Eastern garter snake

{{Short description|Subspecies of snake}} {{Subspeciesbox | name = Eastern garter snake | image = Thamnophis sirtalis sirtalis Wooster.jpg | image_caption = | status = T5 | status_system = TNC | status_ref= {{sfn|NatureServe|2016}} | genus = Thamnophis | species = sirtalis | subspecies = sirtalis | authority = (Linnaeus, 1758) }}

The '''eastern garter snake''' ('''''Thamnophis sirtalis sirtalis''''') is a medium-sized snake endemic to North America.

==Taxonomy== ===Etymology=== The scientific name ''Thamnophis sirtalis sirtalis'' is a combination of Ancient Greek and New Latin that means "bush snake that looks like a garter strap". The generic name ''Thamnophis'' is derived from the Greek "thamnos" (bush) and "ophis" (snake) and the specific name ''sirtalis'' is derived from the New Latin "siratalis" (like a garter), a reference to the snake's color pattern resembling a striped garter strap.{{sfn|Krulikowski|2004}}

==Description== Eastern garter snakes average between {{convert|18|-|26|in|cm|disp=flip|abbr=on}} long. The longest recorded length was {{convert|48.7|in|cm|disp=flip|abbr=on}} long. Females are typically larger than males. They are either a greenish, brown, or black color and have a distinct yellow or white stripe.

=== Venom === Although the eastern garter snake is often considered non-venomous, garter snakes do have a Duvernoy's gland, and the secretion from the gland may be chewed into prey during bites. The secretion is noted to cause hemorrhaging in mice and has produced non-allergic symptoms in at least one bite on a human.{{sfn|Hayes|Hayes|1985}}{{sfn|Vest|1981}}{{sfn|Gomez|Davis|Phillips|McKinney|1994}}

==Distribution and habitat== The eastern garter snake has the widest geographic range of any garter snake, extending from the Atlantic to the Pacific coasts and reaching farther north than any other snake species in the Western Hemisphere.<ref>{{Cite book |last=Rossman |first=Douglas A. |title=The garter snakes: evolution and ecology |last2=Ford |first2=Neil B. |last3=Seigel |first3=Richard A. |date=1996 |publisher=University of Oklahoma Press |isbn=978-0-8061-2820-7 |series=Animal natural history series |location=Norman}}</ref> Their distribution ranges all across America but tends not to be present in western deserts.{{sfn|Shine|Phillips|Waye|Lemaster|2004}} In New England, the snake is described as the "most widespread and ubiquitous" serpent, from wilderness to urban environments and from sea level to high elevations.{{sfn|Krulikowski|2004}}

The eastern garter snake will live in a variety of environments, with a preference for grassy or shrubby fields, including abandoned farmland, outbuildings and trash dumps.{{sfn|Krulikowski|2004}} In particular the snake likes to inhabit stone walls that separate the forest from fields. It is also found along moist habitats such as lakes, rivers, streams, swamps, bogs, ponds, drainage ditches, and quarries. Snakes are present in urban environments in habitats that include "city parks, cemeteries and suburban yards and gardens".{{sfn|Krulikowski|2004}} Eastern garter snakes like to conceal themselves under logs, stones and other debris that allow them to bask in the sunlight and quickly seek refuge from predators. Eastern garter snakes have also been found to inhabit crayfish burrows during the hibernating season.<ref>{{cite web |title=Activity Patterns and Spatial Resource Selection of the Eastern Garter Snake (Thamnophis sirtalis sirtalis) |url=https://ecommons.luc.edu/cgi/viewcontent.cgi?article=2464&context=luc_theses}}</ref> Krulikowski notes that "old poultry farms with discarded sheet-metal incubation trays provide warm, moist hiding places."{{sfn|Krulikowski|2004}}

{{Multiple image | image1 = Eastern Garter Snake imported from iNaturalist photo 122620448 on 6 December 2024.jpg | image2 = Eastern Garter Snake imported from iNaturalist photo 183586093 on 6 December 2024 (cropped).jpg | image3 = Eastern Garter Snake imported from iNaturalist photo 189879310 on 6 December 2024.jpg | image4 = Eastern Garter Snake imported from iNaturalist photo 169352879 on 6 December 2024 (cropped).jpg | image5 = Eastern Garter Snake imported from iNaturalist photo 46623001 on 6 December 2024 (cropped).jpg | total_width = 900 | align = center | image6 = Eastern Garter Snake imported from iNaturalist photo 327649580 on 6 December 2024.jpg | footer = Colour variation in the eastern garter snake }}

