:Lizard

The adult length of species within the suborder ranges from a few centimeters for chameleons such as Brookesia micra and geckos such as Sphaerodactylus ariasae{{cite news|last1=Muir|first1=Hazel|title=Minute gecko matches smallest reptile record|url=https://www.newscientist.com/article/dn1635-minute-gecko-matches-smallest-reptile-record/|work=New Scientist|date=3 December 2001|access-date=12 July 2017|archive-date=17 September 2015|archive-url=https://web.archive.org/web/20150917030703/https://www.newscientist.com/article/dn1635-minute-gecko-matches-smallest-reptile-record/|url-status=live}} to nearly {{convert|3|m|0|abbr=on}} in the case of the largest living varanid lizard, the Komodo dragon.{{cite news|title=The world's top 10 reptiles – in pictures|url=https://www.theguardian.com/environment/gallery/2016/may/05/the-worlds-top-10-reptiles-in-pictures|work=The Guardian|date=5 May 2016|access-date=12 July 2017|archive-date=2 May 2021|archive-url=https://web.archive.org/web/20210502195839/https://www.theguardian.com/environment/gallery/2016/may/05/the-worlds-top-10-reptiles-in-pictures|url-status=live}} Most lizards are fairly small animals.

File:Mediterranean house gecko1.jpg in the process of moulting.|300px]]

Lizards typically have rounded torsos, elevated heads on short necks, four limbs and long tails, although some are legless.{{cite book|editor=McDiarmid, Roy W.|display-editors=etal |title=Reptile Biodiversity: Standard Methods for Inventory and Monitoring|year=2012|contribution=Reptile Diversity and Natural History: An Overview|author=McDiarmid, Roy W.|page=13|publisher=University of California Press |isbn=978-0520266711}} Lizards and snakes share a movable quadrate bone, distinguishing them from the rhynchocephalians, which have more rigid diapsid skulls.{{cite journal| author=Jones| display-authors=etal| title=Hard tissue anatomy of the cranial joints in Sphenodon (Rhynchocephalia): sutures, kinesis, and skull mechanics| journal=Palaeontologia Electronica| date=2011| volume=14(2, 17A)| pages=1–92| url=https://palaeo-electronica.org/2011_2/251/index.html| access-date=2019-02-04| archive-date=2012-11-29| archive-url=https://web.archive.org/web/20121129115710/https://palaeo-electronica.org/2011_2/251/index.html| url-status=live}} Some lizards such as chameleons have prehensile tails, assisting them in climbing among vegetation.

As in other reptiles, the skin of lizards is covered in overlapping scales made of keratin. This provides protection from the environment and reduces water loss through evaporation. This adaptation enables lizards to thrive in some of the driest deserts on earth. The skin is tough and leathery, and is shed (sloughed) as the animal grows. Unlike snakes which shed the skin in a single piece, lizards slough their skin in several pieces. The scales may be modified into spines for display or protection, and some species have bone osteoderms underneath the scales.{{cite book|author1=Starr, C. |author2=Taggart, R. |author3=Evers, C. |year=2012|title=Biology: The Unity and Diversity of Life|publisher=Cengage Learning|page=429|isbn=978-1111425692}}

File:Red Tegu Skull.jpg) skull, showing teeth of differing types]]

The dentitions of lizards reflect their wide range of diets, including carnivorous, insectivorous, omnivorous, herbivorous, nectivorous, and molluscivorous. Species typically have uniform teeth suited to their diet, but several species have variable teeth, such as cutting teeth in the front of the jaws and crushing teeth in the rear. Most species are pleurodont, though agamids and chameleons are acrodont.{{cite book |author=Pough|display-authors=etal|orig-year=1992 |title=Herpetology |edition=Third |publisher=Pearson Prentice Hall |date=2002 }}

The tongue can be extended outside the mouth, and is often long. In the beaded lizards, whiptails and monitor lizards, the tongue is forked and used mainly or exclusively to sense the environment, continually flicking out to sample the environment, and back to transfer molecules to the vomeronasal organ responsible for chemosensation, analogous to but different from smell or taste. In geckos, the tongue is used to lick the eyes clean: they have no eyelids. Chameleons have very long sticky tongues which can be extended rapidly to catch their insect prey.

Three lineages, the geckos, anoles, and chameleons, have modified the scales under their toes to form adhesive pads, highly prominent in the first two groups. The pads are composed of millions of tiny setae (hair-like structures) which fit closely to the substrate to adhere using van der Waals forces; no liquid adhesive is needed.{{cite journal |last1=Spinner |first1=Marlene|display-authors=etal|title=Subdigital setae of chameleon feet: Friction-enhancing microstructures for a wide range of substrate roughness |journal=Scientific Reports |date=2014 |volume=4 |pages=5481 |doi=10.1038/srep05481 |pmid=24970387 |pmc=4073164 |bibcode=2014NatSR...4.5481S }} In addition, the toes of chameleons are divided into two opposed groups on each foot (zygodactyly), enabling them to perch on branches as birds do.{{efn|Chameleon forefeet have groups composed of 3 inner and 2 outer digits; the hindfeet have groups of 2 inner and 3 outer digits.}}

File:Gecko foot on glass.JPGs to climb vertically.]]

Aside from legless lizards, most lizards are quadrupedal and move using gaits with alternating movement of the right and left limbs with substantial body bending. This body bending prevents significant respiration during movement, limiting their endurance, in a mechanism called Carrier's constraint. Several species can run bipedally,{{cite journal|url=http://jeb.biologists.org/content/202/9/1047|title=Comparative three-dimensional kinematics of the hindlimb for high-speed bipedal and quadrupedal locomotion of lizards|first1=D. J.|last1=Irschick|first2=B. C.|last2=Jayne|date=1 May 1999|journal=Journal of Experimental Biology|volume=202|issue=9|pages=1047–1065|doi=10.1242/jeb.202.9.1047|via=jeb.biologists.org|pmid=10101105|bibcode=1999JExpB.202.1047I |access-date=6 July 2017|archive-date=31 December 2020|archive-url=https://web.archive.org/web/20201231195836/https://jeb.biologists.org/content/202/9/1047|url-status=live}} and a few can prop themselves up on their hindlimbs and tail while stationary. Several small species such as those in the genus Draco can glide: some can attain a distance of {{convert|60|m|ft|abbr=off}}, losing {{convert|10|m|ft|abbr=off}} in height.Piper, Ross (2007), Extraordinary Animals: An Encyclopedia of Curious and Unusual Animals, Greenwood Press. Some species, like geckos and chameleons, adhere to vertical surfaces including glass and ceilings. Some species, like the common basilisk, can run across water.Pianka and Vitt, 23–24

Lizards make use of their senses of sight, touch, olfaction and hearing like other vertebrates. The balance of these varies with the habitat of different species; for instance, skinks that live largely covered by loose soil rely heavily on olfaction and touch, while geckos depend largely on acute vision for their ability to hunt and to evaluate the distance to their prey before striking. Monitor lizards have acute vision, hearing, and olfactory senses. Some lizards make unusual use of their sense organs: chameleons can steer their eyes in different directions, sometimes providing non-overlapping fields of view, such as forwards and backwards at once. Lizards lack external ears, having instead a circular opening in which the tympanic membrane (eardrum) can be seen. Many species rely on hearing for early warning of predators, and flee at the slightest sound.{{cite book |last=Wilson |first=Steve |title=Australian Lizards: A Natural History |url=https://books.google.com/books?id=NXg0N_vm2W4C&pg=PA65 |year=2012 |publisher=Csiro Publishing |isbn=978-0-643-10642-0 |pages=65–74}}

File:Nile Monitor (Varanus niloticus) (16545024096).jpg

As in snakes and many mammals, all lizards have a specialised olfactory system, the vomeronasal organ, used to detect pheromones. Monitor lizards transfer scent from the tip of their tongue to the organ; the tongue is used only for this information-gathering purpose, and is not involved in manipulating food.{{cite journal |author=Frasnelli, J.|display-authors=etal|title=The vomeronasal organ is not involved in the perception of endogenous odors |journal=Hum. Brain Mapp. |volume=32 |issue=3 |pages=450–60 |date=2011 |pmid=20578170 |pmc=3607301 |doi=10.1002/hbm.21035}}

File:Bearded Dragon Skeleton.jpg sp.) on display at the Museum of Osteology.]]

