It’s typical to associate the centennial state with snow-covered mountains and ski resorts, not exactly somewhere you’d imagine snakes living!
The truth is, Colorado features a diverse array of habitat types and an equally distinct population of snakes – over 30 species and subspecies, to be precise.
Whether you’re wondering if there are any dangerous snakes in Colorado, or you want to identify an interesting-looking serpent you saw on a hike, you’ve come to the right place.
Our definitive Colorado snake identification guide will teach you what Colorado snakes look like, where they live, and what to do if you encounter one.
In This Article
In Short
- Admire all wild animals, including snakes, from a distance.
- There are over 30 species and subspecies of Colorado snakes; only three are venomous.
- Most venomous snake bites occur because someone tries to kill, relocate, or harass the snake.
- Snakes play an integral role in the Colorado ecosystem, including reducing pest populations.
Colorado Snakes Identification: The Basics
This guide is only for Colorado snake identification. Snakes in other regions may look different, even if they’re the same species.
Some key features to look for when attempting to identify any wild snake:
- Scales – are they keeled or smooth?
- Length – is the snake long or short?
- Pupil Shape – are they round or elliptical?
- Body Shape – is the snake’s body slender or stout?
- Color and Pattern – most species have a wide range of “normal,” but if you can differentiate splotches from bands, you’re off to a great start.
- Unique Characteristics – are there any distinctive features, like the upturned snout of the Western Hognose Snake?
Venomous Snakes in Colorado
There are only three venomous snake species in Colorado. They’re all rattlesnakes, which belong to the pit viper family of snakes.
The Prairie Rattlesnake is the largest and most widespread rattler in the state.
Quickly Identifying Colorado’s Rattlesnakes
A snake’s pattern isn’t always a reliable way to identify a rattlesnake because many harmless species mimic the colors and patterns of venomous species.
The Great Basin Gopher Snake is a great example. Its loud pattern and heavily-keeled snakes cause it to look like a rattlesnake.
There are also a handful of harmless Colorado snakes that mimic coral snakes.
With a bit of know-how, it’s easy to differentiate pit vipers from most North American colubrids by identifying these key characteristics:
- Broad, triangular heads
- Elliptical, cat-like pupils*
- Rattle on tail (rattlesnakes only)
- Heat-sensing pits between the nostrils and eyes
*While almost all North American colubrids have round pupils, Colorado is home to one harmless snake species with elliptical pupils: the Texas Night Snake.
Texas Night Snakes still lack the heavy-bodied build, triangular head shape, and tail rattle of Colorado’s venomous snakes.
Colorado’s Three Venomous Pit Vipers
Only one of Colorado’s three venomous species is abundant throughout most of the state: the Prairie Rattlesnake.
The other two species, the Midget Faded Rattlesnake and the Western Massasauga Rattlesnake, only occupy small pockets of habitat in Colorado.
Prairie Rattlesnake
Scientific Name: | Crotalus viridis |
|---|---|
Range: | Statewide, except a small portion of west-central Colorado |
Size: | 3 – 4 ft. |
Description: | Heavy-bodied Keeled scales Rattle on tip of tail Triangular head with elliptical pupils Tan to brown body with reddish, dark brown, or gray symmetrical blotches |
Habitat: | Any habitat less than 9,500 feet in elevation |
Venomous/Non-Venomous: | Venomous |
Midget Faded Rattlesnake
Scientific Name: | Crotalus oreganus concolor |
|---|---|
Range: | Northwestern corner of Colorado |
Size: | 20 – 24 in. |
Description: | Heavy-bodied Keeled scales Rattle on tip of tail Triangular head with elliptical pupils Pinkish, tan, cream, yellowish, reddish, or yellow-brown body with brown oval to rectangular dorsal blotches (pattern fades with age) |
Habitat: | Desert shrublands, canyons, and pinyon-juniper woodlands with south-facing sandstone outcrops and walls |
Venomous/Non-Venomous: | Venomous |
Western Massasauga Rattlesnake
Scientific Name: | Sistrurus catenatus |
|---|---|
Range: | Southeastern corner of Colorado |
Size: | 20 – 22 in. |
Description: | Heavy-bodied Keeled scales Rattle on tip of tail Triangular head with elliptical pupils Light brown or tan body with dark brown dorsal and lateral blotches in a loosely checkered pattern(dorsal blotches may have white outline) |
Habitat: | Dry, low-elevation grasslands and sandhills |
Venomous/Non-Venomous: | Venomous |
Harmless Snakes in Colorado
While harmless (non-venomous or mildly venomous) snakes aren’t capable of inflicting serious injuries upon humans, I suggest you still avoid handling or harassing any wild snake.
