View source for Gecko

{{Short description|Lizards belonging to the suborder Gekkota}}
{{About|the type of reptile}}
{{Automatic taxobox
| name = Gecko
| fossil_range = {{Fossil range|100|0|earliest=113}}[[Cenomanian]] – [[Holocene|present]]<br />Stem-groups present since [[Aptian]]-[[Albian]]<ref>{{Cite journal |last1=Villa |first1=Andrea |last2=Wings |first2=Oliver |last3=Rabi |first3=Márton |date=2022 |editor-last=Angielczyk |editor-first=Kenneth |title=A new gecko (Squamata, Gekkota) from the Eocene of Geiseltal (Germany) implies long-term persistence of European Sphaerodactylidae |url=https://ddd.uab.cat/pub/artpub/2022/259562/pappal_a2022v8n3ae1434.pdf |journal=Papers in Palaeontology |language=en |volume=8 |issue=3 |doi=10.1002/spp2.1434 |bibcode=2022PPal....8E1434V |s2cid=249358350 |issn=2056-2799}}</ref>
| image = Phelsuma l. laticauda.jpg
| image_caption = [[Gold dust day gecko]]
| taxon = Gekkota
| authority = [[Georges Cuvier|Cuvier]], 1817
| subdivision_ranks = Subgroups
| subdivision = *'''[[Pygopodoidea]]'''
**[[Carphodactylidae]]
**[[Diplodactylidae]]
**[[Pygopodidae]]
*'''Gekkonoidea'''
**[[Eublepharidae]]
**[[Gekkonidae]]
**[[Phyllodactylidae]]
**[[Sphaerodactylidae]]
}}

'''Geckos''' are small, mostly carnivorous [[lizard]]s that have a wide distribution, found on every continent except [[Antarctica]]. Belonging to the [[Order (biology)|suborder]] '''Gekkota''', geckos are found in warm [[climate]]s. They range from {{Convert|1.6|to|67|cm|in|1|abbr=off|lk=on}}.

Geckos are unique among lizards for their [[Animal communication|vocalisations]], which differ from species to species. Most geckos in the family [[Gekkonidae]] use chirping or clicking sounds in their social interactions. [[Tokay gecko]]s (''Gekko gecko'') are known for their loud [[mating call]]s, and some other species are capable of making hissing noises when alarmed or threatened. They are the most species-rich group of lizards, with about 1,500 different species worldwide.<ref>{{Cite web|url=http://reptile-database.reptarium.cz/advanced_search?taxon=gecko&submit=Search|title=Search results – gecko|website=Reptile-Database.Reptarium.cz|publisher=The Reptile Database|access-date=2022-02-01|archive-date=2020-11-27|archive-url=https://web.archive.org/web/20201127120136/https://reptile-database.reptarium.cz/advanced_search?taxon=gecko&submit=Search|url-status=live}}</ref>

All geckos, except species in the family [[Eublepharidae]], lack eyelids; instead, the outer surface of the eyeball has a [[transparency and translucency|transparent]] membrane, the [[brille]]. They have a fixed [[lens (anatomy)|lens]] within each [[Iris (anatomy)|iris]] that enlarges in darkness to let in more light. Since they cannot [[blink]], species without eyelids generally lick their own brilles when they need to clear them of dust and dirt, in order to keep them clean and moist.<ref name=Badger_Lizards>{{Cite book|last=Badger|first=David|date=2006|title=Lizards: a Natural History of Some Uncommon Creatures|publisher=Voyageur Press|location=St. Paul, MN|isbn=978-0-7603-2579-7|page=47}}</ref>

