- a common European snake, Natrix natrix, having a collar of bright orange or yellow.
- any of various small, slender snakes of North America, as the garter snake or green snake.
- a harmless nonvenomous European colubrid snake, Natrix natrix, having a brownish-green body with variable markings
- any of several similar related European snakes, such as Natrix maura (viperine grass snake)
