston: Houghton Mifflin Company. xviii + 429 pp. + Plates 1-48. {{ISBN|978-0-395-19979-4}} (hardcover), {{ISBN|978-0-395-19977-0}} (paperback). (Genus ''Thamnophis'', p.&nbsp;157).
* [[Leopold Fitzinger|Fitzinger L]] (1843). ''Systema Reptilium, Fasciculus Primus, Amblyglossae.'' Vienna: Braumüller & Seidel. 106 pp. + indices. (''Thamnophis'', new genus, p.&nbsp;26). (in Latin).
* [[:fr:Coleman Jett Goin|Goin, Coleman J.]], Goin, Olive B.; [[:de:George Robert Zug|Zug, George R.]] (1978). ''Introduction to Herpetology, Third Edition''. San Francisco: W.H. Freeman and Company. xi + 378 pp. {{ISBN|978-0-7167-0020-3}}. (''Thamnophis'', pp.&nbsp;132, 156, 326).
* [[Robert Powell (herpetologist)|Powell R]], Conant R, [[Joseph T. Collins|Collins JT]] (2016). ''Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition''. Boston and New York: Houghton Mifflin Harcourt. xiv + 494 pp., 47 plates, 207 figures. {{ISBN|978-0-544-12997-9}}. (Genus ''Thamnophis'', p.&nbsp;426).
* [[Alexander Grant Ruthven|Ruthven AG]] (1908). "Variation and Genetic Relationships of the Garter-snakes". ''Bulletin of the United States National Museum'' '''61''': 1–201, 82 figures.
* [[Karl Patterson Schmidt|Schmidt, Karl P.]]; Davis, D. Dwight (1941). ''Field Book of Snakes of the United States and Canada''. New York: G.P. Putnam's Sons. 365 pp., 34 plates, 103 figures. (Genus ''Thamnophis'', p.&nbsp;236).
* [[Robert C. Stebbins|Stebbins RC]] (2003). ''A Field Guide to Western Reptiles and Amphibians, Third Edition''. The Peterson Field Guide Series. Boston and New York: Houghton Mifflin Company. xiii + 533 pp., 56 plates. {{ISBN|978-0-395-98272-3}}. (Genus ''Thamnophis'', pp.&nbsp;373–374).
* [[John Van Denburgh|Vandenburgh J]], [[Joseph Richard Slevin|Slevin JR]] (1918). "The Garter-snakes of Western North America". ''Proceedings of the California Academy of Sciences, Fourth Series'' '''8''': 181–270, 11 plates.

==External links==
* {{cite journal | last1 = González-Fernández | first1 = Andrea | last2 = Manjarrez | first2 = Javier | last3 = García-Vázquez | first3 = Uri | last4 = D'Addario | first4 = Maristella | last5 = Sunny | first5 = Armando | year = 2018 | title = Present and future ecological niche modeling of garter snake species from the Trans-Mexican Volcanic Belt | journal = PeerJ | volume = 6 | article-number = e4618 | doi = 10.7717/peerj.4618 | pmid = 29666767 | pmc = 5903425 | doi-access = free }}
{{NIE Poster|year=1906|Garter-snake}}
* [http://www.anapsid.org/gartcare.html Anapsid.org: Garter snakes]
* [http://johnbokma.com/mexit/2006/05/03/snake-road.html Several pictures of a Mexican ribbon snake (''Thamnophis proximus rutiloris'')]
* [http://www.herpnet.net/Iowa-Herpetology/reptiles/snakes/plains-garter-snake-thamnophis-radix/ Plains garter snake - ''Thamnophis radix''. Species account from the Iowa Reptile and Amphibian Field Guide]
* [http://www.herpnet.net/Iowa-Herpetology/reptiles/snakes/eastern-garter-snake-thamnophis-sirtalis/ Eastern garter snake - ''Thamnophis sirtalis''. Species account from the Iowa Reptile and Amphibian Field Guide]
* [https://web.archive.org/web/20130927015325/http://garter-snake.com/index.html Descriptions and biology of garter snakes]
* {{EMBL genus|genus=Thamnophis}}

{{Taxonbar|from=Q1149509}}
{{Authority control}}

[[Category:Thamnophis|⠀]]
[[Category:Reptiles of Canada]]
[[Category:Reptiles of the United States]]
[[Category:Reptiles of Mexico]]
[[Category:Snake common names]]
[[Category:Snakes of Central America]]
[[Category:Snakes of North America]]
[[Category:Taxa named by Leopold Fitzinger]]
[[Category:Extant Miocene first appearances]]
[[Category:Symbols of Massachusetts]]