List of largest reptiles

This list of largest reptiles takes into consideration both body length and mass of large reptile species, including average ranges and maximum records. The crocodilians reaching a length of 4 m (13 ft) and a mass of 500 kg (1,100 lb) or more. It is worth mentioning that unlike the upper weight of mammals, birds or fish, mass in reptiles is frequently poorly documented, thus subject to conjecture and estimation.
The saltwater crocodile is considered to be the largest extant reptile, verified at up to 6.32 m (20.7 ft) in length and around 1,000–1,500 kg (2,200–3,300 lb) in mass. Larger specimens have been reported albeit not fully verified, the maximum of which is purportedly 7 m (23 ft) long with an estimated mass of 2,000 kg (4,400 lb).
The following table below lists the 15 largest extant reptile species ranked according to their average mass range, with maximum reported/reliable/estimated mass also being provided.
The larger of the two extant species of the New Zealand native tuataras is the Brothers Island tuatara (Sphenodon guntheri). The maximum size is 1.4 kg (3.1 lb) and 76 cm (30 in).
Some of these marine reptiles were comparable in size to modern cetaceans. Until 2024, the largest ichthyosaur was believed to be the Late Triassic species Shastasaurus sikanniensis, at approximately 21 m (69 ft) long and 81.5 t (180,000 lb) in weight, from the Norian stage in what is now British Columbia. However, in 2018, a specimen from the Rhaetian stage of Lilstock was discovered to be 25 percent larger, approximately 26 m (85 ft) in length. The specimen was referred in 2024 to Ichthyotitan severnensis, with revised estimates of 25 metres (82 ft) making it the largest known marine reptile. Shonisaurus popularis is another enormous ichthyosaur. It reached 15 m (49 ft) in length and 29.7 t (65,000 lb) in weight. Cymbospondylus youngorum is the largest Middle Triassic ichthyosaur, with 17.65 m (57.9 ft) in length and 45 t (99,000 lb) in weight. In 2022 the tooth of a giant predatory ichthyosaur (unofficially named Swiss Tyrant) was discovered in the Swiss Alps. Based on crown diameter, the animal was about 18 m (59 ft) long and weighed 55 t (121,000 lb), making it one of the largest marine reptiles ever.
A terrestrial relative of turtles survived until about 2,000 years ago, the Australasian Meiolania at about 2.6 m (8 ft 6 in) long and a weight of over 1 t (2,200 lb). Later research suggests the maximum length possibly over 3 m (9.8 ft).
Plesiosaurs were aquatic reptiles of the Mesozoic era. They had a broad flat body, a short tail, and strong flippers. Most of the Plesiosauroidea group are identified by their long necks, while Pliosauroidea are usually short-necked. The largest known plesiosauroid is Aristonectes, with a body length of 10–11.86 metres (32.8–38.9 ft) and body mass of 10.7–13.5 t (24,000–30,000 lb). The largest well known pliosauroid is Pliosaurus funkei at 10–13 m (33–43 ft) in length. With a series of neck vertebrae from the Kimmeridge Clay Formation indicate a pliosaur, probably Pliosaurus, that may have been up to 14.4 metres (47 ft) long.
A Mesozoic reptile is believed to have been the largest flying animal that ever existed: the pterosaur Quetzalcoatlus northropi, from North America during the late Cretaceous. This species is believed to have weighed up to 126 kg (278 lb), measured 7.9 m (26 ft) in total length (including a neck length of over 3 m (9.8 ft)) and measured up to 10–12 m (33–39 ft) across the wings. Another possible contender for the largest pterosaur is Hatzegopteryx, which is estimated to have had an 11–12 m (36–39 ft) wingspan. An unnamed Mongolian pterodactyloid pterosaur and Arambourgiania from Jordan could reach a wingspan of nearly 10 m (33 ft).