Northern Watersnake

A non-venomous, but aggressive, species of snake found in eastern Colorado.

Northern Watersnake, Jessica Bolser, FWS

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About This Species

Front portion of body crossbanded, rear portion crossbanded or blotched; pattern sometimes obscure, especially in large individuals; belly often with red or orange blotches; upper scales keeled, with a pair of tiny pits near the tip of each scale; anal scale divided; more than two scales between eye and nostril.

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Physical Characteristics

Maximum total length about 150 cm (59 inches), but very few in Colorado exceed 100 cm (39 inches); males usually less than 62 cm (24 inches) snout-vent length, females usually less than 82 cm (32 inches) snout-vent length; end of tail often missing.

Range

Along streams in the plains region of eastern Colorado at elevations below about 5,500 feet. Fairly common.​​

Habitat

Creeks, rivers, reservoirs, ponds, marshes, flooded meadows, and canals along major drainage systems; rarely found away from the immediate vicinity of water. Usually seen swimming along marsh edges or basking in semi-secluded onshore sites, on log jams in streams, on mats of algae, on clumps of dead cattails, or up to several feet high in woody streamside vegetation; sometimes under rocks or wood at the water’s edge.

Diet

​The Northern watersnake forages in shallow water for fishes, adult and larval amphibians, and sometimes crayfish or other small animals.

Reproduction

Females give birth to their young usually between mid-August and mid-September. Litters can range from four to 100, but are usually 20-40.

Reptile
Nerodia sipedon