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.

Photo Caption: When northern water snakes have a reddish, banded coloration they often fool observers into thinking they are copperheads. Alternately, nearly black specimens can cause people to believe they have seen a water moccasin (also called a cottonmouth).

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.

Eliza Lord

I'm a Greenville, SC native (the Appalachian foothills) who wears the hats of Greenville Master Gardener & Upstate Master Naturalist. I love to write about food and sustainability.

12 thoughts on “How to Identify a Northern Water Snake”

  1. Anna - May 13, 2010 8:58 am

    Have you ever noticed a cucumber smell around water snakes? Lucy cornered one a few years ago and I smelled cucumber very strongly, but the internet thinks only copperheads smell like cucumbers. (This was definitely not a copperhead — I got a good look after freaking out that our dog was about to get bit by a poisonous snake.)
    .-= Anna´s last blog ..Anna: May flowers =-.

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - July 1, 2010 11:45 am

      I’ve noticed a cucumber smell around water before… I always thought Lake Hartwell smelled like cucumber or watermelon. I don’t think I’ve sniffed enough snakes to know if it could be attributed to them. :)
      .-= Sustainahillbilly´s last blog ..How to Be Even More Excited About Home Than Wherever You Vacationed Garden Photo Essay =-.

  2. Meredith - May 13, 2010 11:40 pm

    Um… this picture looked enough like a copperhead that I’d still stay away from it. I probably am not going to get close enough to check the shape of its head, LOL. I guess I am a sissy. 😉

    I saw plenty of water moccasins growing up in Georgia, but I have yet to see one in South Carolina. Didn’t know that about their range!
    .-= Meredith´s last blog ..wordless wednesday: welcome =-.

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - July 1, 2010 11:55 am

      Yeah… that’s like the identifying feature of brown recluse spiders where they have 6 eyes instead of 8. I don’t know many people who will lean in to count!
      .-= Sustainahillbilly´s last blog ..How to Be Even More Excited About Home Than Wherever You Vacationed Garden Photo Essay =-.

  3. Meredith - May 13, 2010 11:49 pm

    Oh, what a great resource that third link is, though! Thanks for that. I’ve already id’ed a snake we saw in our yard last season. :)
    .-= Meredith´s last blog ..wordless wednesday: welcome =-.

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - July 1, 2010 12:24 pm

      Cool!
      .-= Sustainahillbilly´s last blog ..How to Be Even More Excited About Home Than Wherever You Vacationed Garden Photo Essay =-.

  4. Bill - June 6, 2010 2:40 pm

    Just bumped into your blog. It’s terrific. Up here in New England we have a good northern water snake population. They like to climb trees and hang out, literally, above the water. The one caution is that they have a very painful bite, nonpoisionous, but it can become infected none the less. Happened to me as a kid carrying one home with it tucked under my arm as I rode my bicycle. Pretty dumb, and a heck of a way to learn respect.

    Bill:www.wildramblings.com

    1. Sustainahillbilly
      Twitter: appalachianfeet
      - July 1, 2010 12:49 pm

      Yikes! I think most larger snakes can hurt pretty bad, venom or not. Sometimes I hear about childhood “lessons” that I’m relieved I didn’t learn firsthand… and this is one of them. :)
      .-= Sustainahillbilly´s last blog ..How to Be Even More Excited About Home Than Wherever You Vacationed Garden Photo Essay =-.

  5. water snakes - October 17, 2011 12:37 pm

    I must say that you have given nice info on how to identify water snakes. This is very useful and can help people to identify them quickly.

  6. jeff - October 30, 2012 2:57 am

    I was walking my dog one dayu on the trail n we got down there and she kept sniffing the ground. Then i happen to look to the side my the grass and it was a cotton mouth snake coming accross the path going to the water. If she didn’y look real good while he was sitting there you wood have thought it was a branch from a tree.

  7. ken
    Twitter: ken_talbott
    - September 22, 2013 5:08 pm

    Just found a HUGE northern water snake about a mile from my lake. Recent rains probable encourage it to roam a bit farther afield. It is a cool day and this handsome fellow was sunning himself in my driveway. After observing for 15 minutes I was forced to pick him up and move him to the grass

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