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Quick Reference Guide: Native Snakes Easily Mistaken for Introduced Constrictors in Florida1

Steve A. Johnson and Monica E. McGarrity 2

Three non-native species of large constrictor snakes are now breeding in Florida, and several others have been encountered but have not yet established wild populations. This fact sheet, best viewed as a pdf (https://edis.ifas.ufl.edu/pdffiles/UW/UW35000.pdf), is a quick reference guide to identification of the native snakes you might easily mistake for introduced constrictors in Florida. Like the introduced constrictors, these similar native snakes are large, aquatic, or have blotched markings. It is important to learn to recognize these native snakes so that you do not report them via the EDDMapS Florida invasive species reporting portal online at http://www.IveGot1.org. Learn more about how to scan for, recognize, and report introduced constrictors by completing the Introduced Reptile Early Detection and Documentation training course. Visit http://ufwildlife.ifas.ufl.edu/reddy.shtml to learn more and get REDDy!

Large Native Snakes

Eastern Indigo Snake (Drymarchon couperi)

Status: rarely encountered

Size: up to 8 feet

Head: reddish marks on chin

Body: iridescent blue-black with no markings

Figure 1. Eastern indigo snake.
Figure 1.  Eastern indigo snake.
Credit: Monica E. McGarrity, UF

Eastern Diamondback Rattlesnake (Crotalus adamanteus)

Status: venomous, occasionally encountered throughout Florida

Size: up to 6–8 feet

Head: blocky, dark eyestripe with cream borders, vertical pupil

Body: dark diamonds with cream borders

Figure 2. Eastern diamondback rattlesnake.
Figure 2.  Eastern diamondback rattlesnake.
Credit: Monica E. McGarrity, UF

Aquatic Native Snakes

Cottonmouth or Water Moccasin (Agkistrodon piscivorus)

Status: venomous, common throughout Florida

Size: usually 2–4 feet

Head: blocky, dark eyestripe, vertical pupil

Body: blotched bands, older individuals may be solid black

Figure 3. Cottonmouth or water moccasin.
Figure 3.  Cottonmouth or water moccasin.
Credit: Monica E. McGarrity, UF

Brown Watersnake (Nerodia taxispilota)

Status: common throughout Florida

Size: usually 2–4 feet

Head: top unmarked, yellow flecks on chin

Body: squarish dark blotches in a "checkerboard" pattern

Figure 4. Brown watersnake.
Figure 4.  Brown watersnake.
Credit: Monica E. McGarrity, UF

Blotched Native Snakes

Cornsnake or Red Ratsnake (Pantherophis guttatus)

Status: common throughout Florida

Size: usually 2–3 feet

Head: reddish arrowhead

Body: reddish blotches with dark outlines, checkerboard pattern on belly

Figure 5. Cornsnake or red ratsnake.
Figure 5.  Cornsnake or red ratsnake.
Credit: Monica E. McGarrity, UF

Acknowledgments

This project was made possible in part by a grant from the South Florida National Parks Trust and the Ferris Greeney Family Foundation, and by the USDA-RREA. This document was originally created as additional reference material for the Introduced Reptile Early Detection and Documentation training program, also known as REDDy. For more information, visit http://ufwildlife.ifas.ufl.edu/reddy.shtml.

Footnotes

1. This document is WEC305, one of a series of the Department of Wildlife Ecology and Conservation, UF/IFAS Extension. Original publication date December 2010. Revised June 2017. Reviewed July 2020. Visit the EDIS website at https://edis.ifas.ufl.edu for the currently supported version of this publication.
2. Steve A. Johnson, associate professor and Extension specialist; and Monica E. McGarrity, biological scientist; Department of Wildlife Ecology and Conservation, UF/IFAS Extension, Gainesville, FL 32611.