How to Determine Venomous From Nonvenomous Snakes

The monochrome garter snake is not poisonous.

It's important to know how to identify a poisonous snake, even if you live in a area that is not normally inhabited by them. You don't always need to see a snake to identify it. A snake can also be identified by its bite markings, choice of prey or habitat. Knowing how to identify a poisonous snake may save a life.

Instructions

1. Know about snakes that are indigenous to your area. Learn what characteristics your local venomous snakes have (See References 1 and 2).

2. 

   Poisonous snakes have eyes like a cat.

   Take note of the snake's eyes. The eyes of non-venomous snakes have round pupils. Venomous snakes typically have an elliptical pupil, like cat's eyes (See Reference 1).

3. 

   A Western Diamondback snake in the desert.

   If possible, look carefully at the colors or markings of the snake. Stripes running from head to tail indicate a nonpoisonous snake. Diamond-shapes usually indicate a poisonous snake especially if they are in three colors (See References 1 and 2).

4. 

   A rattlesnake poised to strike.

   Listen for any warnings the snake might give off, like a hiss or a rattle. A snake that makes a noise when you approach or displays any aggression is more likely a venomous snake (See References 1 and 2).

5. Use bite marks left by the snake to determine if it is venomous or not. A venomous snake will leave two distinct puncture wounds. The affected area will also swell and discolor very quickly (See Reference 3).

6. Be aware of your immediate surroundings and watch how the snake uses them. A snake that moves through a wet area and stays on the top of the water is almost certainly a venomous snake (See Reference 1).

Tips & Warnings

• To make your yard or the surrounding area less hospitable to snakes, keep the grass and other shrubs short and well-trimmed. Snakes like to hide in thick roots and tall grasses. Line your property with mothballs to scare off the rodents that often make up a snake's diet. Snakes are also repelled by ammonia, which doesn't harm them (See Reference 1).

• There are more than two types of deadly snakes in the United States, but the Diamondback Rattler and the Coral Snake are the most deadly. The Rattler is easy to identify by sound, but the diamond red pattern on the back of the Coral Snake leads it to be often confused with the harmless garter snake. If the snake has yellow diamonds as well as red and black ones, it is a Coral snake (See Reference 2).

References

• Snake Education: General Snake Information
• Snake Education: Snake Bites