Comparison of Cottonmouth and Water Snake

herp-ap01.jpg
Cottonmouth: The eyes cannot be seen from the top of the head
herp-nf01.jpg
Water Snake: The eyes can be seen from the top of the head
 
herp-ap02.jpg
Cottonmouth: The pupil of the eye is a catlike vertical slit, and there is a pit on the side of the head between the eye and the nostril.
herp-nf02.jpg
Water Snake: The pupil of the eye is round, and there is no pit on the side of the head between the eye and the nostril.
 
herp-ap03.jpg
Cottonmouth: The top of the head is relatively flat.
herp-nf03.jpg
Water Snake: The top of the head is relatively rounded.
 

The watersnake illustrated here is the banded watersnake, Nerodia fasciata.