Many non-venomous colubrids evolved to resemble venomous snakes, making it difficult to tell them apart definitively. Better safe than sorry!
Most Common Snakes in Colorado
Most of Colorado’s snakes have a limited range, so the most common species technically depends on where you are in the state.
Here are five of Colorado’s most commonly encountered snakes. These species might have large ranges, be habitat generalists, or have abundant populations.
Bullsnake
Scientific Name: | Pituophis catenifer sayi |
|---|---|
Range: | Eastern Colorado |
Size: | 4 – 6 ft. |
Description: | Keeled scales Proportionate body Black bands on the tail Small head with round pupils Yellow body with brown, white, black, or reddish blotching – one row of large dorsal blotches and three rows of small lateral blotches |
Habitat: | Grasslands, prairies, and meadows |
Venomous/Non-Venomous: | Non-Venomous |
Plains Garter Snake
Scientific Name: | Thamnophis radix |
|---|---|
Range: | Eastern Colorado |
Size: | 2 – 4 ft. |
Description: | Proportionate Rough, keeled scales Light yellow spots on top of head Round pupils and dark vertical bars on lips Gray-green underside with small dark spots along the edges Black or gray body with distinctive orange or yellow dorsal stripe and greenish-yellow lateral stripes |
Habitat: | Open, grassy habitats along edges of streams, marshes, and lakes |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Fun Fact: Like most Garter Snake species, the Plains Garter Snake Snake specializes in eating toads and other amphibians.
Yellow-Bellied Racer
Scientific Name: | Coluber constrictor flaviventris (Eastern Yellow-Bellied Racer) Coluber constrictor mormon (Western Yellow-Bellied Racer) |
|---|---|
Range: | Easternmost and Westernmost Colorado |
Size: | 2 – 5 ft. |
Description: | Slender-bodied Smooth, shiny scales Small head with large eyes Patternless green, blue or brown body with a distinct yellow underside Juveniles are tan or cream-colored with brown or grey blotches (pattern fades with age) |
Habitat: | Summer: open grassland, pastures, and prairie Spring and Fall: rocky wooded hillsides |
Venomous/Non-Venomous: | Non-Venomous |
Great Basin Gopher Snake
Scientific Name: | Pituophis catenifer deserticola |
|---|---|
Range: | Western Colorado |
Size: | 36 – 66 in. (3 – 5.5 ft.) |
Description: | Round pupils Proportionate Pointed head Rough, keeled scales Cream-colored underside with small, dark, irregular blotches Tan body with dark brown or black dorsal splotches connected by narrow lines Dark stripe surrounded by light color on each side of neck that break into dashes towards the tail |
Habitat: | Varied |
Venomous/Non-Venomous: | Non-Venomous |
Expert Tip: The Great Basin Gopher Snake makes a great pet snake, too! Always check your local laws before you bring an exotic pet home, and purchase your pet from a responsible breeder.
Wandering Western Terrestrial Garter Snake
Scientific Name: | Thamnophis elegans vagrans |
|---|---|
Range: | Statewide except the Easternmost edge of Colorado |
Size: | 18 – 41 in. (1.5 – 3.5 ft.) |
Description: | Round pupils Slender-bodied Rough, keeled scales Light-colored lateral stripes (fade with age) Brown or gray body with gray and light tan checkerboard pattern Wandering Garter Snakes from southeastern Colorado have prominent light-colored dorsal stripe |
Habitat: | Habitats with moist vegetation |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Colorado’s Other Harmless Snakes
There’s a diverse array of harmless snakes in Colorado, and almost all of them belong to the colubrid family of snakes.
There’s only one exception: the Texas Blind Snake, belonging to the family Leptotyphlopidae, which consists of diminutive, fossorial snakes that lack true eyes and upper teeth.
Let’s “dig deeper” to uncover this burrowing anomaly, as well as Colorado’s other unique snakes.
