There is some debate regarding the maximum size of this species. Mehrtens (1987) states that the average adult length is 18 to 20 feet (5.5–6.1 m), with 25 feet (7.6 m) specimens being very rare. He sets a more conservative maximum at 23 feet (7.0 m). Estimates of 35 to 40 feet (11–12 m) are based on vague data and should be regarded with caution. In a study of 1,000 specimens captured in Venezuela, the largest was 17 feet (5.2 m) long and weighed 100 pounds (45 kg). Females are significantly longer than males, having the most conspicuous sexual dimorphism of all snakes.