27 Types of Snakes in Iowa: A Field Guide to Every Native Species
October 16, 2026
Iowa might not carry the snake-heavy reputation of Texas or Arizona, but the Hawkeye State hides a surprising amount of serpent diversity in its prairies, river bottoms, and timbered bluffs. There are 27 species of snakes in Iowa, ranging from a foot-long brown snake hiding under porch steps to a six-foot black rat snake climbing trees for bird eggs. Sorting through the types of snakes in Iowa starts with one reassuring fact: Iowa has only four venomous snakes, and their bites are rarely fatal if treated.
This guide walks through every native Iowa snake species, organized the way field herpetologists catalog them, with identification notes, habitat preferences, and conservation status for each. Some of these snakes share range with species found in neighboring states, and a few turn up as far away as the Gulf Coast or the Rocky Mountains. For readers curious about Iowa’s broader wildlife beyond reptiles, the state’s caterpillars found across Iowa show a similar pattern of hidden diversity tucked into the same prairies and woodlands.
Important Note: Some sources list Iowa’s snake count at 28 rather than 27. The discrepancy usually comes down to whether the eastern and western massasauga are counted as one species or two, and whether certain subspecies (like the two hognose snakes) are tallied separately. This guide follows the 27-species count used by the Iowa DNR-sourced records on iowaherps.com.
1. Black Rat Snake
The black rat snake (Pantherophis obsoletus) is one of the largest snakes in Iowa, and Iowa’s snakes vary in size to serve the needs of the ecosystem, from small snakes less than a foot long to large, 6-foot-long black rat snakes. Adults are glossy black with a white or yellowish chin, though juveniles show a blotched pattern that fades as they mature.
These snakes are strong climbers, often found in tree cavities, barn lofts, and abandoned buildings while hunting rodents, birds, and eggs. Despite their intimidating size, black rat snakes are nonvenomous constrictors that pose no real threat to people, though they will vibrate their tails and strike when cornered.
2. Brown Snake
The brown snake (Storeria dekayi) is among the smallest and most overlooked snakes in the state. Brown snakes in Iowa are among the shortest snake species in the state, and at just 13 inches, the brown snake is the smallest snake on this list and poses no threat to humans.
Gray to brown in color with two rows of faint dark spots running down the back, brown snakes are frequently mistaken for baby garter snakes. They are widespread around Iowa and are a common sight in urban areas, often discovered under mulch, logs, and garden debris where they hunt slugs and earthworms.
3. Bullsnake
Iowa’s bullsnake (Pituophis catenifer sayi) is a heavy-bodied constrictor built for life on the open prairie. The Wikipedia-sourced status table for Iowa reptiles lists the bullsnake as a species of special concern in the state, reflecting its declining prairie habitat.
Yellowish-tan with dark brown blotches, bullsnakes are often confused with rattlesnakes because they hiss loudly and flatten their heads when threatened. A close relative in the same genus occurs far to the west, where readers can compare range and markings in this guide to the snakes found in Oregon. Bullsnakes feed heavily on pocket gophers and ground squirrels, making them valuable allies for farmers.
4. Common Garter Snake
The common garter snake (Thamnophis sirtalis) is easily the most frequently seen snake in Iowa, turning up in backyards, parks, and nearly every wetland edge in the state. It has a distinct pattern of three light stripes running the length of a dark body, though color intensity varies widely between populations.
Only garter snakes can be legally caught, collected or killed in all counties of Iowa, a protection status that sets them apart from every other native species. Readers wanting to understand how this species compares to its many regional cousins can explore the full range of garter snake types found across North America.
5. Copperbelly Water Snake
The copperbelly water snake (Nerodia erythrogaster) is one of Iowa’s rarest reptiles, listed as endangered in the state’s official reptile status table. Its range is restricted to a small corner of southeastern Iowa along the Mississippi River floodplain.
This large, dark water snake earns its name from the orange or copper-colored belly that contrasts with its solid slate-gray to black back. Copperbelly water snakes rarely stray far from the wetlands, sloughs, and swamp forests where they hunt frogs and fish, making habitat loss the primary threat to the population.
6. Copperhead
The copperhead (Agkistrodon contortrix) is one of Iowa’s four venomous snakes and also one of its most restricted in range. Copperheads inhabit only a small portion of southeast Iowa, in Van Buren and Lee counties, and are actually listed as endangered in the state and considered a very rare find.