Lined Snake
Scientific Name: | Tropidoclonium lineatum |
|---|---|
Range: | Most of Eastern Colorado |
Size: | 10 – 17 in. |
Description: | Proportionate Rough, keeled scales Narrow head, small eyes with round pupils Olive green or brown body with tan or yellow dorsal and lateral stripes Two rows of halfmoon-shaped black spots down the middle of the underside |
Habitat: | Underneath debris on hillsides of open prairies and woodland edges |
Venomous/Non-Venomous: | Non-Venomous |
Glossy Snake
Scientific Name: | Arizona elegans philipi (Painted Desert Glossy Snake) Arizona elegans elegans (Kansas Glossy Snake) |
|---|---|
Range: | Statewide, except northernmost and westernmost edges of Colorado |
Size: | 2 – 4 ft. |
Description: | Proportionate White underside Smooth, glossy scales Light gray body with dark gray or brown dorsal blotches outlined in black Dark line from angle of the jaw through the eye on each side of the head |
Habitat: | Grasslands with sand and loose soil |
Venomous/Non-Venomous: | Non-Venomous |
Texas Blind Snake
Scientific Name: | Rena dulcis |
|---|---|
Range: | Southeastern corner of Colorado |
Size: | 9 – 11 in. |
Description: | Worm-like Proportionate body Smooth, shiny scales Small head with two dark dots for eyes Patternless, pinkish-brown body |
Habitat: | Loose soil in stony hillsides, prairies, and sandy or rocky deserts Under stones, boulders, and occasionally house foundations Most often observed after heavy rainfall |
Venomous/Non-Venomous: | Non-Venomous |
Long-Nosed Snake
Scientific Name: | Rhinocheilus lecontei |
|---|---|
Range: | Southeastern corner of Colorado |
Size: | 2 – 3 ft. |
Description: | Proportionate Smooth scales White underside Long, slightly upturned snout Yellow or cream body with black blotches separated by pink or reddish bands Cream-colored spots inside the black blotches |
Habitat: | Open prairies, sandy habitats, and underneath rocks on canyon slopes |
Venomous/Non-Venomous: | Non-Venomous |
Texas Night Snake
Scientific Name: | Hypsiglena (torquata) jani |
|---|---|
Range: | Southeastern corner of Colorado |
Size: | 10 – 16 in. |
Description: | Proportionate Smooth scales Unmarked underside Elliptical pupils when exposed to light Gray or brown head with three elongated dark brown blotches on the neck Grayish-yellow body with dark brown dorsal blotches |
Habitat: | Grasslands and prairies |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Common Kingsnake
Scientific Name: | Lampropeltis getula (Common Kingsnake) Lampropeltis (getula) holbrooki (Speckled Kingsnake) Lampropeltis (getula) splendida (Desert Kingsnake) |
|---|---|
Range: | Southeastern and Southwestern corners of Colorado |
Size: | 2 – 4 ft. |
Description: | Proportionate Smooth scales Chocolate brown to black body with yellow or white markings that range from clean bands to irregular specks |
Habitat: | Plains and grasslands |
Venomous/Non-Venomous: | Non-Venomous |
Western Coachwhip
Scientific Name: | Coluber flagellum testaceus |
|---|---|
Range: | Statewide except the Northwestern corner of Colorado |
Size: | 4 – 6 ft. |
Description: | Slender-bodied Large eyes with round pupils Smooth scales with braided appearance Patternless yellow-brown body or burgundy body that fades to yellow-brown towards the tail Juveniles are yellowish-brown with dark brown crossbands on front of body (pattern fades with age) White underside with two rows of dark spots on front half |
Habitat: | Open grasslands and prairies |
Venomous/Non-Venomous: | Non-Venomous |
Smooth Green Snake
Scientific Name: | Opheodrys vernalis |
|---|---|
Range: | Spotty |
Size: | 14 – 20 in. |
Description: | Round pupils Slender-bodied Smooth, shiny scales Patternless green body and white or cream underside, separated by hints of yellow |
Habitat: | Marshes, meadows, open woodlands, and along stream edges |
Venomous/Non-Venomous: | Non-Venomous |
Expert Tip: The Smooth Green Snake is Colorado’s only BRIGHT green snake.
Northern Water Snake
Scientific Name: | Nerodia sipedon |
|---|---|
Range: | Northeastern and Southeastern corners of Colorado |
Size: | 32 – 53 in. (2.5 – 4.5 ft.) |
Description: | Round pupils Heavy-bodied Rough, keeled scales Patternless light-colored underside Brown, grey, reddish, or black body with dark crossbands on neck that fade into dorsal blotches down the body (pattern fades and color darkens with age) |
Habitat: | Aquatic habitats |
Venomous/Non-Venomous: | Non-Venomous |
Common Garter Snake
Scientific Name: | Thamnophis sirtalis |
|---|---|
Range: | Northeastern corner of Colorado |
Size: | 3 – 4 ft. |
Description: | Slender-bodied Keeled scales Small head with large eyes Dark-colored body with three yellow stripes; black spots on a red background between the stripes Belly is white, green, or gray, with a row of small dark spots along edges |
Habitat: | Moist, heavily vegetated habitats such as marshes, wet meadows, pond margins, woodlands and woodland edges, floodplains, and agricultural fields |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Variable Ground Snake
Scientific Name: | Sonora semiannulata |
|---|---|
Range: | Southern and Eastern edges of Colorado |
Size: | 8 – 19 in. |
Description: | Round pupils Proportionate Smooth, glossy scales Underside patternless cream or white Brown, red, or orange body may be patternless or have black crossbands or stripes |
Habitat: | Grasslands with sand and loose soil |
Venomous/Non-Venomous: | Non-Venomous |
Fun Fact: A Variable Ground Snake on your property is great for pest control. This species specializes in eating invertebrates like spiders, scorpions, and centipedes.
