World's Biggest Anaconda.....? . . . . . The world's largest anaconda is the green anaconda (Eunectes murinus), native to the tropical rainforests of South America. This massive snake holds the title for being the heaviest and one of the longest snakes in the world. Record Size: Length: The green anaconda typically grows up to 20–30 feet (6–9 meters). The longest verified specimen measured 33 feet (10 meters). Weight: It can weigh up to 550 pounds (250 kilograms). Girth: Its girth can reach up t