A member of the boa family, South America’s green anaconda is, pound for pound, the largest snake in the world. Its cousin, the reticulated python, can reach slightly greater lengths, but the enormous girth of the anaconda makes it almost twice as heavy.

Anacondas explained: How these snakes become the world's largest The semiaquatic snakes weigh as much as 550 pounds, and can be as long as a school bus. Learn how they maintain their massive size.

Massive Size

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.

On Land and in Water

Anacondas live in swamps, marshes, and slow-moving streams, mainly in the tropical rain forests of the Amazon and Orinoco basins. They are cumbersome on land, but stealthy and sleek in the water. Their eyes and nasal openings are on top of their heads, allowing them to lay in wait for prey while remaining nearly completely submerged.

Diet and Hunting

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.

Reproduction