The green anaconda is the largest snake in South America and one of the world's big three (the other two are Asian and African pythons). Most of the herpetologists, or reptile biologists, consider 26 feet to be the maximum length, but anacondas longer than 15 feet are rare in the wild these days.

If it is not the longest snake species, it is definitely the heaviest. A 26-footer can weigh 400 pounds. This great bulk is put to use catching and subduing prey. Anacondas are constrictors. (They are not venemous). These semi-aquatic snakes lie submerged along stream banks to ambush their prey. When a caiman, peccary, deer, or large bird comes within striking distance, an anaconda lunges, bites, and holds the prey while it throws several coils of its body around the animal. Then the snake constricts, tightening the coils when the prey inhales, quickly suffocating it. Food is swallowed whole. Constrictors do not crush their prey - jagged broken bones would damage their digestive systems.

From Amazon Rising: Seasons of the River. Shedd Aquarium