Common garter snake
The common garter snake, scientifically known as Thamnophis sirtalis, is a non-venomous snake species native to North America. Recognizable by its slender body that can exceed four feet in length, it features various color combinations, typically highlighted by three light stripes running along its length. This species includes five recognized subspecies, each adapted to different regions across North America, from southern Canada to Central America. Common garter snakes thrive in diverse habitats, including near water bodies like ponds and streams, as well as urban settings such as parks and gardens.
These snakes are carnivorous, preying on frogs, toads, fish, and small mammals, using their sharp teeth to strike and consume prey whole. Their mating season occurs in spring, following a period of hibernation, during which females can lay between 12 to 80 eggs that incubate for about three months. Although they are not harmful to humans, common garter snakes face threats from predators and human encounters, where they are often misunderstood and killed. With an average lifespan of around 12 years, the common garter snake is cherished in some cultures, including being recognized as the official reptile of Massachusetts.
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Common garter snake
The common garter snake species is native to the North American continent. The species is identifiable by its long, thin body which can grow to over four feet in length. The venom of the garter snake is not dangerous to humans, although it can cause discomfort. Each of the five different sub-species of common garter snakes live in certain parts of North America.
Kingdom: Animalia
Phylum: Chordata
Class: Reptilia
Order: Squamata
Family: Colubridae
Genus: Thamnophis
Species: Sirtalis
Common garter snakes can be found in several different color combinations: yellow, yellow & red, green, yellow & red, blue, green, and yellow. They typically have three light stripes that appear along the lengths of their bodies. Many also have dark spots.
The five different sub-species are the eastern common garter snake, the San Francisco garter snake, the Texas garter snake, the blue-striped garter snake, and the California red-sided garter snake. These species grow to be between two and two and half feet (60 and 75 centimeters) long. Females are typically larger than males.
Another characteristic of garter snakes is their eyes. The species have round pupils, and brilles instead of eyelids. Pupils are the black parts of the eyes which open and close to let in light. Round pupils are circles located in the middle of the iris, or colored part of the eye. Brilles are transparent, or clear, coverings that shield snakes' eyes from dirt. They often cause snakes to have a dazed, glassy-eyed appearance. Like many other snakes, common garter snakes also have pits located directly above their mouths. Pits are heat-sensory organs which read temperatures called infrared heat rays. These rays help the snakes to identify the difference between an animal and its surroundings.
Common garter snakes usually live near water such as ponds or streams, but also inhabit city parks, gardens, and backyards. They are equally at home on land and in water. Common garter snakes are found throughout North America from southern Canada through the United States and Central America. As they slither through the grass and weeds, they flick their forked tongues to search their surroundings. Common garter snakes pick up chemicals on their tongues. They carry those chemicals back into their mouths and place them in special organs, specifically designed to measure what chemicals are in the environment. This knowledge helps the common garter snakes trail prey, recognize predators, and find mates.
Many species of snakes constrict, or choke, their prey. Others use venom to subdue their prey. Common garter snakes are venomous carnivores. They live on a diet of frogs, toads, fish, salamanders, earthworms, birds, small mammals, like rodents, and dead animal flesh, called carrion. They kill their prey by striking with their sharp teeth when their prey least expects it, and bite them hard in the neck. Once their prey is dead, common garter snakes begin to swallow them whole. First, they open their mouths and slide them over the head of the prey and grip them with their teeth. They push their prey into their mouths until they are completely inside. Since snakes have very stretchy, flexible skin, and a simple bone structure, they can swallow their prey whole without breaking prey apart, even inside their bodies.
Mating season for common garter snakes takes place shortly after hibernation ends. Hundreds of common garter snakes gather in the fall to sleep through the winter together in a rock crevice, ground hole, or empty burrow. This time of little activity is called torpor. In the springtime the snakes awaken from their torpor and mate. The females then lay clutches, or batches, of between 12 and 80 eggs. The eggs have an incubation period, the amount of time between when the eggs are laid and when they hatch, of about three months.
Predators of the common garter snakes are birds, larger snakes, skunks, racoons, opossums, and humans. People often encounter and kill common garter snakes in their backyards.
Native American folklore claims the year's first sound of thunder awakens common garter snakes from their winter hibernation. The state of Massachusetts claims the common garter snake as its official reptile.
Common garter snakes have an average life span of about 12 years.
Related species from the genus Thamnophis:
- Ribbon snake(Thamnophis sauritus)
- Western black-necked garter snake(Thamnophis cyrtopsis)
- Eastern black-necked garter snake(Thamnophis cyrtopsis ocellatus)
- Tropical black-necked garter snake (Thamnophis cyrtopsis collaris)
Bibliography
“Common Garter Snake.” Animalia, 2024, animalia.bio/common-garter-snake. Accessed 2 Apr. 2024.
Fantauzzo, Sofia. “What Do Garter Snakes Look Like? 3 Quick Ways to ID Them.” A-Z Animals, 26 Jan. 2024, a-z-animals.com/blog/what-do-garter-snakes-look-like-how-to-identify. Accessed 3 Apr. 2024.
Zimmerman, Ryan. “Thamnophis sirtalis Common Garter Snake.” Animal Web Diversity, 2013, animaldiversity.org/accounts/Thamnophis‗sirtalis. Accessed 3 Apr. 2024.