There are four species of the anaconda snake, which live in the swamps and rivers of tropical South America. The Green Anaconda, which has been reliably reported in the 9 metre range (30 feet) in length (although most are considerably smaller). Although shorter than the longest recorded species, the Reticulated Python, it is considerably heavier and is bigger around. In fact, it is the heaviest snake species in existence: it can weigh 250 kg (551 pounds) and have a diameter of more than 30 cm (11.8 inches). Females average 6.7-7.9m (22-26ft) in length, while males average 3-4m (12-16ft). These are found mainly in northern South America.