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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.

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Common name: Florida Watersnake

Taxonomy: available through www.itis.gov

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, 2003; 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; Bartlett and Bartlett, 2003; Ernst and Ernst, 2003; Gibbons and Dorcas, 2004; Winne and Gibbons, 2008).

Size: TL (total length) of 610-1,588 mm

Native Range: 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, 2003; Conant and Collins, 1998; Ernst and Ernst, 2003; Gibbons and Dorcas, 2004; King, 2006).

Alaska	Hawaii	Puerto Rico & Virgin Islands	Guam Saipan

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

Means of Introduction: In Brownsville, Texas, N. f. pictiventris was introduced by an animal dealer known as the Snake King when his cages containing Florida watersnakes were destroyed after a hurricane in September, 1933; additional snakes were probably released intentionally by the same individual, years prior to and after the storm, to provide a population of snakes to feed his captive cobras (Conant, 1977; Tennant et al., 1998; Werler and Dixon, 2000).

The origin of the population in Los Angeles, California, is unknown.

The means of introduction of N. fasciata in Sacramento, California, has not been explored (Balfour and Stett, 2002; Balfour et al., 2008b).

Status: Nerodia f. pictiventris is established in the Brownsville area, including the Rio Grande Valley, of southeastern Cameron County, Texas, but has not spread beyond this county (Tennant et al., 1998; Dixon, 2000; Werler and Dixon, 2000). It remains unknown if Florida watersnakes have crossed the Rio Grande River into adjacent Mexico (Smith and Dixon, 1987; Smith and Smith, 1993).

Although Bury and Luckenbach (1976) indicated that the N. fasciata collected from Los Angeles was a single waif and not indicative of an established population, the discovery (2005-2008) of self-sustaining populations of the Florida Watersnake in Los Angeles and Sacramento counties, indicates that the species is now a potential threat to ecosystems in southern California (M. Fuller, pers. comm. 2007; Balfour et al., 2008b).

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

Remarks: The taxonomy of N. fasciata has been studied or summarized by Lawson (1987), Lawson et al. (1991), Boundy et al. (2000), Collins and Taggart (2002), Gibbons and Dorcas (2004), and Crother et al. (2008). A wide variety of reviews have covered the literature and natural history of the various subspecies 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; Ernst and Ernst, 2003; Gibbons and Dorcas, 2004; Winne and Gibbons, 2008).  Scientific and standard English names follow Crother (2008).

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; Ernst and Ernst, 2003; Tennant, 2003; Gibbons and Dorcas, 2004; Winne and Gibbons, 2008). 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; Ernst and Ernst, 2003; Gibbons and Dorcas, 2004). 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; Winne and Gibbons, 2008).

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., D. Brown, E. W. Stitt, K. Grinsell, and A. K. Buchanan. 2008a. Geographic distribution. Nerodia sipedon (northern watersnake). USA: California: Placer Co. Herpetological Review 38(4):489.

Balfour, P. S., E. W. Stitt, M. M. Fuller, and T. K. Luchan. 2008b. Geographic distribution. Nerodia fasciata pictiventris (Florida watersnake). Herpetological Review 38(4):489.

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

Bartlett, R. D., and P. [P.] Bartlett. 2003. Florida’s Snakes. A Guide to Their Identification and Habits. University Press of Florida, Gainesville. 183 pp.

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.

Collins, J. T., and T. W. Taggart. 2002. Standard Common and Current Scientific Names for North American Amphibians, Turtles, Reptiles & Crocodilians. Fifth Edition. The Center for North American Herpetology, Lawrence, Kansas.  44 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.

Crother, B. I., J. Boundy, F. T. Burbrink, and J. A. Campbell. 2008. Squamata—snakes. Pp. 46-65. 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. Sixth Edition. Society for the Study of Amphibians and Reptiles Herpetological Circular (37):1-84.

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.

Ernst, C. H., and E. M. Ernst. 2003. Snakes of the United States and Canada. Smithsonian Institution Press, Washington, D.C. 668 pp.

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

Gibbons, J. W., and M. E. Dorcas. 2004. North American Watersnakes. A Natural History. University of Oklahoma Press, Norman. 438 pp.

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. 2006. 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/herpetology/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.

Stitt, E. W., P.S. Balfour, T. Luckau, and T. E. Edwards. 2005. The southern watersnake (Nerodia fasciata) in Folsom, California: History, population attributes, and relation to other introduced watersnake in North America. Final report to US Fish and Wildlife Service. ECORP Consulting Inc.

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

Tennant, A. 2003. Snakes of Florida. Second Edition. Taylor Trade Publishing, Lanham, Maryland. 271 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.

Winne, C. T., and [J.] W. Gibbons. 2008. Banded watersnake. Nerodia fasciata. Pp. 375-377. In: J. B. Jensen, C. D. Camp, [J.] W. Gibbons, and M. J. Ellliott (editors).
Amphibians and Reptiles of Georgia. University of Georgia Press, Athens. 575 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.] 

Other Resources:
Florida water snakes discovered in California

Author: Somma, L.A.

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.