- The row of subocular scales found in Nerodia cyclopion is a unique character that separates it from all other species of Nerodia. Unfortunately, to accurately see this character it requires a close examination of the snake's head, which may result in a painful bite from the non-venomous water snake.
Keeled dorsal scales, in rows of 27 to 29 near midbody.
- Divided anal plate.
- The dorsal surface is a deep olive or brown, with a gray or brown belly, and yellow throat.
Generally only a hint of dark dorsal pattern evident on dark dorsal surface.
The belly is marked with a random assortment of light colored spots or crescents.
Adult Nerodia cyclopion are 76-114 cm (30-45 in) in length
The range of Nerodia cyclopion is restricted to the United States. This species is found in much of the lower Mississippi River valley and parts of the coastline adjacent to the Mississippi River delta. It can be found as far north as Illinois, and is found along the Gulf of Mexico coastline from Texas to the Florida Panhandle.
Eating a variety of fish, frogs, toads and salamanders, the non-venomous Nerodia cyclopion is primarily nocturnal, searching for its prey along the mud- and sand-lined banks of ponds or slow moving bodies of water at night. When cornered this non-aggressive snake will zealously defend itself with an arsenal of quick, repeated bites and a foul smelling musk released from its vent.
Nerodia cyclopion is a live-bearing snake and incredibly prolific, with as many as 101 offspring recorded in a single litter. The neonates measure 23-28 cm (9-11 in) at birth, which may take place between June and September.
Nerodia cyclopion is one of the few water snakes in Texas which can occassionally be found in brackish water, though it is generally found in the fresh-water confines of lakes, marshes and swamps.
The Mississippi green watersnake is not a protected species in Texas and can be legally collected with a hunting license.
In Texas, Nerodia cyclopion is present along the upper Gulf Coast, from Port Aransas eastward to the Louisiana border. Additionally, N. cyclopion is found in the lower portions of the Sabine River, as it flows along the border between Texas and Louisiana.