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Drama. These guys all normally get along pretty well, but here a squirrel decided to start something and nearly got kicked in the head as reward. Moments later they were back to munching sunflower seeds side-by-side again.

Scientific and Common Names: Thamnophis sirtalis sirtalis is the scientific name of what is commonly referred to as the eastern garter snake. This species is also often referred to as the common garter snake, although this classification includes other subspecies of garter snakes as well (Rossman et al, 1996).

Habitat and Geographic Range: Garter snakes of the genus Thamnophis are relatively adaptable organisms, ranging geographically throughout most of Mexico, the United States, and Southern Canada (Carpenter, 1952). Thamnophis sirtalis sirtalis, specifically, are found eastward of the Mississippi River in the United States (Carpenter, 1952). Additionally, Thamnophis sirtalis sirtalis can be found in the southern regions of all of Canada’s provinces, but do not inhabit the northern territories (“Animal Facts: Common Garter Snake,” 2006).
Although eastern garter snakes can be found across such a wide geographic area, they are quite particular in regards to their habitat choice. During winter months of hibernation, Thamnophis sirtalis sirtalis inhabit well drained, grassy areas, usually on the southward-facing side of a hill or dirt bluff (Carpenter, 1952). In the warmer months, the eastern garter snake tends to occupy areas exhibiting similar conditions, but broaden their range to the shallow banks of marshes when faced with excessive heat (Carpenter, 1952). Additionally, eastern garter snakes tend to take refuge underneath, rocks, logs, or other debris when faced with higher, summer temperatures (Rossman et al, 1996). As temperatures begin to cool down, Thamnophis sirtalis sirtalis is still most commonly found on grassy hillsides, but may also be found in small trees or bushes, usually only a few feet off of the ground, where they are closer to the sun’s rays, and relative humidity is higher than in open areas (Carpenter, 1952).

Size, Weight, and Lifespan: Thamnophis sirtalis sirtalis is a smaller species of snake, ranging anywhere from 46 to 137 centimeters in length, and weighing approximately 150g on average (“Animal Facts: Common Garter Snake,” 2006). Although eastern garter snakes generally only live about two years in nature, they have been reported to live as long as six to ten years in captivity (“Animal Facts: Common Garter Snake,” 2006).

Diet: Thamnophis sirtalis sirtalis are carnivorous, and have been found to consume a wide variety of prey which slightly varies with seasonality (Carpenter, 1952). Above all else however, Thamnophis sirtalis sirtalis significantly prefers to consume earthworms, which die quickly upon ingestion. Second to worms, eastern garter snakes prefer amphibians; mainly frogs, followed by small mammals, fish, caterpillars, and leeches. Although small insects have been found within the digestive tracks of these snakes, they likely originated in the stomachs of consumed amphibians. Although rare, some instances of small birds, such as sparrows and finches, within the stomachs’ of eastern garter snakes have been reported. Although all eat infrequently, larger eastern garter snakes tend to eat more frequently, and sooner upon emergence from hibernation than smaller snakes, and furthermore prefer to include more warm-blooded prey in their diet. No instances of cannibalism have been reported amongst eastern garter snakes (Carpenter, 1952).

Reproduction and Communication: Thamnophis sirtalis sirtalis communicate similarly to other snake species, primarily relying on their use of the vomeronasal system and pheromones (Rossman et al, 1996). The vomeronasal system involves the use of the snake’s tongue, which it flicks in order to sense chemical cues in its environment. These cues are processed by the Jacobson’s organ, which allows the snake to determine which direction the chemical cue is coming from (Kubie et al, 1978). Additionally, eastern garter snakes produce pheromones, which can be detected by others in order to determine an individual’s age, sex, location, and reproductive status (Rossman et al, 1996).
Eastern garter snakes begin reproduction as soon as they emerge from hibernation, starting with males, which release pheromones that receptive females detect in order to determine the genetic quality of the male (Rossman et al, 1996). Thamnophis sirtalis sirtalis have been known to display courtship behavior, during which a male positions its head close to the females (Gillingham & Dickinson, 1980). If the female does not grant mating access, however, the male may mount or even bite the female in order to force copulation. Furthermore, courtship behaviors are often disrupted by mating balls, in which multiple males swarm a female to compete for mating access. Females generally only mate once a year, while males often attempt to mate with multiple females in one breeding session (Gillingham & Dickinson, 1980).

Predation: The eastern garter snake possesses many natural predators, primarily consisting of larger mammals including raccoons, fox, opossums, minks, and skunks, although they are occasionally consumed by various species of larger, local birds (Carpenter, 1952). Interestingly, eastern garter snakes have also been found fatally wounded, but not consumed by, some species of crayfish and turtles (Carpenter, 1952).

Conservation Status: Due to their large population sizes and extensive geographic range, Thamnophis sirtalis sirtalis are not considered in need of protection in Canada (Carpenter, 1952). However, despite the fact that they are not listed as an endangered species, human interference leading to habitat destruction continues to threaten eastern garter snake populations in effected areas (Carpenter, 1952).

Did You Know? Female Thamnophis sirtalis sirtalis can store a male's sperm within their bodies for up to years at a time prior to insemination (Rossman et al, 1996). Following insemination, females may produce as many as eighty offspring in a single litter (“Animal Facts: Common Garter Snake,” 2006).

Works Cited
Animal facts: common garter snake. (2006, July 17). Retrieved October 20, 2015, 
     from Canadian Geographic website: https://www.canadiangeographic.ca/article/ 
     animal-facts-common-garter-snake 

Carpenter, C. C. (1952). Comparative Ecology of the Common Garter Snake 
     (Thamnophis s. sirtalis), the Ribbon Snake (Thamnophis s. sauritus), and 
     Butler's Garter Snake (Thamnophis butleri) in Mixed Populations. 
     Ecological Monographs, 22(4), 235-258. http://dx.doi.org/10.2307/1948469

Dickinson, J. A., & Gillingham, J. C. (1980). Postural orientation during 
     courtship in the eastern garter snake, Thamnophis s. sirtalis. 
     Behavioural and Neural Biology, 28(2), 211-217. http://dx.doi.org/ 
     10.1016/S0163-1047(80)91583-6

Kubie, J. L., Vagvolgyi, A., & Halpern, M. (1978). Roles of the vomeronasal and 
     olfactory systems in courtship behavior of male garter snakes. American 
     Psychological Association, 92(4), 627-641. http://dx.doi.org/10.1037/ 
     h0077502

Rossman, D. A., Ford, N. B., & Seigel, R. A. (1996). The garter snakes: 
     Evolution and ecology (Vol. 2). Retrieved from https://books.google.ca/ 
     books?hl=en&lr=&id=n2rW7E8_uJoC&oi=fnd&pg=PP25&dq=eastern+garter+snake+conser
vation&ots=KcbuP9uAc0&sig=CG2u5j1XcCxdWUWPJkTuppbAH8#v=onepage&q&f=false