Adult long (up to 150 cm TL) and slender with shiny, uniformly blue, blue-green, or black back. Belly yellowish white to slate gray. Throat distinctly lighter (yellow in northwest, white elsewhere). Hatchling and juvenile up to about 80 cm TL, blue-gray with 55-85 reddish brown blotches on back that become less distinct toward tail, and small dark spots along sides and belly.