Scientific name: Thamnophis sirtalis
Common name: Common garter snake

Habitat and Geographic Area
A variety a habitats are occupied by Thamnophis sirtalis, varying from moist margins of bodies of water to woodland and prairies as well as urban environments in all geographic areas of North America, from Alaska to Florida. It can live in extremely different environments that fluctuate in rainfall, temperature and vegetation. The common garter can survive in the dry prairies where there is limited precipitation, and temperatures are extreme and highly variable in addition to wet marshes where there is ample rainfall and more constant temperatures. It is adapted to most ecosystems ranging from the east cost to the west coast North America with the exception of the remarkably hot and dry desert like Southwestern states.
There is an assortment of colors associated with Thamnophis sirtalis, the coloration is dependent on the specific environment in which it resides. The colors differ on the upper, under, head and stripe area. In hotter, dryer climates the coloration is lighter, more orange and grey, in more wet, vegetation-dominant areas they are greener and finally, in the colder more artic regions they are increasingly black in color. The differences allow for survival, reproduction and the ability to flourish within their given habitat.

Size, Weight and Lifespan
Ranging in size from 12.5 to 23 centimeters at birth, and 46 to 137 centimeters as an adult and weighing roughly 150 grams; it has a lifespan of 2 years in the wild and up to 10 years in captivity

Diet
It is carnivorous, preying upon a multitude of animals including fish, amphibians, worms, insects, slugs and small birds (Arkive, 2011). The most essential source of food is earthworms; they are easy to hunt and available in high quantities, making them the ideal target, “garter snakes will eat up to 14 worms per hour.” (Pennsylvania State University, 2002) Although worms are the most common source of food, the snakes prefer larger and more plentiful prey in the colder months near hibernation, consuming small birds, fish and amphibians. There are two methods of locating prey, through the use of olfactory senses and visual cues. Mainly hunting is done through the use of olfactory senses or the sense of smell. The Jacobson’s organ is located in the roof of the mouth and used to locate prey through a process of sweeping the air for scent molecules and inserting the scent into the pits in the roof of the mouth (Pennsylvania State University, 2002). Using this method the location of the prey can be identified and thus hunted. The other technique is to use visual cues, once seen it is pursued. The prey is immobilized through the use of fangs and a mild neurotoxin making it easier to subdue. The snake then swallows its prey whole where it is suffocated and broken down by hydrochloric acid in the stomach and intestinal tract.

Reproduction and Communication
Snakes are solidarity creatures, but in the case of communication it is done through touch and smell and commonly during mating season. Through the use of the Jacobson’s organ most of the communication is done, in which other organisms can be tracked and located through the chemical signals they have left.
Mating season begins in the spring once the organism has emerged from hibernation and lasts till they reenter hibernation. Males emerge first in order to prepare for courting of the females, and once the females exit the courtship begins. Females give off a chemical substance affecting behavior and physiology called pheromones; they indicate age and reproductive state. This attracts males to their location and allow for the mating process to occur. Males can also give off pheromones that are indicative of females in order to trick and lure other males towards them, rather than the females (Reed College, 2014). Once copulation has occurred, the female stores the fertilized eggs in the uterus throughout the spring and summer, approximately 2 to 3 months, and births the live young in the fall prior to hibernation. In a single litter there can be anywhere from 4 to 80 young, with the average range being 10 to 40 (University of Michigan, 2013).

Predation
The common garter snake is also hunted by a variety of animals, large fish, birds, mammals and reptiles (Arkive, 2011) are the main predators; specifically hawks, crows, bullfrogs and foxes. There are two forms of protection possessed by the common garter in order to avoid predation, agility and secretion of odor through the cloaca. The cloaca is a gland located in the posterior orifice near the opening of the urinal tract; this gland is responsible for the release of a foul smelling aroma, which deters predators and aids in escape

Conservation Status
Thamnophis sirtalis is the most abundant and widespread snake is North America and as determined by the International Union for the Conservation of Nature’s Red List of Threated Species it is categorized under least concern (Live Science, 2014). Water contamination, urbanization and industrialization are the main threats, but due to its extensive range and adaptations the common garter snake is under no immediate threat.

Did you know
Garter snakes are ovoviviparous, meaning that they give birth to live young unlike most snakes who lay eggs.
The snakes posses a cloaca which is a gland located in the posterior orifice near the opening of the urinal tract that releases of a foul smelling aroma,much like a skunk. less ↑