Garter snakes sit squarely in the middle of the food web, eaten by a surprisingly long list of predators that includes hawks, owls, crows, herons, bullfrogs, large fish, other snakes, raccoons, foxes, shrews, and even spiders. Their small size, widespread habitat, and habit of basking in the open make them a convenient meal for almost any predator that can overpower them. The story gets more interesting when you look at which predators specialize in garter snakes, how vulnerability changes with the snake’s age, and the remarkable chemical defense some garter snake populations have stumbled into by eating toxic newts.
Birds That Hunt Garter Snakes
Raptors are among the most consistent predators of garter snakes across North America. Hawks, falcons, and owls all include snakes in their diet, and garter snakes, which spend considerable time exposed on rocks, trails, and grassy edges, are easy targets from the air. Red-tailed hawks, Cooper’s hawks, and broad-winged hawks all take garter snakes when the opportunity arises. Research on raptor-snake encounters has documented that while raptors feed on a wide range of prey from invertebrates to mammals, snakes are a regular component, though the interaction sometimes goes badly for the bird when the snake is large or venomous enough to fight back.1Oxford Academic (Ornithology). When predators get more than they bargained for: Naïve attacks on snakes by hawks, falcons, and owls Garter snakes, being nonvenomous and relatively small, rarely pose that kind of threat to a raptor.
Crows deserve special mention. At communal garter snake dens, where hundreds or thousands of snakes emerge in spring, American crows can be devastating. A study of red-sided garter snakes at a large den site found that crows killed roughly 590 snakes, focusing mostly on smaller individuals of both sexes. Crows typically removed the snake’s liver and left the rest of the carcass behind, though very small snakes were sometimes carried away whole, presumably to feed nestlings.2Evolution. BUMPUS IN THE SNAKE DEN: EFFECTS OF SEX, SIZE, AND BODY CONDITION ON MORTALITY OF RED‐SIDED GARTER SNAKES That liver-targeting behavior is oddly specific and suggests crows have learned to extract the most nutritious organ efficiently.
Wading birds round out the avian threat. Great blue herons, green herons, and egrets will snatch garter snakes from pond edges and stream banks, where the snakes often forage for frogs and fish. Domestic chickens and turkeys have been observed eating small garter snakes as well, which tends to surprise people who think of poultry as strict seed-eaters.
Mammalian Predators
A wide variety of mammals eat garter snakes, and for most of them it is opportunistic rather than targeted. Raccoons, opossums, skunks, and foxes will all grab a garter snake if they stumble across one. Coyotes eat them occasionally. Domestic and feral cats are efficient garter snake predators in suburban and rural settings, where the snake’s habit of sheltering under garden debris puts it right in a cat’s patrol zone.
Shrews are a less obvious predator but a real one. Short-tailed shrews produce venomous saliva that can immobilize small prey, and they have been documented killing snakes close to their own body length. Because shrews have ferocious metabolisms and eat almost constantly, even a small garter snake represents a worthwhile caloric investment for them.
Weasels, mink, and other mustelids are among the more effective mammalian predators of garter snakes, especially near water. Mink in particular overlap heavily with garter snakes in riparian habitats and will pursue them into burrows and under cover. Bears are not a meaningful predator, though they have been observed casually eating garter snakes at den sites during spring emergence when snakes are sluggish and densely concentrated.
Other Snakes
One of the most significant predators of garter snakes is another snake. Kingsnakes are well-known ophiophages, meaning they specialize in eating other snakes, and garter snakes are on the menu. A detailed study of California kingsnake feeding ecology found that of 129 snakes recovered from kingsnake stomachs, the genus Thamnophis (garter snakes) was among the 14 colubrid genera identified as prey. Colubrids made up about 65% of the kingsnakes’ snake diet overall.3Herpetological Conservation and Biology. Feeding ecology of a generalist predator, the California Kingsnake (Lampropeltis californiae): why rare prey matter Kingsnakes are immune to pit viper venom, but they do not need that immunity to handle garter snakes; they simply overpower them through constriction.
Racers and coachwhips, both fast-moving colubrid snakes, also eat smaller garter snakes. In areas where their ranges overlap, a juvenile or small adult garter snake encountering a racer is in real trouble. Garter snakes seem to recognize the chemical cues of kingsnakes and racers and will attempt to flee or become defensive when they detect them, suggesting strong evolutionary pressure from snake-on-snake predation.
Fish, Frogs, and Other Aquatic Predators
Garter snakes spend a lot of time near or in water, which exposes them to aquatic predators they might not face on dry land. Largemouth bass, northern pike, and other large predatory fish will eat a garter snake that enters the water. Research on largemouth bass diets in central Nebraska found that these fish consume a range of terrestrial and semi-aquatic vertebrates, and small snakes are among them.4DigitalCommons@University of Nebraska – Lincoln. Terrestrial and Semi-Aquatic Vertebrates in Diets of Largemouth Bass in Central Nebraska A swimming garter snake, especially a young one, looks and moves much like any other small aquatic prey item from a bass’s perspective.