Some lizards, particularly iguanas, have retained a photosensory organ on the top of their heads called the parietal eye, a basal ("primitive") feature also present in the tuatara. This "eye" has only a rudimentary retina and lens and cannot form images, but is sensitive to changes in light and dark and can detect movement. This helps them detect predators stalking it from above.{{citation | last = Brames | first = Henry | title = Aspects of Light and Reptile Immunity | journal = Iguana: Conservation, Natural History, and Husbandry of Reptiles | volume = 14 | issue = 1 | year = 2007 | pages = 19–23 | url = http://www.ircf.org/downloads/wwdigitalmembers/Iguana_14-1web.pdf }}{{dead link|date=January 2018 |bot=InternetArchiveBot |fix-attempted=yes }}

File:AZ Gila Monster 02.jpg are venomous.]]

{{further|Evolution of snake venom}}

Until 2006 it was thought that the Gila monster and the Mexican beaded lizard were the only venomous lizards. However, several species of monitor lizards, including the Komodo dragon, produce powerful venom in their oral glands. Lace monitor venom, for instance, causes swift loss of consciousness and extensive bleeding through its pharmacological effects, both lowering blood pressure and preventing blood clotting. Nine classes of toxin known from snakes are produced by lizards. The range of actions provides the potential for new medicinal drugs based on lizard venom proteins.{{cite journal |last1=Fry |first1=Bryan G.|display-authors=etal|title=Early evolution of the venom system in lizards and snakes |journal=Nature |date=16 November 2005 |volume=439 |issue=7076 |pages=584–588 |doi=10.1038/nature04328|pmid=16292255 |bibcode=2006Natur.439..584F |s2cid=4386245}}{{cite magazine |last1=Casey |first1=Constance |title=Don't Call It a Monster |url=http://www.slate.com/articles/health_and_science/science/2013/04/gila_monster_revolting_creature_the_large_venomous_lizard_of_the_u_s_southwest.html |magazine=Slate |date=26 April 2013 |access-date=5 July 2017 |archive-date=10 October 2018 |archive-url=https://web.archive.org/web/20181010001503/http://www.slate.com/articles/health_and_science/science/2013/04/gila_monster_revolting_creature_the_large_venomous_lizard_of_the_u_s_southwest.html |url-status=live }}

Genes associated with venom toxins have been found in the salivary glands of a wide range of lizards, including species traditionally thought of as non-venomous, such as iguanas and bearded dragons. This suggests that these genes evolved in the common ancestor of lizards and snakes, some 200 million years ago (forming a single clade, the Toxicofera). However, most of these putative venom genes were "housekeeping genes" found in all cells and tissues, including skin and cloacal scent glands. The genes in question may thus be evolutionary precursors of venom genes.{{cite journal |last1=Hargreaves |first1=Adam D. |display-authors=etal |title=Testing the Toxicofera: Comparative transcriptomics casts doubt on the single, early evolution of the reptile venom system |journal=Toxicon |date=2014 |volume=92 |pages=140–156 |doi=10.1016/j.toxicon.2014.10.004 |pmid=25449103 |bibcode=2014Txcn...92..140H |url=https://research.bangor.ac.uk/portal/en/researchoutputs/testing-the-toxicofera-comparative-reptile-transcriptomics-casts-doubt-on-the-single-early-evolution-of-the-reptile-venom-system(5e889426-c4ec-4324-81e8-6df67558bd3b).html |hdl=2160/26793 |hdl-access=free |access-date=2019-08-19 |archive-date=2020-11-06 |archive-url=https://web.archive.org/web/20201106092216/https://research.bangor.ac.uk/portal/en/researchoutputs/testing-the-toxicofera-comparative-reptile-transcriptomics-casts-doubt-on-the-single-early-evolution-of-the-reptile-venom-system(5e889426-c4ec-4324-81e8-6df67558bd3b).html |url-status=live }}

Recent studies (2013 and 2014) on the lung anatomy of the savannah monitor and green iguana found them to have a unidirectional airflow system, which involves the air moving in a loop through the lungs when breathing. This was previously thought to only exist in the archosaurs (crocodilians and birds). This may be evidence that unidirectional airflow is an ancestral trait in diapsids.{{cite journal |author1=Schachner, Emma R. |author2=Cieri, Robert L. |author3=Butler, James P. |author4=Farmer, C. G. |year=2014 |title=Unidirectional pulmonary airflow patterns in the savannah monitor lizard |journal=Nature |volume=506 |issue=7488 |pages=367–370 |doi=10.1038/nature12871|pmid=24336209 |bibcode=2014Natur.506..367S |s2cid=4456381 |url=http://nrs.harvard.edu/urn-3:HUL.InstRepos:32631102 |url-access=subscription }}{{cite journal |author1=Robert L. |author2=Craven, Brent A. |author3=Schachner, Emma R. |author4=Farmer, C. G. |year=2014 |title=New insight into the evolution of the vertebrate respiratory system and the discovery of unidirectional airflow in iguana lungs |journal=PNAS |volume=111 |issue=48 |pages=17218–17223 |doi=10.1073/pnas.1405088111|pmid=25404314 |pmc=4260542 |bibcode=2014PNAS..11117218C |doi-access=free }}

File:Trachylepis maculilabris mating.jpg mating]]

As with all amniotes, lizards rely on internal fertilisation and copulation involves the male inserting one of his hemipenes into the female's cloaca.Pianka and Vitt, pp. 108. Female lizards also have

hemiclitorises, a doubled

clitoris. The majority of species are oviparous (egg laying). The female deposits the eggs in a protective structure like a nest or crevice or simply on the ground. Depending on the species, clutch size can vary from 4–5 percent of the females body weight to 40–50 percent and clutches range from one or a few large eggs to dozens of small ones.Pianka and Vitt, pp. 110–111.

File:EasternFenceLizard Egg.png egg layered onto one image.]]

In most lizards, the eggs have leathery shells to allow for the exchange of water, although more arid-living species have calcified shells to retain water. Inside the eggs, the embryos use nutrients from the yolk. Parental care is uncommon and the female usually abandons the eggs after laying them. Brooding and protection of eggs do occur in some species. The female prairie skink uses respiratory water loss to maintain the humidity of the eggs which facilitates embryonic development. In lace monitors, the young hatch close to 300 days, and the female returns to help them escape the termite mound where the eggs were laid.Pianka and Vitt, pp. 115–116.

