Garter snakes
Garter snakes | ||||||||||||
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Coastal garter snake ( Thamnophis elegans terrestris ) |
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Systematics | ||||||||||||
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Scientific name | ||||||||||||
Thamnophis | ||||||||||||
Fitzinger , 1834 |
Garter Snakes ( Thamnophis ) is the generic name of a variety of American snake species. They are characterized by a wide variety of colors. What they all have in common are the mostly brightly contrasting back and side stripes, to which they owe the name "garter snakes". Some representatives of the genus are popular terrarium animals .
features
Garter snakes are medium-sized snakes that usually reach body lengths of around 30 to 110 centimeters, with the largest species, the giant garter snake ( T. gigas ), up to 160 centimeters. When fully grown, the females are usually significantly larger than the males. The body color is very variable within the genus. The name is derived from the lighter stripes running along the body, which are reminiscent of a garter belt and are usually designed as a back stripe and two side stripes. The latter usually run on the second to fourth row of back scales. Back and side stripes are often different colors and can have a dark border. In addition, various patterns of spots appear. It is believed that the body drawing serves as a somatolytic camouflage that obscures the body shape from possible attackers.
The pholidosis of the garter snake is often variable, even within a species, and depends on various factors such as temperature and hormonal effects during development as well as genetic factors. The head has paired internasal , prefrontal and parietal shields and a single frontal scutum . The eye is usually surrounded by one pre- , one supra- and two to four postocular shields, behind which there are usually three temple shields . The supralabial shields number six to nine, the sublabial shields eight to twelve. The back scales run in 17 to 23 rows and are keeled. Garter snakes differ from the American swimming snakes ( Nerodia ) by their mostly undivided anal shield .
Way of life
In nature, garter snakes have a very wide range of prey . They feed on earthworms , leeches , nudibranchs , small fish , amphibians and their tadpoles , small rodents and even young birds .
Most species mate in spring, some even in summer. Unlike most snakes , garter snakes are viviparous ( ovoviviparous ). The young animals are already fully developed when they lay their eggs and are only surrounded by a thin, transparent egg shell. This shell must be pierced by the young animals during or immediately after birth, otherwise they will suffocate. A garter snake litter usually contains 10–20 young animals. In individual cases, however, litter sizes of more than 80 young animals have been observed.
distribution
The natural habitat of the garter snakes stretches from Canada and the United States to parts of Central America .
They belong to the subfamily of the water snakes (Natricinae). As a result, most of the species can be found near bodies of water.
Although the genus is one of the most common snakes in America, some species and subspecies of the garter snake are threatened with extinction and are under special protection.
species
The genus Garter Snakes is divided into 34 species . However, as a result of new discoveries and genetic studies, the assignments to species and subspecies have been changing continuously to this day.
- T. atratus
- T. bogerti
- Short-headed garter snake ( T. brachystoma )
- Butler's garter snake ( T. butleri )
- Golden-headed garter snake ( T. chrysocephalus )
- T. conanti
- Couch's garter snake ( T. couchii )
- Black-necked garter snake ( T. cyrtopsis )
- Mountain garter snake ( T. elegans )
- Mexican garter snake ( T. eques )
- Mexican migratory garter snake ( T. errans )
- Dwarf garter snake ( T. exsul )
- Guatemala garter snake ( T. fulvus )
- Giant garter snake ( T. gigas )
- Godman's garter snake ( T. godmani )
- Two-lined garter snake ( T. hammondii )
- T. lineri
- Checkered garter snake ( T. marcianus )
- Mexican black-bellied garter snake ( T. melanogaster )
- Mexican mountain garter snake ( T. mendax )
- Durango garter snake ( T. nigronuchalis )
- Northwestern garter snake ( T. ordinoides )
- Mexican lowland garter snake ( T. postremus )
- Western banded snake ( T. proximus )
- Yellow-necked garter snake ( T. pulchrilatus )
- Prairie garter snake ( T. radix )
- Rossman's garter snake ( T. rossmani )
- Red spotted garter snake ( T. rufipunctatus )
- Eastern banded snake ( T. sauritus )
- Stair garter snake ( T. scalaris )
- Mexican highland garter snake ( T. scaliger )
- Common garter snake ( T. sirtalis )
- Saddle-spot garter snake ( T. sumichrasti )
- Mexican west coast garter snake ( T. validus )
swell
- Martin Hallmen, Jürgen Chlebowy: Garter Snakes . Nature and Animal, Münster 2001, ISBN 3-931587-49-5 .
- Douglas Athon Rossman, Neil B. Ford, Richard A. Seigel: The garter snakes: evolution and ecology . University of Oklahoma Press, Norman, Oklahoma 1996, ISBN 978-0-8061-2820-7 .