Giant snake stories abound - due to the wild imaginations of many early explorers, the difficulties in estimating or measuring the length of live animals which refuse to stay still and the fact that large snake skins can be stretched by more than 30% without causing much noticeable distortion. In reality, even among the Pythons (Pythoninae) and Boas (Boinae), giant individuals are very rare.
However, there are a few authenticated records of snakes exceeding a length of 9.14m (30ft). The record-holder is the reticulated python (Python Reticulatus) of southeast Asia, Indonesia and the Philippines, which regularly exceeds 6.25m (20.5ft).
The greatest proven length for this species is 10m (32ft 9.5in) for a specimen shot on the north coast of Celebes, Indonesia, in 1912; it was accurately measured with a surveying tape by civil engineers working at a nearby mining camp. The closest runner-up is an African rock python (Python Sabae) measuring 9.81m (32ft 2.25in), which was shot in 1932 by Mrs Charles Beart, in the grounds of a school in Bingerville, Ivory Coast, West Africa; however, this particular individual was truly exceptional, since the average length for this species is only 3-5m (9ft 10in - 16ft 5in)
The largely aquatic anaconda (Eunectes murinus) of South America is a close contender for the longest snake record, although it has probably been the subject of more exaggerated claims regarding its size than any other living animal. Early Spanish settlers in South America spoke of individuals measuring 18-24m (60-80ft) and even larger specimens have been reported. But, in reality, it rarely exceeds 6.25m (20ft 6in).
Perhaps the most famous of the claims that have been taken seriously was made in 1907 by LtCol Percy Fawcett of the Royal Artillery. He shot an unusually large anaconda while navigating the Rio Negro, in the Amazon, Brazil, as it made its way up a riverbank. He claimed that "as far as it was possible to measure, a length of 45ft [13.7m] lay out of the water, and 17ft [5.2m] in it, making a total length of 62ft [18.9m]". Fawcett was very meticulous in all the observations he entered in his journal, but his explorations often read like a comic-book adventure so the reliability of his giant anaconda has often been questioned. The truth will never be known for sure.
The longest (and heaviest) snake ever held in captivity was a female reticulated python named ' Colossus' which was 8.68m (28ft 6in) long and weighed 145Kg (320lb) at her heaviest. She died at Highland Park Zoo, Pennsylvania, USA, on April 15 1963.
Most modern herpetologists have a healthy scepticism about any snake claimed to be longer than 9.14m (30ft). However, it has been calculated, by taking into account the biomechanical and physiological stresses imposed on a large snake moving over land, that the upper length limit is probably about15m (49ft); a longer snake would have to spend most of its time in the water, to support its enormous weight. These calculations, combined with many un-authenticated reports of giant snakes suggest that specimens in the 12-15m (40-50ft) range may well be found in the future.