Garter snakes, belonging to the genus Thamnophis, are one of the most widespread and commonly encountered snakes across North America. Their presence often prompts immediate concern for the safety of humans and household pets due to general fear and misidentification of snakes. While they are technically classified in a way that suggests a potential threat, the consensus is that garter snakes are functionally harmless to people and larger animals like dogs and cats. Understanding the true nature of this common reptile provides a clear answer to any concerns about safety.
The Truth About Garter Snake Venom
For many years, garter snakes were categorized as non-venomous, but modern research refined this classification. These snakes are now understood to be mildly venomous, possessing a specialized saliva that contains a neurotoxin produced in the Duvernoy’s gland. This gland is analogous to the venom glands of vipers, and the mild venom is effective for subduing their small, natural prey, which often includes amphibians like frogs and salamanders.
The saliva is introduced into prey through small, grooved teeth located in the rear of the mouth, not through the large, hollow fangs characteristic of medically significant venomous snakes. Garter snakes lack the necessary muscular mechanism to efficiently inject this saliva deep into the tissue of a human or a large pet. The body size of a person or a dog renders the snake’s delivery system ineffective.
A bite from a garter snake may cause minor, localized effects, such as slight swelling, redness, or bruising at the site of the wound. These symptoms are transient and mild, posing no systemic medical risk to a healthy human or pet. The effects are negligible when compared to the serious consequences of an encounter with a pit viper or other front-fanged venomous species.
Key Characteristics for Identification
Identifying a garter snake accurately is necessary for reducing unnecessary fear, as misidentification is the most significant risk. These snakes are slender-bodied and small to medium in length, with adults commonly measuring between 18 and 42 inches long. Their most recognizable feature is the presence of three thin, light-colored longitudinal stripes running down the length of a dark body.
The body color is typically a shade of black, dark brown, or gray, while the stripes themselves can vary significantly, often appearing yellow, white, blue, or green. A dark, checkered pattern may be visible in the background coloration between the stripes, giving the snake a mottled appearance from the side. The snake’s dorsal scales are keeled, meaning each scale has a prominent raised ridge.
Minor Defensive Actions and Potential Risks
When a garter snake feels threatened or is handled, it will employ defensive strategies that, while unpleasant, confirm its non-aggressive nature toward larger creatures. The most immediate defense is biting, which occurs when the snake perceives itself to be in danger and cannot escape. These bites are non-venomous to humans and pets, feeling more like a light scratch due to their small, fine teeth.
The primary risk from a bite is the possibility of minor bacterial infection, which is true of any scratch from an animal. Simple first aid, such as washing the wound thoroughly with soap and water, is the only treatment generally required. A more common and noticeable defensive action is the release of a foul-smelling, musky secretion from glands near the cloaca. This non-toxic fluid is highly deterrent and is the most likely consequence a person or pet will experience from disturbing a garter snake.
Coexisting with Garter Snakes
Garter snakes provide a benefit to the local environment, particularly in residential areas and gardens, where they act as natural pest controllers. Their diet includes a variety of organisms that gardeners often want to eliminate, such as slugs, snails, earthworms, and small rodents like mice and voles. Allowing these snakes to inhabit a yard contributes to a healthier, more balanced ecosystem.
Homeowners can make their property less attractive to snakes if they prefer to encourage them to move elsewhere. This can be achieved by removing potential hiding spots, such as piles of debris, rocks, or excessive clutter, and by keeping grass and vegetation trimmed low. Eliminating the snake’s primary food source will also encourage them to relocate naturally.
If a garter snake is found inside a home or in an unwanted area, it can be gently encouraged to leave without being harmed. The snake can be coaxed toward an open exit or safely scooped into a container, like a bucket or box, using a broom or a long stick. Relocation should be to a nearby, suitable natural area, as moving any snake species a significant distance away greatly reduces its chances of survival.