Welcome to the world of Colorado snakes. With around thirty different snake species, it’s surprising that most Colorado residents and tourists barely come into contact with six of them on a day to day basis.
Of course the topic of Colorado snakes often leads to questions about the state’s venomous snakes. There are three, all rattlesnakes, Prairie rattlesnake, Western rattlesnake, and the Massasauga rattlesnake. Prairie rattlesnakes are common throughout the state, including mountain areas below the tree line. So, yes there is danger.
For the record, tourists visiting during the ski season need not worry about any of the three venomous Colorado snakes. All snakes are cold blooded animals and they hibernate during the winter ski season. There’s always an exception to the rule of course. If it’s a seventy degree spring day in the mountains and the ski season is coming to an end, there may be a rattlesnake that’s come out to lay in the sun for the afternoon. That’s the exception not the rule.
Tourists concerned about snakes during the summer hiking and camping season need only take a few precautions. For example, only one snake, the Western Terrestrial Garter Snake (Thamnophis elegans), is a resident of the Rocky Mountain National Park. Park elevation is too high to support a snake population.
Other snakes do live in the Mountains. However, their habitat is often limited to spaces marked in thousand feet elevations. Again, for example, the Great Plains Gartersnake (Thamnophis radix) inhabits most of eastern Colorado and can be found on the eastern slopes of the Rocky Mountains up to elevations of about 6,000 feet.
Bullsnakes, Milksnakes, Racers, Ratsnakes and the Prairie Rattlesnake also follow a similar habitat pattern. This small group of snakes might rightfully be labeled the most common of the Colorado Snakes. Along with a gartersnake or two, they are the six most familiar to Colorado residents.
Colorado geography accounts for most of that seeming contradiction. The eastern part of the state consists of the prairies or grasslands common to the Midwest. The Rocky Mountains define the geography from north to south down the center of the state. The western areas of Colorado consist mainly of high desert or shrub lands areas.
By a large margin most of the state’s two dozen or so snakes live in the eastern prairies. Only a portion of that snake population shows overlap into the Rocky Mountains, and by default into the larger metropolitan areas on the eastern borders of the mountains such as Colorado Springs, Denver and Fort Collins.
The Great Plains Ratsnake pictured at the top of the page is a great example. Their territory extends through much of the southeast plains of Colorado to the borders of Colorado Springs. A population also made its way to the state’s western high desert border areas.
Kingsnakes and Milk Snakes
Colorado’s kingsnakes and milk snake populations provide another example of the geographical divide that explains Colorado snakes. The picture shows the black body of the California King Snakes. It’s really the West Coast variant of the Eastern King Snake. A very small population lives in the southwest corner of the state.
It color contrasts nicely with Colorado’s most common family member the milk snake. A few different subspecies live everywhere in the state except for the highest mountain elevations.
Speckled Kingsnakes (Lampropeltis holbrooki) complete the geographical divide common for Colorado snakes. They are a Midwest species with a very small population in the southeast.
Racers and Whipsnakes
As mentioned earlier, Racers (Coluber constrictor) ranks as one of the most common of Colorado snakes. It’s very adaptable and found everywhere except for the highest mountan elevations.
In fact eleven different subspecies inhabit almost every state in the lower 48 states. Color is a common name applied to many of the species. The Colorado racer is better known as the Yellow-bellied racer. Populations exist in the west and east of the state.
Whipsnakes (Coluber flagellum), another common species come in a variety of body colors, depending on the subspecies. Red racers as they are called, live in the southeast part of the state.
Striped Whipsnakes (Masticophis taeniatus) range through most of the high desert on lower foothills of the Rocky Mountains.
The body stripes and long, thin body akes it difficult to misidentify it.
Four different gartersnake species live in Colorado. Three of them are common the the Denver and Fort Collins metropolitan areas.
Red markings on the side of the Common Garter Snake (Thamnophis sirtalis) add a bit of color to the otherwise bland looking snake. Unlike the name, they are not the most common of the state’s gartersnakes. They are found in the northeast part of the state with a range that spills into the Fort Collins and Denver metropolitan areas.
In these metropolitan areas they share space with the Western Terrestrial Garter Snake (Thamnophis elegans), the most common of the state’s gartersnakes.
The black-necked gartersnake (Thamnophis cyrtopsis) is typically described as a Southwest species. It’s range does extend to the southeast a bit south of Colorado Springs.
Plains Gartersnake (Thamnophis radix) occupy most areas east of the Rocky Mountains, including the areas around Colorado Springs, Denver and Fort Collins.
The Northern Watersnake (Nerodia sipedon) is probably the species with the widest range. It’s found in all states east of the Rocky Mountains. Body color changes depending on age and location, so often it’s not the best field identification clue. Knowing that it’s the only species in the state is the best clue.
More Colorado Colubrids
Gopher Snakes or Bullsnakes (Pituophis melanoleucus) are another common Colorado snakes. They can grow large and bulky. Because they somewhat resemble rattlesnakes and they tend to do a lot of basking in the sun, they tend to scare people. Approach the snake with caution and look for a rattle. If no rattle, think Bullsnake.
- Long-nosed Snake (Rhinocheilus lecontei)
- Groundsnake (Sonora semiannulata)
- Smooth Greensnake (Opheodrys vernalis)
- Lined Snake (Tropidoclonion lineatum)
- Glossy Snake (Arizona elegans)
- Great Plains Ratsnake (Pantherophis emoryi)
- Plains Hog-nosed Snake (Heterodon nasicus)
- Desert Nightsnake (Hypsiglena chlorophaea)
- Chihuahuan Nightsnake (Hypsiglena jani)
- Ring-necked Snake (Diadophis punctatus)
- New Mexico Threadsnake (Rena dissectus)
- Plain’s Blackhead Snake
- Smith’s Black-headed Snake (Tantilla hobartsmithi)