==Ecology and behavior== ===Hunting and diet=== [[File:Eastern garter snake eating frog.jpg|thumb|An eastern garter snake eating a northern leopard frog (''Lithobates pipiens'').]] The majority of the eastern garter snake's diet (~80%) consists of earthworms, though they have a secondary preference (~15%) for amphibian prey (esp. frogs) as well.<ref name="Carpenter1952p239a"/> As they mature, their preference in prey will undergo an ontogenetic shift. Younger eastern garter snakes (those under {{cvt|40|cm}} in length) prey almost exclusively upon earthworms (~88%) and smaller amphibians (~8%), such as spring peepers and northern cricket frogs, and generally avoid taking warm-blooded prey. Mature snakes rely more on amphibian prey (which now comprise ~19% of their diet), especially larger amphibians like green frogs and northern leopard frogs, though earthworms still make up the bulk of their diet (~76%).<ref name="Carpenter1952p239b"/>

However, eastern garter snakes are opportunistic predators, and will readily consume almost any creature they can swallow. Other prey records for this subspecies include caterpillars,<ref name="Carpenter1952p239a"/> leeches,<ref name="Carpenter1952p241b"/> mudminnows,<ref name="Carpenter1952p241b"/> the Jefferson salamander,<ref name="Carpenter1952p241a"/> and the eastern meadow vole.<ref name="Carpenter1952p242a"/> Large adults will even target small birds if the opportunity presents itself, such as song sparrows,<ref name="Carpenter1952p242b"/> goldfinches,<ref name="Carpenter1952p242b"/> and chipping sparrows.<ref name="Carpenter1952p242c"/>

===Predator avoidance=== The eastern garter snake is known to flatten its head and anterior body and strike forward if it is bothered. Juveniles have been observed to engage in this behavior and strike at such a force that they leave the ground entirely. Adults also will spray musk from glands in their tail, and sometimes defecate to discourage predators.{{cn|date=May 2024}} Body temperature influences defensive behaviors. Snakes with higher body temperatures tend to flee as they have more energy.{{sfn|Passek|Gillingham|1997}} Larger males and pregnant females are more likely to stand their ground.<ref>{{cite web |title=Exploratory and defensive behaviours change with sex and body size in eastern garter snakes (Thamnophis sirtalis) |url=https://www.researchgate.net/publication/278398565 |website=Research Gate}}</ref>

=== Social behavior === Movement and home range for eastern garter snakes is dependent on resource availability. Females typically have a larger home range compared to males.<ref>{{cite web |title=Activity Patterns and Spatial Resource Selection of the Eastern Garter Snake (Thamnophis sirtalis sirtalis) |url=https://ecommons.luc.edu/cgi/viewcontent.cgi?article=2464&context=luc_theses}}</ref> Juvenile eastern garter snakes will actively seek out social interactions, will join and remain with large groups, and can recognize specific individuals and groups.<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) |url=https://link.springer.com/article/10.1007/s00265-020-2827-0 |journal=Behavioral Ecology and Sociobiology |language=en |volume=74 |issue=5 |page=51 |doi=10.1007/s00265-020-2827-0 |issn=1432-0762|url-access=subscription }}</ref>

===Reproduction=== Eastern garter snakes are ovoviviparous, giving birth to live young. Mating occurs in mid-to-late April and in the fall. Mating occurs "mating balls" where many males try to court a single female. Mating can last up to 5 days or more.<ref>{{Cite web |date=2002 |title=Reproductive Biology of Male Eastern Garter Snakes (Thamnophis sirtalis sirtalis) from a Denning Population in Central Wisconsin |work=The American Midland Naturalist |url=https://www.academia.edu/89908201 |last1=Bautista |first1=Alma Karen }}</ref> The young are {{convert|5|-|9|in|cm|disp=flip|abbr=on}} long at birth.

