Recommended Free Tools
Some links on this page are affiliate links: if you buy through them we may earn a commission, at no extra cost to you.
Colorado snakes include three medically significant rattlesnakes and many nonvenomous species that help control rodents, insects, and other prey. The exact statewide total depends on the source: the University of Colorado Museum of Natural History lists 29 species, while Colorado State University Extension reported 25 in 2025. This guide follows the museum’s 29-species roster and explains how to recognize the main look-alikes, where snakes occur, and what to do if you encounter one. For photographs, compare the entries with the University of Colorado Museum’s Colorado snake pages; do not approach or handle a snake to get a better view.
Which snakes in Colorado are dangerous to people?
The three Colorado snakes the University of Colorado Museum identifies as medically significant venomous species are prairie rattlesnakes, western massasaugas, and midget faded rattlesnakes. All are rattlesnakes. Most of the state’s other snakes are not medically dangerous to people, although a few produce low-risk venom or toxic saliva that helps subdue prey.
As an Amazon Associate I earn from qualifying purchases.
Free tools Windows power users keep installed
One-click scans. No signup required.
“Venomous” does not always mean a serious human health risk. Colorado Parks and Wildlife describes the common garter snake as mildly venomous but non-dangerous to people, and says the plains garter snake’s venom is not toxic to humans. Ring-necked snakes use venom on prey but are harmless to people and other mammals, according to CPW. The western hognose and night snake also use toxic or venomous saliva on prey; ordinary encounters with them are not comparable to rattlesnake bites.
Coral snakes and cottonmouths do not occur in Colorado. A milksnake’s red, black, and pale bands can suggest a coral snake, and a northern water snake may be mistaken for a cottonmouth, but neither comparison means the absent species is present. A snake’s appearance alone is not a reason to handle it.
Popular on Amazon
- Dog multivitamins chewable for skin & coat : Dog multivitamin is rich in Omega-3 fatty acids and vitamin E,which can relieve skin allergies,dryness,itching and other problems.Multivitamin for dogs nourishes skin follicles.Long-term consumption of dog vitamins multivitamin can make dog hair stronger and smoother,and reduce coat loss.The COQ10 in dog multivitamin chewable can resist oxidation and delay cell aging.Dogs with skin injuries can eat dog vitamins and supplements to promote wound healing
- Dog multivitamin relieves joint inflammation: Dog vitamins for hip and joint can supplement high-quality MSM, glucosamine, and chondroitin sulfate to promote cartilage development and repair. Long-term consumption of dog multivitamins chewable can enhance the elasticity and toughness of joint cartilage, improve joint flexibility, and move more freely. Dog multivitamin chews can reduce joint friction and relieve joint pain. Dog vitamins and supplements can prevent and improve dog joint problems
- Dog multivitamin chews are good for the gut: Vet-endorsed formula dog vitamins and supplements made from natural ingredients.Dog vitamins multivitamin chewables contain a rich blend of probiotics to support intestinal and digestive health.Dog vitamins for small dogs can regulate the balance of intestinal flora,help calcium absorption,and promote bone development.Dog multivitamins chewables improve energy metabolism,converting food into energy, making dogs more energetic in their daily activities
- Dog multivitamin chews protect overall health:Senior dog vitamins and supplements help improve blood circulation and prevent cardiovascular disease.Dog multivitamins chewable support normal liver function,promote liver detoxification,and improve negative mood.For dog with heart problems and older dog,taking dog vitamins and supplements in moderation is an auxiliary health care measure.Dog vitamins multivitamin helps enhance white blood cell activity,improve immunity,prevent infection and disease
- Dog multivitamins chewable promote brain development: The DHA in krill oil in multivitamin for dogs is an important component of the brain and retina. Dog vitamins and supplements can improve dog cognitive ability. When training puppies to learn basic commands, puppies who are properly supplemented with dog vitamins multivitamin will behave more intelligently and improve memory.Dog supplements & vitamins can prevent and relieve eye problems such as dry eyes and tear stains, and keep eyes healthy
How can I identify a snake in Colorado without getting close?
Start with distance and location, not a close inspection. From a safe position, note whether the snake has a rattle, its overall pattern and approximate size, and the habitat; those clues can narrow the possibilities without requiring you to touch or corner it.
Colorado State University Extension lists six features associated with rattlesnakes: a rattle, fangs, facial pits, vertical elliptical pupils, one row of scales beneath the tail, and a broad triangular head with a narrow neck. Several features are difficult or unsafe to assess on a live snake. Never approach one to check its pupils, scales, or fangs; if you cannot tell what it is from a safe distance, treat it as a rattlesnake and give it room.
