Colorado Snakes Identification Guide: Profiles, Pics, & Tips

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 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

Eastern Massasauga Rattlesnake with its rattle showing surrounded by grass, rocks and dead leaves — The Eastern Massasauga Rattlesnake, pictured, looks nearly identical to its Western counterpart.

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

Western Terrestrial Garter Snake on salt flats — This Western Terrestrial Garter Snake is likely from the Southeastern region of Colorado because of its distinct dorsal stripe.

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

Desert Kingsnake on top of rocks — This Desert Kingsnake is so lightly speckled that it appears nearly patternless.

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.