Around 20 percent of lizard species reproduce via viviparity (live birth). This is particularly common in Anguimorphs. Viviparous species give birth to relatively developed young which look like miniature adults. Embryos are nourished via a placenta-like structure.Pianka and Vitt, pp. 117–118. A minority of lizards have parthenogenesis (reproduction from unfertilised eggs). These species consist of all females who reproduce asexually with no need for males. This is known to occur in various species of whiptail lizards.Pianka and Vitt, pp. 119. Parthenogenesis was also recorded in species that normally reproduce sexually. A captive female Komodo dragon produced a clutch of eggs, despite being separated from males for over two years.{{cite news |author=Morales, Alex |publisher=Bloomberg Television |url=https://www.bloomberg.com/apps/news?pid=20601082&sid=apLYpeppu8ag&refer=canada |title=Komodo Dragons, World's Largest Lizards, Have Virgin Births |access-date=28 March 2008 |date=20 December 2006 |archive-date=8 October 2007 |archive-url=https://web.archive.org/web/20071008112514/http://www.bloomberg.com/apps/news?pid=20601082 |url-status=live }}

Sex determination in lizards can be temperature-dependent. The temperature of the eggs' micro-environment can determine the sex of the hatched young: low temperature incubation produces more females while higher temperatures produce more males. However, some lizards have sex chromosomes and both male heterogamety (XY and XXY) and female heterogamety (ZW) occur.

A significant component of aging in the painted dragon lizard Ctenophorus pictus is fading breeding colors.Olsson M, Tobler M, Healey M, Perrin C, Wilson M. A significant component of ageing (DNA damage) is reflected in fading breeding colors: an experimental test using innate antioxidant mimetics in painted dragon lizards. Evolution. 2012 Aug;66(8):2475-83. doi: 10.1111/j.1558-5646.2012.01617.x. Epub 2012 Apr 9. PMID 22834746 By manipulating superoxide levels (using a superoxide dismutase mimetic) it was shown that this fading coloration is likely due to gradual loss with lizard age of an innate capacity for antioxidation due to increasing DNA damage.

The majority of lizard species are active during the day, though some are active at night, notably geckos. As ectotherms, lizards have a limited ability to regulate their body temperature, and must seek out and bask in sunlight to gain enough heat to become fully active.Pianka and Vitt, pp. 32–37. Thermoregulation behavior can be beneficial in the short term for lizards as it allows the ability to buffer environmental variation and endure climate warming.{{Cite journal |last1=Buckley |first1=Lauren B. |last2=Ehrenberger |first2=Joseph C. |last3=Angilletta |first3=Michael J. |date=2015 |title=Thermoregulatory behaviour limits local adaptation of thermal niches and confers sensitivity to climate change |journal=Functional Ecology |volume=29 |issue=8 |pages=1038–1047 |doi=10.1111/1365-2435.12406 |jstor=48577009 |issn=0269-8463|doi-access=free |bibcode=2015FuEco..29.1038B }}

In high altitudes, the Podarcis hispaniscus responds to higher temperature with a darker dorsal coloration to prevent UV-radiation and background matching. Their thermoregulatory mechanisms also allow the lizard to maintain their ideal body temperature for optimal mobility.{{Cite journal|last1=Ortega|first1=Jesús|last2=Martín|first2=José|last3=Crochet|first3=Pierre-André|last4=López|first4=Pilar|last5=Clobert|first5=Jean|date=2019-03-15|title=Seasonal and interpopulational phenotypic variation in morphology and sexual signals of Podarcis liolepis lizards|journal=PLOS ONE|volume=14|issue=3|pages=e0211686|doi=10.1371/journal.pone.0211686|issn=1932-6203|pmc=6419997|pmid=30875384|bibcode=2019PLoSO..1411686O|doi-access=free}}

File:Fighting Sand lizards (Lacerta agilis) 4295304.jpg]]

Most social interactions among lizards are between breeding individuals.Pianka and Vitt, pp. 86. Territoriality is common and is correlated with species that use sit-and-wait hunting strategies. Males establish and maintain territories that contain resources that attract females and which they defend from other males. Important resources include basking, feeding, and nesting sites as well as refuges from predators. The habitat of a species affects the structure of territories, for example, rock lizards have territories atop rocky outcrops.Pianka and Vitt, pp. 94–106. Some species may aggregate in groups, enhancing vigilance and lessening the risk of predation for individuals, particularly for juveniles.{{cite journal |author1=Lanham, E. J. |author2=Bull. M. C. |year=2004 |title=Enhanced vigilance in groups in Egernia stokesii, a lizard with stable social aggregations |journal=Journal of Zoology |volume=263 |issue=1 |pages=95–99 |doi=10.1017/S0952836904004923}} Agonistic behaviour typically occurs between sexually mature males over territory or mates and may involve displays, posturing, chasing, grappling and biting.

{{main|Lizard communication}}

File:Green anole.jpg) signalling with its extended dewlap]]

Lizards signal both to attract mates and to intimidate rivals. Visual displays include body postures and inflation, push-ups, bright colours, mouth gapings and tail waggings. Male anoles and iguanas have dewlaps or skin flaps which come in various sizes, colours and patterns and the expansion of the dewlap as well as head-bobs and body movements add to the visual signals. Some species have deep blue dewlaps and communicate with ultraviolet signals. Blue-tongued skinks will flash their tongues as a threat display. Chameleons are known to change their complex colour patterns when communicating, particularly during agonistic encounters. They tend to show brighter colours when displaying aggression{{cite journal |last1=Ligon |first1=Russell A. |last2=McGraw |first2=Kevin J. |doi=10.1098/rsbl.2013.0892 |title=Chameleons communicate with complex colour changes during contests: different body regions convey different information |journal=Biology Letters |volume=9|issue=6 |page=20130892 |year=2013 |pmid=24335271 |pmc=3871380}} and darker colours when they submit or "give up".{{cite journal |last1=Ligon |first1=Russell A |doi=10.1007/s00265-014-1713-z |title=Defeated chameleons darken dynamically during dyadic disputes to decrease danger from dominants |journal=Behavioral Ecology and Sociobiology |volume=68 |issue=6 |pages=1007–1017 |year=2014|bibcode=2014BEcoS..68.1007L |s2cid=18606633 }}

Several gecko species are brightly coloured; some species tilt their bodies to display their coloration. In certain species, brightly coloured males turn dull when not in the presence of rivals or females. While it is usually males that display, in some species females also use such communication. In the bronze anole, head-bobs are a common form of communication among females, the speed and frequency varying with age and territorial status. Chemical cues or pheromones are also important in communication. Males typically direct signals at rivals, while females direct them at potential mates. Lizards may be able to recognise individuals of the same species by their scent.Pianka and Vitt, pp. 87–94.

