Eastern Garter Snake
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The eastern garter snake (''Thamnophis sirtalis sirtalis'') is a medium-sized snake indigenous to North America.


Taxonomy


Etymology

The scientific name ''Thamnophis sirtalis sirtalis'' is a combination of
Ancient Greek Ancient Greek (, ; ) includes the forms of the Greek language used in ancient Greece and the classical antiquity, ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), 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 Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...
''sirtalis'' is derived from the New Latin "siratalis" (like a garter), a reference to the snake's color pattern resembling a striped
garter A garter is an article of clothing comprising a narrow band of fabric fastened about the leg to keep up stockings. In the eighteenth to twentieth centuries, they were tied just below the knee, where the leg is most slender, to keep the stocking f ...
strap.


Description

Eastern garter snakes average between long. The longest recorded length was 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 The Duvernoy's gland is a gland found in some groups of ''colubridae, colubrid'' snakes. It is distinguished from the venom gland and is not found in ''viperidae, viperids'' or ''elapidae, elapids''. It was named for France, French zoologist Geo ...
, 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.


Distribution and habitat

The eastern garter snake has a wide range across eastern North America and as far north as southern Ontario and Quebec to the
Gulf of Mexico The Gulf of Mexico () is an oceanic basin and a marginal sea of the Atlantic Ocean, mostly surrounded by the North American continent. It is bounded on the northeast, north, and northwest by the Gulf Coast of the United States; on the southw ...
in the south, along the eastern shores of America to the
Mississippi River The Mississippi River is the main stem, primary river of the largest drainage basin in the United States. It is the second-longest river in the United States, behind only the Missouri River, Missouri. From its traditional source of Lake Ita ...
. Their distribution ranges all across America but tends not to be present in western deserts. In
New England New England is a region consisting of six states in the Northeastern United States: Connecticut, Maine, Massachusetts, New Hampshire, Rhode Island, and Vermont. It is bordered by the state of New York (state), New York to the west and by the ...
, the snake is described as the "most widespread and ubiquitous" serpent, from wilderness to urban environments and from sea level to high elevations. 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. 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". 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. Krulikowski notes that "old poultry farms with discarded sheet-metal incubation trays provide warm, moist hiding places."


Ecology and behavior


Hunting and diet

The majority of the eastern garter snake's diet (~80%) consists of
earthworm An earthworm is a soil-dwelling terrestrial invertebrate that belongs to the phylum Annelida. The term is the common name for the largest members of the class (or subclass, depending on the author) Oligochaeta. In classical systems, they we ...
s, though they have a secondary preference (~15%) for
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 ...
prey (esp.
frog A frog is any member of a diverse and largely semiaquatic group of short-bodied, tailless amphibian vertebrates composing the order (biology), order Anura (coming from the Ancient Greek , literally 'without tail'). Frog species with rough ski ...
s) as well. As they mature, their preference in prey will undergo an ontogenetic shift. Younger eastern garter snakes (those under in length) prey almost exclusively upon earthworms (~88%) and smaller amphibians (~8%), such as
spring peeper The spring peeper (''Pseudacris crucifer'') is a small chorus frog widespread throughout the eastern United States and Canada. It prefers permanent ponds due to its advantage in avoiding predation; however, it is very adaptable with respect to t ...
s 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 frog ''Lithobates pipiens''Integrated Taxonomic Information System nternet2012''Lithobates pipiens'' pdated 2012 Sept; cited 2012 Dec 26Available from: www.itis.gov/ formerly ''Rana pipiens'', commonly known as the northern leopard frog, is a s ...
s, though earthworms still make up the bulk of their diet (~76%). However, eastern garter snakes are opportunistic predators, and will readily consume almost any creature they can swallow. Other prey records for this subspecies include
caterpillar Caterpillars ( ) are the larval stage of members of the order Lepidoptera (the insect order comprising butterflies and moths). As with most common names, the application of the word is arbitrary, since the larvae of sawflies (suborder ...
s,
leech Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthwor ...
es, mudminnows, the
Jefferson salamander The Jefferson salamander (''Ambystoma jeffersonianum'') is a mole salamander native to the northeastern United States, southern and central Ontario, and southwestern Quebec. It was named after Jefferson College in Pennsylvania. It is typically ...
, and the
eastern meadow vole The eastern meadow vole (''Microtus pennsylvanicus''), sometimes called the field mouse or meadow mouse, is a North American vole found in eastern Canada and the United States. Its range extends farther south along the Atlantic coast. The weste ...
. Large adults will even target small birds if the opportunity presents itself, such as
song sparrow The song sparrow (''Melospiza melodia'') is a medium-sized New World sparrow. Among the native sparrows in North America, it is easily one of the most abundant, variable and adaptable species. Description Adult song sparrows have brown upperp ...
s,
goldfinch Goldfinch or The Goldfinch may refer to: Birds * European goldfinch, ''Carduelis carduelis'' * Some species of the genus '' Spinus'': ** American goldfinch, ''Spinus tristis'' ** Lawrence's goldfinch, ''Spinus lawrencei'' ** Lesser goldfinch, ...
es, and
chipping sparrow The chipping sparrow (''Spizella passerina'') is a species of New World sparrow, a passerine bird in the family Passerellidae. It is widespread, fairly tame, and common across most of its North American range. The chipping sparrow has five sub ...
s.


