The Nonindigenous Occurrences section of the NAS species profiles has a new structure. The section is now dynamically updated from the NAS database to ensure that it contains the most current and accurate information. Occurrences are summarized in Table 1, alphabetically by state, with years of earliest and most recent observations, and the tally and names of drainages where the species was observed. The table contains hyperlinks to collections tables of specimens based on the states, years, and drainages selected. References to specimens that were not obtained through sighting reports and personal communications are found through the hyperlink in the Table 1 caption or through the individual specimens linked in the collections tables.

Nerodia fasciata fasciata
Nerodia fasciata fasciata
(Southern Watersnake)
Native Transplant

Copyright Info
Nerodia fasciata fasciata (Linnaeus, 1766)

Common name: Southern Watersnake

Taxonomy: available through www.itis.govITIS logo

Identification: There are currently three recognized subspecies (races) of southern watersnakes; the broad-banded watersnake, Nerodia fasciata confluens (Blanchard, 1923), the banded watersnake, Nerodia fasciata fasciata (Linnaeus, 1766), and the Florida watersnake, Nerodia fasciata pictiventris (Cope, 1895) (Conant and Collins, 1998; Boundy et al. 2000). All three subspecies usually have some kind of banded pattern (highly variable; rarely stripes) dorsally with keeled scales; the head has one anterior temporal scale, no subocular scale, usually only ten lower labial scales, and a dark line present from the eye to the angle of the jaw (Conant and Collins, 1998; Powell et al., 1998). Some kind of variable dark markings are present on the pale ventral scales (Powell et al., 1998). Nerodia f. confluens has only 11-17 broad, dark, dorsal crossbands (black, brown, or red) on a yellow or yellow-brown background; N. f. fasciata has 22-39 dorsal crossbands (red, brown, black, or red edged in black) on a background of tan, gray, yellow or sometimes red; N. f. pictiventris has a dorsal crossband pattern similar to N. f. fasciata (black, brown, or reddish) on a background of gray, tan or reddish, often with secondary lateral, dark spots between the crossbands, and "wormy," dark markings ventrally (Palmer and Braswell, 1995; Conant and Collins, 1998; Johnson, 2000; Tennant and Bartlett, 2000; Werler and Dixon, 2000). In all three subspecies the dorsal crossbands can become obscured in older, darker adults, with some individuals pigmented entirely black (Wright and Wright, 1957; Ernst and Barbour, 1989; Palmer and Braswell, 1995; Conant and Collins, 1998; Tennant and Bartlett, 2000; Werler and Dixon, 2000). The total lengths for the three races of southern watersnakes are:  560-1,143 mm (22-45 in) for N. f. confluens, 610-1,524 mm (24-60 in) for N. f. fasciata, and 610-1,588 mm (24-62.5 in) for N. f. pictiventris (Conant and Collins, 1998). The entire suite of features of southern watersnakes should be consulted in order to separate this species from other species of Nerodia.


All three subspecies of Nerodia fasciata, including a wide array of pattern and pigment variations, have been illustrated by numerous authorities (Wright and Wright, 1957; Smith, 1961; Mount, 1975; Behler and King, 1979; Martof et al., 1980; Ashton and Ashton, 1981; Smith and Brodie, 1982; Jackson, 1983; [Sievert] and Sievert, [1988]; Dundee and Rossman, 1989; Ernst and Barbour, 1989; Carmichael and Williams, 1991; Palmer and Braswell, 1995; Boundy, 1997; Tennant, 1997; Conant and Collins, 1998; Powell et al., 1998; Shine, 1998; Tennant et al., 1998; Behler, 1999; Johnson, 2000; Tennant and Bartlett, 2000; Werler and Dixon, 2000).

Size: total length of 560-1,588 mm

Native Range: Nerodia f. fasciata is indigenous to most of the U.S. Coastal Plain including North Carolina, South Carolina, Georgia, southern Mississippi, southern Alabama, and the Florida panhandle, but excluding peninsular Florida (Martof, 1956; Mount, 1975; Linzey, 1979; Martof et al., 1980; Ashton and Ashton, 1981; Lohoefener and Altig, 1983; Moler, 1988; Gibbons and Semlitsch, 1991; Palmer and Braswell, 1995; Tennant, 1997; Conant and Collins, 1998). This subspecies intergrades with N. f. confluens across southern Mississippi and southwestern Alabama (Mount, 1975; Lohoefener and Altig, 1983; Conant and Collins, 1998), and may occasionally hybridize with various subspecies of Nerodia sipedon (northern watersnake) in very limited areas of Georgia and the Carolinas (Conant and Collins, 1998).