The Tool Desk
Outbyte PC Repair FREERepair Windows errors before they cause bigger problemsFix Now →Outbyte Driver Updater FREEScan for outdated or missing drivers - takes under a minuteDriver Scan →A bullsnake or gopher snake can vibrate its tail and imitate the sound of a rattler, sometimes against dry leaves or other ground cover. A tail vibration by itself does not prove that a snake has a rattle. Conversely, the absence of a sound is not proof that a nearby snake is harmless. Some rattlesnakes may not rattle before a person notices them.
Other useful clues include body pattern, habitat, time of activity, and the snake’s range. For example, a fast, daytime snake in southeastern Colorado could be a coachwhip, while a small snake seen at night in rocky or sandy country could be a night snake. These are clues, not guarantees. The museum’s species descriptions and photographs can help with later identification from a safe observation or a photograph taken from a safe distance.
Also popular on Amazon
- Joint Health Supplement for Dogs: Cosequin is the #1 vet recommended retail joint health supplement brand, supporting joint health in dogs for over 25 years
- Contains Glucosamine for Dogs: Cosequin contains glucosamine hydrochloride (FCHG49) and sodium chondroitin sulfate (TRH122), plus methylsulfonylmethane (MSM). This unique combination of ingredients supports healthy joints
- For Any Breed or Size: Whether you have a young or senior dog, a small or large breed, Cosequin helps support their joint health
- Tasty Chews for Daily Use: Cosequin comes in a tasty chewable tablet, making daily administration easy and convenient
- Exceptional Quality: Cosequin is backed by science, undergoing thorough quality inspections to ensure your dog receives a safe, high-quality product. It is manufactured in the United States with globally sourced ingredients
What snakes live in Colorado? A guide to all 29 on the museum roster
The following roster follows the University of Colorado Museum of Natural History’s list. Range notes are general: a species may be localized, and habitat or county boundaries do not reliably identify an individual snake. “Low-risk venom” below refers to venom or toxic saliva used on prey, not a claim that handling a snake is safe.
- Coachwhip (Masticophis flagellum) — Found in southeastern Colorado. This large, fast-moving daytime snake may strike if cornered, but it is not a rattlesnake and is not medically venomous. Look for: a slender, active snake; do not interpret defensive behavior as evidence that it is a rattler.
- Prairie ringneck snake (Diadophis punctatus) — Associated with southeastern canyon bottoms and riparian areas. Look for: an orange neck ring and a colorful belly. Ring-necked snakes use venom to subdue prey, but CPW says they are harmless to people and mammals.
- Smooth green snake (Liochlorophis vernalis blanchardii) — A Western Slope species. Look for: a uniformly grass-green body. It eats insects and is nonvenomous.
- Plains black-headed snake (Tantilla nigriceps) — Occurs in foothills and grasslands, including around Boulder. Look for: a small, secretive snake with a dark head. It is not one of Colorado’s rattlesnakes.
- Variable ground snake (Sonora semiannulata) — Small and found in varied habitats. Look for: variable tan, orange, red, or black markings. It feeds on arthropods and is nonvenomous.
- Western hognose snake (Heterodon nasicus) — Look for: its distinctive upturned snout. When threatened, it may put on a dramatic defensive display or feign death. Its saliva is toxic to prey, but it is not considered medically dangerous to people. Leave it undisturbed.
- Western terrestrial garter snake (Thamnophis elegans) — Widespread in Colorado except the northeast, often near water. Look for: the striped pattern typical of garter snakes. It is not a medically significant venomous species.
- Lined snake (Tropidoclonion lineatum) — A secretive snake of canyon bottoms. Look for: a striped back and dotted belly. It is nonvenomous and is more likely to be overlooked than encountered in the open.
- Prairie rattlesnake (Crotalus viridis) — Occurs in many Colorado habitats and is medically significant. Look for: a rattle, keeled scales, and the typical pit-viper build, but do not approach to confirm any feature. Give it a wide berth.
- Great Plains rat snake (Pantherophis emoryi) — Found in southeastern and west-central Colorado, often near permanent water. Look for: a nonvenomous snake that hunts rodents. Do not confuse a large or defensive snake with a rattler based on behavior alone.
- Night snake (Hypsiglena torquata jani) — A small, nocturnal snake. Its venomous saliva helps subdue prey, but it is not considered dangerous to people in ordinary encounters. Look for: its small size and night-time activity; do not pick it up to identify it.
