The largest living reptile, a representative of the order Crocodilia, is the saltwater crocodile (Crocodylus porosus) of Southern Asia and Australia, with adult males being typically 3.9–5.5 m (13–18 ft) long. The largest confirmed saltwater crocodile on record was 6.32 m (20.7 ft) long, and weighed about 1,360 kg (3,000 lb). Unconfirmed reports of much larger crocodiles exist, but examinations of incomplete remains have never suggested a length greater than 7 m (23 ft). Also, a living specimen estimated at 7 m (23 ft) and 2,000 kg (4,400 lb) has been accepted by the Guinness Book of World Records. However, due to the difficulty of trapping and measuring a very large living crocodile, the accuracy of these dimensions has yet to be verified. A specimen caught alive in the Philippines in 2011 (now enclosed at a zoo) was found to have measured 6.17 m (20.2 ft) in length.
The following is a list of the heaviest living reptile species, which is dominated by the crocodilians. Unlike the upper weights of mammals, birds or fish, mass in reptiles is frequently poorly documented and many are subject to conjecture and estimation.
The previously discussed Saltwater crocodile is the largest living member of this order, and of the crocodile family. The Nile crocodile, verified up to 6.45 m (21.2 ft) and a weight of 1,090 kg (2,400 lb), is the second largest crocodile, and very similar in size to the saltwater crocodile. The largest living specimen of a nile crocodile is purported to be a man-eater from Burundi named Gustave; he is believed to be more than 6.1 m (20 ft) long. The extinct Crocodylus thorbjarnarsoni was the largest true crocodile to exist, growing up to 7.6 m (25 ft) in length. Lolong was the largest saltwater crocodile in captivity measured at 20 ft 3 in (6.17 m) making him the largest crocodile measured in captivity from snout-to-tail.
The gharial, which has been measured up to 7 m (23 ft), is the largest member of its family and one of the largest crocodilians. Despite its length, specimens rarely exceed 450 kg (990 lb) in weight. The largest member of this family to ever exist was the extinct Rhamphosuchus from Miocene Asia. It was one of the largest crocodilians to exist, attaining a length up to possibly 18 m (59 ft) long, though was more typically 11 m (36 ft). Based on its fossils, the latter species was less massive and heavy than the other giant crocodilians, weighing an estimated 3 tonnes.
The largest member of the family Alligatoridae is either the Black caiman or American alligator which have been confirmed to grow up to 4.6 m (15 ft) in length and weigh up to 453 kg (999 lb), not as large as the preceding crocodilians but still impressive. Unverified reports suggest lengths of up to 6 m (20 ft) for the black caiman and 5.8 m (19 ft) for the American alligator. The largest member of this family was the caiman-like Purussaurus, from northern South America during the Miocene epoch. It grew to 10–12 m (33–39 ft) long and could weigh up to 8 tonnes, making it one of the largest crocodilians ever.
Other contenders for the largest crocodilian ever include the late Cretaceous period Deinosuchus of what is now North America, at up to 12 m (39 ft) and 8.5 tonnes. Sarcosuchus imperator of the early Cretaceous was found in the Sahara desert and could also measure up to 12 m (39 ft) and weigh an estimated 8 tonnes.
Lizards and snakes (Squamata)
The most massive living member of this highly diverse reptilian order is the green anaconda (Eunectes murinus) of the neotropical riverways. These may exceed 8.8 m (29 ft) and 227 kilograms (500 lb), although such reports are not fully verified. Rumors of larger anacondas also persist. The reticulated python (Python reticulatus) of Southeast Asia is longer but more slender, and has been reported to measure as much as 10 m (33 ft) in length and to weigh up to 158 kilograms (350 lb). The fossil of the largest snake ever, the extinct boa Titanoboa were found in coal mines in Colombia. This snake was estimated to reach a length of 12.8 m (42 ft) and weighed about 1,135 kg (2,500 lb),
Among the colubrids, the most diverse snake family, the longest specimens are reported in Chinese Ratsnake (Ptyas korros), at up to 4.75 m (15.6 ft).