Nerodia f. confluens is indigenous to the U.S. central lowlands including eastern Texas, extreme southeastern Oklahoma, Arkansas, Louisiana, extreme southeastern Missouri, western Mississippi, extreme western Tennessee and Kentucky, and the extreme southern tip of Illinois (Smith, 1961; Webb, 1970; Lohoefener and Altig, 1983; [Sievert] and Sievert, [1988]; Carpenter and Krupa, 1989; Dundee and Rossman, 1989; Boundy, 1997; Conant and Collins, 1998; Tennant et al., 1998; Dixon, 2000; Johnson, 2000; Werler and Dixon, 2000).


Nerodia f. pictiventris is indigenous to peninsular Florida and the extreme corner of southeastern Georgia (Martof, 1956; Stevenson, 1976; Behler and King, 1979; Ashton and Ashton, 1981; Moler, 1988; Carmichael and Williams, 1991; Tennant, 1997; Conant and Collins, 1998; King, 2000).

Hydrologic Unit Codes (HUCs) Explained
Interactive maps: Point Distribution Maps

Nonindigenous Occurrences:

Table 1. States with nonindigenous occurrences, the earliest and latest observations in each state, and the tally and names of HUCs with observations†. Names and dates are hyperlinked to their relevant specimen records. The list of references for all nonindigenous occurrences of Nerodia fasciata fasciata are found here.

StateFirst ObservedLast ObservedTotal HUCs with observations†HUCs with observations†
AZ201520161Lower Colorado
CA200920101San Gabriel

Table last updated 4/15/2024

† Populations may not be currently present.

Ecology: The taxonomy of N. fasciata has been studied or summarized by Lawson (1987), Lawson et al. (1991), and Boundy et al. (2000). A wide variety of reviews have covered the literature and natural history of southern watersnakes (Wright and Wright, 1957, 1962; Carpenter and Krupa, 1989; Ernst and Barbour, 1989; Gibbons and Semlitsch, 1991; Palmer and Braswell, 1995; Dixon, 2000; Tennant and Bartlett, 2000; Werler and Dixon, 2000).


Nerodia fasciata are typical aquatic snakes which inhabit any type of aquatic habitat and feed on aquatic vertebrates; mostly fish and amphibians (Ashton and Ashton, 1981; Ernst and Barbour, 1989; Palmer and Braswell, 1995; Tennant and Bartlett, 2000; Werler and Dixon, 2000). Mushinsky et al. (1982) found that southern watersnakes in Louisiana tended to eat fish while at a smaller body size, but included an increasing number of frogs in their diet as they grew larger. The largest individuals in their study ate mostly frogs (Mushinsky et al., 1982). Female N. fasciata give birth to a litter of 2-57 young in summer or fall (Ernst and Barbour, 1989; Palmer and Braswell, 1995; Johnson, 2000; Werler and Dixon, 2000; Balfour and Stett, 2002).

Means of Introduction: The means of introduction of N. f. fasciata in Sacramento, California, was not explored by Balfour and Stett (2002).


Nerodia f. fasciata in Sacramento, California, is an established reproductive population (Balfour and Stitt, 2002). It is not known if these snakes are invasive or will spread beyond this site.

Impact of Introduction: The impact of these snakes has not been explored. Given their diet of fish and frogs (see remarks below), the southern watersnake can potentially impact indigenous aquatic environments.

Remarks: When captured, southern watersnakes, like most Nerodia, defend themselves by biting vigorously and emitting jets of malodorous musk, often mixed with feces (Werler and Dixon, 2000).

References: (click for full references)

Ashton, R. E., Jr., and P. S. Ashton. 1981. Handbook of Reptiles and Amphibians of Florida. Part One. The Snakes. Windward Publishing, Inc., Miami. 176 pp.


Balfour, P. S., and E. W. Stitt. 2002. Geographic distribution: Nerodia fasciata fasciata (banded watersnake). USA: California: Sacramento Co. Herpetological Review 33(2):150.

Behler, J. L. 1999. National Audubon Society First Field Guide. Reptiles. Scholastic, Inc., New York. 160 pp.

