Original description : A size comparison of four different snakes; comparing large individuals of the extant green anaconda (Eunectes murinus) and reticulated python (Malayopython reticulatus) to total length estimates of the extinct Gigantophis and Titanoboa.

• The green anaconda is the largest (most massive) extant snake. The silhouette is scaled to 5.21 metres (17.1 ft) which was the longest measured and published in a study by Jesús Antonio Rivas that measured hundreds of anacondas.^[2] There are reports of longer anacondas, but these reports have been questioned.^[3][4][5]

• The reticulated python is the longest extant snake. The silhouette is scaled to 6.95 metres (22.8 ft) which is the length of a reliably measured wild reticulated python.^[6] A captive reticulated python named "Medusa" is reported to measure 7.67 metres (25.2 ft).^[7] There are reports of ~10 metres (33 ft) specimens but these are questionable.^[4][5][6]

• Gigantophis is thought to be a member of the extinct snake family Madtsoiidae. Gigantophis is only known from a few vertebrae and the morphology of Madtsoiidae snakes are not very well known. However, Gigantophis has been estimated as one of the largest snakes to have lived. It was estimated between 9.3 and 10.7 metres (31 and 35 ft) in length by Jason Head & P. David Polly in 2004 using regression analysis (the silhouette shown here is 10 metres (33 ft)). Another similar analysis by Jonathan P. Rio & Philip D. Mannion estimated it at 6.9 metres (23 ft) (+/- 0.3 m).^[8][9]

• Titanoboa is known from vertebrae and skull material and estimates make it the largest snake known. In 2009, Jason Head and colleagues estimated it at 12.8 metres (42 ft) (+/-2.18 m) by measuring the vertebrae and performing a regression analysis. In a later conference abstract, Head et al. estimated a length of 14.3 metres (47 ft) (+/-1.28 m) based on skull material, and comparisons to Eunectes.^[10][11]

• Human scaled to 180 cm (5 ft 11 in).