The longest venomous snake is the South Asian king cobra (Ophiophagus hannah), with lengths (recorded in captivity) of up to 5.7 m (19 ft) and a weight of up to 12.7 kg (28 lb). It is also the largest elapid.
The Gaboon viper, a very bulky species with a maximum length of around 2 m (6.6 ft),is typically the heaviest non-constrictor snake and the biggest member of the viper family, with unverified specimens reported to as much as 20 kg (44 lb). While not quite as heavy, another member of the viper family is longer still, the South American bushmaster (Lachesis muta), with a maximum length of 3.65 m (12.0 ft).
The largest of the monitor lizards (and the largest extant lizard in general) is the Komodo dragon (Varanus komodoensis), endemic to the island of its name, at a maximum size of 3.13 m (10.3 ft) long and 166 kg (366 lb). The prehistoric Australian Megalania (Varanus priscus), which may have existed up to 40,000 years ago, is the largest terrestrial lizard known to exist, but the lack of a complete skeleton has resulted in a wide range of size estimates. Molnar's 2004 assessment resulted in an average weight of 320 kg (710 lb) and length of 4.5 m (15 ft), and a maximum of 1,940 kg (4,280 lb) at 7 m (23 ft) in length, which is toward the high end of the early estimates.
The largest extant gecko is the New Caledonian Giant Gecko (Rhacodactylus leachianus) of New Caledonia, which can grow to 14 inches in length. It was surpassed in size by the extinct Kawekaweau (Hoplodactylus delcourti) of New Zealand, which grew to a length of 23 inches.
By far the largest-ever members of this order were the giant mosasaurs (including Hainosaurus, Mosasaurus, and Tylosaurus), which grew to around 17 m (56 ft) and were projected to weigh up to 20 tonnes.
The largest known plesiosaur was
Mauisaurus haasti, from the late Cretaceous oceans around what is now New Zealand. It is estimated to have grown to around 20 m (66 ft) in length and to have weighed 30 tonnes.
The largest of these marine reptiles (extinct for 90 million years) was the species
Shastasaurus sikanniensis, at approximately 21 m (69 ft) long and 68 tonnes. This massive animal, from the Norian stage in what is now British Columbia, is considered the largest marine reptile so far found in the fossil record.
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).
The largest living turtle is the leatherback sea turtle (Dermochelys coriacea), reaching a maximum total length of 3 m (9.8 ft) and a weight of 932 kg (2,055 lb).
The largest extant freshwater turtle is possibly the North American alligator snapping turtle (Macrochelys temminckii), which has an unverified maximum reported weight of 183 kg (403 lb), although this is challenged by several rare, giant softshell turtle from Asia (Rafetus and Pelochelys) unverified to 200 kg (440 lb) and nearly 2 m (6.6 ft) in total length.
The Galápagos tortoise (Chelonoidis nigra) and the Aldabra giant tortoise (Aldabrachelys gigantea) are considered the largest truly terrestrial reptiles alive today. While the Aldabra tortoise averages larger at 205 kg (452 lb), the more variable-sized Galapagos tortoise can reach a greater maximum size of 400 kg (880 lb) and 1.85 m (6.1 ft) in total length. A much larger tortoise survived until about 2000 years ago, the Australasian Meiolania at about 2.6 m (8.5 ft) long and a weight of over 1 tonne. The tortoise Colossochelys atlas, of the Pleistocene era from what is now Pakistan and India, was even larger, at nearly 3.1 m (10 ft) and 2 tonnes.
There are many extinct turtles that vie for the title of the largest ever. The largest seems to be the freshwater turtle Stupendemys, with an estimated total carapace length of more than 3.3 m (11 ft) and weight of up to 1,814–2,268 kg (3,999–5,000 lb). A close contender is Archelon ischyros, a sea turtle, which reached a length of 4.84 m (15.9 ft) across the flippers and a weight of over 2,200 kg (4,900 lb).
A dinosaur-era reptile (although not actually a dinosaur) 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 250 kg (550 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 11 m (36 ft) across the wings. Another possible contender for the largest pterosaur is
Hatzegopteryx, which is also estimated to have had an 11 m (36 ft) wingspan.