Behler, J. L., and F. W. King. 1979. The Audubon Society Field Guide to North American Reptiles and Amphibians. Alfred A. Knopf, Inc., New York. 743 pp.

Boundy, J. 1997. Snakes of Louisiana. Louisiana Department of Wildlife & Fisheries, Baton Rouge. 32 pp.

Boundy, J., J. [A.] Campbell, B. [I.] Crother, and T. Taggart. 2000. Squamata—snakes. Pp. 56-74. In: B. I. Crother (chair), and Committee on Standard English and Scientific Names (editors). Scientific and standard English names of amphibians and reptiles of North America north of Mexico, with comments regarding confidence in our understanding. Society for the Study of Amphibians and Reptiles Herpetological Circular (29):i-iii, 1-82.

Bury, R. B., and R. A. Luckenbach. 1976. Introduced amphibians and reptiles in California. Biological Conservation 1976(10):1-14.

Carmichael, P., and W. Williams. 1991. Florida's Fabulous Reptiles and Amphibians. World Publications, Tampa. 120 pp.

Carpenter, C. C., and J. J. Krupa. 1989. Oklahoma Herpetology. An Annotated Bibliography. University of Oklahoma Press, Norman. 258 pp.

Conant, R. 1977. The Florida water snake (Reptilia, Serpentes, Colubridae) established at Brownsville, Texas, with comments on other herpetological introductions in the area. Journal of Herpetology 11(2):217-220.

Conant, R., and J. T. Collins. 1998. A Field Guide to Reptiles & Amphibians. Eastern and Central North America. Third Edition, Expanded. Houghton Mifflin Company, Boston. 616 pp.

Dixon, J. R. 2000. Amphibians and Reptiles of Texas. Second Edition. Texas A & M University Press, College Station. 421 pp.

Dundee, H. A., and D. A. Rossman. 1989. The Amphibians and Reptiles of Louisiana. Louisiana State University Press, Baton Rouge and London. 300 pp + unattached erratum.

Ernst, C. H., and R. W. Barbour. 1989. Snakes of Eastern North America. George Mason University Press, Fairfax, Virginia. 282 pp.

Fuller, M.M. and B.W. Trevett.  2006.  Invasion of the Florida water snake (Nerodia fasciata pictiventris) in Southern California.  Herpetological Review 37:363.

Gibbons, J. W., and R. D. Semlitsch. 1991. Guide to the Reptiles and Amphibians of the Savannah River Site. The University of Georgia Press, Athens, Georgia, and London. 131 pp.

Jackson, J. J. 1983. Snakes of the Southeastern United States. Publications Section, Georgia Extension Service, [Athens, Georgia]. 112 pp.

Johnson, T. R. 2000. The Amphibians and Reptiles of Missouri. Revised and Expanded Second Edition. Missouri Department of Conservation, Conservation Commission of the State of Missouri, Jefferson City. 400 pp.

King, F. W. 2000. Florida Museum of Natural History's Checklist of Florida Amphibians and Reptiles [online]. Florida Museum of Natural History, University of Florida, Gainesville. Available on URL: http://www.flmnh.ufl.edu/herps/FL-GUIDE/Flaherps.htm.

Lawson, R. 1987. Molecular studies of thamnophine snakes. I. The phylogeny of the genus Nerodia. Journal of Herpetology 21(2):140-157.

Lawson, R., A. J. Meier, P. G. Frank, and P. E. Moler. 1991. Allozyme variation and systematics of the Nerodia fasciata-Nerodia clarki complex of water snakes (Serpentes: Colubridae). Copeia 1991(3):639-659.

Linzey, D. W. 1979. Snakes of Alabama. The Strode Publishers, Inc., Huntsville, Alabama. 136 pp.

Lohoefener, R., and R. Altig. 1983. Mississippi herpetology. Mississippi State University Research Center Bulletin (1):i-vi, 1-66.

Martof, B. S. 1956. Amphibians and Reptiles of Georgia. University of Georgia Press, Athens, Georgia. 94 pp.

Martof, B. S., W. M. Palmer, J. R. Bailey, and J. R. Harrison III. 1980. Amphibians and Reptiles of the Carolinas and Virginia. The University of North Carolina Press, Chapel Hill. 264 pp.

