How cool is it to find a snake in your garden! Some people might not agree, but I am always intrigued to find them either slithering among the plants or a wonderful surprise when I take the cover off the woodpile or even pull up the welcome mat. They are definitely welcome in our yard! Garter snakes (Thamnophis s. sirtalis) are the most common and abundant snake in North America. They range from the Arctic Circle south into Mexico. There are 30 species of garter snakes and many sub-species. Because they are so adaptable to habitats and temperatures they can exist in a wide variety of areas.
The name some believe comes from the fact that their stripes resemble “garters” men used to use to hold-up their socks. Another theory is that is comes a corruption of the German word for garden – which is garten. Garter snakes are often mistakenly called garden snakes.
Their habitats include meadows, marshes, woodlands, hillsides and they are often found near water. Garter snakes are active year-round in southern and coastal regions; March to October in northern regions. They are extremely cold resistant and can be active longer in the season than any other snake, between 68-98.6oF. Like other cold-blooded, ectothermic, animals they regulate their temperature by basking in the sun and, although solitary during the day, at night they sleep together to control their body temperature. They are found in damp areas, beneath logs, boards or other debris, where they can soak up moisture. Garter snakes display regular activity patterns so if you have discovered them in one location…look again about the same time and you might them there.
The common garter snake has a yellowish stripe that runs down the center of its back and two yellow stripes along the sides. There is much variation in the colors and patterns, it often varies from dark-green to olive-green to black. They have a distinctive checkerboard pattern of dark squares and flecks of white or red that are usually between their keeled scales. Females have much shorter tails than males. The venter, or underside of the snake, is yellowish, greenish or bronze. They have a red tongue with a black tip. They are usually 18-26″, but can measure up to 42″. Since there are even regional differences in colors and patterns, biologist look at the labial scales around the mouth to identify a species. The ribbon snake is very similar to the garter snake. The common ribbon snake (Thamnophis sauritus) is a Connecticut species of special concern.
Garter snakes den in mammal burrows, rock-outcrops or areas under stumps and logs. They “brumate” for the winter months. Unlike hibernating animals that sleep, brumating animals are awake, but inactive. Shortly after emerging from their winter dens they begin mating. At this time sometimes there are reports from people that their yards are being overrun with snakes. Their amazing courtship ritual involves “mating balls” when a hundred or more garter snakes are intertwined, with a female at the center, until the female chooses a mate. After mating the female moves off on her own and five months later, July/August, will give birth to between 10-40 live young that emerge within a transparent sack that they quickly come out of. At this time the newborns are 7-9″ long and are identical to the adults in pattern and color.
As they grow they shed their outer skin. A new outer layer of skin grows beneath the old one and lymphatic fluid spreads between the layers. This fluid gives the eyes a grayish or bluish milky appearance. The fluid is then reabsorbed and the snake will rub its nose and head against a rough material, gradually moving forward and leaving the old skin behind. The whole process can take a few days. The shed skin will be larger than the actual snake since it stretches as it is removed.
The mother might remain with the newborns for several days, but provides no care. The young are able to get their own food. The newborns might remain together for several weeks before dispersing. Their diet varies depending on what is available. They eat earthworms, slugs, frogs, toads, salamanders and fish also birds and small mammals. Like other snakes they swallow their prey whole.
They in turn have a wide variety of predators from hawks and crows to other snakes, turtles, large fish, foxes and raccoons. Garter snakes are not venomous, but can inflict a painful bite. If grabbed they will secrete a foul smelling musk and if picked-up will also urinate on the attacker.
Although they are harmless sometimes humans have killed them out of fear. They are shy and not aggressive and they will often hide or retreat if left alone. Their numbers have decreased due to habitat destruction, water pollution, pesticide use and having been collected for the pet trade.
Garter snakes, like other snakes, are an important part of the ecosystem. Connecticut is home to 14 different snakes, of which only two are venomous and are rarely ever seen. Learn more about snakes and you also might want to welcome them into your backyard!
Just for Kids – Snakes
Wildlife Fact Sheet – Common Garter Snake
Stokes Guide to Amphibians and Reptiles by Thomas F. Tyning
Washington State’s Species Spotlight: Garter Snake YouTube 5:45 minutes