With owning a pond comes the inevitable occurrence of encountering all kinds of wildlife. Most will be harmless creatures looking for water, but you will certainly come across a snake or two. While snakes certainly have an unsavory reputation, they can be beneficial creatures to have around. They control populations of rodents and other pests that might otherwise enter your home. However, it is important to know the difference between a harmless water snake and a poisonous water moccasin, as a false identification can have a devastating result. Unless you can confidently tell the difference between harmless and poisonous snakes, it’s best to always treat all snakes as poisonous.
There are several key differences that can help identify which of these snakes you may encounter. The most noticeable difference is the shape of the head. A water snake’s head will be thin and flow smoothly into the neck, while a water moccasin’s head is much thicker and the neck much narrower when it meets the head. Also, water moccasins are commonly known as “cottonmouths” because the inside of their mouth is white, which they often display as a sign of defense.
The second difference would be the shape of the body. Water snakes tend to have a long, slender body type, while water moccasins have a short, stocky build. However, this alone should not be used as a key identifier, as body shape can vary from snake to snake. Also, in some cases, the water moccasin may be lighter in color. However, both snakes can range from brown to black, so again, color should also not be used alone to draw a conclusion about the identity of the snake.
Next is the shape of the pupil. If you are close enough to see the snake’s pupil (and we suggest you avoid that close), water snakes have a round pupil and water moccasins have a vertical pupil.
In terms of the behavior of both snakes, the water moccasin in general appears much more aggressive with a predominant head, stocky body, and vertical pupil. Water moccasin stings have been known to cause severe symptoms, including bleeding, numbness of extremities, skin discoloration, and even death. Therefore, as mentioned above, unless you can safely, easily, and properly identify a snake, it is best to treat it as a venomous snake to avoid any danger.