Moler, P. 1988. A Checklist of Florida's Amphibians and Reptiles. Nongame Wildlife Program, Florida Game and Fresh Water Fish Commission, Tallahassee. 18 pp.

Mount, R. H. 1975. The Reptiles and Amphibians of Alabama. Auburn University Agricultural Experiment Station, Auburn. 347 pp.

Mushinsky, H. R., J. J. Hebrard, and D. S. Vodopich. 1982. Ontogeny of water snake foraging ecology. Ecology 63(6):1624-1629.

Palmer, W. M., and A. L. Braswell.1995. Reptiles of North Carolina. The University of North Carolina Press for North Carolina State Museum of Natural Sciences, Chapel Hill and London. 412 pp.

Powell, R., J. T. Collins, and E. D. Hooper, Jr. 1998. A Key to Amphibians & Reptiles of the Continental United States and Canada. University Press of Kansas, Lawrence. 131 pp.

Shine, R. 1998. Snakes. Pp. 174-211. In: H. G. Cogger and R. G. Zweifel (editors). Encyclopedia of Amphibians & Reptiles. Second Edition. Academic Press, San Diego. 240 pp.

[Sievert], G., and L. Sievert. [1988]. A Field Guide to Reptiles of Oklahoma. Oklahoma Department of Wildlife Conservation, Oklahoma City. 96 pp.

Smith, H. M., and E. D. Brodie, Jr. 1982. A Guide to Field Identification. Reptiles of North America. Golden Press, New York. 240 pp.

Smith, H. M., and J. R. Dixon. 1987 [1988]. The amphibians and reptiles of Texas: A guide to records needed for Mexico. Bulletin of the Maryland Herpetological Society 23(4):154-157.

Smith, H. M., and R. B. Smith. 1993. Synopsis of the Herpetofauna of Mexico. Volume VII. Bibliographic Addendum IV and Index, Bibliographic Addenda II-IV, 1979-1991. University Press of Colorado, Niwot, Colorado. 1082 pp.

Smith, P. A. 1961. The amphibians and reptiles of Illinois. Illinois Natural History Survey Bulletin 28(1):[i-v], 1-298. (Reprinted 1986.)

Stevenson, H. S. 1976. Vertebrates of Florida. Identification and Distribution. University Presses of Florida, Gainesville. 607 pp.

Tennant, A. 1997. A Field Guide to Snakes of Florida. Gulf Publishing Company, Houston. 257 pp.

Tennant, A., and R. D. Bartlett. 2000. Snakes of North America. Eastern and Central Regions. Gulf Publishing Company, Houston. 588 pp.

Tennant, A., J. E. Werler, J. E. Forks, and G. T. Salmon. 1998. A Field Guide to Texas Snakes. Second Edition. Gulf Publishing Company, Houston. 291 pp. + poster.

Webb, R. G. 1970. Reptiles of Oklahoma. University of Oklahoma Press, Norman. 370 pp.

Werler, J. E., and J. R. Dixon. 2000. Texas Snakes. Identification, Distribution, and Natural History. University of Texas Press, Austin. 437 pp.

Wright, A. H., and A. A. Wright. 1957. Handbook of Snakes of The United States and Canada. Volumes I-II. Comstock Publishing Associates, Ithaca and London. 1105 pp.

Wright, A. H., and A. A. Wright. 1962. Handbook of Snakes of the United States and Canada. Volume III. Bibliography. A. H. and A. A. Wright, Ithaca. 179 pp. [Reprinted 1979 by Society for the Study of Amphibians and Reptiles, Oxford, Ohio.]

Author: Somma, L.A.

Revision Date: 3/1/2007

Citation Information:
Somma, L.A., 2024, Nerodia fasciata fasciata (Linnaeus, 1766): U.S. Geological Survey, Nonindigenous Aquatic Species Database, Gainesville, FL, https://nas.er.usgs.gov/queries/FactSheet.aspx?speciesID=2271, Revision Date: 3/1/2007, Access Date: 4/15/2024

This information is preliminary or provisional and is subject to revision. It is being provided to meet the need for timely best science. The information has not received final approval by the U.S. Geological Survey (USGS) and is provided on the condition that neither the USGS nor the U.S. Government shall be held liable for any damages resulting from the authorized or unauthorized use of the information.


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Citation information: U.S. Geological Survey. [2024]. Nonindigenous Aquatic Species Database. Gainesville, Florida. Accessed [4/15/2024].

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