List of largest reptiles

Lizards and snakes (Squamata)

Snakes

• The most massive living member of this highly diverse reptilian order is the green anaconda of the neotropical riverways. These may exceed and, although such reports are not fully verified. Rumors of larger anacondas also persist. The reticulated python of Southeast Asia is longer but more slender, and has been reported to measure as much as in length and weigh up to. The Burmese python, a south-east Asian species is known to reach up to and weigh as much as and is generally among the three heaviest species of snakes. Several other species of python can reach or exceed in length and in weight. Fossils of what may be the largest snake ever, the extinct boa Titanoboa were found in coal mines in Colombia. It has been estimated to reach a length of and weighed about. Length estimates for another very long extinct snake, the madtsoiid Vasuki indicus of India, range from.
• Among the colubrids, the most diverse snake family, the largest snake may be the keeled rat snake at up to. The Indian rat snake is also very large with maximum sizes of up to, making it the second-largest species in the genus Ptyas. The Tiger rat snake, which usually grows to about, has been reported to reach up to, ranking it among the largest colubrids. The genus Drymarchon also contains some of the largest colubrids such as the Eastern indigo snake and the indigo snake which can both reach lengths of more than. Few other species in the colubrid family can reach lengths of, but they are relatively slender and generally do not exceed in weight.
• The longest venomous snake is the king cobra, with lengths of up to and a weight of up to. It is also the largest elapid. The second-longest venomous snake in the world is possibly the African black mamba, which can grow up to. Among the genus Naja, the longest member arguably may be the forest cobra, which can reportedly grow up to. The King brown snake, reaching lengths of up to and weights of or more, is the largest venomous snake in Australia. The Yellow sea snake is the largest of the sea snakes growing up to a length of. Few other elapids can reach or exceed in length and in weight.
• The Gaboon viper, a very bulky species with a maximum length of around, is typically the heaviest non-constrictor snake and the biggest member of the viper family, with unverified specimens reported to as much as. The Eastern diamondback rattlesnake is nearly as large, with the maximum length being and maximum weight being. The rattlesnake genus Crotalus, which includes the aforementioned eastern diamondback rattlesnake and western diamondback rattlesnake, reaches a maximum length of, and according to W. A. King one large specimen had a length of and a mass of. The third largest rattlesnake is the Mexican west coast rattlesnake, which reaches long and mass, and one captive-raised male was weighed at in 2020. While not quite as heavy, other members of the viper family are longer still, the South American bushmaster and Central American bushmaster, with a maximum length in the range of, with the former being considered as the third-longest venomous snake in the world.

Lizards

• The largest of the monitor lizards is the Komodo dragon, endemic to the island of its name, at a maximum size of long and, although this is currently the only record that places the mass above. Crocodile monitor is probably the longest extant lizard, known to grow as much as, with reported lengths of up to and weights of up to. The Asian water monitor is also one of the largest lizards in the world, with sizes of up to and reported weights of up to. Few other species can reach or possibly exceed in length and in weight. The prehistoric Australian megalania, 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 and length of, and a maximum of at in length, which is toward the high end of the early estimates.
• Iguanas are very large lizards, some of which can reach lengths of up to 2 m and weigh more than. They are the largest lizards after some large species of monitor lizards, and the largest lizards in the New World. Iguanas vary considerably in size and form, but even the smallest lizards in this family are still quite large. Many sources describe the green iguana as the largest iguanid, often reaching lengths up to 1.5 metres and masses of, and with a maximum length of 2 m and a mass of and in some cases even. However, the heaviest species in this family is the blue iguana, with a total length of up to 1.5 m, a SVL of 51–76 cm and a mass of up to It is the eighth-heaviest and largest extant lizard. Other large species in this family include the Galapagos land iguana, with a length of about 1.5 m and a mass of up to. It is the second-heaviest iguanid after the blue iguana and the ninth-heaviest and largest lizard in the world. Another large species from the same genus is the Santa Fe land iguana, reaching a SVL of and a mass of. The Galapagos pink land iguana have snout-vent length and the mass of. The marine iguana is also among the largest iguanas in the world, and the largest reptile on Galapagos Islands after the Galapagos land iguana, not including turtles reaching a maximum total length of 1.4 m, a SVL of from 12 till 56 cm and a mass of from depending on islands.
• The largest extant gecko is the New Caledonian giant gecko of New Caledonia, which can grow to 14 inches in length. It was surpassed in size by the extinct Kawekaweau of New Zealand, which grew to a length of.

Mosasaurs

• The largest members of this order were the giant mosasaurs, which grew to around and were projected to weigh up to.

Tuataras (Sphenodontia)

Ichthyosaurs (Ichthyosauria)

Pantestudines

Turtles and tortoises (Testudines)

