Yellow-Bellied Watersnake (Yellow-Bellied Water Snake)
A medium-sized, heavy-bodied, dark-colored, semiaquatic snake with a plain yellow belly. It is mainly gray, greenish gray, or brownish black, with little or no pattern. The belly is plain yellow with some orange showing on some individuals. The young are strongly patterned with brown dorsal and lateral blotches that may be joined to form transverse bars.
Similar species: The blotched watersnake (Nerodia erythrogaster transversa), a subspecies, occurs in southwestern and western Missouri. It is gray or greenish brown with brown blotches along the back and sides; the belly is plain yellow with a wash of orange, especially under the tail. In summer, it often ventures away from water onto land. Watersnakes are often confused with the venomous western cottonmouth and needlessly killed. Cottonmouths are more heavy-bodied, with a larger, chunky head and a facial pit between the nostril and eye; they are darker and have a light line from the eye to the corner of the mouth.