NON-VENOMOUS 

Other common names

Diamondback watersnake, Northern diamond-backed watersnake

Basic description

Most adult diamond-backed watersnakes are about 30-60 inches (76-152 cm) in total length. These stout-bodied snakes are light grayish-brown with a dark chain-like pattern down the entire body. The scales are strongly keeled (each scale has a prominent raised ridge). Juvenile coloration is similar to that described for adults.

gray and green snake with diamond pattern
Diamond-backed Watersnake. Photo courtesy of kaptiankory/iNaturalist

Range in Florida

The presence of diamond-backed watersnakes in Florida is based solely on a single specimen collected in Santa Rosa County in the 1950s. Therefore, it is not known whether an established population exists in Florida.

Assessment of risk to people and pets

Non-venomous Diamond-backed watersnakes are not dangerous to people or pets, but they will readily bite to defend themselves. These snakes are not aggressive and avoid direct contact with people and pets. Virtually all bites occur when the snakes are intentionally bothered.

Comparison with other species

dark snake with tan striped head
Photo by Coleman Sheehy.

Florida Cottonmouth (Agkistrodon conanti) If the head is viewed from above, the eyes of cottonmouths cannot be seen while the eyes of watersnakes are visible. Cottonmouths have vertically elliptical (cat-like) pupils, whereas watersnakes have round pupils. Cottonmouths have a facial pit between the nostril and the eye, whereas watersnakes do not.

Saltmarsh watersnake
Photo courtesy of Luke Smith.

Saltmarsh snake (Nerodia clarkii) Saltmarsh waternsnakes often have several dark stripes running down the entire or partial length of the body, and they are usually only found along the coast in saltwater and brackish habitats.

dark snake in marsh
Photo courtesy of johnjinjohny/iNaturalist

Florida Green Watersnake (Nerodia floridana) Florida green watersnakes are dark green and have scales between the eye and the scales on the upper lip.

snake with blotched pattern blending with road surface
Photo courtesy of hunterewgley/iNaturalist

Midland Watersnake (Nerodia sipedon pleuralis) Midland watersnakes have fewer than 30 darker brown crossbands near the neck, which break up into alternating blotches further down the body, and the belly is yellowish marked with two rows of half-moons.

Southern watersnake
Photo courtesy of Todd Pierson.

Southern Watersnake (Nerodia fasciata) Southern waternsnakes have broad black, brown, or red crossbands (often bordered with black) down the back and a dark stripe that extends from the eye to the angle of the jaw.

Share your observations

You can help scientists better understand the biology and distribution of this species by sharing your observations. Send photos or videos of interesting observations, along with associated information, by emailing the herpetology staff at the Florida Museum for documentation in the Museum’s Herpetology Master Database. You can also post your observations on iNaturalist.

Additional helpful information

Do you have snakes around your house? Learn how to safely co-exist with snakes.

Still have questions about snakes or identifications? Feel free to email the herpetology staff at the Florida Museum with your questions or feedback on this profile.

Banner photo courtesy kaptiankory/iNaturalist/CC-BY 4.0. Please credit any photographers on the page and see our copyright policy.