6 Types of Water Snakes Found in Iowa! (ID Guide)

What kinds of water snakes can you find in Iowa?

Common Water Snakes in Iowa

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 6 water snakes that live in Iowa.

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

Types of Water Snakes found in Iowa

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 is common to find in eastern Iowa!

 

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 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!

YouTube video

 

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.

 

Northern Watersnake populations are considered to be stable in Iowa. However, like many other water snakes, this species faces habitat loss and degradation. Unfortunately, they are also commonly killed by people out of fear.


#2. Plain-bellied Watersnake

  • Nerodia erythrogaster

Water Snakes species that live in Iowa


Identifying Characteristics:

  • Adults have a thick body and range from 24 to 40 inches in length.
  • Solid coloration of gray, brown, olive, or black.
  • As the name suggests, they have a plain unmarked underside varying from red to yellow.
  • Also called Redbelly, Yellowbelly, Copperbelly, or Blotched Watersnake.

 

The Plain-bellied Watersnake can be found near various water sources, including rivers, floodplains, lakes, ponds, and wetlands. This species spends an unusual amount of time on land compared with other water snakes found in Iowa. Especially during hot, humid weather, they can be found in woodlands quite far from a water source.

 

Plain-bellied Watersnake Range Map

plain bellied watersnake range map

Credit: Virginia Herpetological Society

 

They feed on BOTH aquatic and terrestrial prey, including crayfish, fish, salamanders, frogs, and other amphibians. Another unusual feature of this species is that they will sit and wait to ambush their prey, especially on land. Almost all other water snakes actively hunt and chase their victims!

 

The females give birth in August or September to live young. Litters average 18 young, but one of 55 has been reported! These unique water snakes can also produce offspring via parthenogenesis, a form of asexual reproduction in which an embryo develops without fertilization by sperm.

YouTube video

 

If captured, they release a foul-smelling musk and are not afraid to bite! Plain-bellied Watersnakes are eaten by largemouth bass, egrets, hawks, and sometimes other larger snakes.

 


#3. Diamond-backed Watersnake

  • Nerodia rhombifer

Common Water Snakes species in Iowa

Identifying Characteristics:

  • Adults range from 30 to 48 inches in length.
  • Coloration is brown, dark brown, yellowish, or olive green. Look for a dark chain-like pattern down the back.
  • Thick body with a yellow belly that has dark half-moons.

 

The Diamond-backed Watersnake can be found in Iowa in a variety of freshwater habitats. They generally prefer slow-moving bodies of water with overhanging vegetation such as ponds and swamps and slow rivers and streams.

 

These water snakes are common in their range and can be spotted on overhanging branches looking for prey, which mainly include frogs and fish. Once they grab their target, they haul it to shore and wait for it to die before consuming it. This behavior is unique as most other water snakes consume their prey alive.

Diamond-backed Watersnake Range Map

diamond backed watersnake range map

Credit: U.S. Geological Survey, Department of the Interior/USGS

 

When disturbed, Diamond-backed Watersnakes will quickly flee into the water and dive below the surface to swim away. If captured, they will bite and release a foul-smelling musk from glands near the base of their tail.

 

They are relatively common and aren’t considered a threatened species. Unfortunately, they are sometimes killed out of ignorance. People often mistake them for venomous cottonmouths and rattlesnakes.

 


#4. Graham’s Crayfish Snake

  • Regina grahamii

grahams crayfish snake range map

Identifying Characteristics:

  • Adults range from 18 to 28 inches in length.
  • Coloration is a dull brown, yellowish-brown, or gray.
  • Look for yellowish-tan stripes down the sides and sometimes a faint tan stripe down the middle of the back.

 

This water snake is rather reclusive and hard to find in Iowa.

 

Look for Graham’s Crayfish Snakes in slow-moving bodies of water such as ponds, prairie streams, marshes, and roadside ditches. They prefer areas with abundant vegetation, rocks, logs, and other debris along the water’s edge, which allows them to hide from predators. Like other water snakes, they can commonly be seen basking on branches overhanging the water.

Graham’s Crayfish Snake Range Map

graham's crayfish snake range map

Credit: U.S. Geological Survey, Department of the Interior/USGS

 

As the name suggests, Graham’s Crayfish Snakes primarily feed on crayfish. They hunt exclusively for individuals that recently molted and temporarily have soft bodies. However, they’ll also prey on fish and amphibians, including tadpoles and frogs.

YouTube video

 

Like many other water snakes, this species is often mistaken for cottonmouths and killed, even though they are MUCH smaller.

 


#5. Western Ribbon Snake

  • Thamnophis proximus

western ribbon snake

Identifying Characteristics:

  • Adults range from 17 to 50 inches in length. A slender snake with a long tail!
  • Coloration is blackish, brown, or olive with three light-colored stripes; one down the back and one down each side.
  • The sides and top of the head are dark, and the upper lip is whitish.

Did you see a VERY long, slender snake in Iowa near freshwater?

If so, it was probably a Western Ribbon Snake! This semi-aquatic reptile is rarely found far from a water source. They typically occupy brush-heavy areas around streams, lakes, ponds, and other water bodies. You may also spot them basking on rocks, flat vegetation, and dry sandy areas near water.

western ribbon snake range map

The Western Ribbon Snake has an incredible, unique hunting technique. As they move over land, they make quick, light thrusts of their head and upper body in different directions in sequences of three. It’s similar to a strike, but with their mouth closed. This action disturbs resting frogs, which alerts them to their location. From there, this snake uses its superior speed to catch its prey.

When they feel threatened, they flee into the water or hide in thick brush. Their coloration provides superb camouflage in dense, brushier areas. If grabbed, Western Ribbon Snakes rarely bite but will thrash around, defecate, and release musk from their anal glands. This species can also shed its tail to escape, but unfortunately, it doesn’t regenerate like some lizard species.


#6. 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 Iowa 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.


Do you need additional help identifying a water snake?

Try this field guide!

 


Which of these water snakes have you seen in Iowa?

 

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