Primarily aquatic, they eat a wide variety of prey including fish, birds, a variety of mammals, and other reptiles. Particularly large anacondas may even consume large prey such as tapir, deer, capybara and caiman. There are many local stories and legends regarding the anaconda as a man-eater, but there is very little evidence to support any such activity.
Cannibalism among green anacondas is also known, most recorded cases involving a larger female consuming a smaller male.
Anacondas are ovoviviparous, which means that the females carry the eggs within their bodies until the babies are ready to hatch. Then, the pregnant female can give birth to anywhere from 12 to more than 80 2-foot-long baby snakes. Young anacondas are independent as soon as they are born, but will not breed for many years.