Nerodia clarkii compressicauda Mangrove Salt Marsh Snake Kenneth L. Krysko photo.
Adults are variable in color.
They may be grayish-olive, brown, or rusty orange with faint darker bands. Some individuals may be almost entirely black. There may be dark stripes on the neck. The scales are keeled , and there are 21-23 dorsal scale rows at midbody. The pupil is round.