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Garter snakes are extremely common across North America, from Canada to Central America, and an everyday find in gardens. They are the single most widely distributed species of reptile in North America, and in fact, the common garter snake, T. sirtalis, is the only species of snake to be found in Alaska.


 

There is little variation within the pattern of scales among the different varieties of garter snakes, but coloration varies widely across varieties and geographic regions.

I see a pattern here: The pattern on these snakes consists of one or three longitudinal stripes on the back, typically red, yellow or white. The snake genus got its common name because people described the stripes as resembling a garter. In between the stripes on the pattern are rows with blotchy spots. Even within a single species the color in the stripes and spots and background can differ. In some species the stripes vary little in color from the adjacent bands or background and are not readily seen. Most garter snakes are under 60 cm (24 inches) long, but can be larger. T. gigas is capable of attaining lengths of 160cm.

Author: Marshal Hedin. This file is licensed under the Creative Commons Attribution ShareAlike 2.5 License. In short: you are free to share and make derivative works of the file under the conditions that you appropriately attribute it, and that you distribute it only under a license identical to this one.


Anywhere in the world: It is one of the northernmost species of snake in the world, possibly second only to the Crossed Viper, Vipera berus. The genus is so far ranging due to its unparticular diet and adaptability to different biomes and landforms, from marshes to hillsides to drainage ditches and even vacant lots, in both dry and wet regions, with varying proximity to water and rivers. Though, as you approach the western portion of the continent these snakes are more water-loving than on the eastern portion. Northern populations hibernate in larger groups than southern ones. Despite the decline in their population from collection as pets (especially in the more northerly regions in which large groups are collected at hibernation), pollution of aquatic areas, and introduction of bullfrogs and bass as predators, this is still a very commonly found snake. The San Francisco garter snake, Thamnophis sirtalis tetrataenia, however, is an endangered subspecies and has been on the endangered list since 1967. Predation by crayfish has also been responsible for the decline of the narrowhead garter snake.

I, the author of this work, hereby publish it under the following licenses: Permission is granted to copy, distribute and/or modify this document under the terms of the GNU Free Documentation License, Version 1.2 or any later version published by the Free Software Foundation; with no Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. A copy of the license is included in the section entitled "GNU Free Documentation License".Too numerous to count: There is no real consensus exactly how many species of Thamnophis there are, and disagreement among taxonomists 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.

What's for dinner?: Garter snakes, like all snakes, are carnivorous. Their diet consists of almost any creature that they are capable of overpowering: insects, slugs, snails, earthworms, leeches, rodents, lizards, amphibians and sometimes they will even consume carrion and even baby birds. When near the water, they will eat fish. The ribbon snake in particular loves frogs (including tadpoles), readily eating them despite their strong chemical defenses. Food is swallowed whole. Although dining mostly upon live animals, they will sometimes eat eggs as well.

This image is licensed under the Creative CommonsQuite the charmer: Garter snakes of all species are gregarious (when not in hibernation or aestivation). They have complex systems of pheromonal communication. They can locate other snakes by following their pheromone-scented trails. Male and female skin pheromones are so different as to be immediately distinguishable. However, sometimes a male garter snake is born that has both male and female pheromones. During mating season, male snakes are often fooled into thinking these snakes are female by their pheromones, and will try to mate with them. These males with the female pheromone genetic variation are among the first to mate, attracting females while other males are still fooled into being attracted to them.

Run and Hide: If disturbed, a garter snake may strike, and will often coil, but typically it will hide its head and flail its tail about. These snakes will also discharge a malodorous, musky-scented secretion from their anal gland. 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, crows, raccoons, crayfish and other snake species (such as the coral snake and king snakes) will eat garter snakes, with even shrews and frogs eating the juveniles.

Laying Out: Being heterothermic like all reptiles, garter snakes bask in the sun to keep their body temperature warm (at 28 to 32 degrees Celsius) during the morning. The temperature is lower during the evening. Garter snakes will often sleep together to keep their body temperature warm at night. They also sleep in large nests next to one another's body during hibernation. These snakes will migrate large distances to hibernate.


Empty Nest: Garter snakes begin mating as soon as they emerge from hibernation. During mating season, the males will mate with several females. Males comes out of their dens and, as soon as the females begin coming out, will surround them. A male sends out pheromones, and the female will follow the pheromones to an attractive male and mate with him. Once impregnated, a female will retire from the mating ring and find food and a place to give birth. Female garter snakes are able to store the male's sperm before beginning the accouchement. The young are incubated in the lower abdomen, at about the midpoint of the length of the mother's body. Garter snakes are ovoviviparous. Gestation is two to three months. As few as 3 or as many as 50 may be born in a single litter. The babies are independent upon birth, abandoning the mother.

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 Kingdom: Animalia

 Phylum: Chordata

 Class: Reptilia

 Order: Squamata

 Family: Colubridae

 Genus: Thamnophis