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الخميس، 25 أبريل 2013

The garter snake (Thamnophis elegans terrestris)

 : A comprehensive video clip about this snake





The garter snake is a colubrid snake genus (Thamnophis) common across North America, ranging from the Alaskan Panhandle to Central America. It is the single most widely distributed genus of reptiles in North America . The garter snake is also the Massachusetts state reptile.
With no real consensus on the classification of species of Thamnophis, disagreement amongtaxonomists and sources, such as field guides, over whether two types of snakes are separate species or subspecies of the same species is common.  They are also closely related to the snakes of the genus Nerodia, and some species have been moved back and forth between genera

Synonyms
Atomarchus, Chilopoma, Coluber, Eutaenia, Eutainia, Leptophis, Natrix, Nerodia, Phamnovis, Prymnomiodon, Stypocemus, Tropidonote, Tropidonotus, Vipera[1]



File:Coast Garter Snake.jpg

Scientific classification
Kingdom:Animalia
Phylum:Chordata
Subphylum:Vertebrata
Class:Reptilia
Order:Squamata
Suborder:Serpentes
Family:Colubridae
Subfamily:Natricinae
Genus:Thamnophis
Fitzinger, 1843

Habitat

Garter snakes spread throughout North America. The common garter snake (Thamnophis sirtalis) is the only species of snake to be found in Alaska, and is one of the northernmost species of snake in the world, possibly second only to the crossed viper, Vipera berus. The genus is as far ranging due to its less discriminant diet and adaptability to different biomesand landforms, with varying proximity to water. However, in the western part of North America, these snakes are more aquatic than in the eastern portion. Northern populations hibernate in larger groups than southern ones.
File:Thamnophis range.png



Diet


A garter snake eating a frog
Garter snakes, like all snakes, are carnivorous. Their diets consist of almost any creature they are capable of overpowering: slugsearthwormsleecheslizardsamphibiansantsfrogeggs, toads, and rodents. When living near water, they will eat other aquatic animals. Theribbon snake (Thamnophis sauritus) in particular favors frogs (including tadpoles), readily eating them despite their strong chemical defenses. Food is swallowed whole. Garter snakes often adapt to eating whatever they can find, and whenever, because food can be scarce or abundant. Although they feed mostly upon live animals, they will sometimes eat eggs.

Behavior


Common garter snake

The posterior tooth of a garter snake

A young garter snake
Garter snakes have complex systems of pheromonal communication. 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 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 afterhibernation, allowing them to become more active.  Male snakes giving off both male and female pheromones have been shown to garner more copulations than normal males in the mating balls that form at the den when females enter the mating melee.
If disturbed, a garter snake may coil and strike, but typically it will hide its head and flail its tail. These snakes will also discharge a malodorous, musky-scented secretion from a gland near the cloaca. 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.Hawkscrowsraccoonscrayfish, and other snake species (such as the coral snake andking snake) will eat garter snakes, with even shrews and frogs eating the juveniles.
Being heterothermic, like all reptiles, garter snakes bask in the sun to regulate their body temperature. During hibernation, garter snakes typically occupy large, communal sites called hibernacula. These snakes will migrate large distances to brumate.

Reproduction

Garter snakes go into brumation before they mate. They stop eating for about two weeks beforehand to clear their stomachs of any food that would rot there otherwise. Garter snakes begin mating as soon as they emerge from brumation. During mating season, the males mate with several females. In chillier parts of their range, male common garter snakes awaken from brumation first, giving themselves enough time to prepare to mate with females when they finally appear. Males come out of their dens and, as soon as the females begin coming out, surround them. Female garter snakes produce a sex-specific pheromone that attracts male snakes in droves, sometimes leading to intense male-male competition and the formation of mating balls of up to 25 males per female. After copulation, a female leaves the den/mating area to find food and a place to give birth. Female garter snakes are able to store the male's sperm for years before fertilization. The young are incubated in the lower abdomen, at about the midpoint of the length of the female's body. Garter snakes areovoviviparous, meaning they give birth to live young. However, this is different from being trulyviviparous, which is seen in mammals. Gestation is two to three months in most species. As few as three or as many as 80 snakes are born in a single litter. The young are independent upon birth. On record, the greatest number of garter snakes reported to be born in a single litter is 98

Baby garter snakes as pets

Baby garter snakes shed their first skin almost immediately, and will begin eating soon after. The first shedding is very fine and often disintegrates in minutes under the slithering masses of new snakes. Feeding baby garter snakes can be tricky; most often meal worms, goldfish, and tadpoles (thawed fully and waved before the snake) will entice appetites. A few weeks may pass before a baby garter snake eats; it takes them some time to become accustomed to new settings

Venom

Garter snakes were long thought to be nonvenomous, but recent discoveries have revealed they do, in fact, produce a mild neurotoxic venom.  Garter snakes cannot kill humans with the small amounts of comparatively mild venom they produce, and they also lack an effective means of delivering it. They do have enlarged teeth in the back of their mouths, but their gums are significantly larger.  The Duvernoy's glands of garters are posterior (to the rear) of the snake's eyes.   The mild venom is spread into wounds through a chewing action.

