3 Types of WATER Snakes Found in Colorado! (2024)

What kinds of water snakes can you find in Colorado?

water snakes in Colorado

Is it just me, or do you also find water snakes fascinating? There’s something about the way they move across the water that is incredibly interesting. Whenever I am near a pond, marsh, or other body of water, I make sure to look for any water snakes moving about.

Today, you are going to learn about 3 water snakes that live in Colorado.

The species below are considered either aquatic or semi-aquatic, which means that it’s very likely that you will see them actively swimming or extremely close to water, such as sunning themselves on a bank.


#1. Northern Water Snake

  • Nerodia sipedon sipedon

water snakes in Colorado

Identifying Characteristics:

  • Adults range from 24 to 55 inches in length.
  • Coloration is pale grey to dark brown with reddish-brown to black bands.
  • Large adults become darker with age and appear almost plain black or dark brown.
  • Females tend to be larger than males, and coloration is most vivid in juvenile and wet individuals.

This water snake can be found in eastern Colorado!

Northern Watersnakes prefer slow-moving or standing water such as ponds, lakes, vernal pools, marshes, and slow-moving rivers and streams. They’re most often seen basking on rocks or logs in or near the water.

Common Watersnake Range Map (Northern Water Snakes are a subspecies)

common watersnake range map

Credit: Virginia Herpetological Society

These water snakes primarily feed on fish and amphibians by hunting during the day along the water’s edge and shallow water. They grab their prey and quickly swallow while it’s still alive!

When disturbed, Northern Watersnakes flee into the water to escape. However, if grabbed or captured, they’re quick to defend themselves. They will release a foul-smelling musk from glands near the base of their tale, flatten their body, and strike the attacker.

While non-venomous, they can deliver a painful bite!

Their saliva contains a mild anticoagulant that can cause bites to bleed, making the injury appear worse. These important defense mechanisms help water snakes survive predators such as raccoons, snapping turtles, foxes, opossums, other snakes, and birds of prey.


#2. Plains Garter Snake

  • Thamnophis radix

plains garter snake

Identifying Characteristics:

  • Adults average 36 inches in length.
  • The coloration is gray-green with a distinctive orange stripe down the back and a greenish-yellow stripe down each side.
  • Distinct light yellow spots on the very top of the head!

Plains Garter Snakes are almost always found in eastern Colorado in prairies and grasslands near freshwater sources. They have a fairly large population and adapt well to human-modified landscapes. You may spot them near abandoned buildings, trash heaps, or vacant lots.

plains garter snake range map

This species is considered one of the most cold-tolerant of all snakes! In fact, they will even come out of hibernation on warmer winter days.

Plains Garter Snakes feed primarily on earthworms, slugs, and small amphibians. However, they have also been observed preying on small mammals and birds, including the Eastern Meadowlark and Bank Swallow.


#3. Black-necked Garter Snake

  • Thamnophis cyrtopsis

black necked garter snake

Identifying Characteristics:

  • Western Black-necked Garter Snakes are dark olive with an orange-yellow stripe down the back and a yellow to white stripe down each side. It can be up to 42 inches long.
  • Eastern Black-necked Garter Snakes are smaller and only grow up to 20 inches in length. They have a checkered pattern of black and yellow on their body, between their three stripes.
  • Both subspecies have a gray head, contrasting strongly with the body. In addition, there is a dark blotch on each side of the neck.

Black-necked Garter Snakes are found in many habitats, including desert scrub, plains, arid grasslands, and pine-oak woodlands. They’re almost always associated with water sources such as streams, ciénegas, and cattle tanks.

black necked garter snake range map

There are two subspecies of this snake: the Western AND Eastern. They look different (see photo above), but they also behave uniquely. The Western subspecies (Thamnophis cyrtopsis cyrtopsis) are water snakes and most often found in the water. The Eastern (Thamnophis cyrtopsis ocellatus) subspecies prefer to live on DRY LAND very close to water.

In Colorado, you will only find the WESTERN Black-necked Garter Snake.

The Black-necked Garter Snake’s preferred prey is frogs, toads, and tadpoles, including poisonous species like the Sonoran Desert Toad. However, they have been known to feed on a wide range of other prey, including earthworms, skinks, salamanders, crustaceans, and birds.


Do you need additional help identifying a water snake in Colorado?

Try this field guide!


Which of these water snakes have you seen in Colorado?

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