Most adult brown watersnakes are about 30-60 inches (76-152 cm) in total length, with a record length of 69.5 inches (176.6 cm). These stout-bodied snakes are light tan with darker squarish brown blotches down the middle of the back. Dark squarish markings also extend upwards from the belly onto the sides of the body between the blotches on the back. The belly is light-colored with darker blotches and half moons. The scales are strongly keeled (each scale has a prominent raised ridge), and there are 25-33 dorsal scale rows at midbody. The head is large and distinct from the neck, and the pupil is round. Juvenile coloration is similar to that described for adults.

In Florida, brown watersnakes are commonly found in rivers, cypress strands, sawgrass prairies, swamps, lakes, ponds, canals, and flooded stands of melaleuca. Adults and juveniles of this species are occasionally found in suburban neighborhoods where development encroaches into favorable habitats.

When approached, brown watersnakes will typically flee into the water and dive below the surface. If grabbed or pinned, they will typically bite the attacker and release a foul-smelling musk from a pair of glands in the base of the tail. Nonetheless, these snakes are not aggressive, and striking is only used in defense as a last resort.

Brown watersnakes feed almost exclusively on freshwater fishes, especially catfishes. These snakes are not constrictors and overpower their prey by grabbing it in their jaws, hauling it to shore, and swallowing it after it has been subdued. Brown watersnakes are typically diurnal (active during the day) during the spring and fall, but they become more active at night during the hot summer months.

In Florida, females typically give live birth to 4-61 young in late summer or early fall.

No subspecies are currently recognized in Florida.

Brown watersnakes are excellent climbers and can be found 20 feet up in trees, though they are most frequently seen basking on tree limbs that extend over the water. When frightened by a rapidly approaching boat, these snakes will escape by jumping off the limb into the water. Occasionally their attempts to flee come too late and they fall not into the water but into the boat.

Unfortunately, many watersnakes are killed every year by Florida residents who mistake them for cottonmouths. Although cottonmouths occur throughout Florida, they are not nearly as abundant as the eight species of harmless watersnakes (species in the genus Nerodia) that occur in much the same habitats. If you see a snake in or near the water, most likely it is a harmless watersnake, and it is best for everyone involved to simply leave it alone.

County data coming soon.

If you have a new or interesting observation for this species, please email the herpetology staff at the Florida Museum.

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

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

Krysko, K.L., K.M. Enge, and P.E. Moler. 2019. Amphibians and Reptiles of Florida. University of Florida Press, Gainesville, Florida. 706 pp.

Powell, R., R. Conant, and J.T. Collins. 2016. Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America. Fourth edition. Houghton Mifflin Harcourt Publishing Company, Boston and New York. xiv + 494 pp.