NORTHERN WATERSNAKE (Nerodia sipedon sipedon)

Learning to identify the VERY VARIABLE Northern Watersnake:
-herpnet says: Generally, they have light brown or reddish markings on a brown or grayish ground color. The markings consist of bands on the neck that become blotches on the back. There are smaller alternating spots on the sides and the ones closest to the ventral scales have a tendency to be red or reddish. (example of reddish scales on the sides, close to the ventral (bottom) are in a photo below)
http://www.herpnet.net/Iowa-Herpetology/index.php?option=com_content&task=view&id=55&Itemid=26
-habits (including when cornered) and food:
http://www.herpnet.net/Iowa-Herpetology/reptiles/snakes/northern-water-snake-nerodia-sipedon/
-several resources with more information:
http://www.paherps.com/herps/snakes/northern-water-snake/
http://www.virginiaherpetologicalsociety.com/reptiles/snakes/northern-watersnake/northern_watersnake.php
http://srelherp.uga.edu/snakes/nersip.htm

juv. photo, scroll down:
https://www.marylandbiodiversity.com/viewSpecies.php?species=878
positive id of juv by John White of Virginia Herpetological Society:
http://animal.memozee.com/view.php?tid=1&did=11262
link from David where more juvs can be found:
http://www.californiaherps.com/snakes/pages/n.sipedon.html

there are 3 subspecies, more info can be found by searching on individual names:
-Nerodia sipedon insularum - Lake Erie water snake - one example description:
https://ecos.fws.gov/ecp0/profile/speciesProfile?spcode=C04P
-Nerodia sipedon pleuralis - midland water snake - one example description:
https://en.wikipedia.org/wiki/Nerodia_sipedon_pleuralis
-Nerodia sipedon williamengelsi - Carolina water snake - one example description:
https://www.flickr.com/photos/nathanphotography/9646204453/
and
http://www.naherp.com/viewrecord.php?r_id=47055