Wednesday, June 10, 2009

Garter Snake

This is a common garter snake in the genus Thamnophis. There are many different species of garter snakes worldwide, and in the United States they are probably the most prevalent genus of reptiles. Completely harmless to humans, but they can be testy. Without a doubt they are very defensive and quick to try to bite and defend themselves. I've been bitten by this species of snake more than any of the other snakes I've handled combined. They will shake their tail in dry leafy vegetation to mimic a rattlesnakes rattle. They will emit a strong musky scent that is very offensive, especially if you are sensitive to smells. While they are consider no threat to humans and are listed as non-venomous it has been recently discovered they do in fact have a type of venom. It is a very mild neurotoxin. It is harmless to humans because of the low amounts of venom that is produced and their inability to deliver a bite of any importance. They do not possess fangs like other venomous snakes therefore they cannot release copious amounts of the toxin into our bloodstream. Instead the venom is delivered in a "chewing" fashion. The toxin may cause mild itching, swelling or irritation but rarely anything more severe. The secret to their success in numbers is due in large part to their ability to adapt to many different habitats and to human encroachment. They are also an opportunistic eater, they will eat anything from eggs, insects, frogs, toads (pictured), slugs, earthworms, small lizards, spiders, leeches and small mammals. We had one enter a birdhouse this year and eat two wren eggs. A testament to their survival skills is one particular garter snake (T. sirtalis) which is the only snake found in Alaska. In the western portion of the United States garter snakes tend to prefer watery habitats. The Eastern variety are less particular. They will be found most anywhere, even in our homes. I have found several of these in my basement over the years. We presume they come up the outside drain. Garter snakes vary little in their pattern, but largely in their coloration. Patterns will always include, one, two or three longitudinal stripes down their backs, these stripes will be white, red, yellow, blue or orange. These stripes are where they get their common name. Individuals felt their stripes looked very much like the garters worn by women. In between the stripes will be rows of blotchy spots. These blotches of color can vary greatly even among members of the same species. They rarely reach lengths over 3 feet, average size is 2 feet. They may live up to 6 or 7 years. While they are adept hunters, sometimes the hunter becomes the hunted and these snakes must overcome many obstacles in the wild, including hawks, owls, raccoons, mink, crawdads, shrews, large frogs and fish as well as other snakes, especially snakes in the King Snake family which all like to dine on these snakes. They also face pollution of many aquatic areas as well as collection by humans for the pet trade. In spite of all this they are still quite common and their populations seem to be stable throughout their range with the exception of one species in the west called the San Francisco Garter Snake which has been listed as endangered since 1967, and another, the Narrow Headed Garter Snake (T. rufipunctatus) is in peril due to the predation of crawdads. Garter snakes use pheromones as a way of communicating and locating other individuals of their species. Males and females each emit a different scent and they are able to locate mates by following scent trails. In some cases the males are able to give off the same scent as the female, they are so effective at doing this it commonly fools other males and you will find males trying to mate with males. These "She-males" have been recorded as receiving more attention than that of the actual female counterparts in the breeding balls that form during mating season. About two weeks before mating they will stop eating. This prevents any food that may remain in their stomachs from rotting; this phenomena is known as brumation. As soon as they come out of brumation mating will begin. Males will mate with several females. Males appear first, and as soon as females begin appearing from their dens males will surround them. The female pheromone is very intoxicating to the males, in fact it is not unheard of for up to 100 males to surround a single female all intent on mating with her. Males will typically "fight" each other. Once she is mated she will leave the area and seek food and a place to deliver her babies. In the case of garter snakes they give "live birth". They do not lay eggs like most reptiles and many other snakes do. She may give birth to as many as 50 young snakes. These newborns are independent from birth and do not rely on any care from their mother. Good thing too, because does not offer any. We have so many of these snakes around our farm that they are a common sight. They hang around our goldfish pond and hunt the frogs and toads living there. We find them in the flower gardens, and near the vegetable garden. They are a beautiful snake, but best left alone. Of course I say that, and at the next opportunity I will be nursing another bite because I can't resist the temptation to catch one for a closer look.

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