- Common kingsnake (Lampropeltis getula) — Occurs in remote southeastern and southwestern corners of the state. Look for: a nonvenomous snake that may eat other snakes, including rattlesnakes. That does not make it safe to handle or a substitute for keeping distance from rattlesnakes.
- Great Basin gopher snake (Pituophis catenifer deserticola) — A Western Slope subspecies of gopher snake. It is nonvenomous and may vibrate its tail when alarmed. Look for: a large snake that can be mistaken for a rattler, especially when the tail is moving.
- Common garter snake (Thamnophis sirtalis) — Found around northern floodplains and streams. Look for: a striped snake near water. CPW calls it mildly venomous but non-dangerous to humans; it is not a medically significant rattlesnake.
- Glossy snake (Arizona elegans) — Found in eastern grasslands and canyon bottoms. Look for: shiny scales. It may strike repeatedly when defending itself, but it is nonvenomous to people.
- Bullsnake (Pituophis catenifer sayi) — One of Colorado’s most widespread and largest snakes, reaching about six feet. It is a nonvenomous rodent predator. Look for: its size and possible tail-vibrating display; vibration does not mean it has a rattler.
- Blackneck garter snake (Thamnophis cyrtopsis) — The least common of Colorado’s four garter snake species, found in the south near permanent water. Look for: the dark neck area and striped garter-snake form. It is not one of the medically significant venomous species.
- Texas blind snake (Leptotyphlops dulcis) — Restricted to the southeastern corner. This burrowing snake eats ants and termites. Look for: a small, wormlike body; it is nonvenomous and spends much of its time underground.
- Central Plains milk snake (Lampropeltis triangulum gentilis) — Widespread below about 8,000 feet, in habitats ranging from prairies and sandhills to canyons and woodlands. Look for: red or orange, black, and pale bands. It is nonvenomous. Colorado has no coral snakes, despite the superficial color resemblance.
- Western ribbon snake (Thamnophis proximus) — Has a small range in southeastern Colorado. Look for: cream and olive stripes. It is a nonvenomous garter-snake relative.
- Eastern yellow-bellied racer (Coluber constrictor flaviventris) — Found in eastern Colorado. A daytime-active racer may look brown, olive, or teal above, with a yellow belly. It is nonvenomous and can move quickly.
- Western yellow-bellied racer (Coluber constrictor mormon) — The western counterpart of the eastern racer, found in northwest and west-central Colorado. Look for: the racer’s slender build and plain coloration; it is nonvenomous.
- Northern water snake (Nerodia sipedon) — Colorado’s only water-snake species, found near permanent water in the northeast and southeast. It is sometimes mistaken for a cottonmouth, which does not occur in Colorado. A water-side location alone cannot identify a snake; observe from a distance.
- Striped whipsnake (Masticophis taeniatus; also listed by CPW as Coluber taeniatus) — Found in western Colorado’s semidesert, piñon-juniper, rocky slopes, and arroyos. It is fast, striped, and nonvenomous. Look for: the habitat and long, slender build, not a close-up examination.
- Western massasauga (Sistrurus catenatus) — A medically significant rattlesnake of dry, sandy southeastern habitats. It is smaller than many rattlesnakes and has a smaller rattle; twitching behavior is also described for this species. Treat it as dangerous and do not approach.
- Long-nosed snake (Rhinocheilus lecontei) — Found in the southeastern corner. This nocturnal, burrowing snake has black, red, and cream patterning. It is nonvenomous.
- Southwestern black-headed snake (Tantilla hobartsmithi) — Found in western canyon bottoms with sandy or rocky soil. It is a tiny arthropod eater and is not a medically significant danger to people.
- Midget faded rattlesnake (Crotalus oreganus concolor) — Restricted to far west-central Colorado, including Colorado National Monument. Smaller than prairie rattlesnakes, it still has medically significant venom. Do not approach because of its size.
- Plains garter snake (Thamnophis radix) — Found in eastern Colorado and along Front Range water corridors; it may also occur in residential areas, grasslands, and sandhills. Look for: a bright orange or yellow stripe down its back. CPW says its venom is non-toxic to humans.
Why do Colorado snake totals differ?
The University of Colorado Museum’s current webpage says Colorado has 29 snake species; Colorado State University Extension’s 2025 article gives a total of 25. The figures differ because sources may use different taxonomy or inclusion criteria, and the roster presented here follows the museum’s 29 names rather than treating every published total as interchangeable.