{{Listen

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Acoustic communication is less common in lizards. Hissing, a typical reptilian sound, is mostly produced by larger species as part of a threat display, accompanying gaping jaws. Some groups, particularly geckos, snake-lizards, and some iguanids, can produce more complex sounds and vocal apparatuses have independently evolved in different groups. These sounds are used for courtship, territorial defense and in distress, and include clicks, squeaks, barks and growls. The mating call of the male tokay gecko is heard as "tokay-tokay!".{{cite web|author=Langley, L.|date=24 October 2015|title=Are Lizards as Silent as They Seem?|publisher=news.nationalgeographic.com|access-date=9 July 2017|url=http://news.nationalgeographic.com/2015/10/151024-animal-behavior-lizards-reptiles-geckos-science-anatomy/|archive-url=https://web.archive.org/web/20151025213158/http://news.nationalgeographic.com/2015/10/151024-animal-behavior-lizards-reptiles-geckos-science-anatomy/|url-status=dead|archive-date=October 25, 2015}}{{cite journal|author1=Frankenberg, E. |author2=Werner, Y. L. |year=1992|title= Vocal communication in the Reptilia–facts and questions|publisher=Acta Zoologica|volume=41|pages=45–62|url=https://www.researchgate.net/publication/285079253}} Tactile communication involves individuals rubbing against each other, either in courtship or in aggression. Some chameleon species communicate with one another by vibrating the substrate that they are standing on, such as a tree branch or leaf.{{cite journal|author1=Barnett, K. E.|author2=Cocroft, R. B.|author3=Fleishman, L. J.|year=1999|title=Possible communication by substrate vibration in a chameleon|journal=Copeia|volume=1999|issue=1|pages=225–228|url=http://www.biosci.missouri.edu/cocroft/Publications/RBC%20pubs/1999%20Cocroft%20Copeia.pdf|doi=10.2307/1447408|jstor=1447408|access-date=2017-07-11|archive-date=2021-02-16|archive-url=https://web.archive.org/web/20210216044500/http://www.biosci.missouri.edu/cocroft/Publications/RBC%20pubs/1999%20Cocroft%20Copeia.pdf|url-status=dead}}

Lizards are normally quick and agile to easily outrun attackers.{{cite book| title = Exploring Life Sciences| volume = 6|pages = 474-475|ISBN = 0-7614-7141-3|publisher = Marshall Cavendish}}

File:Lizard namely Oriental Garden Lizard.jpg

File:Lizard of tharparkar.jpg desert]]

Lizards are found worldwide, excluding the far north and Antarctica, and some islands. They can be found in elevations from sea level to {{convert|5000|m|abbr=on}}. They prefer warmer, tropical climates but are adaptable and can live in all but the most extreme environments. Lizards also exploit a number of habitats; most primarily live on the ground, but others may live in rocks, on trees, underground and even in water. The marine iguana is adapted for life in the sea.

File:Western Green Lizard.jpg ambushes its grasshopper prey.]]

The majority of lizard species are predatory and the most common prey items are small, terrestrial invertebrates, particularly insects. Many species are sit-and-wait predators though others may be more active foragers.Pianka and Vitt, pp. 53–55. Chameleons prey on numerous insect species, such as beetles, grasshoppers and winged termites as well as spiders. They rely on persistence and ambush to capture these prey. An individual perches on a branch and stays perfectly still, with only its eyes moving. When an insect lands, the chameleon focuses its eyes on the target and slowly moves toward it before projecting its long sticky tongue which, when hauled back, brings the attached prey with it. Geckos feed on crickets, beetles, termites and moths.

Termites are an important part of the diets of some species of Autarchoglossa, since, as social insects, they can be found in large numbers in one spot. Ants may form a prominent part of the diet of some lizards, particularly among the lacertas. Horned lizards are also well known for specializing on ants. Due to their small size and indigestible chitin, ants must be consumed in large amounts, and ant-eating lizards have larger stomachs than even herbivorous ones.Pianka and Vitt, pp. 162. Species of skink and alligator lizards eat snails and their power jaws and molar-like teeth are adapted for breaking the shells.{{cite book |author1=Bauer, A. M. |author2=Kluge, A. G. |author3=Schuett, G. |year=2002 |contribution=Lizards |title=The Firefly Encyclopedia of Reptiles and Amphibians |editor=Halliday, T. |editor2=Adler, K. |publisher=Firefly Books |pages=[https://archive.org/details/fireflyencyclope0000unse_p6l7/page/139 139–169] |isbn=978-1-55297-613-5 |url=https://archive.org/details/fireflyencyclope0000unse_p6l7/page/139 }}

File:Komodo Dragon Eating Rinca.jpg carcass]]

File:Marine Iguana (Amblyrhynchus cristatus), Galápagos Islands, Ecuador - foraging under water (5755672016).jpg

Larger species, such as monitor lizards, can feed on larger prey including fish, frogs, birds, mammals and other reptiles. Prey may be swallowed whole and torn into smaller pieces. Both bird and reptile eggs may also be consumed as well. Gila monsters and beaded lizards climb trees to reach both the eggs and young of birds. Despite being venomous, these species rely on their strong jaws to kill prey. Mammalian prey typically consists of rodents and leporids; the Komodo dragon can kill prey as large as water buffalo. Dragons are prolific scavengers, and a single decaying carcass can attract several from {{convert|2|km|abbr=on}} away. A {{convert|50|kg|abbr=on}} dragon is capable of consuming a {{convert|31|kg|abbr=on}} carcass in 17 minutes.Pianka and Vitt, pp. 41–51.

Around 2 percent of lizard species, including many iguanids, are herbivores. Adults of these species eat plant parts like flowers, leaves, stems and fruit, while juveniles eat more insects. Plant parts can be hard to digest, and, as they get closer to adulthood, juvenile iguanas eat faeces from adults to acquire the microflora necessary for their transition to a plant-based diet. Perhaps the most herbivorous species is the marine iguana which dives {{convert|15|m|abbr=on}} to forage for algae, kelp and other marine plants. Some non-herbivorous species supplement their insect diet with fruit, which is easily digested.

File:Frilled-lizard500.jpg with fully extended frill. The frilled neck serves to make it look bigger than it actually is.]]

{{main|Antipredator adaptation}}

Lizards have a variety of antipredator adaptations, including running and climbing, venom, camouflage, tail autotomy, and reflex bleeding.

Lizards exploit a variety of different camouflage methods. Many lizards are disruptively patterned. In some species, such as Aegean wall lizards, individuals vary in colour, and select rocks which best match their own colour to minimise the risk of being detected by predators.{{cite journal |author1=Marshall, Kate |author2=Philpot, Kate E. |author3=Stevens, Martin |title=Microhabitat choice in island lizards enhances camouflage against avian predators |journal=Scientific Reports |date=25 January 2016 |volume=6 |page=19815 |doi=10.1038/srep19815|pmid=26804463 |pmc=4726299 |bibcode=2016NatSR...619815M }} The Moorish gecko is able to change colour for camouflage: when a light-coloured gecko is placed on a dark surface, it darkens within an hour to match the environment.{{cite magazine |last1=Yong |first1=Ed |title=Lizard 'Sees' With Its Skin For Automatic Camouflage |url=http://phenomena.nationalgeographic.com/2014/07/16/lizard-sees-with-its-skin-for-automatic-camouflage/ |archive-url=https://web.archive.org/web/20140719043136/http://phenomena.nationalgeographic.com/2014/07/16/lizard-sees-with-its-skin-for-automatic-camouflage/ |url-status=dead |archive-date=July 19, 2014 |magazine=National Geographic |date=16 July 2014}} The chameleons in general use their ability to change their coloration for signalling rather than camouflage, but some species such as Smith's dwarf chameleon do use active colour change for camouflage purposes.{{cite journal |last1=Stuart-Fox |first1=Devi |last2=Moussalli |first2=Adnan |last3=Whiting |first3=Martin J. |title=Predator-specific camouflage in chameleons |journal=Biology Letters |date=23 August 2008 |volume=4 |issue=4 |doi=10.1098/rsbl.2008.0173 |pmid=18492645 |pages=326–329|pmc=2610148 }}

The flat-tail horned lizard's body is coloured like its desert background, and is flattened and fringed with white scales to minimise its shadow.{{cite book | title=Introduction to horned lizards of North America | publisher=University of California Press | author=Sherbrooke, WC | year=2003 | pages=117–118 | isbn=978-0-520-22825-2 | url=https://books.google.com/books?id=zXlLdu3956gC&pg=PA118}}{{Clear}}