• The largest extant turtle is the leatherback sea turtle, reaching a maximum total length of and a weight of. The second-largest extant testudine is the Loggerhead sea turtle. It tends to weigh slightly more on average than the green sea turtle, and reaches more massive top sizes. The Loggerhead sea turtle reaches a maximum size of and weight of, while the Green sea turtle reaches a maximum weight in the range of. The Flatback sea turtle may reach a weight of up to. Other species of Sea turtles are small-medium in size, but are still considered as large-sized for a typical turtle.
• The largest extant freshwater turtle is possibly the North American alligator snapping turtle, which has an unverified maximum reported weight of, although this is challenged by several rare, giant softshell turtle from Asia unverified to and nearly in total length. The Yangtze giant softshell turtle, a critically endangered species of softshell turtle, is sometimes considered as the largest extant freshwater turtle. The heaviest recorded specimen was reported to weigh. Some researchers have claimed that a related species, the Asian giant softshell turtle, is the largest living species of freshwater turtle. However, such claims are fraught with problems, because it now seems likely that this species is actually a composite, i.e., consisting of several separate, presently undifferentiated species that have all been traditionally but erroneously lumped together taxonomically as a single species. In the genus chitra, two species of critically endangered turtles have been reported to grow to massive sizes. The Asian narrow-headed softshell turtle, at up to, and the Indian narrow-headed softshell turtle, at up to, are also contenders for the title of the largest extant freshwater turtle.
• The Galápagos tortoise and the Aldabra giant tortoise are considered the largest truly terrestrial reptiles alive today. While the Aldabra tortoise averages larger at, the more variable-sized Galapagos tortoise can reach a greater maximum size of and in total length. The Aldabra giant tortoise has a maximum recorded weight of. The African spurred tortoise is the third-largest extant tortoise in the world. The large adults of this species may reach in length and weigh more than. Other relatively large-sized tortoises include the Yellow-footed tortoise and Leopard tortoise, at up to, and the Asian forest tortoise, at up to or more, can be rather large as well. The tortoise Megalochelys, of the Pleistocene epoch from what is now Pakistan and India, was even larger, at nearly in shell length and.
• The largest of side-necked turtles is the Arrau turtle. Its carapace length is up to and adults can reach up to in weight. There are also reports of these turtles weighing up to. The Mata mata is another large species of side-necked turtle with a carapace length of up to and weight of more than.
• There are many extinct turtles that vie for the title of the largest ever. The largest freshwater turtle seems to be Stupendemys, with an estimated parasagittal carapace length of and weight of up to. A close contender is Archelon ischyros, a sea turtle, which reached a length of and a weight of.

Meiolaniformes

Plesiosaurs (Plesiosauria)

Crocodilians (Crocodilia)

• Some species of crocodiles such as Saltwater crocodile, Nile crocodile, American crocodile and the critically endangered Orinoco crocodile can reach lengths of or more. The largest known specimen among the living crocodilians was an Orinoco crocodile with a length of . One of the largest known Saltwater crocodile measured and was shot in Papua New Guinea. A long individual was captured alive in Mindanao in 2011. The largest confirmed Saltwater crocodile on record was long, and weighed about. In 2006, Guinness World Records accepted claims of a, male saltwater crocodile, living within Bhitarkanika National Park. Due to the difficulty of trapping and measuring a large living crocodile, the accuracy of these dimensions is yet to be verified. These observations and estimations have been made by park officials over the course of ten years, from 2006 to 2016, however, regardless of the skill of the observers it cannot be compared to a verified tape measurement, especially considering the uncertainty inherent in visual size estimation in the wild. The largest Nile crocodile accurately measured, shot near Mwanza, Tanzania, measured and weighed about. Another large Nile crocodile specimen was purported to be a man-eater from Burundi named Gustave; it was thought to have been more than long. The American crocodile is also one of the largest crocodile species, with large males in the southern part of their range reported to approach in size. Based on projections from various skulls, the largest males may have reached in length, and their predicted mass reached up to. Other crocodiles can also grow to large sizes, such the Mugger crocodile, which typically reaches an average maximum length of, and has a maximum reported length of. The extinct Crocodylus thorbjarnarsoni was the largest species in its genus, growing up to in length. The largest true crocodile ever existed is Euthecodon which estimated to have reached or even long.
• A long gharial was killed in the Ghaghara River in Faizabad in August 1920. Male gharials may grow up to a length of. The heaviest recorded gharial was a male measuring in total length and weighing. The False gharial is also a large crocodilian with males reaching in length, weighing up to at least. The largest gavialid to ever exist was the extinct Rhamphosuchus from the Miocene of Asia. It was originally thought to be long and more than in weight but later estimations suggest and. Based on its fossils, the latter species was less massive and heavy than the other giant crocodilians, weighing an estimated.
• The largest member of the family Alligatoridae is the Black caiman with the American alligator sometimes growing to similar lengths. Black caimans can reach more than in length and weigh up to. American alligators can be almost as large, with males reaching in length and weighing over. Unverified reports suggest lengths of up to for the black caiman and for the American alligator, reaching weights of over, but such lengths are probably exaggerated.

• The giant prehistoric caiman, Purussaurus, from northern South America during the Miocene epoch grew up to 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 who according to a 2025 study D. riograndensis reached total lengths of Sarcosuchus imperator of the early Cretaceous was found in the Sahara desert and could measure up to and weigh an estimated.

Pterosaurs (Pterosauria)

Non-avian dinosaurs (Dinosauria)

• The main contender for the largest sauropod and the longest known vertebrate is Bruhathkayosaurus matleyi known from now disentereated remains which was upto in length and in weight. With paleontologist Michael Benton, giving Bruhathkayosaurus a length of 45 metres. Another large sauropod is Maraapunisaurus fragillimus. Known only by lost vertebra, it was estimated at in length and in weight but later studies suggest smaller size, about in length and in weight. Breviparopus taghbaloutensis was mentioned in The Guinness Book of Records as the longest dinosaur at but this animal is known only from fossil tracks. In 2020 Molina Perez & Larramendi suggested that the narrow-gauge track, the position of the claws, and the era all indicate that it belonged to an enormous diplodocoid, and estimated its size at 33.5 m and 62 t. The better studied Supersaurus was possibly as long as over. One of the heaviest sauropods was Argentinosaurus at in length and or even in body mass. The tallest sauropods were probably Xinjiangtitan and Sauroposeidon with total height of and, respectively.
• The largest non-avian theropod was Tyrannosaurus rex, estimated at 12.1-12.2 m in length and around in weight.
• The largest thyreophoran was Ankylosaurus at in length and in weight.
• The largest ceratopsian was Triceratops, reaching in length and in weight.
• The largest ornithopod was the Late Cretaceous Shantungosaurus at up to, and in length.