Blue Ridge Foothills & Lakes Virginia Master Naturalists

When I was growing up in the southern part of Roanoke County, fourth and seventh grade history and geography were all about Virginia. We learned names and dates and places . . . and snakes.

There are three types of poisonous snakes in Virginia, we learned quite specifically. Copperheads can be found all over the state, we were told, and rattlesnakes in the mountains, where we lived, and the cottonmouth water moccasin in the southeastern swamps. These three snakes are pit vipers, so we were given information on their fangs, vertical eye slits and the heat-sensing eye-pits between eyes and nostrils, should we be unfortunately close enough to notice these features. But we southwestern Virginia kids didn’t have to worry much about the cottonmouth water moccasin, it was said, because it is never, NEVER found north or west of Colonial Heights.  

Now, all these years later, I live at Smith Mountain Lake, and any number of times I have heard people tell of seeing cottonmouths in the lake. Can’t be so, I always think, or else my teachers Mrs. Cary and Mrs. Flora would have told me. But why do folks think they see cottonmouths, I have wondered. Could they really be there? Is it that the lake, which was quite new when I was in grade school, has lured those snakes westward? Could it be climate change? 

I had no answer until I took BRFAL’s Virginia Master Naturalist class. Nell Fredericksen gave us a fascinating class on herpetology. I asked her the burning question, and she had the answer.

They are not seeing cottonmouths, she said. They are seeing the Northern Water Snake. It has a white mouth, like the cottonmouth, but people are not close enough to see that it is not a pit viper. Another clue is its swimming style. The Northern Water Snake’s body is underwater, with its head up like a periscope. The cottonmouth does a sidewinder style of swimming on the surface.

The Northern Water Snake, found all over the eastern US, can also be mistaken for a copperhead on dry land. My first close encounter with a Northern Water Snake was when I saw one in mortal combat with a catfish. The snake, which did look like a copperhead, tried to pull the fish out of the water onto the bank, heaving it up the rocks a few inches at a time, until the catfish responded by flopping back into the water, dragging the snake behind it. This back and forth duel went on for more than an hour, giving us plenty of time to ID the snake. Sure enough, round eyes, no eye pits. We couldn’t see the mouth as it was tightly clenched over the fish’s back.  In the end, the catfish pulled free and escaped, while the snake lay exhausted on the bank, where we could see that it had rows of teeth.

So yes, the Northern Water Snake has a white mouth and can be mistaken for two different pit vipers at a distance. It is well known for a nasty attitude and I’m not saying it won’t try to bite you if you annoy it. But no fangs, round eyes, no eye pits, non venomous.  And not a cottonmouth.