Eastern 1/3 of the state. The northern watersnake is most
common in clear, rocky streams. There are two subspecies in Oklahoma,
the northern watersnake, N.s. sipedon, found primarily in
the northern counties along the Kansas border, and midland water
snake, N.s. pleuralis, found elsewhere within its range.
They are the only watersnake in Oklahoma that lacks a yellow belly,
but instead is white and marked with red marbling or "half
moons". Like all watersnakes, they are found near water, but
may wander far from water in search of food, which includes fish,
frogs, salamanders, and crustaceans.