Bullfrogs are another underappreciated predator. American bullfrogs are large enough to swallow small snakes, and they are ambush predators that sit at the water’s edge waiting for anything of appropriate size to pass by. Snapping turtles will grab a garter snake from below the surface as well, though this is more common in shallow, weedy water where both animals forage.
Spiders and Invertebrate Predators
This one catches people off guard, but spiders genuinely do kill and eat garter snakes, particularly neonates and very young juveniles. A comprehensive review of spider predation on snakes found that garter snakes, specifically the black-necked garter snake and the common garter snake, are among the North American colubrid species most frequently reported as spider prey. Along with ringneck snakes, garter snakes have been documented trapped in spider webs with unusual frequency.5The Journal of Arachnology. Spiders (Arachnida: Araneae) feeding on snakes (Reptilia: Squamata)
The vast majority of snake victims in these encounters are neonates or juveniles with very low body weight. A newborn garter snake can weigh only a few grams, which puts it well within the size range that a large orb-weaver or widow spider can subdue. The spider’s venom does the heavy lifting; the web just has to hold the snake long enough for the venom to take effect. These events are not common enough to be a major population-level threat, but they are a real source of mortality for the smallest and most vulnerable garter snakes.
Why Small and Young Garter Snakes Face the Worst Odds
A recurring theme across predator categories is that smaller garter snakes die at higher rates. The crow predation study found that crows concentrated their kills on small snakes of both sexes, which makes sense from an energy perspective: a small snake is easier to catch, easier to handle, and less likely to escape or deliver a defensive bite.2Evolution. BUMPUS IN THE SNAKE DEN: EFFECTS OF SEX, SIZE, AND BODY CONDITION ON MORTALITY OF RED‐SIDED GARTER SNAKES Spider predation is almost exclusively limited to neonates and juveniles.5The Journal of Arachnology. Spiders (Arachnida: Araneae) feeding on snakes (Reptilia: Squamata) Even among mammalian and avian predators, the probability of being killed drops substantially as a garter snake grows.
Garter snakes compensate for this with high reproductive output. A single female can give birth to anywhere from a handful to over 80 live young in one litter, depending on the species and her body size. Most of those babies will not survive their first year. The strategy, in evolutionary terms, is to produce enough offspring that some make it through the gauntlet of predators, cold snaps, and starvation to reach adult size, where the predator list shrinks considerably. An adult garter snake still gets eaten by hawks, kingsnakes, and coyotes, but it is largely safe from crows, spiders, bullfrogs, and bass.
How Garter Snakes Try to Avoid Being Eaten
Garter snakes have a modest defensive toolkit. Their first line of defense is simply not being seen. Research on garter snake color patterns has shown that natural selection favors combinations of color and escape behavior that work together to confuse visually oriented predators. Striped garter snakes tend to flee in a straight line, and the longitudinal stripes create an optical illusion that makes it hard for a pursuing bird or mammal to judge the snake’s speed and direction.6PubMed. CORRELATIONAL SELECTION FOR COLOR PATTERN AND ANTIPREDATOR BEHAVIOR IN THE GARTER SNAKE THAMNOPHIS ORDINOIDES Spotted or blotched individuals, by contrast, tend to rely more on holding still and blending in.
When caught, garter snakes musk. This involves releasing a foul-smelling secretion from glands at the base of the tail, often while smearing feces on the predator. The smell is genuinely unpleasant and can deter some predators, particularly mammals that rely on scent. Whether it actually causes a predator to drop the snake probably depends on how hungry the predator is, but it is a common enough behavior that any herpetologist who has handled garter snakes can describe the experience vividly.
Garter snakes will also flatten their bodies to appear larger, strike with an open mouth (their small teeth can break skin but do little real damage), and vibrate their tails in leaf litter to mimic the sound of a rattlesnake. None of these defenses are especially effective against a determined predator, which is part of why garter snakes remain such a staple food source across so many predator guilds.
