The Eunectes Murinus (derived from the Greek ευνήκτης meaning "good swimmer" and the Latin murinus meaning "of mice" for being thought to prey on mice), commonly known as the green anaconda, is a nonvenomous boa found in South America. It is the heaviest known snake species, and second longest (behind the reticulated python) known extant snake species.
The Green Anaconda is one of the world's longest snakes, reaching more than 6.6 m (22 ft) long. It is the largest snake native to the Americas and probably the heaviest extant species of snake or squamate. 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 lacking. 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 verified 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.
Although charismatic, little is known of the the biology of anacondas in the wild. Most of our knowledge comes from the work of Dr. Jesus Rivas and his team from their work in the Venezuelan llanos.
The primarily nocturnal anaconda species tend to spend most of its life in or around water. Anacondas are also sometimes known as the 'Water Boa'; they spend more time in water than any of the boas. Because of their large size, they seem rather slow and sluggish when traveling on land. Completely the opposite in water, however, anacondas are known to have the potential to reach high speeds in all depths of water. They tend to float atop the surface of the water with the snout barely poking out above the surface. When prey passes by or stops to drink, a hungry anaconda will snatch it with its jaws (without eating or swallowing it) and coil around it with its body. The snake will then constrict until it has successfully suffocated the prey.
Primarily aquatic, they eat a wide variety of prey, almost anything they can manage to overpower, including fish, birds, a variety of mammals, and other reptiles. Particularly large anacondas may even consume large prey such as tapir, deer, capybara and caiman, but such large meals are not regularly consumed. There are many local stories and legends regarding the anaconda as a man-eater, but there is very little evidence to support any such activity. They employ constriction to subdue their prey. Cannibalism among green anacondas is also known, most recorded cases involving a larger female consuming a smaller male. While the exact reason for this is not understood, scientists cite several possibilities, including the dramatic sexual dimorphism in the species, and the possibility that a female anaconda requires additional food intake after breeding to sustain the long period of gestation. The nearby male simply provides the opportunistic female a ready source of nutrition.
Eunectes murinus is found in South America east of the Andes, in countries including Colombia, Venezuela, the Guianas, Ecuador, Peru, Bolivia, Brazil, the island of Trinidad and as far south as northern Paraguay. The type locality given is "America".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 lie in wait for prey while remaining nearly completely submerged.