Green Anaconda Snake – Eunectes murinus (World’s Longest/Largest Snake)
Common names: Green Anaconda, Anaconda, Common Anaconda, Water Boa. The Green Anaconda is one of the world’s longest snakes, reaching more than 5 m (16 ft) long. Reports of anacondas 35–40 feet or even longer also exist but such claims need to be regarded with caution as no specimens of such lengths have ever been deposited in a museum and hard evidence is required. There is a $50,000 cash reward for anyone that can catch an anaconda 30 ft (9.1 m) or longer, but the prize has not been claimed yet. Although the reticulated python is longer, the anaconda is the heaviest snake. The longest (and heaviest) scientifically recorded specimen was a female measuring 521 cm (17 ft 1 in) long and weighing 97.5 kilograms (215 lb).
The color pattern consists of olive green background overlaid with black blotches along the length of the body. The head is narrow compared to the body, usually with distinctive orange-yellow striping on either side. The eyes are set high on the head, allowing the snake to see out of the water while swimming without exposing its body. 
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.
Green anacondas can grow to more than 29 feet (8.8 meters), weigh more than 550 pounds (227 kilograms), and measure more than 12 inches (30 centimeters) 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.
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.
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 (0.6 meters) long when they are born and are almost immediately able to swim and hunt. Their lifespan in the wild is about ten years.
Fast Facts about Green Anaconda Snake
Type: Reptile
Diet: Carnivore
Average life span in the wild: 10 years
Size: 20 to 30 ft (6 to 9 m)
Weight: Up to 550 lbs (227 kg)
Group name: Bed or knot
Did you know? In mating, several competing males form a breeding ball around one female that can last up to four weeks.

Courtesy : http://animals.nationalgeographic.com, http://en.wikipedia.org/
Green Anaconda Snake Images / Pictures