As usual, when we are talking about the largest of anything, it all depends why you mean by largest. And, worlds largest snake is no exception.
The green anaconda is certainly a candidate for the largest snake. The green anaconda is also called the giant anaconda, when we are looking at giant snakes. The green anaconda has been reliably measured at 28 feet long and over 500 pounds in weight. There have beenCredit: http://commons.wikimedia.org/wiki/File:Eunectes_murinus2.jpg reports of anacondas of much larger size, but either the snake is not able to be presented for verification, or when the snake is found, the specimen is measured at being much smaller.
There are several problems with the sizes of snakes that make the rumors of large sizes so persistent. While viewing a snake of a large size, it is difficult to estimate the length. It seems that the percentage of error grows with the length of the snake. In addition, any skins of snakes procured, either from the killing of a snake, or being found when the snake sheds it, can stretch up to 50%, making any measurement of this type unreliable. The large specimens of these snakes are usually found in remote areas, so transportation of live specimens is difficult.
Asiatic Reticulated Python
The Asiatic reticulated python is also a candidate for largest snake. While the green anaconda is a candidate for worlds largest snake for because of being the heaviest snake, the Asiatic reticulated python is a candidate because it is the longest snake. Credit: http://en.wikipedia.org/wiki/File:Python_reticulatus_%D1%81%D0%B5%D1%82%D1%87%D0%B0%D1%82%D1%8B%D0%B9_%D0%BF%D0%B8%D1%82%D0%BE%D0%BD-2.jpgThese pythons usually grow to a length of 10-20 feet, but the adults can regularly grow to be over 28 feet in length.
However, just as with the green anaconda, the measurement of the length of these snakes has some problem also. There was a specimen at a zoo in Pittsburgh, Pennsylvania that was reported to be measured at 28.5 feet. When it died in 1963, her body was donated to the Carnegie Museum of Natural History. When they measured it, it was found to be much shorter. Live pythons are hard to measure, since with a specimen that large, it is hard to get it to stretch out without harming it.
Pythons, while not normally a danger to humans, have been known to harm them, or even kill and eat them. At least 11 people in the United States have been killed by these snakes since 1980, with more close calls. There have been stories from Indonesia and the Philippines of people being eaten by pythons.
Larger Than 30 Feet Claims
There was a story circulating in 2003 about a giant python in Indonesia measuring 49 feet and weighing 983 pounds. The snake reportedly ate three or four dogs a month. However, when two different reporters were sent to check on the story, each found the snake to measure about 21 feet. The details of this story can be found at Snopes.com.
While there have been lots of claims of both of these species of snakes being over 30 feet, the Wildlife Conservation Society has offered a reward of $50,000 for the delivery of a live snake of 30 feet or more in length for some time, but no one has every claimed the reward.
Whichever way you want to decide to judge which snake is largest, either by weight or length, everyone can certainly agree that both these snakes are giants. The worlds largest snake title is now yours to award.