(Agkistrodon piscivorus piscivorus)
This is a large, venomous, semi-aquatic snake. When it opens its mouth, the distinctive white interior is displayed. It grows to average lengths of 30-48 in. (76-122 cm) and may reach 74 in. The back is olive, brown or black with black crossbands that extend onto the belly. The belly is cream with patches or streaks of black. Older adults may be uniformly dark. The head is triangular and flattened on top. Juveniles have the same patterns as adults but are brighter, have more distinct crossbands, body color may be more pinkish, and the tip of the tail is yellow. This snake is fond of basking on a rock, log, or stump during the day. If approached, it will stand its ground, or crawl away very slowly. When standing its ground, this species will coil, slowly vibrate its tail, and open its mouth wide to show the white inside. Males are known to perform a combat dance. This species is generally not aggressive, but will not hesitate to strike if molested. It emits a musk from a gland at the base of the tail when captured. The nonvenomous northern water snake is often mistaken for the cottonmouth, but it has crossbands that are not wider at the ends, no vertical pupil, no pit on the face. The northern water snake can be identified by observing that the crossbands near the head of the snake do not widen at the ends. Also, when swimming, most of its body is below the water and only the head shows when motionless, unlike the cottonmouth, which swims with the entire body on the surface of the water.
None have been found north or west of Colonial Heights. Most known populations occur south of the James River. This is a semiaquatic snake found in lowland habitats, including swamps, freshwater and brackish marshes, ponds, ditches, streams, rivers, and forested and grassland areas next to wet areas. It is often found in cultivated fields adjacent to swamp or sluggish streams.
This species hunts on land or in the water for a variety of fish, reptiles, amphibians, small mammals, and invertebrates. Prey animals are usually grabbed and held while the venom works.