From Ohio History Central
The northern water snake (Natrix sipedon sipedon) is abundant and can be found throughout Ohio around any permanent body of water, including lakes, ponds, swamps, marshes, streams, and rivers as habitats.
The species breeds between April and June, producing 8 - 99 live young, averaging 15 - 30.
It is stocky and comes in a variety of colors and patterns ranging from reddish brown to brown-black with dark blotches on its back and sides. Its body length ranges from 22 - 53 inches. It looks very similar to the venomous water moccasin, or cottonmouth, neither of which lives in Ohio. Despite this fact, the northern water snake is frequently killed because of their appearance.
It's frequently seen sunning itself on logs and rocks, but will go into the water when disturbed. As a defensive measure, if necessary, it will bite viciously. A water snake bite will bleed a lot because of a substance in the snake's saliva that slows the clotting of blood.
Northern water snakes typically eat frogs, small fish, salamanders, small turtles, crustaceans, and small mammals.