Adult males larger than 4.5 m are rare today, but were much more common earlier in the century when 5 to 6 m long males were found. A bony nasal bridge is present. Older animals lose the yellow banding, and turn dark green and brown. The ventral surface is a much paler yellow colour. The presence and extent of ventral osteoderms varies with different populations.
Eyes are silvery.
Captive individuals appear to have broader heads - a possible indication of their more sedentary lifestyle. Dietary range increases substantially as they grow larger, with large adults able to tackle any aquatic or terrestrial prey which comes within range. They will also take carrion if the opportunity presents itself. Females reach sexual maturity at an average of 1.8 m. Both sexes communicate using aural, visual, tactile and olfactory cues.