File:Severed skink tail.webm]]

Many lizards, including geckos and skinks, are capable of shedding their tails (autotomy). The detached tail, sometimes brilliantly coloured, continues to writhe after detaching, distracting the predator's attention from the fleeing prey. Lizards partially regenerate their tails over a period of weeks. Some 326 genes are involved in regenerating lizard tails.[https://www.independent.co.uk/news/science/scientists-discover-how-lizards-regrow-tails-9681841.html Scientists discover how lizards regrow tails] {{Webarchive|url=https://web.archive.org/web/20171027042902/http://www.independent.co.uk/news/science/scientists-discover-how-lizards-regrow-tails-9681841.html |date=2017-10-27 }}, The Independent, August 20, 2014 The fish-scale gecko Geckolepis megalepis sheds patches of skin and scales if grabbed.{{cite journal|last1=Scherz|first1=Mark D.|display-authors=etal|title=Off the scale: a new species of fish-scale gecko (Squamata: Gekkonidae: Geckolepis) with exceptionally large scales|journal=PeerJ |date=2017 |volume=5 |pages=e2955 |pmid=28194313 |doi=10.7717/peerj.2955 |pmc=5299998 |doi-access=free }}

Many lizards attempt to escape from danger by running to a place of safety;{{cite journal |last1=Cooper | first1=William E. Jr. |title=Initiation of Escape Behavior by the Texas Horned Lizard (Phrynosoma cornutum) |journal=Herpetologica |date=2010 |volume=66 |issue=1 |pages=23–30 |doi=10.1655/08-075.1 |s2cid=84653226 }}{{efn|The BBC's 2016 Planet Earth II showed a sequence of newly-hatched marine iguanas running to the sea past a waiting crowd of racer snakes. It was edited for dramatic effect but the sections were all genuine.{{cite web |title=From Planet Earth II, a baby iguana is chased by snakes |url=http://www.bbc.com/earth/story/20161114-from-planet-earth-ii-a-baby-iguana-is-chased-by-snakes |publisher=BBC |date=15 November 2016 |access-date=6 July 2017 |archive-date=2 May 2021 |archive-url=https://web.archive.org/web/20210502200038/http://www.bbc.com/earth/story/20161114-from-planet-earth-ii-a-baby-iguana-is-chased-by-snakes |url-status=live }}}} for example, wall lizards can run up walls and hide in holes or cracks. Horned lizards adopt differing defences for specific predators. They may play dead to deceive a predator that has caught them; attempt to outrun the rattlesnake, which does not pursue prey; but stay still, relying on their cryptic coloration, for Masticophis whip snakes which can catch even swift prey. If caught, some species such as the greater short-horned lizard puff themselves up, making their bodies hard for a narrow-mouthed predator like a whip snake to swallow. Finally, horned lizards can squirt blood at cat and dog predators from a pouch beneath its eyes, to a distance of about {{convert|2|m|ft|abbr=off|spell=in}}; the blood tastes foul to these attackers.{{cite web |last1=Hewitt |first1=Sarah |title=If it has to, a horned lizard can shoot blood from its eyes |url=http://www.bbc.com/earth/story/20151105-if-it-has-to-a-horned-lizard-can-shoot-blood-from-its-eyes |publisher=BBC |date=5 November 2015 |access-date=6 July 2017 |archive-date=2 May 2021 |archive-url=https://web.archive.org/web/20210502200020/http://www.bbc.com/earth/story/20151105-if-it-has-to-a-horned-lizard-can-shoot-blood-from-its-eyes |url-status=live }}

File:DalinghesaurusLongidigitus-PaleozoologicalMuseumOfChina-May23-08 (cropped).jpg, Early Cretaceous, China]]

The closest living relatives of lizards are rhynchocephalians, a once diverse order of reptiles, of which is there is now only one living species, the tuatara of New Zealand. Some reptiles from the Early and Middle Triassic, like Sophineta and Megachirella, are suggested to be stem-group squamates, more closely related to modern lizards than rhynchocephalians, however, their position is disputed, with some studies recovering them as less closely related to squamates than rhynchocephalians are.{{Cite journal |last1=Tałanda |first1=Mateusz |last2=Fernandez |first2=Vincent |last3=Panciroli |first3=Elsa |last4=Evans |first4=Susan E. |last5=Benson |first5=Roger J. |date=2022-11-03 |title=Synchrotron tomography of a stem lizard elucidates early squamate anatomy |url=https://www.nature.com/articles/s41586-022-05332-6 |journal=Nature |language=en |volume=611 |issue=7934 |pages=99–104 |doi=10.1038/s41586-022-05332-6 |pmid=36289329 |bibcode=2022Natur.611...99T |s2cid=253160713 |issn=0028-0836 |access-date=2022-12-31 |archive-date=2023-12-28 |archive-url=https://web.archive.org/web/20231228173131/https://www.nature.com/articles/s41586-022-05332-6 |url-status=live }} The oldest undisputed lizards date to the Middle Jurassic, from remains found In Europe, Asia and North Africa.{{Citation |last=Evans |first=Susan E. |title=The Origin and Early Diversification of Squamates |date=2022-08-11 |url=https://www.cambridge.org/core/product/identifier/9781108938891%23CN-bp-2/type/book_part |work=The Origin and Early Evolutionary History of Snakes |pages=7–25 |editor-last=Gower |editor-first=David J. |access-date=2024-01-10 |edition=1 |publisher=Cambridge University Press |doi=10.1017/9781108938891.004 |isbn=978-1-108-93889-1 |editor2-last=Zaher |editor2-first=Hussam|url-access=subscription }} Lizard morphological and ecological diversity substantially increased over the course of the Cretaceous.{{Cite journal |last1=Herrera-Flores |first1=Jorge A. |last2=Stubbs |first2=Thomas L. |last3=Benton |first3=Michael J. |date=March 2021 |title=Ecomorphological diversification of squamates in the Cretaceous |journal=Royal Society Open Science |language=en |volume=8 |issue=3 |pages=rsos.201961, 201961 |doi=10.1098/rsos.201961 |issn=2054-5703 |pmc=8074880 |pmid=33959350|bibcode=2021RSOS....801961H }} In the Palaeogene, lizard body sizes in North America peaked during the middle of the period.{{Cite journal |last=ElShafie |first=Sara J. |date=5 January 2024 |editor-last=Meloro |editor-first=Carlo |title=Body size estimation from isolated fossil bones reveals deep time evolutionary trends in North American lizards |journal=PLOS ONE |language=en |volume=19 |issue=1 |pages=e0296318 |doi=10.1371/journal.pone.0296318 |doi-access=free |issn=1932-6203 |pmc=10769094 |pmid=38180961 |bibcode=2024PLoSO..1996318E }}

