Iowa's Snakes

If you’re in the habit of turning over logs or poking through woodpiles, you might be lucky enough to find one of Iowa’s 28 native snake species. Richly diverse, these species range from the western worm snake (Carphophis vermis), tiny and rarely reaching a foot in length, to the gopher (or bull) snake (Pituophis catenifer), a thick-bodied snake that frequently reaches over 6 feet.

Snakes can be found in any of Iowa’s ecosystems. Smooth green snakes (Opheodrys vernalis) slither through the tall grass of the prairie, plainbelly watersnakes (Nerodia erythrogaster) swim through marshy wetlands, and black rat snakes (Pantherophis obsoletus) clamber up trees. Yet, despite their many habitats, varying diets, and behavioral differences, they have one striking similarity: all but 4 are listed as Species of Greatest Conservation Need (SGCN) in Iowa. This label is given by the Iowa DNR to species experiencing declining population trends, as well as those heavily impacted by resource loss.

Iconic and Ecologic

Other than maintaining the overall diversity necessary for a healthy ecosystem, snakes occupy a unique role as both predator and prey. Mice and other rodents may have plenty of predators, but many of these are unable to work their way into the small spaces that mice so easily occupy. Snakes, on the other hand, can follow them with relative ease (which is why you’ve likely heard stories of encountering a snake chilling in someone’s bathroom). Without this service, rodent numbers would bloom. High rodent populations don’t only affect urban areas; they cause severe damage to agricultural production. In a state as reliant on agriculture as Iowa, loss of snakes would prove disastrous.

However, snakes aren’t just handy pest control. While we normally imagine (and appreciate!) snakes as predators, there are many animals that eat them instead. Birds of prey, such as hawks and owls, will grab on to a snake if they can find them, as will coyotes and bobcats. Some species of snakes will even prey on others! One of the most well-known examples are kingsnakes, which are named after their eating habits and position as ‘kings’ among snakes. Iowa has two native kingsnake species, the Prairie Kingsnake (Lampropeltis calligaster) and Speckled Kingsnake (Lampropeltis holbrooki).

Snake Stigma

While much of snake population decline can be attributed to habitat loss, human persecution is not insignificant. Fearmongering around snakes is rampant, despite the importance of these animals. Much of this fear revolves around venomous species, which can be dangerous to humans. Yet, despite what many believe, venomous snake bites are relatively rare. In fact, you’re far more likely to suffer a bite from a non-venomous species! Producing venom is energy-consuming and used almost entirely for hunting, where there will be payoffs for using this costly product.

Defensive Maneuvers

Instead of biting when confronted with danger, many venomous species utilize sound, smell, and visual deterrents as warning displays. Rattlesnakes are a common example, warning off threats with the rattles at the end of their tails. Some non-venomous snakes, such as fox snakes, will mimic this method by wiggling their tails in dry leaves or brush.

Iowa’s other venomous snake, the copperhead (Agkistrodon contortrix), utilizes the ‘freeze’ method. Like many prey species, both snaky and not, this species relies on its excellent camouflage to blend in until the threat goes away.

The most unique defensive mechanism is that of the hognose, which are the thespians of the snake world. When threatened, hognoses put on an intense performance that includes dramatically flopping onto their back, sticking out their tongue, emitting a foul musk, and defecating. Upon being rolled back onto their stomach they will insist on continuing to be ‘dead’, flipping onto their back and resuming their position.

Snakes are an essential piece of a vibrant, healthy Iowa, serving far more roles in the ecosystem than we could imagine. Big and small, venomous or constricting, each of these species has its own niche that’s just as important as any other. While many of these species are in need of conservation efforts, proper ecosystem management and restoration will allow them to continue thriving. And if you’re still unsure about snakes, don’t worry— they’re happy to keep their distance.