Northern water snake The belly also varies in color. It can be white, yellow, or gray. Usually it also has reddish or black crescents. The northern water snake is nonvenomous and harmless to humans, but superficially resembles the venomous cottonmouth and is often killed unnecessarily as a result of this mistaken identity. The two can be easily distinguished by morphological traits: the water snake has a longer, more slender body and a flattened head the same width as the neck, round pupils, and no heat-sensing pits. The cottonmouth has a fatter body, a wedge-shaped head with prominent venom glands that are wider than
Brazos water snake Brazos water snake The Brazos water snake ("Nerodia harteri" ), also called commonly Harter's water snake, is a species of mostly aquatic, nonvenomous snake in the family Colubridae. The species is endemic to Texas in the United States. "N. harteri" is found only in central Texas in the Brazos River system. The preferred habitat of "N. harteri" is rocky areas along the Brazos River. Due to its limited range, "N. harteri" is considered to be a threatened species in the State of Texas. The specific name or epithet, "harteri", is in honor of American amateur herpetologist Philip Harter, who collected