Mosasaurs likely evolved from an extinct group of aquatic lizards{{cite AV media |last= Dash |first= Sean |title= Prehistoric Monsters Revealed |location= United States |publisher= Workaholic Productions / History Channel |date= 2008 |url= https://www.youtube.com/watch?v=lEEhm4rzxEg | archive-url=https://web.archive.org/web/20160127070909/https://www.youtube.com/watch?v=lEEhm4rzxEg| archive-date=2016-01-27|access-date= December 18, 2015}} known as aigialosaurs in the Early Cretaceous. Dolichosauridae is a family of Late Cretaceous aquatic varanoid lizards closely related to the mosasaurs.{{Cite journal|author1=Ilaria Paparella |author2=Alessandro Palci |author3=Umberto Nicosia |author4=Michael W. Caldwell |year=2018 |title=A new fossil marine lizard with soft tissues from the Late Cretaceous of southern Italy |journal=Royal Society Open Science |volume=5 |issue=6 |pages=172411 |doi=10.1098/rsos.172411 |pmid=30110414 |pmc=6030324 |bibcode=2018RSOS....572411P }}{{Cite journal|date=1999-01-01|title=Squamate phylogeny and the relationships of snakes and mosasauroids|journal=Zoological Journal of the Linnean Society|volume=125|issue=1|pages=115–147|doi=10.1006/zjls.1997.0144|issn=0024-4082|last1=Caldwell|first1=M.|doi-access=free}}

The position of the lizards and other Squamata among the reptiles was studied using fossil evidence by Rainer Schoch and Hans-Dieter Sues in 2015. Lizards form about 60% of the extant non-avian reptiles.{{Cite journal | last1=Schoch | first1=Rainer R. | last2=Sues | first2=Hans-Dieter | title=A Middle Triassic stem-turtle and the evolution of the turtle body plan | journal=Nature | volume=523 | issue=7562 | pages=584–587 | doi=10.1038/nature14472 | date=24 June 2015 | pmid=26106865 | bibcode=2015Natur.523..584S | s2cid=205243837 }}

{{clade

|label1=Archelosauria

|1={{clade

|1=Archosauromorpha100px40 px

|label2=Lepidosauromorpha

|2={{clade

|1={{clade

|1=Pantestudines 70px

|2={{clade

|1={{extinct}}Kuehneosauridae80px

|label2=Lepidosauria

|2={{clade

|1=Rhynchocephalia80px

|2=Squamata80px

}}

}}

}}

}}

}}

}}

Both the snakes and the Amphisbaenia (worm lizards) are clades deep within the Squamata (the smallest clade that contains all the lizards), so "lizard" is paraphyletic.{{cite journal |last1=Reeder |first1=Tod W. |last2=Townsend |first2=Ted M. |last3=Mulcahy |first3=Daniel G. |last4=Noonan |first4=Brice P.|last5=Wood |first5=Perry L. |last6=Sites |first6=Jack W. |last7=Wiens |first7=John J.|title=Integrated Analyses Resolve Conflicts over Squamate Reptile Phylogeny and Reveal Unexpected Placements for Fossil Taxa |journal=PLOS ONE |date=2015 |volume=10 |issue=3 |pages=e0118199 |doi=10.1371/journal.pone.0118199 |pmid=25803280|pmc=4372529|bibcode=2015PLoSO..1018199R |doi-access=free }}

The cladogram is based on genomic analysis by Wiens and colleagues in 2012 and 2016.{{cite journal | last1=Wiens | first1=J. J. | last2=Hutter | first2=C. R. | last3=Mulcahy | first3=D. G. | last4=Noonan | first4=B. P. | last5=Townsend | first5=T. M. | last6=Sites | first6=J. W. | last7=Reeder | first7=T. W. | year=2012 | title=Resolving the phylogeny of lizards and snakes (Squamata) with extensive sampling of genes and species | journal=Biology Letters | volume=8 | issue=6| pages=1043–1046 | doi=10.1098/rsbl.2012.0703 | pmid=22993238 | pmc=3497141}}{{cite journal|last1=Zheng |first1=Yuchi|last2=Wiens |first2=John J. |title=Combining phylogenomic and supermatrix approaches, and a time-calibrated phylogeny for squamate reptiles (lizards and snakes) based on 52 genes and 4162 species |journal=Molecular Phylogenetics and Evolution |date=2016 |volume=94 |issue=Pt B|pages=537–547 |doi=10.1016/j.ympev.2015.10.009|pmid=26475614|bibcode=2016MolPE..94..537Z }} Excluded taxa are shown in upper case on the cladogram.

{{clade| style=font-size:85%;line-height:80%

|label1=Squamata

|1={{clade

|label1=Dibamia

|1=Dibamidae

|label2=Bifurcata

|2={{clade

|label1=Gekkota

|1={{clade

|label1=Pygopodomorpha

|1={{clade

|1=Diplodactylidae 70 px

|2={{clade

|1=Pygopodidae 70 px

|2=Carphodactylidae

}}

}}

|label2=Gekkomorpha

|2={{clade

|1=Eublepharidae

|label2=Gekkonoidea

|2={{clade

|1=Sphaerodactylidae

|2={{clade

|1=Phyllodactylidae 70 px

|2=Gekkonidae 70px

}}

}}

}}

}}

|label2=Unidentata

|2={{clade

|label1=Scinciformata

|1={{clade

|label1=Scincomorpha

|1=Scincidae 70 px

|label2=Cordylomorpha

|2={{clade

|1=Xantusiidae

|2={{clade

|1=Gerrhosauridae 70 px

|2=Cordylidae 70 px

}}

}}

}}

|label2=Episquamata

|2={{clade

|label1=Laterata

|1={{clade

|label1=Teiformata

|1={{clade

|1=Gymnophthalmidae 70 px

|2=Teiidae 70 px

}}

|label2=Lacertibaenia

|2={{clade

|label1=Lacertiformata

|1=Lacertidae 70 px

|2=AMPHISBAENIA (worm lizards, not usually considered "true lizards") 70 px

}}

}}

|label2=Toxicofera

|2={{clade

|1={{clade

|label1=Anguimorpha

|1={{clade

|label1=Palaeoanguimorpha

|1={{clade

|label1=Shinisauria

|1=Shinisauridae

|label2=Varanoidea

|2={{clade

|1=Lanthanotidae

|2=Varanidae 90 px

}}

}}

|label2=Neoanguimorpha

|2={{clade

|label1=Helodermatoidea

|1=Helodermatidae 70 px

|2={{clade

|label1=Xenosauroidea

|1=Xenosauridae

|label2=Anguioidea

|2={{clade

|1=Diploglossidae

|2={{clade

|1=Anniellidae

|2=Anguidae 60px

}}

}}

}}

}}

}}

|label2=Iguanomorpha

|2={{clade

|label1=Acrodonta

|1={{clade

|1=Chamaeleonidae 70 px

|2=Agamidae 55 px

}}

|label2=Pleurodonta

|2={{clade

|1=Leiocephalidae

|2={{clade

|1=Iguanidae 70 px

|2={{clade

|1={{clade

|1=Hoplocercidae

|2={{clade

|1=Crotaphytidae

|2=Corytophanidae 70px

}}

}}

|2={{clade

|1=Tropiduridae

|2={{clade

|1={{clade

|1=Phrynosomatidae

|2={{clade

|1=Dactyloidae

|2=Polychrotidae

}}

}}

|2={{clade

|1=Liolaemidae

|2={{clade

|1=Leiosauridae

|2=Opluridae

}}

}}

}}

}}

}}

}}

}}

}}

}}

|2=SERPENTES (snakes, not considered to be lizards) 120 px

}}

}}

}}

}}

}}

}}

{{Main|List of Lacertilia families}}

Image:Prognathodon3.jpg]]

