Blue racers are long slender snakes with smooth scales. Dorsal coloration ranges from gray to light blue to bluish-green. The head is usually darker than the rest of the body and the belly is white or white-blue. Juvenile racers are gray with darker (brown, black, or red) splotches and spots. If disturbed (or if a human attempted to pick it up), the racer will musk, defecate, and strike out.