The genus Natrix, found in both hemispheres, comprises about 15 North American species and sub-species. They are rough-scaled, non-venomous serpents living in the vicinity of water and producing living young, often in large broods. They are closely related to the garter snakes. Some of them are commonly known as "'Water moccasins." The different species usually range between two and four feet in length. They are especially abundant in the southern states. Among the smaller species of the genus is one known as Graham's watersnake Natrix grahamii (Baird and Girard). It seldom reaches a yard in length and appears not to be common in Iowa. The general color of this species is dark brown above, with a median light line bordered narrowly with black: and with a creamy white stripe low on the sides, edged below by a conspicuous zig-zag line at the place where dorsal scales meet ventral plates. Ventrally there is usually a partial median line of dark clots on an otherwise unmarked light surface.
Proceedings of the Iowa Academy of Science
©1930 Iowa Academy of Science, Inc.
Guthrie, J. E.
"Freak Color Inheritance in Graham's Watersnake,"
Proceedings of the Iowa Academy of Science, 37(1), 375-377.
Available at: https://scholarworks.uni.edu/pias/vol37/iss1/102