The Tetrodotoxin Trick
Some common garter snake populations in the Pacific Northwest have stumbled into a chemical defense that is far more potent than musking. These snakes feed on rough-skinned newts, which carry tetrodotoxin (TTX) in their skin. TTX is the same neurotoxin found in pufferfish, and it is extraordinarily lethal to most vertebrates. After eating a newt, the snake retains significant amounts of active TTX in its own tissues, especially the liver. Three weeks after consuming just one newt, snakes contained an average of about 42 micrograms of TTX in the liver, enough to severely incapacitate or kill a bird predator, and potentially harm a mammal as well.7PubMed. A resistant predator and its toxic prey: persistence of newt toxin leads to poisonous (not venomous) snakes
The toxin does not just flash through the snake’s system and disappear. Garter snakes harbor TTX in the liver for a month or more after eating a single newt, and for at least seven weeks after eating a diet of multiple newts.7PubMed. A resistant predator and its toxic prey: persistence of newt toxin leads to poisonous (not venomous) snakes More recent research has confirmed that snakes retain substantial amounts of TTX and projected that they could be dangerous to their own predators for days to weeks following the ingestion of even a single newt.8PubMed. Where Does All the Poison Go? Investigating Toxicokinetics of Newt (Taricha) Tetrodotoxin (TTX) in Garter Snakes (Thamnophis) This makes the snake, in effect, a poisonous animal. Not venomous, because it does not inject venom through a bite, but genuinely toxic to eat. A hawk or crow that kills and consumes one of these snakes could be in serious trouble.
This is worth pausing on because it is not a defense the snake evolved on its own. It is borrowed toxicity. The snake eats a toxic newt, survives thanks to evolved resistance, and then becomes toxic itself as a side effect. Whether predators in the Pacific Northwest have learned to avoid these particular garter snakes is still an open question, but the chemical potential is clearly there.
The Evolutionary Arms Race Behind the Toxin
The relationship between common garter snakes and rough-skinned newts is one of the best-studied examples of an evolutionary arms race in nature. The newt produces TTX to avoid being eaten. The garter snake evolves resistance to TTX so it can eat the newt anyway. The newt responds by producing more toxin. The snake responds with greater resistance. This cycle has been playing out for a long time, and the results are dramatic.
Early research established that garter snake populations living alongside toxic newts had resistance levels far exceeding those of populations that did not encounter newts, providing strong evidence that the predator-prey arms race concept applies to this system.9Evolution. TETRODOTOXIN RESISTANCE IN GARTER SNAKES: AN EVOLUTIONARY RESPONSE OF PREDATORS TO DANGEROUS PREY Later molecular work revealed that some garter snake populations have evolved TTX resistance through changes in not just one but three different sodium channel genes. Previous research had identified mutations in the skeletal muscle sodium channel that confer resistance, but parallel evolution of resistance was also found in two additional sodium channel genes expressed in the peripheral nervous system, meaning the snake’s body had to adapt at multiple molecular sites simultaneously to handle the toxin.10PubMed Central. Fast Track Parallel Evolution of Tetrodotoxin Resistance in Three Voltage-Gated Sodium Channel Genes in the Garter Snake Thamnophis sirtalis
The cost of this resistance is not trivial. Garter snakes with higher TTX resistance tend to be slower crawlers, which makes them more vulnerable to the very predators the toxin might deter. So there is an evolutionary tradeoff: becoming resistant enough to eat toxic newts makes you slightly easier to catch. Populations that do not live near toxic newts have not evolved this resistance and do not pay the speed penalty, but they also do not get the chemical defense benefit. The geography of the arms race creates a patchwork where some garter snake populations are effectively poisonous to their predators and others are completely palatable.
Predators That Leave Garter Snakes Alone
Given the length of the predator list, you might wonder if anything coexists with garter snakes without eating them. Deer, rabbits, and other herbivores obviously have no interest. Most songbirds are too small to handle even a baby garter snake. Squirrels and chipmunks are sometimes aggressive toward snakes but rarely kill and eat them. Large tortoises and most lizards ignore garter snakes entirely.
Among predators that could eat garter snakes but generally do not, wolves and mountain lions stand out. These large predators are focused on much bigger prey, and a garter snake is not worth the caloric effort of catching. The same goes for most large raptors like bald eagles and golden eagles, which prefer fish, waterfowl, and mammals. They could eat a garter snake if one happened to be in front of them, but they do not seek them out. The predators that matter most for garter snake populations are the mid-sized ones: crows, hawks in the buteo and accipiter range, kingsnakes, raccoons, and the occasional largemouth bass. These animals are abundant, widespread, and the right size to find a garter snake worth pursuing.
Garter Snakes in Suburban and Urban Habitats
Garter snakes are among the most adaptable snakes in North America, and they thrive in gardens, parks, and suburban edges where their wild predators may be less common. That does not mean they are safe. Domestic cats are probably the single largest predator of garter snakes in suburban settings, and they often kill without eating, which makes the impact worse from the snake’s perspective. Dogs occasionally kill garter snakes as well, though dogs more often just harass them.
Lawnmowers and cars kill large numbers of garter snakes too, though these are not predation events in the biological sense. In suburban areas, the relevant predators shift: fewer kingsnakes and hawks, more cats and crows. Raccoons and opossums adapt well to human landscapes and continue to eat garter snakes at roughly the same rate they would in wilder settings. If you are trying to encourage garter snakes in your garden for pest control, the most effective intervention is keeping cats indoors and providing dense ground cover like rock piles, brush heaps, or thick mulch beds where snakes can retreat from both aerial and ground-level threats.