Garter snakes are common reptiles found across North America, often encountered in diverse environments from suburban gardens to natural wetlands. Their widespread presence frequently leads to questions about their potential danger, particularly regarding whether they are “poisonous” or “venomous.” This article aims to clarify common misconceptions and provide information about black garter snakes, including their characteristics, defensive behaviors, and how to interact with them safely.
Are Garter Snakes Venomous?
Garter snakes are not poisonous, meaning they are not harmful if ingested. However, they do possess a mild venom. This distinction is important: “venomous” refers to an animal that injects toxins, typically through a bite, while “poisonous” refers to an animal that releases toxins when touched or eaten. Discoveries in the early 2000s revealed garter snakes produce a neurotoxic venom in their modified saliva.
This venom is primarily used to subdue small prey, such as amphibians, earthworms, slugs, and small rodents. While the venom can cause hemorrhaging in mice, it is generally not considered medically significant or harmful to humans. Bites to humans typically result in only minor, localized symptoms like slight itching, burning, or mild swelling. Garter snakes also lack an efficient delivery system, meaning they often need to chew on their prey for the venom to take effect.
When threatened, garter snakes primarily rely on defensive behaviors. They may coil and strike as a bluff, or hide their head and flail their tail. A common defense mechanism is releasing a foul-smelling, musky secretion from a gland near their cloaca, which deters predators. Some garter snakes may also feign death or quickly slither into water to escape danger.
Identifying Black Garter Snakes
Black garter snakes exhibit variations in appearance but share common physical characteristics. They are typically small to medium-sized, ranging from about 18 to 51 inches (46 to 130 cm) in total length. They have a slender build, and their scales are “keeled,” meaning they have a raised ridge down the center, giving them a rough texture. Their eyes are typically large and round with rounded pupils.
While some garter snakes are entirely black, many “black” garter snakes may still have faint stripes or lighter markings. For instance, some common garter snakes are black or brown with a yellowish stripe down their back and sides. The black-necked garter snake (Thamnophis cyrtopsis), found in the southwestern U.S., is typically dark grey or olive-grey with distinct black neck patches and a bright yellow or orange dorsal stripe. These snakes are often found in moist, grassy areas, near water sources like ponds, streams, and wetlands, as well as in gardens and woodlands.
What to Do If Bitten
Garter snake bites are generally harmless and rarely medically significant for humans. If a bite occurs, remain calm. The wound should be thoroughly cleaned with soap and water to prevent infection. After cleaning, apply an antiseptic and cover the area with a clean bandage.
Monitor the bite site for any signs of infection, such as increased redness, swelling, pus, or if you develop a fever or chills. While garter snake bites are rarely serious, seeking medical attention is advised if these symptoms appear, or if the individual has underlying health conditions or experiences an allergic reaction. Severe allergic reactions are very uncommon.
Ecological Role and Coexistence
Garter snakes play an important role in ecosystems as natural pest controllers. Their diet includes a variety of small animals often considered pests, such as slugs, earthworms, leeches, insects, and small rodents. By preying on these organisms, garter snakes help maintain a balance in local environments, including gardens and agricultural areas, potentially reducing the need for chemical pesticides.
These snakes are not aggressive and are more likely to flee than confront a threat. Their presence indicates a healthy ecosystem. To promote peaceful coexistence, observe garter snakes from a distance and avoid handling them. Maintaining a tidy yard can reduce hiding spots for their prey, making your yard less attractive to snakes if preferred elsewhere. Appreciating their beneficial role fosters understanding and respect for these native reptiles.