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. Body temperature influences defensive behaviors. Snakes with higher body temperatures tend to flee as they have more energy. Larger males and pregnant females are more likely to stand their ground.


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. Juvenile eastern garter snakes will actively seek out social interactions, will join and remain with large groups, and can recognize specific individuals and groups.


Reproduction

Eastern garter snakes are
ovoviviparous Ovoviviparity, ovovivipary, ovivipary, or aplacental viviparity is a "bridging" form of reproduction between egg-laying oviparity, oviparous and live-bearing viviparity, viviparous reproduction. Ovoviviparous animals possess embryos that develo ...
, 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. The young are long at birth.


Conservation status

, the eastern garter snake has not been assessed by the
IUCN Red List The International Union for Conservation of Nature (IUCN) Red List of Threatened Species, also known as the IUCN Red List or Red Data Book, founded in 1964, is an inventory of the global conservation status and extinction risk of biological ...
, nor has it been assessed by the
Committee on the Status of Endangered Wildlife in Canada The Committee on the Status of Endangered Wildlife in Canada (COSEWIC, French: Comité sur la situation des espèces en péril au Canada, COSEPAC) is an independent committee of wildlife experts and scientists whose "raison d'être is to identify s ...
(COSEWIC). Its parent species, the common garter snake (''Thamnophis sirtalis''), was last assessed by the
IUCN The International Union for Conservation of Nature (IUCN) is an international organization working in the field of nature conservation and sustainable use of natural resources. Founded in 1948, IUCN has become the global authority on the status ...
in 2007 and determined to be of
least-concern A least-concern species is a species that has been evaluated and categorized by the International Union for Conservation of Nature (IUCN) as not being a focus of wildlife conservation because the specific species is still plentiful in the wild ...
due its wide geographic distribution, (presumed) large population, and lack of significant threats to its survival. In 2016,
NatureServe NatureServe, Inc. is a non-profit organization based in Arlington County, Virginia, United States, US, that provides proprietary wildlife conservation-related data, tools, and services to private and government clients, partner organizations, and ...
assessed the eastern garter snake to be a secure subspecies (G5T5) globally, and nationally secure (N5) in
Canada Canada is a country in North America. Its Provinces and territories of Canada, ten provinces and three territories extend from the Atlantic Ocean to the Pacific Ocean and northward into the Arctic Ocean, making it the world's List of coun ...
.


References


Citations


Bibliography

* * * * * * * * * * {{Taxonbar, from=Q307020 Thamnophis sirtalis Reptiles described in 1758 Taxa named by Carl Linnaeus Symbols of Virginia Reptiles of the United States Reptiles of Canada