Clonophis, Coluber, Ischnognathus, Natrix, Regina, Storeria, Tropidoclonion, Tropidonothus, Tropidonotus, Vipera
Nerodia is a genus of nonvenomous colubrid snakes commonly referred to as water snakes due to their aquatic behavior. The genus includes nine species, all native to North America. Five of the species have recognized subspecies.
Nerodia species vary greatly, but all are relatively heavy-bodied snakes, sometimes growing to 1.2 m (4 feet) or longer in total length (including tail). They have flattened heads, with small eyes that have round pupils, and keeled dorsal scales. Species like N. fasciata display distinct banding, whereas other species, like N. erythrogaster, have blotching, and those like N. rhombifer have diamond-shaped patterning. Most species are brown or olive green, or some combination thereof with markings being brown, or black. Yellow or cream-colored accenting is common.[citation needed]
As the common name water snakes implies, species in the genus Nerodia are largely aquatic. They spend the vast majority of their time in or very near permanent sources of water. Often, they can be found basking on tree branches that overhang slow-moving streams or ponds.[citation needed]
The primary diet of Nerodia species is fish and amphibians, and they are quite adept at catching both in their aquatic environment. They will also consume small reptiles and rodents that live near water.[citation needed]
While their initial instinct is to flee when disturbed, water snakes of the genus Nerodia readily defend themselves if they are unable to escape. They do not often hesitate to strike or bite if handled, and often expel a foul-smelling musk from their cloacae.[citation needed]