Northern Water Snake vs. Cottonmouth (Water Moccasin): Know the Difference

Northern Water Snake vs. Cottonmouth (Water Moccasin): Know the Difference

Location:

• Northern Water Snake – Found all over Massachusetts
• Cottonmouth – Found in the southern U.S., not in Massachusetts

Venomous?

• Northern Water Snake – No
• Cottonmouth – Yes

Body Shape:

• Northern Water Snake – Slender to moderately thick
• Cottonmouth – Heavier, more muscular build

Color Pattern:

• Northern Water Snake – Banded or blotchy; darkens with age
• Cottonmouth – Dark bands; juveniles have a bright pattern and yellow tail

Head Shape:

• Northern Water Snake – Narrow, oval
• Cottonmouth – Broad, triangular (classic “venomous” look)

Behavior:

• Northern Water Snake – May bite if handled, but prefers to flee
• Cottonmouth – Defensive and will stand its ground

Pupil Shape:

• Northern Water Snake – Round pupils
• Cottonmouth – Vertical, cat-like pupils

Mouth Color:

• Northern Water Snake – Normal pink or gray
• Cottonmouth – White interior (hence the nickname “cottonmouth”)