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Are There Water Snakes in Colorado?

Colorado is known for its varied landscapes. Not only is the state home to the Rocky Mountains, but it has deserts, nearly 24.5 million acres of forest, and the biggest mineral hot springs pool in the world! You can find many animals throughout Colorado, including 29 species of snake. Clearly, there are plenty of snakes in The Centennial State, but does Colorado have any water snakes?

You can find one species of true water snake in Colorado: the Northern water snake. These aquatic snakes can be found around many bodies of water in Colorado and are especially common in the eastern half of the state. Read on to learn more about the Northern water snake and other Colorado snakes.

Colorado’s Northern Water Snake

Northern water snake basking
Northern water snake basking | image by via Flickr | CC BY 2.0
  • Scientific name: Nerodia sipedon
  • Length: 24” to 55”
  • Venomous: No

Northern water snakes have long, thick bodies and dark scales. Snakes can be brown, gray, or black and usually have cross-like markings along their bodies. Most snakes become darker with age, and many older snakes are entirely black.

Colorado is right at the edge of the Northern water snake’s range, which is why it’s primarily found in Northeastern and Southeastern Colorado. It can also be found near the waters of the Colorado River. They feed on other aquatic creatures, like fish and amphibians, and are known to swallow their prey whole!

The breeding period for the Northern water snake spans from April to May, and new snakes are born between August and October. Mothers can give birth to anywhere from five to 60 snakes! Young snakes are around 7 to 10 inches long, but they grow quickly. When fully grown, female snakes tend to be larger than males.

People sometimes mistake Northern water snakes for cottonmouths, which aren’t found in Colorado. Northern water snakes are non-venomous and aren’t aggressive, but they will bite humans if they feel threatened. Snakes may also release a strong, skunk-like odor from their scent glands to scare predators away.

Although Colorado’s winters are moderate, most Northern water snakes enter a period of inactivity called brumation in November. During this period, snakes often retreat to abandoned animal dens, such as beaver lodges and muskrat burrows. It’s common for snakes to group together so that it’s easier for them to retain heat.

Snakes usually emerge from their water dens in March or April, and they can often be seen basking near the water throughout spring and summer. While experts aren’t sure how long the Northern water snake can live in the wild, species in captivity have recorded lifespans up to 9 years.

Other Snakes In Colorado

The Northern water snake is Colorado’s only true water snake, but all snakes are able to swim! These are some of the other snakes you might spot in the waters of Colorado.

1. Coachwhip

Coachwhip | image by vet-adrianh-orozco via Flickr | CC BY 2.0


  • Scientific name: Masticophis flagellum
  • Length: 42” to 60”
  • Venomous: No
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The coachwhip snake is one of Colorado’s largest and longest snakes, with some snakes measuring more than 5 feet. They’re frequently spotted in Southeastern Colorado and prefer dry and open habitats.

Coachwhips are usually red, pink, or light brown. They hunt actively during the day and eat birds, rodents, and other small mammals.

2. Smooth Green Snake

Smooth green snake
Smooth green snake | image by Peter Paplanus via Flickr | CC BY-SA 2.0
  • Scientific name: Opheodrys vernalis
  • Length: 14” to 22”
  • Venomous: No

It’s easy to spot these small, slender snakes thanks to their bright green scales. The smooth green snake is found throughout Colorado’s Western Slope and is usually seen near bodies of water. Due to its size, it feeds on smaller prey, such as insects and spiders.

3. Great Plains Rat Snake

Great plains rat snake
Great plains rat snake | image by Peter Paplanus via Flickr | CC BY 2.0
  • Scientific name: Pantherophis emoryi
  • Length: 24” to 36”
  • Venomous: No

The Great Plains rat snake has pale scales and is covered in dark brown spots. As its name suggests, it loves to feed on rats and other rodents.

It can be found in West, Central, and Southeastern Colorado and prefers to live near streams, rivers, and other bodies of water. During warmer months, it’s active at night and hides under rocks and logs during the day.

4. Common Garter Snake

Common garter snake
Common garter snake | image by Greg Schechter via Wikimedia Commons | CC BY 2.0
  • Scientific name: Thamnophis sirtalis
  • Length: 18” to 26”
  • Venomous: No

You can find these striped snakes throughout Northern Colorado, but they’re most likely be spotted near streams and flood plains. They’re opportunistic eaters and feed on various prey, including frogs, small birds, and earthworms.

Although they’re not dangerous to humans, the saliva of these snakes is toxic to many small animals. Garter snakes are also closely related to water snakes.

5. Midget Faded Rattlesnake

Midget Faded Rattlesnake
Midget Faded Rattlesnake| image by Robb Hannawacker
  • Scientific name: Crotalus oreganus concolor
  • Length: 20” to 30”
  • Venomous: Yes

This pit viper is one of a few venomous snakes found in Colorado. Although it’s usually a docile snake, its bite can be extremely toxic.

It’s exclusively found in West-Central Colorado, where it lives in areas with plenty of rock cover. Snakes have pale-brown or yellow-brown scales and are able to blend in with their environment.