Copperheads have a coppery-red head and a body patterned with hourglass-shaped crossbands over a tan or pinkish background. They favor rocky, wooded hillsides and are far more likely to freeze or retreat than strike. Readers in states farther east where the species is more common can compare notes with the snakes documented in Maryland, where copperheads are considerably more widespread.
7. Diamondback Water Snake
The diamondback water snake (Nerodia rhombifer) carries a threatened status in Iowa, where it occupies large rivers and backwaters mostly in the southeastern part of the state. It is one of the bulkier water snakes, with a net-like, diamond-shaped pattern across an olive or brown body.
Diamondback water snakes are strong swimmers that bask on logs and low branches over the water, dropping into the current at the first sign of disturbance. They feed almost exclusively on fish and amphibians, and despite their heavy build and defensive hissing, they carry no venom.
8. Eastern Hognose Snake
The eastern hognose snake (Heterodon platirhinos) is best known for its dramatic defensive act: when threatened, it flips onto its back, opens its mouth, and plays dead with startling commitment. This upturned, shovel-shaped snout helps it dig for its favorite prey, toads, in sandy soils across the state.
Coloration ranges from solid black to heavily blotched yellow-brown, which has led to frequent misidentification. This theatrical death-feigning behavior isn’t unique to Iowa’s hognose snakes; readers can see how widespread the trick is among other snake species that play dead when cornered. The eastern hognose also occurs well beyond Iowa, with populations documented among the snakes native to South Carolina.
9. Graham’s Crayfish Snake
Graham’s crayfish snake (Regina grahamii) is a specialist that lives almost entirely on a diet of soft-shelled crayfish, which it hunts along the muddy edges of ponds, marshes, and slow streams. Its body is olive to brown with a pale yellow stripe running down each side.
Because it spends most of its life hidden in crayfish burrows and dense aquatic vegetation, this snake is rarely seen even in counties where it is relatively common. Graham’s crayfish snake is harmless to humans and will typically flee into the water rather than defend itself when disturbed.
10. Lined Snake
The lined snake (Tropidoclonion lineatum) closely resembles a small garter snake, with a pale central stripe running down a gray-brown back and a double row of dark crescent marks on its belly. It rarely exceeds 10 inches in length.
Lined snakes favor prairie remnants, vacant lots, and rocky hillsides, where they hide under flat stones and debris during the day. They feed primarily on earthworms and are completely harmless, though they are seen far less often than the common garter snakes they resemble.
11. Massasauga Rattlesnake
The massasauga rattlesnake (Sistrurus catenatus) is Iowa’s smallest and most imperiled venomous species. The eastern massasauga rattlesnake is a small, venomous snake recently listed as threatened by the U.S. Fish and Wildlife Service, and in Iowa it carries a state-level endangered designation.
Adults typically reach only about two feet long, with a thick gray or brown body covered in dark, saddle-shaped blotches and a small, dark rattle. Iowa biologists have conducted radio telemetry studies at Sweet Marsh Wildlife Management Area in Bremer County to better understand the species’ remaining strongholds. Readers interested in how this species compares to other rattlesnake diversity nationwide can browse the much larger lineup of rattlesnake species found in Arizona.
12. Milk Snake
The milk snake (Lampropeltis triangulum) is a strikingly patterned constrictor with reddish-brown to orange blotches outlined in black over a cream or tan background. This bold coloring often gets it mistaken for a venomous coral snake or copperhead, despite posing zero danger to people.
Common Mistake: Many Iowans kill milk snakes on sight, assuming the banded pattern signals venom. Iowa has no coral snakes, and the state’s only venomous banded species, the copperhead, has hourglass crossbands rather than the milk snake’s blotches.
Milk snakes are secretive, spending most of their time under rocks, logs, and old farm debris while hunting rodents, other snakes, and small reptiles. For a closer look at how this species compares to its many regional color forms, see this breakdown of milk snake varieties across North America.
13. Northern Water Snake
The northern water snake (Nerodia sipedon) is Iowa’s most commonly encountered water snake, found along nearly every river, pond, and lake in the state. It has a heavy body with dark reddish-brown or black crossbands that often darken with age until the pattern is barely visible.
Northern water snakes are frequently mistaken for venomous cottonmouths, a species that does not occur in Iowa or anywhere near it. They are aggressive when handled, biting and musking readily, but carry no venom. The species ranges widely across the eastern half of the country, including populations noted among the snakes found in Delaware.