Taxonomy


Eastern blackneck garter, Thamnophis cyrtopsis ocellatus
  • Longnose garter snake, T. angustirostris (Kennicott, 1860)
  • Aquatic garter snakeT. atratus
    • Santa Cruz garter snake, T. a. atratus (Kennicott, 1860)
    • Oregon garter snake, T. a. hydrophilus Fitch, 1936
    • Diablo Range garter snake, T. a. zaxanthus Boundy, 1999
  • Shorthead garter snake, T. brachystoma (Cope, 1892)
  • Butler's garter snakeT. butleri (Cope, 1889)
  • Goldenhead garter snake, T. chrysocephalus (Cope, 1885)
  • Western aquatic garter snake, T. couchii (Kennicott, 1859)
  • Blackneck garter snakeT. cyrtopsis
    • Western blackneck garter snake, T. c. cyrtopsis (Kennicott, 1860)
    • Eastern garter snake, T. c. ocellatus (Cope, 1880)
    • Tropical blackneck garter snake, T. c. collaris (Jan, 1863)
    • Tepalcatepec Valley garter snake, T. c. postremus H.M. Smith, 1942
    • Yellow-throated garter snake, T. c. pulchrilatus (Cope, 1885)

Checkered garter snakeThamnophis marcianus
  • Western terrestrial garter snakeT. elegans
    • Arizona garter snake, T. e. arizonae V. Tanner & Lowe, 1989
    • Mountain garter snake, T. e. elegans (Baird & Girard, 1853)
    • Mexican wandering garter snake, T. e. errans H.M. Smith, 1942
    • Coast garter snake, T. e. terrestris Fox, 1951
    • Wandering garter snake, T. e. vagrans (Baird & Girard, 1853)
    • Upper Basin garter snake, T. e. vascotanneri W. Tanner & Lowe, 1989
    • Sierra San Pedro Mártir garter snake, T. e. hueyi]] Van Denburgh & Slevin, 1923
  • Thamnophis eques
    • Mexican garter snake, T. e. eques (Reuss, 1834)
    • Laguna Totolcingo garter snake, T. e. carmenensis Conant, 2003
    • T. e. cuitzeoensis Conant, 2003
    • T. e. diluvialis Conant, 2003
    • ''T. e. insperatus Conant, 2003
    • Northern Mexican garter snake, T. e. megalops (Kennicott, 1860)
    • T. e. obscurus Conant, 2003
    • T. e. patzcuaroensis Conant, 2003
    • T. e. scotti Conant, 2003
    • T. e. virgatenuis Conant, 1963

Eastern Plains garter gnake, T. radix radix, a disputed subspecies of Thamnophis radix
  • Montane garter snake, T. exsul Rossman, 1969
  • Highland garter snake, T. fulvus (Bocourt, 1893)
  • Giant garter snakeT. gigas Fitch, 1940
  • Godman's garter snake, T. godmani (Günther, 1894)
  • Two-striped garter snake, T. hammondii (Kennicott, 1860)
  • Checkered garter snakeT. marcianus (Baird & Girard, 1853)
    • T. m. marcianus (Baird & Girard, 1853)
    • T. m. praeocularis (Bocourt, 1892)
    • T. m. bovalli (Dunn, 1940)
  • Blackbelly garter snake, T. melanogaster
    • Gray blackbelly garter snake, T. m. canescens H.M. Smith, 1942
    • Chihuahuan blackbelly garter snake, T. m. chihuahuanensis W. Tanner, 1959
    • Lined blackbelly garter snake, T. m. linearis H.M. Smith, Nixon & P.W. Smith, 1950
    • Mexican blackbelly garter snake, T. m. melanogaster (W. Peters, 1864)

Redstripe ribbon snake, T. proximus rubrilineatus
  • Tamaulipan montane garter snake, T. mendax Walker, 1955
  • Northwestern garter snakeT. ordinoides (Baird & Girard, 1852)
  • Western ribbon snakeT. proximus
    • Chiapas Highland western ribbon snake, T. p. alpinus Rossman, 1963
    • Arid land western ribbon snake, T. p. diabolicus Rossman, 1963
    • Gulf Coast western ribbon snake, T. p. orarius Rossman, 1963
    • Western ribbon snake, T. p. proximus (Say, 1823)
    • Redstripe ribbon snakeT. p. rubrilineatus Rossman, 1963
    • Mexican ribbon snake, T. p. rutiloris (Cope, 1885)
  • Plains garter snakeT. radix (Baird & Girard, 1853)
  • Rossman's garter snake, T. rossmani Conant, 2000
  • Narrowhead garter snake, T. rufipunctatus
    • T. r. nigronuchalis Thompson, 1957
    • T. r. unilabialis W. Tanner, 1985
    • T. r. rufipunctatus (Cope, 1875)
  • Ribbon snakeT. sauritus

Common garter snake,Thamnophis sirtalis

Texas garter snake, Thamnophis sirtalis annectens
    • Red-spotted garter snake, T. s. concinnus (Hallowell, 1852)
    • New Mexico garter snake, T. s. dorsalis (Baird & Girard, 1853)
    • Valley garter snake, T. s. fitchi Fox, 1951
    • California red-sided garter snake, T. s. infernalis (Blainville, 1835)
    • T. s. lowei W. Tanner, 1988
    • Maritime garter snake, T. s. pallidulus]] Allen, 1899
    • Red-sided garter snake, T. s. parietalis]] (Say, 1823)
    • Puget Sound garter snake, T. s. pickeringii (Baird & Girard, 1853)
    • Bluestripe garter snake, T. s. similis Rossman, 1965
    • Eastern garter snake, T. s. sirtalis (Linnaeus, 1758)
    • Chicago garter snakeT. s. semifasciatus (Cope, 1892)
    • San Francisco garter snake, T. s. tetrataenia (Cope, 1875)
  • Sumichrast's garter snake, T. sumichrasti (Cope, 1866)
  • West Coast garter snake, T. valida
    • Mexican Pacific Lowlands garter snake, T. v. celaeno (Cope, 1860)
    • T. v. isabellae Conant, 1953
    • T. v. thamnophisoides Conant, 1961
    • T. v. valida (Kennicott, 1860)

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