The green or common anaconda (Eunectes murinus) is a kind of constrictive snake of the Boidae family. It is endemic to the rivers of the tropics of South America. Of all snakes this is the longest; it rivals the cross-linked python (Malayopython reticulatus) by the title of the world's largest snake, which is usually more voluminous, but less long. There are known cases of adult humans attacked, although no snake (Malayopython reticulatus as an exception) tends to attack a human being, except for self-defense (when a human is attacking or scaring it), as they are not part of their trophic chain.
Green anacondas can grow to more than 29 feet, weigh more than 550 pounds, and measure more than 12 inches in diameter. Females are significantly larger than males. Other anaconda species, all from South America and all smaller than the green anaconda, are the yellow, dark-spotted, and Bolivian varieties.
They reach their monumental size on a diet of wild pigs, deer, birds, turtles, capybara, caimans, and even jaguars. Anacondas are nonvenomous constrictors, coiling their muscular bodies around captured prey and squeezing until the animal asphyxiates. Jaws attached by stretchy ligaments allow them to swallow their prey whole, no matter the size, and they can go weeks or months without food after a big meal.
Female anacondas retain their eggs and give birth to two to three dozen live young. Baby snakes are about 2 feet long when they are born and are almost immediately able to swim and hunt. Their lifespan in the wild is about ten years.