14. Plains Garter Snake
The plains garter snake (Thamnophis radix) looks similar to its common garter snake cousin but typically shows a brighter orange or yellow dorsal stripe against a dark olive-green body. It favors drier upland prairies and grasslands more than its wetland-loving relative.
This species is active during the day and tolerates a wide range of habitats, including agricultural edges and suburban yards. Plains garter snakes give birth to live young in late summer, with litters sometimes exceeding 20 offspring, and they feed on earthworms, insects, and small amphibians.
15. Prairie Kingsnake
The prairie kingsnake (Lampropeltis calligaster) is a secretive, burrowing constrictor with a light tan or gray body marked by rows of brown blotches that fade with age into a nearly uniform color. It spends most of its life underground or beneath surface debris.
Prairie kingsnakes prey heavily on rodents and other snakes, including venomous species, making them a genuinely beneficial neighbor on farmland. The species shares territory with a close relative documented among the snakes native to Alabama, where kingsnake diversity is considerably higher than in Iowa.
16. Prairie Rattlesnake
The prairie rattlesnake (Crotalus viridis) is the rarest of Iowa’s rattlesnakes, restricted almost entirely to the Loess Hills of western Iowa. Prairie rattlesnakes are extremely rare in Iowa and are only found in a small area of the Loess Hills in the western part of the state, and the species holds endangered status statewide.
Light brown to greenish-gray with dark brown blotches, prairie rattlesnakes rely on steep, dry, grass-covered bluffs where they den communally in rock crevices through winter. For a broader look at how many rattlesnake species exist across North America and how Iowa’s three fit into that picture, see this overview of rattlesnake species diversity.
17. Prairie Ringneck Snake
The prairie ringneck snake (Diadophis punctatus arnyi) is a small, secretive species identified instantly by the bright yellow or orange ring around its neck, set against a smooth, slate-gray or olive back. The belly is similarly bright, often orange-yellow with small black spots.
Ringneck snakes are nocturnal and spend daylight hours hidden under rocks, logs, and leaf litter in open woodlands and rocky hillsides. When disturbed, they curl their tail into a tight spiral to flash the bright underside as a startle display, a behavior that rarely fails to surprise anyone who turns over the wrong rock.
18. Racer
The racer (Coluber constrictor) is a fast, slender, uniformly dark snake found throughout nearly all of Iowa in prairies, woodland edges, and farmland. Adults are typically solid black or dark gray above with a pale belly, and juveniles show a blotched pattern that disappears as they mature.
True to its name, the racer relies on speed rather than venom or camouflage, fleeing quickly into brush when approached and rarely allowing a close look. This species ranges across most of the continental United States and well into Canada, where it appears among the snake species documented in Canada.
19. Redbelly Snake
The redbelly snake (Storeria occipitomaculata) is a tiny, secretive species rarely growing past 10 inches, with a reddish-brown back and a belly that ranges from bright red to orange. Three faint light spots often mark the neck just behind the head.
Redbelly snakes favor moist woodlands, leaf litter, and rotting logs, where they feed almost exclusively on slugs and earthworms. They are among the least often seen snakes in Iowa simply because of their small size and strictly nocturnal, burrowing habits.
20. Smooth Earth Snake
The smooth earth snake (Virginia valeriae) is a small, plain brown or gray burrowing species with smooth, glossy scales and almost no distinct markings. It rarely tops 10 inches and is easily mistaken for a large earthworm at a glance.
True to its name, this species spends nearly its entire life underground or beneath surface litter, surfacing mainly after rain. Smooth earth snakes feed on soft-bodied prey like earthworms and slugs, and because they are so rarely encountered, much of their Iowa distribution remains poorly documented.
21. Smooth Green Snake
The smooth green snake (Opheodrys vernalis) is one of Iowa’s most strikingly colored species, with bright grass-green scales above and a pale yellow or white belly that offer near-perfect camouflage in tallgrass prairie. Smooth green snakes slither through the tall grass of the prairie alongside several other native species found in the same remnant grasslands.
This slender, docile snake feeds almost entirely on insects and spiders, making it one of the few truly insectivorous snakes in the state. Populations have declined with prairie loss, though isolated pockets persist as far northeast as the snake species found in Maine, where the species also occurs at the eastern edge of its range.
22. Speckled Kingsnake
The speckled kingsnake (Lampropeltis holbrooki) is a glossy, black-bodied constrictor marked with a yellow or white speckle at the center of nearly every scale, giving it a salt-and-pepper look that led to its “salt-and-pepper snake” nickname in some regions.