In the 13th century, lizards were recognized in Europe as part of a broad category of reptiles that consisted of a miscellany of egg-laying creatures, including "snakes, various fantastic monsters, […], assorted amphibians, and worms", as recorded by Vincent of Beauvais in his Mirror of Nature.{{cite book | last = Franklin-Brown | first = Mary | title = Reading the world : encyclopedic writing in the scholastic age | publisher = The University of Chicago Press | location = Chicago London | year = 2012 | isbn = 9780226260709|page=223;377}} The seventeenth century saw changes in this loose description. The name Sauria was coined by James Macartney (1802);James Macartney: Table III in: George Cuvier (1802) "Lectures on Comparative Anatomy" (translated by William Ross under the inspection of James Macartney). Vol I. London, Oriental Press, Wilson and Co. it was the Latinisation of the French name Sauriens, coined by Alexandre Brongniart (1800) for an order of reptiles in the classification proposed by the author, containing lizards and crocodilians,Alexandre Brongniart (1800) "Essai d'une classification naturelle des reptiles. 1ère partie: Etablissement des ordres." Bulletin de la Science. Société Philomathique de Paris 2 (35): 81–82 later discovered not to be each other's closest relatives. Later authors used the term "Sauria" in a more restricted sense, i.e. as a synonym of Lacertilia, a suborder of Squamata that includes all lizards but excludes snakes. This classification is rarely used today because Sauria so-defined is a paraphyletic group. It was defined as a clade by Jacques Gauthier, Arnold G. Kluge and Timothy Rowe (1988) as the group containing the most recent common ancestor of archosaurs and lepidosaurs (the groups containing crocodiles and lizards, as per Mcartney's original definition) and all its descendants.{{Cite journal| last=Gauthier | first=J. A. | author-link=Jacques Gauthier |author2=Kluge, A. G. |author3=Rowe, T. | title=Amniote phylogeny and the importance of fossils | journal=Cladistics | volume=4 | issue=2 | pages=105–209 | date=June 1988 | doi=10.1111/j.1096-0031.1988.tb00514.x| pmid=34949076 | hdl=2027.42/73857 | s2cid=83502693 | url=https://deepblue.lib.umich.edu/bitstream/2027.42/73857/1/j.1096-0031.1988.tb00514.x.pdf | hdl-access=free }} A different definition was formulated by Michael deBraga and Olivier Rieppel (1997), who defined Sauria as the clade containing the most recent common ancestor of Choristodera, Archosauromorpha, Lepidosauromorpha and all their descendants.{{cite journal |author1=Debraga, M. |author2=Rieppel, O. |name-list-style=amp | year=1997 | title=Reptile phylogeny and the interrelationships of turtles | journal=Zoological Journal of the Linnean Society | volume=120 | issue=3 | pages=281–354 | doi=10.1111/j.1096-3642.1997.tb01280.x | doi-access=free }} However, these uses have not gained wide acceptance among specialists.

{{colbegin}}

Suborder Lacertilia (Sauria) – (lizards)

• Family †Bavarisauridae
• Family †Eichstaettisauridae
• Infraorder Iguanomorpha
• Family †Arretosauridae
• Family †Euposauridae
• Family Corytophanidae (casquehead lizards)
• Family Iguanidae (iguanas and spinytail iguanas)
• Family Phrynosomatidae (earless, spiny, tree, side-blotched and horned lizards)
• Family Polychrotidae (anoles)
• Family Leiosauridae (see Polychrotinae)
• Family Tropiduridae (neotropical ground lizards)
• Family Liolaemidae (see Tropidurinae)
• Family Leiocephalidae (see Tropidurinae)
• Family Crotaphytidae (collared and leopard lizards)
• Family Opluridae (Madagascar iguanids)
• Family Hoplocercidae (wood lizards, clubtails)
• Family †Priscagamidae
• Family †Isodontosauridae
• Family Agamidae (agamas, frilled lizards)
• Family Chamaeleonidae (chameleons)
• Infraorder Gekkota
• Family Gekkonidae (geckos)
• Family Pygopodidae (legless geckos)
• Family Dibamidae (blind lizards)

• Infraorder Scincomorpha
• Family †Paramacellodidae
• Family †Slavoiidae
• Family Scincidae (skinks)
• Family Cordylidae (spinytail lizards)
• Family Gerrhosauridae (plated lizards)
• Family Xantusiidae (night lizards)
• Family Lacertidae (wall lizards or true lizards)
• Family †Mongolochamopidae
• Family †Adamisauridae
• Family Teiidae (tegus and whiptails)
• Family Gymnophthalmidae (spectacled lizards)
• Infraorder Diploglossa
• Family Anguidae (slowworms, glass lizards)
• Family Anniellidae (American legless lizards)
• Family Xenosauridae (knob-scaled lizards)
• Infraorder Platynota (Varanoidea)
• Family Varanidae (monitor lizards)
• Family Lanthanotidae (earless monitor lizards)
• Family Helodermatidae (Gila monsters and beaded lizards)
• Family †Mosasauridae (marine lizards)

{{colend}}

File:Anguidae.jpg, are among over twenty groups of lizards that have convergently evolved a legless body plan.]]

Lizards have frequently evolved convergently, with multiple groups independently developing similar morphology and ecological niches. Anolis ecomorphs have become a model system in evolutionary biology for studying convergence.{{cite journal |last1=Losos |first1=Jonathan B. |title=The Evolution of Convergent Structure in Caribbean Anolis Communities |journal=Systematic Biology |date=1992 |volume=41 |issue=4 |pages=403–420 |doi=10.1093/sysbio/41.4.403}} Limbs have been lost or reduced independently over two dozen times across lizard evolution, including in the Anniellidae, Anguidae, Cordylidae, Dibamidae, Gymnophthalmidae, Pygopodidae, and Scincidae; snakes are just the most famous and species-rich group of Squamata to have followed this path.{{cite journal |last1=Brandley |first1=Matthew C.|display-authors=etal|title=Rates And Patterns In The Evolution Of Snake-Like Body Form In Squamate Reptiles: Evidence For Repeated Re-Evolution Of Lost Digits And Long-Term Persistence Of Intermediate Body Forms |journal=Evolution |date=August 2008 |volume=62 |issue=8 |pages=2042–2064 |doi=10.1111/j.1558-5646.2008.00430.x|pmid=18507743 |s2cid=518045|doi-access=free }}

Most lizard species are harmless to humans. Only the largest lizard species, the Komodo dragon, which reaches {{convert|3.3|m|ft|abbr=on}} in length and weighs up to {{convert|166|kg|lb|abbr=on}}, has been known to stalk, attack, and, on occasion, kill humans. An eight-year-old Indonesian boy died from blood loss after an attack in 2007.{{cite web |url=https://www.nbcnews.com/id/wbna19026658 |title=Komodo dragon kills boy in Indonesia |work=NBC News |access-date=2011-11-07 |date=2007-06-04 |archive-date=2017-09-06 |archive-url=https://web.archive.org/web/20170906224720/http://www.nbcnews.com/id/19026658/ |url-status=live }}

File:Kini iguana.jpgs (Iguana iguana), are popular pets.]]

Numerous species of lizard are kept as pets, including bearded dragons, iguanas, anoles,{{cite web|last1=McLeod|first1=Lianne|title=An Introduction to Green Anoles as Pets|url=https://www.thespruce.com/green-anoles-pets-1236900|website=The Spruce|access-date=28 May 2017|archive-date=24 March 2018|archive-url=https://web.archive.org/web/20180324224708/https://www.thespruce.com/green-anoles-pets-1236900|url-status=live}} and geckos (such as the popular leopard gecko).{{cite web |last1=Virata |first1=John B. |title=5 Great Beginner Pet Lizards |url=http://www.reptilesmagazine.com/Lizards/5-Great-Beginner-Pet-Lizards/ |publisher=Reptiles Magazine |access-date=28 May 2017 |archive-url=https://web.archive.org/web/20170517132043/http://www.reptilesmagazine.com/Lizards/5-Great-Beginner-Pet-Lizards/ |archive-date=17 May 2017 |url-status=dead }}Monitor lizards such as the savannah monitor and tegus such as the Argentine tegu and red tegu are also kept.