Western Ribbon Snake
Scientific Name: | Thamnophis proximus |
|---|---|
Range: | Southeastern corner of Colorado |
Size: | 17 – 50 in. (1.5 – 4 ft.) |
Description: | Round pupils Slender-bodied Rough, keeled scales Greenish- or yellowish-white underside White lips against black top and sides of head Black, brown, or olive with three light-colored stripes |
Habitat: | Aquatic habitats |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Great Plains Rat Snake
Scientific Name: | Pantherophis emoryi |
|---|---|
Range: | Southeastern and Westcentral Colorado |
Size: | 36 – 60 in. (3 – 5 ft.) |
Description: | Round pupils Proportionate Smooth scales Dark, square-shaped markings on underside Stripes sides of head form a point between the eyes Light gray or tan body with dark gray, brown, or green-gray dorsal blotches outlined in black |
Habitat: | Grasslands, lightly wooded forests, and agricultural areas |
Venomous/Non-Venomous: | Non-Venomous |
Prairie Ringneck Snake
Scientific Name: | Diadophis punctactus arnyi |
|---|---|
Range: | Southeastern corner of Colorado |
Size: | 10 – 17 in. |
Description: | Round pupils Slender-bodied Smooth, shiny scales Dark gray or black head Yellow or orange ring around neck Patternless slate grey, olive, brown, or bluish-grey body Orange, red, or yellow underside with black spots; more red towards tail |
Habitat: | Plains grasslands, canyon bottoms, or riparian areas with moist soil |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Blackneck Garter Snake
Image of Blackneck Garter Snake
Scientific Name: | Thamnophis cyrtopsis |
|---|---|
Range: | Southern and Eastern edges of Colorado |
Size: | 3 – 4 ft. |
Description: | Keeled scales Slender-bodied Underside is cream or light gray Small head with large eyes Solid black pattern on both sides of neck Dark olive body with an orange or yellow dorsal stripe |
Habitat: | Grasslands near water sources |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Fun Fact: The Blackneck Garter Snake is the least common Garter Snake in Colorado.
Western Hognose Snake
Scientific Name: | Heterodon nasicus |
|---|---|
Range: | Eastern Colorado with a small pocket in the Northwest corner |
Size: | 15 – 36 in. (1 – 3 ft.) |
Description: | Round pupils Heavy-bodied Upturned snout Rough, keeled scales Dark line from eyes to the corners of the mouth Black underside with yellowish-white blotches towards tail Gray, brown, or olive body with dark brown dorsal blotches and two rows of lateral blotches on each side |
Habitat: | Scrubby, flat prairies with loose, sandy soil |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Central Plains Milksnake
Scientific Name: | Lampropeltis (triangulum) gentilis |
|---|---|
Range: | Statewide |
Size: | 16 – 36 in. (1 – 3 ft.) |
Description: | Round pupils Heavy-bodied Smooth, shiny scales White, cream, or light gray body with red blotches outlined in black |
Habitat: | Forests, plains, woodland edges, rocky ledges, and agricultural areas |
Venomous/Non-Venomous: | Non-Venomous |
Desert Striped Whipsnake
Scientific Name: | Masticophis taeniatus taeniatus |
|---|---|
Range: | Western Colorado |
Size: | 2 – 6 ft. |
Description: | Slender-bodied Smooth scales Elongated head with large eyes and round pupils Olive, black, brown, or dark gray body fading to yellow or pink towards the tail Gray, white, or cream lateral stripes with narrow dashed dark lines running down the middle of the stripes |
Habitat: | Flatlands and mountains including shrublands, grasslands, sagebrush flats, canyons, piñon-juniper woodlands, and open pine-oak forests |
Venomous/Non-Venomous: | Non-Venomous |
Plains Black-Headed Snake
Scientific Name: | Tantilla nigriceps |
|---|---|
Range: | Eastern Colorado |
Size: | 7 – 15 in. |
Description: | Round pupils Slender-bodied Smooth, shiny scales Pink or coral underside Black or dark gray head Patternless yellowish-brown body |
Habitat: | Grassland and plains |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
Southwestern Black-Headed Snake
Scientific Name: | Tantilla hobartsmithi |
|---|---|
Range: | Small pocket in West-central Colorado |
Size: | 18 – 41 in. (1.5 – 3.5 ft.) |
Description: | Round pupils Smooth scales Slender-bodied Pink or coral underside Black or dark gray head Patternless light brown body |
Habitat: | Deserts, grasslands, shrublands, and forests with loose soil and leaf litter |
Venomous/Non-Venomous: | Mildly Venomous (not medically significant to humans) |
What You Need to Know
Snakes are shy, reclusive animals that prefer to avoid human encounters. From a snake’s point of view, we are large predators who can harm them.
