There has been reports of Green Anacondas reaching 18.9m long this snake was shot by a British colonel in Brazil in 1907. This snake would have been unable to support its own weight on land and was therefore its reported length was not accurate. The most realistic reports of the Green Anacondas length are just over 10m.
There are far more accurate reports of the size of the Reticulated Python. There are reports of Reticulated Pythons reaching a length of around 8.5m these are quit accurate and a live specimen of this size was in the possession of an animal dealer in 1905. Another specimen that grew to 7.6m in length and was displayed at the National Zoo in Washington and was the largest snake ever to be on display at this zoo.
There are reliable records of this snake approaching 6m. There is a Burmese Python measuring 5.84m housed in the collection of the Bombay Natural History Society which was shot as well as two specimens of 5.8m which were shot in Sri Lanka. There are less reliable reports of this snake reaching 7.6m.
The African Python
This snake is the only large python in Africa and the largest snake on the continent. The Largest size that has been reported for this snake is 7.6m. It was rare forty to fifty years ago to see a specimen of over 6m let alone today. The average length of an adult is regarded to be 4.6-4.9m.
The Amethystine Python
This is the largest python in Australia and a relative of the Carpet Python. Adults average 3-3.7m or less. However there have been reports of this snake reaching much larger sizes. There have been reports of a specimen of 8.5m and one of 7.2m. This Python is not a heavily built snake and is slender in comparison with the other giant pythons. This snake is rarely available for sale in the pet trade and I have not seen one of these pythons for sale or in a snake park. Please tell me if you know of a snake park or zoo that has this snake on display as I would really like to see one.
The Common Boa
The Common Boa is not regarded as the largest species of snake on the planet. Even though many uneducated people, think of huge man eating snake at the mere mention of the word boa constrictor. The largest recorded size for a boa constrictor was 5.64m this specimen was shot by a malaria control work party in Trinidad during the second World War. This snakes remains were not preserved to allow for further study. This record has been dismissed as the snake was probably an anaconda as it was found in a habitat that is unsuitable for boa constrictors. The accepted maximum recorded size for this snake is 4.5m. Most boa constrictors reach around 3m.