Examine the snake for a green shade across the snake's entire body. Grass snakes benefit from blending into grass, which matches the green color of the snake.
Look for vertical streaks or pyramids rising up from the snake's belly to approximately half of the snake's thickness.
Look for a thin white or yellow band that circles the snake's neck.
Look for a black border along the tail-ward side of the white or yellow band.
Consider the snake's overall length, which can reach up to 2 1/2 feet and about 1 to 1 1/2 inches in circumference.
Consider the habitat where you found the snake, including grass, woods or gardens. Additional areas common to the grass snakes include ponds or streams.