There are no true water snakes in North Dakota, but there is still plenty of slithering activity happening in the state’s aquatic ecosystems. Semi-aquatic snakes make up a part of the reptilian fauna living near and within the state’s bodies of water.
These slimy creatures may not quite meet the definition of a water snake, but they are certainly capable of surviving in wetter environments. So, while you won’t find any true water snakes, there is still plenty of serpentine life thriving in North Dakota’s waters. Let’s take a look at the semi-aquatic species that can be found in the state and learn more about these remarkable reptiles.
What are True water Snakes?
True water snakes (genus Nerodia) are a group of aquatic, non-venomous snakes that are all native to North America. They are characterized by their dark coloration, which helps them blend in with their aquatic habitats and avoid predation.
Water snakes have adapted flatter heads, wider bodies, and keeled dorsal scales, all of which help them move swiftly and efficiently through the water. They all primarily feed on fish, frogs, and other small aquatic animals.
All species of water snakes are viviparous, meaning that they give birth to live young rather than laying eggs. Generally, water snakes can be found near rivers, wetland areas, streams, lakes, ponds, and marshes.
The nine species of the Nerodia genus include:
- Nerodia sipedon
- Nerodia erythrogaster
- Nerodia rhombifer
- Nerodia fasciata
- Nerodia cyclopion
- Nerodia clarkii
- Nerodia taxispilota
- Nerodia paucimaculata
- Nerodia harteri
North Dakota is by far, one of the driest states in the United States. It receives an average of just 17 inches of rainfall annually. This semi-arid climate, especially in the west, does not provide a suitable habitat for water snakes to thrive and survive, which is likely why they are not found in North Dakota.
What are semi-aquatic snakes?
Semi-aquatic snakes are adapted to living in wetter habitats, and their range may extend into more aquatic settings. Even though these snakes can thrive in environments with deeper waters, they generally return to drier areas when necessary. While almost all semi-aquatic species feed on fish, amphibians, and other aquatic animals, they may also feed on small mammals and birds.
In North Dakota, there are two species of semi-aquatic snakes – the common garter snake and the plains garter snake.
1. Common garter snake
- Scientific name: Thamnophis sirtalis
- Length: 16-26 inches
- Range: Found throughout North Dakota
The common garter snake is a non-venomous species that has a black or brown body with yellow-colored stripes down the center of its back and two on each side. With the space between the stripes often checkered with red blotches. Its ventral scales are cream or gray, without any pattern. The upper lip may have thin, black stripes on the edges of the scales and red coloring on their tails’ undersides.
During hibernation, garter snakes huddle together in large groups in the hibernaculum. The males emerge first, and when a female comes out of hibernation, many males will try to mate with her, forming a “mating ball,” i.e., a large group of males surrounding the female.
After breeding, these snakes may travel long distances to foraging grounds but always return to the same hibernation sites in the fall. This is because finding suitable hibernation sites is difficult; therefore, hundreds or thousands of snakes use the same den.
Females give birth to approximately 20 live young (they are viviparous snakes), but the litter size can range from 12 to 40. The snakelets are around 7.48-9.06 inches at birth and take two or three years to reach maturity.
They feed on frogs, earthworms, toads, small salamanders, insects, and minnows. This broad diet allows them to adapt to changing environmental conditions and maintain their energy requirements. And given they are neither constrictors nor venomous, they rely on their camouflage and quick reflexes to capture food.
They are generally non-aggressive but will not hesitate to bite and thrash around if handled. The bites are not considered dangerous but may still cause pain. Furthermore, these snakes have scent glands from which they can release a foul-smelling musk whenever they feel threatened.
There is at least one subspecies of garter snake found in North Dakota, the red-sided garter snake.
2. Plains garter snake
- Scientific name: Thamnophis radix
- Length: 15-28 inches
- Range: Found throughout North Dakota
The Plains Garter snake is a non-venomous species with a gray, brown, or reddish body with three stripes running along its length. The middle stripe is usually yellow or orange, while the two side stripes have a bluish-green hue. A double row of spots can also be found between the stripes, and the snake’s underside is usually yellow or white.
These snakes can be found in riparian areas, marshes, ponds, and wet meadows. They mainly feed on amphibians, such as frogs and toads. They also eat small mammals, birds, fish, earthworms, slugs, and salamander larvae.
Like common garter snakes, plains garter snakes also hibernate together in large groups. The males emerge first, and when a female comes out of hibernation, many males will try to mate with her leading to the formation of a mating ball.
Plains garter snakes are ovoviviparous, meaning the eggs hatch inside the female’s body, and she gives birth to between 20 and 40 live young, although larger litters of up to 90 have been reported.
Common questions about North Dakota’s garter snakes
1. Do any of the semi-aquatic snakes take care of their young?
No, none of the garter snakes in North Dakota are known to take care of their young. Their snakelets are born ready to take care of themselves and must fend for themselves from the moment of birth.
2. Are the bites from garter snakes dangerous?
No, given that none of these snakes are venomous, their bites are not considered dangerous. However, they may still cause pain and discomfort, as their rows of small, sharp teeth can break the skin.
3. How long do they live?
The lifespan varies depending on their habitat. In the wild, common garter snakes have been known to live for two to four years, while plains garter snakes may live for as long as eight years. Captive snakes tend to live longer than those in the wild due to better living conditions and food sources. In captivity, they can live up to 20 years.
4. What is the conservation status of North Dakota’s garter snakes?
The conservation status of North Dakota’s garter snakes is currently listed as “Least Concern”. Both the common and plains garter snakes have a wide distribution and are not endangered or threatened. However, their populations could be affected by urbanization and habitat destruction due to human activities.