How to Identify a Northern Water Snake
If I had to guess which snake most commonly gets mistaken for water moccasins (also known as cottonmouths) or copperheads, I’d choose the northern water snake (Nerodia sipedon). They have many color variations as they darken with age, sometimes to a nearly black color. Between its swimming habits and its confusing markings it easily fools paranoid hikers and swimmers. Fortunately, they’re not dangerous to humans.
In addition to blackish-brown and coppery-red hues, northern water snakes can have tan, brown, and gray markings as well. I most often see them with a tan background and bands of red-clay orange that are wider on the back than they are towards the belly. In other regions of the country it is more common to see a brown or tan background with black or dark brown bands. In Paris Mountain State Park I’ve watched a handful of specimens ranging from nearly black to nearly red all feeding from the same shallow lake shore. The herpetologist I was with assured me it was all the same species.
Their bellies also vary, ranging from a more common cream color to orange. Juveniles are more vivid but generally have the same coloration as adults. They can reach up to 40″ in length.
Although there are some other species you may mistake a northern water snake for, you can be certain it isn’t poisonous by looking at its head. Both copperheads and water moccasins are pit vipers, which have distinctively diamond-shaped heads. With water moccasins you should also pay attention to their range. In spite of countless eyewitness accounts they’re not supposed to exist in the Appalachias and foothills.
It’s great to identify a non-venomous snake but you should still show it respect. Even if a snake is not dangerously poisonous to humans it can defend itself. Cornered snakes may still bite and their teeth are unpleasant. They can also musk you, which is the reptile version of being sprayed by a skunk.
Northern water snakes hunt along freshwater shorelines and swim in the shallow water to capture small aquatic life such as fish, frogs, salamanders, and insects. They will also eat mammals or birds if they can find and catch them. They’re commonly seen swimming through the water or sunning themselves next to the shore.
These live-bearing snakes mate in the spring and females give birth to up to 30 baby snakes in the fall.