Speckled kingsnakes are powerful constrictors that readily eat rodents, other snakes, and even venomous species, since kingsnakes have a natural resistance to pit viper venom. The species also ranges south into warmer climates, including among the snakes recorded in South Carolina, where kingsnake diversity runs higher than in the Midwest.
23. Timber Rattlesnake
The timber rattlesnake (Crotalus horridus) is Iowa’s largest venomous species. Timber rattlesnakes are also the largest venomous snakes in Iowa, reaching an impressive six feet in length, with a yellow-brown to gray body marked by dark, jagged crossbands and a black tail.
Massasauga and timber rattlesnakes are rare, but found in eastern and southern Iowa, and timber rattlesnakes are protected in 14 of Iowa’s 99 counties, excluding within 50 yards of an actively occupied residence. For a closer look at how this species and Iowa’s other two rattlesnakes compare side by side, the dedicated guide to rattlesnake species in Iowa breaks down range, size, and habitat for all three.
| Venomous Species | Typical Length | Iowa Range | State Status |
|---|---|---|---|
| Timber Rattlesnake | Up to 6 feet | Eastern and southern Iowa | Protected, limited counties |
| Prairie Rattlesnake | 3 to 4 feet | Loess Hills (western Iowa) | Endangered |
| Massasauga Rattlesnake | About 2 feet | Scattered eastern populations | Endangered |
| Copperhead | 2 to 3 feet | Van Buren and Lee counties | Endangered |
24. Western Fox Snake
The western fox snake (Pantherophis vulpinus) is a heavy-bodied, tan to yellowish snake with square brown blotches running down its back, often mistaken for both a rattlesnake and a copperhead because of its coloring and defensive musk odor, which some say resembles a fox’s scent.
Fox snakes vibrate their tails vigorously against dry leaves when threatened, producing a buzzing sound that mimics a rattle, though they have no rattle of their own. They are strong climbers and swimmers found across most of Iowa except the far northern counties, feeding on rodents, birds, and eggs.
25. Western Hognose Snake
The western hognose snake (Heterodon nasicus) shares its eastern cousin’s upturned snout and dramatic bluffing behavior, but tends toward drier, sandier habitats in western Iowa’s prairies and river sandbars. Its body is typically tan or gray with dark, rounded blotches.
Like the eastern hognose, this species will hiss, flatten its body into a hood-like display, and ultimately flip over to feign death when it feels truly threatened. The western hognose also occurs across a broad swath of the Great Plains and intermountain West, including populations documented among the snake species found in Utah.
26. Western Ribbon Snake
The western ribbon snake (Thamnophis proximus) is a slim, fast-moving relative of the garter snake, identified by a bold orange or yellow stripe running down an otherwise dark olive to black body, with a distinctly long tail relative to its body length.
This species sticks close to water, rarely venturing far from streams, ponds, and marshes where it hunts frogs, tadpoles, and small fish. Western ribbon snakes range well south of Iowa too, with populations extending into the snake species found in Mexico at the southern edge of the range.
27. Western Worm Snake
The western worm snake (Carphophis vermis) is one of Iowa’s smallest and most secretive species, rarely exceeding 11 inches, with smooth, glossy purplish-brown scales above and a bright pink belly. Its small, pointed head helps it burrow through loose soil and leaf litter.
Western worm snakes spend almost their entire lives underground, surfacing mainly after rain or when disturbed by digging. They feed almost exclusively on earthworms, and because they are so rarely seen above ground, this species remains one of the least documented snakes in the state’s herpetological records.
Pro Tip: If you find a snake in your yard and aren’t sure what it is, note the head shape, eye pupil shape, and whether it has a rattle before trying to photograph it from a safe distance. Iowa’s four venomous species all have triangular heads, elliptical pupils, and heat-sensing pits between the eye and nostril; every harmless species in the state has a rounded head and round pupils.
Sorting out the 27 types of snakes in Iowa comes down to a short checklist: head shape, pattern, habitat, and range. Most Iowans will spend a lifetime outdoors and never see one of the state’s four venomous species, since all are rare, localized, and generally reluctant to bite unless handled or startled at close range. The far greater likelihood is crossing paths with a garter snake sunning on a sidewalk or a fox snake sliding through tall grass, both harmless neighbors doing the quiet work of keeping rodent and insect populations in check across Iowa’s fields and woodlands.