Classification and common names can also vary. For example, CPW lists the striped whipsnake as Coluber taeniatus, while the museum roster uses Masticophis taeniatus. When checking an identification, compare the common name, scientific name, description, and range rather than relying on one label alone.
What should I do if I see a snake on a trail?
Give it space and let it move away. The National Park Service’s guidance for Colorado National Monument is simple: if you see a snake on the trail, do not pick it up. That advice applies to any snake, not only one you think might be venomous.
Also popular on Amazon
- 8-in-1 Formula - Zesty Paws Multifunctional Bites are functional supplement chews with premium ingredients that support physical performance, antioxidants, hip & joint, heart, immune, skin, liver, & gut health for dogs of all ages, breeds, and sizes.
- Skin Health & Antioxidants – For animals with sensitive skin, this formula contains Cod Liver Fish Oil and Vitamin E to help maintain normal moisture and CoQ10 to help reduce oxidative stress.
- Hip, Joint & Performance Support - Each dog chew features OptiMSM, a premium form of MSM for muscular support, which works synergistically with the Glucosamine HCl and Chondroitin Sulfate in these chews for hip and joint support plus Cod Liver Oil and B-Complex Vitamins support normal physical performance.
- Gut Health & Probiotics - These chews also contain a six-strain Gut Health Blend (500 million cfu per chew) and a Digestive Health Blend to promote gut flora while supporting normal bowel function for dogs.
- Heart, Liver & Immune Health - Multifunctional Bites feature powerful antioxidants, premium CoQ10, Cod Liver Oil and Vitamins A, C, & E to promote healthy cardiovascular function, support liver health and enhance immune response.
- Stop and give the snake room; if it is close, remain still initially and then back away slowly.
- Do not try to move, catch, kill, or provoke it. A snake that feels cornered may defend itself.
- Watch where you step. Avoid reaching into rock crevices or brush, and do not step over a log or rock before checking the far side.
- Do not rely on a rattle as your only warning. A snake may be nearby without making a sound.
- On National Park Service land, follow the site’s rules. Colorado National Monument says all snakes there are protected and should not be disturbed.
Most Colorado snakes are nonvenomous, harmless, and beneficial, according to CSU Extension. They are predators in local food webs, eating prey such as rodents, lizards, amphibians, insects, and eggs. Leaving a snake alone is usually safer for people and better for the animal.
How can I reduce the chance of snakes around my home?
Make the area less attractive to snakes and their prey, and close off access to buildings. CSU Extension recommends removing brush and rock piles, keeping vegetation away from foundations, controlling rodents and insects, and sealing openings at least 1/4 inch wide.
For rattlesnake areas, Extension specifies a snake-proof fence made from 36-inch-high galvanized hardware cloth with 1/4-inch mesh. The fence should be buried 6 inches and slanted outward at 30 degrees. Fencing is a physical barrier, not a reason to approach a snake already inside it; keep people and pets away and seek help from an appropriate local wildlife professional if removal is necessary.
Rules about killing or disturbing snakes depend on location and species. CSU Extension reports that Colorado Parks and Wildlife allows killing a rattlesnake when necessary to protect life or property, subject to local ordinances, while nonvenomous snakes and certain rattlesnakes are protected as nongame wildlife except as specified by law. Check current county and municipal rules rather than assuming the statewide summary covers every situation. National park protections may be stricter.
Also popular on Amazon
- SYMBIOTIC DIGESTIVE ECOSYSTEM: Our dog probiotics build a 4-way digestive ecosystem: Digestive enzymes pre-break nutrients for easy absorption, while probiotics + prebiotics balance and nourish gut flora. Pumpkin helps dogs with a sensitive stomach maintain regular bowel movements. These layers go beyond ordinary probiotics, turning every meal into steady nourishment, digestive ease, and enduring energy*—so your dog stays balanced and full of life.
- TRIPLE IMMUNE SUPPORT: Gut health drives immunity, and our probiotics for dogs target it. Probiotics help maintain a balanced gut microbiome and support mucosal immunity, while plant antioxidants* (Rosemary & Green Tea) and natural Vitamin E help protect immune cells from daily wear and tear. Formulated for triple immune support - helping your dog stay vibrant and ready for everyday adventures.
- DUAL-ACTION SKIN & COAT NOURISH: True skin and coat health starts from within. Gut and immune support work in sync with Salmon and Flaxseed Oils (Omega-3 & 6) to nourish skin and coat from the inside out. This dual-action care promotes a soft, shiny, and glossy coat you’ll love to touch.