Green iguanas are eaten in Central America, where they are sometimes referred to as "chicken of the tree" after their habit of resting in trees and their supposedly chicken-like taste,{{Cite web |title=Referencias culturales - todo iguanas verdes |url=http://todoiguanasverdes.jimdo.com/01-qu%C3%A9-es-una-iguana/h-referencias-culturales/ |url-status=dead |archive-url=https://web.archive.org/web/20161026234318/http://todoiguanasverdes.jimdo.com/01-qu%C3%A9-es-una-iguana/h-referencias-culturales/ |archive-date=2016-10-26 |access-date=2018-11-25}} while spiny-tailed lizards are eaten in Africa. In North Africa, Uromastyx species are considered dhaab or 'fish of the desert' and eaten by nomadic tribes.Grzimek, Bernhard. Grzimek's Animal Life Encyclopedia (Second Edition) Vol 7 – Reptiles. (2003) Thomson – Gale. Farmington Hills, Minnesota. Vol Editor – Neil Schlager. {{ISBN|0-7876-5783-2}} (for vol.7). p. 48File:Red-tegu-fuego-drinking-water.gif drinking water out of a dispenser.]]Lizards such as the Gila monster produce toxins with medical applications. Gila toxin reduces plasma glucose; the substance is now synthesized for use in the anti-diabetes drug exenatide (Byetta). Another toxin from Gila monster saliva has been studied for use as an anti-Alzheimer's drug.{{cite web |date=5 April 2002 |title=Alzheimer's research seeks out lizards |url=http://news.bbc.co.uk/1/hi/health/1912396.stm |publisher=BBC |access-date=5 July 2017 |archive-date=29 June 2006 |archive-url=https://web.archive.org/web/20060629075246/http://news.bbc.co.uk/1/hi/health/1912396.stm |url-status=live }}

Lizards appear in myths and folktales around the world. In Australian Aboriginal mythology, Tarrotarro, the lizard god, split the human race into male and female, and gave people the ability to express themselves in art. A lizard king named Mo'o features in Hawaii and other cultures in Polynesia. In the Amazon, the lizard is the king of beasts, while among the Bantu of Africa, the god UNkulunkulu sent a chameleon to tell humans they would live forever, but the chameleon was held up, and another lizard brought a different message, that the time of humanity was limited.{{cite book |last=Greenberg |first=Daniel A. |title=Lizards |url=https://books.google.com/books?id=iTZRUNFQ1x0C&pg=PA15 |year=2004 |publisher=Marshall Cavendish |isbn=978-0-7614-1580-0 |pages=15–16}} A popular legend in Maharashtra tells the tale of how a common Indian monitor, with ropes attached, was used to scale the walls of the fort in the Battle of Sinhagad.{{cite book |last=Auffenberg |first=Walter |title=The Bengal Monitor |publisher=University Press of Florida |year=1994 |page=494 |isbn=978-0-8130-1295-7}}

Lizards in many cultures share the symbolism of snakes, especially as an emblem of resurrection. This may have derived from their regular molting. The motif of lizards on Christian candle holders probably alludes to the same symbolism. According to Jack Tresidder, in Egypt and the Classical world, they were beneficial emblems, linked with wisdom. In African, Aboriginal and Melanesian folklore they are linked to cultural heroes or ancestral figures.{{cite book |last1=Tresidder |first1=Jack |title=the Hutchinson Dictionary of Symbols |date=1997 |publisher=Helicon |location=London| isbn=978-1-85986-059-5 |page=125}}

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{{reflist|30em}}

• {{cite book |author1=Pianka, E. R. |author2=Vitt, L. J. |year=2003 |title=Lizards: Windows to the Evolution of Diversity |publisher=University of California Press |isbn=978-0-520-23401-7 |url=https://archive.org/details/lizardswindowsto00pian }}

• {{cite book | last1=Behler | first1=John L. | author-link=John L. Behler | last2=King | first2=F. Wayne | title=The Audubon Society Field Guide to Reptiles and Amphibians of North America | publisher=Alfred A. Knopf | location=New York | page=[https://archive.org/details/audubonsocietyfi00behl/page/581 581] | year=1979 | isbn=978-0-394-50824-5 | url=https://archive.org/details/audubonsocietyfi00behl/page/581 }}
• {{cite book |last1=Capula |first1=Massimo |last2=Behler |first2=John L. |title=Simon & Schuster's Guide to Reptiles and Amphibians of the World |year=1989 |publisher=Simon & Schuster |location=New York |isbn=978-0-671-69098-4 |url=https://archive.org/details/simonschustersgu00capu }}
• {{cite book | last1=Cogger | first1=Harold | author-link=Harold Cogger | last2=Zweifel | first2=Richard | author-link2=Richard G. Zweifel | title=Reptiles & Amphibians | publisher=Weldon Owen | location=Sydney | year=1992 | isbn=978-0-8317-2786-4 | url=https://archive.org/details/reptilesamphibia00coggrich }}
• {{cite book | last1=Conant | first1=Roger | last2=Collins | first2=Joseph | author-link=Roger Conant (herpetologist) | title=A Field Guide to Reptiles and Amphibians Eastern/Central North America | publisher=Houghton Mifflin Company | year=1991 | location=Boston, Massachusetts | isbn=978-0-395-58389-0 | url-access=registration | url=https://archive.org/details/fieldguidetorept00cona }}
• {{cite book | last =Ditmars | first=Raymond L | author-link=Raymond Ditmars | title=Reptiles of the World: The Crocodilians, Lizards, Snakes, Turtles and Tortoises of the Eastern and Western Hemispheres | publisher=Macmillan | year=1933 | location=New York | page=321}}
• {{cite book |last1=Freiberg |first1=Marcos |author-link=:es:Marcos Abraham Freiberg |last2=Walls |first2=Jerry |title=The World of Venomous Animals |year=1984 |publisher=TFH Publications |location=New Jersey |isbn=978-0-87666-567-1 |url=https://archive.org/details/worldofvenomousa00marc }}
• {{cite book | last=Gibbons | first=J. Whitfield |author-link=J. Whitfield Gibbons| title=Their Blood Runs Cold: Adventures With Reptiles and Amphibians | url=https://archive.org/details/theirbloodrunsco0000gibb | url-access=registration | publisher=University of Alabama Press | year=1983 | location=Alabama | page =[https://archive.org/details/theirbloodrunsco0000gibb/page/164 164] |isbn=978-0-8173-0135-4 }}
• {{cite book |last=Greenberg |first=Daniel A. |title=Lizards |date=2004 |publisher=Marshall Cavendish |isbn=9780761415800 |url=https://archive.org/details/isbn_9780761415800 }}
• {{cite book |last=Rosenfeld | first=Arthur | title=Exotic Pets | publisher=Simon & Schuster | location=New York | year= 1987 | page=293|isbn=978-0671636906}}

{{commons category|Sauria}}

• {{wikispecies-inline|Sauria}}
• {{Cite Americana|wstitle=Lizard|author=Ernest Ingersoll |short=x}}

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Category:Paraphyletic groups

Category:Extant Hettangian first appearances