Broad-Banded Watersnake

Image of a broad-banded watersnake
Scientific Name
Nerodia fasciata confluens
Colubridae (nonvenomous snakes) in the order Squamata (lizards and snakes)

The broad-banded watersnake is a medium-sized, semiaquatic snake with broad, irregular-shaped, dark blotches or bands. The blotches or bands may be brown, reddish brown, or black, and are separated by yellow or yellowish gray. There are normally 11–17 bands. Although their shapes are irregular, the bands or blotches are broadest on the back. Some of the bands may be connected. There is often a faint dark line running diagonally from the eye past the corner of the mouth. The belly is yellowish tan and boldly marked with black.

This nonvenomous snake will bite viciously and smear a foul-smelling musk if captured.

Similar species:

  • Missouri has four other species of watersnakes (Nerodia spp.). The restricted range, plus the the irregular dark blotches or bands separated by yellow or yellowish gray, and the black-marked belly, help distinguish the broad-banded watersnake from the others.
  • This and other watersnakes are often confused with the venomous northern cottonmouth (Agkistrodon piscivorus) and killed because of unwarranted fear. The cottonmouth has a distinctly triangular head, a sensory pit between the nostril and eye on either side of the head, and a light line from each eye to the corner of the mouth.
Other Common Names
Broad-Banded Water Snake

Adult length: 22 to 42 inches; occasionally to 62 inches.

Where To Find
Broad-Banded Watersnake Distribution Map

Mainly restricted to the Mississippi Alluvial Basin of southeastern Missouri.

In Missouri, broad-banded watersnakes are normally active between late March and October. In spring, they are most active during the daytime and are often seen resting on thick algal mats in wetlands. At other times of the year, especially during hot weather, this species is most active at night as it forages, though during the day it often basks in sunlight on logs or among branches above the water.

This species resides in and along the edges of cypress swamps, river sloughs, oxbow lakes, sluggish streams, and drainage ditches. Like other watersnakes, broad-banded watersnakes are good swimmers and use side-to-side undulations to swim quickly across the water’s surface. They will dive underwater to escape predators or search for food.

Broad-banded watersnakes usually overwinter in mammal burrows or under rock ledges, tree stumps, and logs, sometimes quite far from water.

Foods are mainly fish and amphibians such as salamanders, frogs, toads, and their larvae. They also sometimes eat crayfish.

This species has been and continues to be quite common within the remaining wetland habitats throughout the lowlands of southeastern Missouri.

Life Cycle

Courtship and mating mostly occur in April and May. Females give birth to live young during late July, August, or early September. A litter may include 6–83 young, with usually about 10–20 young. Larger females bear larger litters. Individuals become sexually mature within two or three years of life.

When threatened and not allowed to escape, this species will flatten its head and neck and try vigorously to defend itself. As with most of our watersnakes, although it is nonvenomous, it is pugnacious. When cornered, an individual will strike or bite viciously. When captured, watersnakes also excrete a foul-smelling musk from glands in the base of the tail that it is often mixed with feces and smeared on the captor.

For as long as there have been humans, snakes have captured our imaginations. In myth, religion, and story, snakes perform the role of seducer, sneak, guardian, healer, killer, and transformer. They symbolize power, wisdom, sexuality, and life itself, and have been worshiped and reviled.

In 1923, when zoologist Frank N. Blanchard formally described this snake for the first time, he used a specimen collected by Julius Hurter in April 1905 from Butler County, Missouri, as the type specimen. Born in Switzerland, Hurter had settled in St. Louis in 1866. Though he was an engineer and draftsman, he was a founder of the St. Louis Zoological Society and in 1911 published the first book on Missouri herpetology. He contributed much to our knowledge of Missouri's amphibians and reptiles.

Aquatic snakes like this one serve to check the populations of the fish and amphibians they eat. Meanwhile, they serve as food for the many animals that prey on them and, especially, their young. When born, these snakes are usually less than 10 inches long. Some snake-eating animals include herons, hawks, osprey, snapping turtles, otters, raccoons, large predatory fish such as pike and bass, and other snakes.

Snakes use organs in their tongues and mouths to detect odors and track their prey. Apparently, this works not only for land snakes but also for watersnakes like this one, making them efficient predators of the fish, frogs, and tadpoles they eat.

Media Gallery
Similar Species
About Reptiles and Amphibians in Missouri
Missouri’s herptiles comprise 43 amphibians and 75 reptiles. Amphibians, including salamanders, toads, and frogs, are vertebrate animals that spend at least part of their life cycle in water. They usually have moist skin, lack scales or claws, and are ectothermal (cold-blooded), so they do not produce their own body heat the way birds and mammals do. Reptiles, including turtles, lizards, and snakes, are also vertebrates, and most are ectothermal, but unlike amphibians, reptiles have dry skin with scales, the ones with legs have claws, and they do not have to live part of their lives in water.