- PURE INGREDIENTS: We believe in complete ingredient integrity. Every batch of our dog probiotic chews is crafted in GMP-certified facilities using trusted, premium sources. They are free from grains, soy, and artificial additives. This commitment to safety and quality ensures a clean formula you can trust for your dog’s overall wellness.
- TASTE DOGS LOVE: Made with natural duck flavor, our probiotic chews are loved by most dogs, even picky eaters. Unlike other hard chews, these soft, easy-to-bite chews are perfect for puppies and senior dogs. They help support digestive comfort, gut balance, and skin & immune health: areas commonly affected by occasional diarrhea, seasonal allergies, itchy skin, or paw licking. A tasty daily chew your dog will love.
What should I do after a suspected rattlesnake bite?
Call 911 or your local emergency number and get to a hospital immediately. A suspected rattlesnake bite is an emergency; do not delay care to catch, kill, photograph, or identify the snake. Antivenom treatment is available for native U.S. pit vipers.
- Move away from the snake and stay as calm and still as possible.
- Remove rings, watches, shoes, or tight clothing near the bite before swelling makes them difficult to remove.
- Keep the bitten limb immobilized in a neutral position at or below heart level.
- Call emergency services and follow the dispatcher’s instructions while arranging urgent transport to a hospital.
Do not apply a tourniquet or ice, cut the wound, or try to suck out venom. Do not attempt to kill the snake: doing so risks another bite and does not improve treatment. If a photo can be taken without moving closer or delaying care, it may help, but medical evaluation takes priority.
Windows Errors? Fix Them Before They Spread
Repair common Windows errors and clear accumulated junk for a smoother, more stable PC - no reinstall needed.Free scan · no reinstallOutdated Drivers Are Slowing You Down
One free scan finds every outdated or missing driver and matches the right update for your exact hardware.Free scan · exact hardware matchWhere can I find a fuller Colorado snake field guide?
The Colorado State Publications Library’s Guide to the Snakes of Colorado is a further reference for species identification. The museum’s current snake pages provide individual species descriptions and photographs. These references can support identification and learning; neither replaces emergency medical care after a suspected venomous bite.
Frequently Asked Questions
Are there coral snakes or cottonmouths in Colorado?
No. Colorado Parks and Wildlife says coral snakes do not occur in the state, and the University of Colorado Museum says cottonmouths are not found here. A milk snake or northern water snake can resemble one of those species, so color or habitat resemblance is not proof of identity.
Also popular on Amazon
- COMPLETE 26-IN-1 DAILY WELLNESS FORMULA: Our advanced multivitamin for dogs is formulated to help support 26 vital nutritional areas as part of a daily routine. With essential vitamins A, C, D3, and E, these gummies help support the immune system and contribute to overall heart and brain health for dogs of all sizes.
- ADVANCED HIP AND JOINT MOBILITY SUPPORT: Formulated with Glucosamine HCl, Chondroitin, and MSM to help support cartilage health, joint flexibility, and everyday mobility — making them a great daily supplement for large breed dogs and active senior dogs.
- SKIN & COAT SUPPORT: Packed with Norwegian Salmon Oil and Biotin, our dog multivitamin helps nourish skin from within and supports a soft, glossy coat. Omega 3 fatty acids contribute to healthy skin and coat as part of a complete daily nutritional routine.
- PROBIOTICS & DIGESTIVE SUPPORT: Features a Six-Probiotic Blend (500 Million CFU) and Digestive Enzymes to help support gut health, smooth digestion, and nutrient absorption. Cranberry Powder is included as part of this comprehensive daily wellness formula.
- UNBEATABLE VALUE 250 COUNT JAR: Our 250-count jar provides lasting daily support in a delicious chicken flavor. Made in the USA in a GMP-certified facility, our soft chews are grain-free and suitable for puppies, adult, and senior dogs alike.
Are snakes protected in Colorado?
Some are, and protections vary by species and place. State rules, local ordinances, and stricter National Park Service requirements can all matter, so check the current rules for the exact location before taking action.
Can a bullsnake hurt my dog or cat?
Bullsnakes are nonvenomous, but a wild snake may bite if a pet corners or attacks it. Keep pets away and give the snake a route to leave rather than allowing an encounter to become a confrontation.
What should I do if my dog is bitten by a snake in Colorado?
Contact an emergency veterinarian immediately and describe the suspected bite and your pet’s location and condition. Do not try to treat the bite with ice, a tourniquet, cutting, or suction, and do not risk another bite by trying to catch the snake.
Leave a Reply