Most snakes will flee or use their camouflage to hide, only biting as a last resort. Most snake bites result from people attempting to handle, relocate, or injure snakes.
The most effective way to avoid a snake bite is by leaving wild snakes alone and giving them space.
Coexisting with Colorado Snakes
Snakes play a vital role in Colorado’s ecosystem.
Some predators, including birds of prey, foxes, and raccoons, rely on snakes as a source of food. Snakes also help to control pest populations.
The best way to coexist with Colorado’s snakes is to give them space and treat them with respect.
You might even consider maintaining a snake-friendly property to deter rodents and pest insects.
Snake Safety 101
Venomous snake bites aren’t a huge concern in Colorado, but it’s better to be safe than sorry! Keep reading to learn what to do if you find a rattlesnake – and how to avoid a bite.
About Venomous Snakes
There are only three dangerous venomous snakes in Colorado, and the Prairie Rattlesnake is the only common one.
The fact is that it’s not common to encounter a western rattlesnake in Colorado.
If you do find one of Colorado’s rattlesnakes in the wild, turn around or make a small detour to give the serpent a respectable amount of space as you pass.
There have only been two fatal snake envenomations in Colorado in over 20 years, since at least 1999. Dying from a snake bite in Colorado is statistically very rare.
Expert Tip: Some snakes, like the Western Hognose Snake, Blackneck Garter Snake, and Common Garter Snake, produce a mild venom that has little to no effect on humans. That’s why we consider these snakes to be harmless.
Treading Carefully in Snake Habitat
- Use a walking stick
- Watch where you step
- Wear sturdy shoes and long pants
- Keep your pets close and on a leash
- Stay on designated paths without overgrown vegetation
- Teach your children to follow these snake safety tips in wilderness areas
- Be cautious of where you put your hands and don’t reach where you can’t see
If You Encounter a Snake
- Do not disturb the snake!
- Stop moving and identify the snake’s exact location or direction of travel
- Back up and put at least five feet of distance between you and the snake
- Turn back or travel around the snake, maintaining the five-foot distance
When to Call for Help
Only reach out to a wildlife professional or snake relocation expert to have a snake removed from your property if you feel that it’s posing a direct threat to you, your children, or your pets.
If you find an injured snake, here’s a list of wildlife rehabilitation experts in Colorado with a chart indicating which ones accept reptilian patients.
If you suspect that a venomous snake bit you or someone you’re helping, call 911 immediately.
Take a photo of the snake or make a mental note of its appearance, if possible. This can help medical professionals provide you with better, more targeted treatment.
Seek emergency veterinary care if a venomous snake bites your pet.
Useful Resources
Emergency Phone Numbers
Colorado Poison Center: 1-800-222-1222
American Society for the Prevention of Cruelty to Animals (ASPCA) Animal Poison Control Center: 1-888-426-4435
Snake Relocation Services
Free Snake Relocation Directory on Facebook
Colorado Parks and Wildlife: (303)866-3437
Educational Resources
Colorado State Parks’ Rattlesnake Management Information
University of Colorado’s Museum of Natural History
Colorado Partners in Amphibian and Reptile Conservation
Articles Similar to Our Colorado Snake Identification Guide
If you’re interested in identifying more of North America’s native reptiles, have a look at our:
- U.S. Turtles Identification Guide
- Florida Snake Identification Guide
- Texas Snakes Identification Guide
- California Lizards Identification Guide
You can also check out our other articles on snakes – we have comprehensive guides to learn from!
Have you ever seen a wild snake in Colorado? Tell us about your cold-blooded experience in the comment section below!
