‹ Compare two snakes
Diamond-backed Watersnake vs Northern Watersnake
(c) Kara Matthews, some rights reserved (CC BY)
Diamond-backed Watersnake
Nerodia rhombifer
Non-venomousMartyn Drabik-Hamshare, no rights reserved
Northern Watersnake
Nerodia sipedon
Non-venomousThe quick way to tell
Look at the back pattern. The Diamond-backed Watersnake has a dark chain-link net that leaves pale diamonds down the back. The Northern Watersnake has crossbands up front that break into blotches, with no chain.
Pattern ★ This settles it
Dark chain-link or diamond-mesh pattern on olive to yellow-brown, with dark side bars.
Crossbands up front breaking into blotches toward the tail; reddish half-moons on the belly.
Head
Narrow head with a pale, heavily marked jaw.
Narrow head barely wider than the neck; flattens when threatened.
Eyes
Round pupil, eyes set high on the head; no heat-sensing pit.
Round pupil, eyes set high on the head; no heat-sensing pit.
Pits
None. There is no pit between the eye and the nostril.
None. There is no pit between the eye and the nostril.
Tail
Thick-based, tapering; no rattle.
Tapers evenly; no rattle.
What it does
Hangs in brush above water and drops in when approached.
Basks on docks and banks; drops into water, bites hard if grabbed.
Where it lives
Central US: Mississippi valley from Illinois and Indiana south to the Gulf, west across Texas, Oklahoma and Kansas.
Eastern and central US from Maine and Ontario south to the Carolinas and the Gulf states (just into the Florida panhandle), west to Colorado, Nebraska and Oklahoma; introduced in California.