Description: The diamondback water snake is predominantly brown, dark brown, or dark olive green in color, with a black net-like pattern along the back, with each spot being vaguely diamond-shaped. Dark vertical bars and lighter coloring are often present down the sides of the snake. In typical counter-colored fashion, the underside is generally a yellow or lighter brown color, often with black blotching. The dorsal scales are heavily keeled, giving the snake a rough texture. The dorsal scales are arranged in 25 or 27 rows at midbody. There are usually 3 postoculars. Adult males have multiple papillae (tubercles) on the under surface of the chin, which are not found on any other species of snake in the United States. Nerodia rhombifer grow to an average total length (including tail) of 30–48 inches. The record total length is 69 inches. Neonates are often lighter in color, making their patterns more pronounced, and they darken with age.
Habitat: The diamondback water snake is one of the most common species of snake within its range. It is found predominantly near slow-moving bodies of water such as streams, rivers, ponds, or swamps.
Range: The diamondback water snake is found in the central United States, predominantly along the Mississippi River valley, but its range extends beyond that. It ranges within the states of Texas, Oklahoma, Kansas, Iowa, Louisiana, Arkansas, Missouri, Illinois, Indiana, Tennessee, Mississippi, Georgia, and Alabama.
Diet: Diamondback water snakes are diurnal hunters, feeding primarily during daylight hours. They feed on a variety of aquatic species including frogs, toads, tadpoles, small fish, minnows, salamanders, and crayfish. They readily feed on carrion as well.
Reproduction: Like other Nerodia species, the diamondback water snake is ovoviviparous. Adults breed in the spring, and gravid females give birth in the late summer or early fall. Neonates are around 8–10 inches in length. Though its range overlaps with several other species of water snakes, interbreeding is not known.
Status: Listed as Least Concern in view of its wide distribution, presumed large population, and because it is unlikely to be declining fast enough to qualify for listing in a more threatened category.
Subspecies: Three with just one found in our region:
Unnamed Diamondback Water Snake - (Nerodia rhombifer blanchardi) Northern Diamondback Water Snake - (Nerodia rhombifer rhombifer)
Unnamed Diamondback Water Snake - (Nerodia rhombifer werleri)
Disclaimer: ITIS taxonomy is based on the latest scientific consensus available, and is provided as a general reference source for interested parties. However, it is not a legal authority for statutory or regulatory purposes. While every effort has been made to provide the most reliable and up-to-date information available, ultimate legal requirements with respect to species are contained in provisions of treaties to which the United States is a party, wildlife statutes, regulations, and any applicable notices that have been published in the Federal Register. For further information on U.S. legal requirements with respect to protected taxa, please contact the U.S. Fish and Wildlife Service.