California Reptiles & Amphibians

Nerodia fasciata - Southern Watersnake

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Range Introduction in California: Red

Introduced: not native to California.

Adult, Sacramento County. © Gary Nafis. Specimen courtesy of Eric Stitt

Adult, Sacramento County

Two adults breeding on top of
a log in a pond in Sacramento County

Adult, Sacramento County,
© Eric Stitt

Habitat, Sacramento County

Description

Nonvenomous

Considered harmless to humans, but the snake's saliva may produce inflammatory reactions around the site of a bite.

Size

Adults are generally 22 - 40 inches long (56 - 101 cm) and up to 60 inches (152 cm.)

Appearance

A dark, heavy-bodied snake with heavily-keeled scales. Yellowish to reddish-gray with 40 or more dark crossbands. Juveniles are paler with a stronger pattern than adults. Old snakes may be almost entirely solid dark brown. There is a dark stripe extending from the eye to the corner of the mouth.

Behavior

Active during the day, and also at night. If threatened, may emit a strong-smelling musk and feces from its cloaca, flatten its body and strike repeatedly. Basks in the sun at water's edge on logs or overhanging limbs, moving into dens along banks in cold weather. Will leave the water and travel overland a mile or more in search of food.

Diet

Eats fish, frogs, salamanders, crayfish.

Reproduction

Live-bearing.

Range

Introduced in and around Lake Natoma in the city of Folsom, Sacramento County.

According to Michael Fuller of the Nerodia Working Group, a reproducing population of N. fasciata has existed in Harbor City for several years. While the snakes key out to N. f. pictiventris morphologially, preliminary mDNA results (as of 9/08) suggest that they are Nerodia clarkii, or possibly hybrids of N. clarkii and N. f. pictiventris. The habitat is a freshwater lake, typical of that used by N. fasciata, while N. clarkii typically inhabit brackish waters.

Habitat

Occurs in and around permanent bodies of water, especially those bordered by woods.

Conservation Issues (Conservation Status)

Spread of this snake downstream into the Sacramento Valley could possibly threaten populations of the already endangered Giant Gartersnake, Thamnophis gigas.

Taxonomy
Family	Colubridae	Colubrids
Genus	Nerodia	American Watersnakes
Species	fasciata	Southern Watersnake
Original Description
Nerodia fasciata - (Linnaeus, 1766) - Syst. Nat., 12th ed., Vol. 1, p. 378 from Original Description Citations for the Reptiles and Amphibians of North America © Ellin Beltz
Meaning of the Scientific Name
Nerodia - Greek - nereis - name of sea nymph fasciata - Latin - banded - refers to the banded pattern on dorsum from Scientific and Common Names of the Reptiles and Amphibians of North America - Explained © Ellin Beltz
Alternate Names
Southern Water Snake
Related or Similar California Snakes
T. s. fitchi - Valley Gartersnake T. gigas - Giant Gartersnake
More Information and References
California Nerodia - a website about Nerodia found in California. Natureserve Explorer California Dept. of Fish and Game The Southern Watersnake (Nerodia fasciata) in Folsolm California (PDF) Balfour, P. S., and E. W. Stitt. 2002. Geographic distribution: Nerodia fasciata fasciata. Herpetological Review 33:150. Conant, Roger, & Collins, Joseph T. A Field Guide to Reptiles and Amphibians Eastern and Central North America Third Edition. Houghton Mifflin Company, 1998. Bartlett, R.D., & Alan Tennant. Snakes of North America - Eastern and Central Regions. Gulf Publishing Co., 2000.

Conservation Status
The following status listings come from the Special Animals List which is published several times each year by the California Department of Fish and Game. This non-native snake is not listed on the Special Animals List.
Organization	Status Listing
U.S. Endangered Species Act (ESA)
California Endangered Species Act (CESA)
California Department of Fish and Game
Bureau of Land Management
USDA Forest Service
Natureserve Global Conservation Status Ranks
World Conservation Union - IUCN Red List