==Conservation status== [[File:Melanistic eastern garter snake (Thamnophis sirtalis ssp. sirtalis), Wellington North, Ontario, CA (99085233).jpg|thumb|Melanistic eastern garter snake]] {{As of|2024}}, the eastern garter snake has not been assessed by the IUCN Red List, nor has it been assessed by the Committee on the Status of Endangered Wildlife in Canada (COSEWIC).<ref name="ONNature2024"/> Its parent species, the common garter snake (''Thamnophis sirtalis''), was last assessed by the IUCN in 2007 and determined to be of least-concern due its wide geographic distribution, (presumed) large population, and lack of significant threats to its survival.<ref name="Frost2007"/> In 2016, NatureServe assessed the eastern garter snake to be a secure subspecies (G5T5) globally, and nationally secure (N5) in Canada.{{sfn|NatureServe|2016}}

==References== ===Citations=== <references>

<ref name="Carpenter1952p239a">{{harvnb|Carpenter|1952|p=239}}: "The Common Garter Snake, while showing a preference for earthworms (80%), also has a secondary preference for amphibians (15%) and consumed a much greater variety of foods, including mammals, fish, caterpillars and leeches (Fig. 4)."</ref>

<ref name="Carpenter1952p239b">{{harvnb|Carpenter|1952|p=239}}: "Common Garter Snakes exceeding 40 cm in length capture more amphibians and take more warm blooded prey than the smaller snakes: earthworms 76% and 88%, amphibians 19% and 8%, mammals 2% and 0%, others 3% and 4%, respectively. The amphibians eaten by the small snakes were all small forms (two Hyla crucifer, one Pseudacris nigrita, one Acris crepitans, and a metamorphosing Rana clamitans). Large Rana clamitans and Rana pipiens, made up 65% of the amphibians eaten by the larger snakes, suggesting that they choose these larger frogs."</ref>

<ref name="Carpenter1952p241a">{{harvnb|Carpenter|1952|p=241}}: "A third disgorged an earthworm and a Jefferson Salamander (Ambystoma Jeffersonianum), one month later a Green Frog, and a little over one year later, three earthworms."</ref>

<ref name="Carpenter1952p241b">{{harvnb|Carpenter|1952|p=241}}: "Six other individuals contained two or three types of food at one time in combinations of earthworms and mammal, earthworm and frog and another had eaten five mudminnows (''Umbra limi''), a tadpole and a leech."</ref>

<ref name="Carpenter1952p242a">{{harvnb|Carpenter|1952|p=242}}: "All of the mammals eaten were ''Microtus pennsylvanicus''. Two were represented by the skull and fur, one by fur only, and the other by fur and newly born young."</ref>

<ref name="Carpenter1952p242b">{{harvnb|Carpenter|1952|p=242}}: "The first record [from the Common Garter Snake] for a bird was an adult Song Sparrow (Melospiza melodia) taken at the Fleming Creek area. There is no evidence to show whether it was dead or alive when taken. The other record was for four Goldfinch nestlings (Spinus tristis) taken in the field just east of the Cherry Hill area, but the Goldfinches may have been alive, as indicated by adult activity near the nest, though the condition of the nest led me to believe they were dead when eaten."</ref>

<ref name="Carpenter1952p242c">{{harvnb|Carpenter|1952|p=242}}: "Walkinshow (1943) reports this species eating Chipping Sparrows (Spizella passerina)."</ref>

<ref name="Frost2007">{{harvnb|Frost|Hammerson|Santos-Barrera|2015}}: "Listed as Least Concern in view of its extremely wide distribution, presumed large population, and because populations are unlikely to be declining."</ref>

<ref name="ONNature2024">{{harvnb|Ontario Nature|2024}}: "Neither the Committee on the Status of Species at Risk in Ontario nor the Committee on the Status of Endangered Wildlife in Canada has assessed the status of the eastern gartersnake. [...] The International Union for Conservation of Nature has not yet assessed the global status of the eastern gartersnake, but lists the common gartersnake (of which the eastern gartersnake is a subspecies) as Least Concern."</ref>

</references>

===Bibliography=== {{refbegin}}

* {{cite journal|last=Carpenter|first=Charles C.|title=Comparative Ecology of the Common Garter Snake (''Thamnophis s. sirtalis''), the Ribbon Snake (''Thamnophis s. sauritus''), and Butler's Garter Snake (''Thamnophis butleri'') in Mixed Populations|date=October 1952|journal=Ecological Monographs|volume=22|number=4|pages=235–258|publisher=Wiley|doi=10.2307/1948469|jstor=1948469}}

