Dark green in color (hence the name Green Anaconda) with alternating oval black spots; similar spots with yellow-ochre centers are along the sides of its body; head is large and narrow and is not distinct from the thick neck area. Eyes and nostrils are set on the top of the head.  Body is exceptionally stocky compared to other boas and extremely muscular; covered with scales with spurs, small claw like appendages, on either side of the cloaca. The only area without scales is the cloaca. This area contains glands that emit a foul smelling toffee colored musk.  This species is a constrictor and not venomous. Adults of this species reach average lengths of 18 – 20 ft.  Extreme lengths in excess of 29 ft have not been scientifically documented.  Adults may weigh up to 440 lbs. (200 kg).