The ribbon snake (Thamnophis saurita) is a common species of garter snake native to Eastern North America. It is a non-venomous species of snake in the subfamily Natricinae of the family Colubridae. The ribbon snake averages 16 to 35 inches (41 to 89 cm) in total length (including tail). It is dark brown with bright yellow stripes. The ribbon snake is not sexually dimorphic; however, females are normally thicker than their male counterparts.