* {{cite IUCN|last1=Frost|first1=Darrel R. | author1-link=Darrel Frost|last2=Hammerson|first2=Geoffrey A.|last3=Santos-Barrera|first3=Georgina|title=''Thamnophis sirtalis''|year=2015|orig-date=3 March 2007|volume=2015|article-number=e.T62240A68308267|doi=10.2305/IUCN.UK.2015-2.RLTS.T62240A68308267.en|access-date=30 May 2024}}

* {{cite journal|last1=Gomez|first1=Hernan F.|last2=Davis|first2=Mark|last3=Phillips|first3=Scott|last4=McKinney|first4=Patrick|last5=Brent|first5=Jeffrey|date=May 1994|title=Human envenomation from a wandering garter snake|journal=Annals of Emergency Medicine|publisher=Elsevier|volume=23|issue=5|pages=1119–1122|doi=10.1016/s0196-0644(94)70113-x|issn=0196-0644|pmid=8185110}}

* {{cite journal|last1=Hayes|first1=William K.|last2=Hayes|first2=Floyd E.|year=1985|title=Human envenomation from the bite of the eastern garter snake, Thamnophis s. sirtalis (Serpentes: Colubridae)|journal=Toxicon|publisher=Elsevier|volume=23|issue=4|pages=719–721|doi=10.1016/0041-0101(85)90376-9|issn=0041-0101|pmid=4060180}}

* {{cite book|last=Krulikowski|first=Linda|title=Snakes of New England / Photographic and Natural History Study|year=2004|publisher=Luvlife Publishing|pages=72–84|isbn=978-0-9764316-0-2}}

* {{cite web|author=NatureServe|url=https://explorer.natureserve.org/Taxon/ELEMENT_GLOBAL.2.100874/Thamnophis_sirtalis_sirtalis|title=''Thamnophis sirtalis sirtalis''|date=2 February 2016|website=NatureServe Explorer|publisher=NatureServe|location=Arlington, Virginia|access-date=30 May 2024}}

* {{cite journal|last1=Passek|first1=Kelly M.|last2=Gillingham|first2=James C.|date=September 1997|title=Thermal influence on defensive behaviours of the Eastern garter snake, ''Thamnophis sirtalis''|journal=Animal Behaviour|publisher=Elsevier|volume=54|issue=3|pages=629–633|doi=10.1006/anbe.1996.0458|issn=0003-3472|pmid=9299047|s2cid=32476200}}

* {{cite journal|last1=Shine|first1=Richard|last2=Phillips|first2=Benjamin|last3=Waye|first3=Heather|last4=Lemaster|first4=Michael|last5=Mason|first5=Robert T.|title=Species-isolating mechanisms in a mating system with male mate choice (garter snakes, ''Thamnophis'' spp.)|date=July 2004|journal=Canadian Journal of Zoology|publisher=Canadian Science Publishing|volume=82|number=7|pages=1091–1098|doi=10.1139/z04-086|url=https://people.wou.edu/~lemastm/Publications/PDF/Shine/2004%20-%20Canadian%20Journal%20of%20Zoology%20(Species%20Isolation).pdf|url-status=live|access-date=30 May 2024|archive-url=https://web.archive.org/web/20240530010117/https://people.wou.edu/~lemastm/Publications/PDF/Shine/2004%20-%20Canadian%20Journal%20of%20Zoology%20(Species%20Isolation).pdf|archive-date=30 May 2024}}

* {{cite journal|last=Vest|first=Darwin K.|date=10 June 1981|title=The toxic Duvernoy's secretion of the wandering garter snake, ''Thamnophis elegans vagrans''|journal=Toxicon|publisher=Elsevier|volume=19|issue=6|pages=831–839|doi=10.1016/0041-0101(81)90079-9|issn=0041-0101|pmid=7336444}}

* {{cite web|author=Ontario Nature|title=Eastern Gartersnake|orig-date=30 October 2017|date=16 January 2024|website=Ontario Nature|url=https://ontarionature.org/programs/community-science/reptile-amphibian-atlas/eastern-gartersnake/|access-date=30 May 2024}}

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Category:Thamnophis sirtalis Category:Reptiles described in 1758 Category:Animal taxa named by Carl Linnaeus Category:Symbols of Virginia Category:Reptiles of the United States Category:Reptiles of Canada Category:Least concern biota of the United States