Unlike most lizards, geckos are usually [[nocturnal]]<ref name="Into the light: Diurnality has evol"/> and have excellent [[night vision]]; their [[colour vision]] in low light is 350 times more sensitive than [[human eye]]s.<ref name=Roth_Pupils>{{Cite journal|last1=Roth|first1=L.S.V.|last2=Lundstrom|first2=L.|last3=Kelber|first3=A.|last4=Kroger|first4=R.H.H.|last5=Unsbo|first5=P.|date=1 March 2009|title=The pupils and optical systems of gecko eyes|journal=[[Journal of Vision]]|volume=9|issue=3|pages=27.1–11|doi=10.1167/9.3.27|pmid=19757966|doi-access=free}}</ref> The nocturnal geckos evolved from [[Diurnality|diurnal]] species, which had lost the [[rod cell]]s from their eyes. The gecko eye, therefore, modified its [[cone cell]]s that increased in size into different types, both single and double. Three different photo-pigments have been retained, and are sensitive to ultraviolet, blue, and green. They also use a multifocal optical system that allows them to generate a sharp image for at least two different depths.<ref>{{Cite journal|first1=Lina S. V.|last1=Roth|first2=Linda|last2=Lundström|first3=Almut|last3=Kelber|first4=Ronald H. H.|last4=Kröger|first5=Peter|last5=Unsbo|date=1 March 2009|title=The pupils and optical systems of gecko eyes|journal=[[Journal of Vision]]|volume=9|issue=3|pages=27.1–11|doi=10.1167/9.3.27|pmid=19757966|doi-access=free}}</ref><ref>{{Cite web|url=http://news.oneindia.in/2009/05/08/geckoinspired-multifocal-contact-lenses-cameras-on-theanv.html|title=Gecko-inspired multifocal contact lenses, cameras on the anvil|website=News.OneIndia.in|date=8 May 2009|access-date=1 February 2022|archive-date=28 March 2017|archive-url=https://web.archive.org/web/20170328200444/http://news.oneindia.in/2009/05/08/geckoinspired-multifocal-contact-lenses-cameras-on-theanv.html|url-status=live}}</ref> While most gecko species are nocturnal, some species are diurnal and active during the day, which have evolved multiple times independently.<ref name="Into the light: Diurnality has evol">{{Cite journal|last1=Gamble|first1=T.|last2=Greenbaum|first2=E.|last3=Jackman|first3=T.R.|last4=Bauer|first4=A.M.|date=August 2015|title=Into the light: Diurnality has evolved multiple times in geckos|journal=[[Biological Journal of the Linnean Society]]|volume=115|issue=4|pages=896–910|doi=10.1111/bij.12536|doi-access=free}}</ref>

Many species are well known for their specialised toe pads, which enable them to grab and climb onto smooth and vertical surfaces, and even cross indoor ceilings with ease. Geckos are well known to people who live in warm regions of the world, where several species make their home inside human habitations. These, for example the [[Hemidactylus|house gecko]], become part of the indoor menagerie and are often welcomed, as they feed on [[insect]] [[Pest (organism)|pests]] including [[moth]]s and [[mosquito]]es. Like most lizards, geckos can [[autotomy|defensively shed their tail]]; the predator may attack the wriggling tail, allowing the gecko to escape.<ref>{{Cite web|last=Mihai|first=Andrei|date=9 September 2009|url=http://www.zmescience.com/medicine/gecko-tail-has-a-mind-of-its-own/|title=Gecko tail has a mind of its own|website=www.ZMEScience.com|publisher=ZME Science|access-date=1 February 2022|archive-date=30 November 2009|archive-url=https://web.archive.org/web/20091130081608/http://www.zmescience.com/medicine/gecko-tail-has-a-mind-of-its-own/|url-status=live}}</ref>

The largest species, ''[[Gigarcanum delcourti]]'', is only known from a single, stuffed specimen probably collected in the 19th century found in the basement of the [[Muséum d'histoire naturelle de Marseille|Natural History Museum of Marseille]] in [[Marseille]], France. This gecko was {{Convert|600|mm|abbr=off|lk=on}} long, and was likely [[endemic]] to [[New Caledonia]], where it lived in native forests.<ref name=":1">{{Cite journal |last1=Heinicke |first1=Matthew P. |last2=Nielsen |first2=Stuart V. |last3=Bauer |first3=Aaron M. |last4=Kelly |first4=Ryan |last5=Geneva |first5=Anthony J. |last6=Daza |first6=Juan D. |last7=Keating |first7=Shannon E. |last8=Gamble |first8=Tony |date=2023-06-19 |title=Reappraising the evolutionary history of the largest known gecko, the presumably extinct Hoplodactylus delcourti, via high-throughput sequencing of archival DNA |journal=Scientific Reports |language=en |volume=13 |issue=1 |page=9141 |doi=10.1038/s41598-023-35210-8 |pmid=37336900 |issn=2045-2322|pmc=10279644 |bibcode=2023NatSR..13.9141H }}</ref> The smallest gecko, the [[Sphaerodactylus ariasae|Jaragua sphaero]], is a mere {{Convert|16|mm|abbr=off}} long and was discovered in 2001 on a small island off the coast of [[Hispaniola]].<ref name=Piper>{{Cite book|last=Piper|first=Ross|date=2007|title=Extraordinary Animals: an Encyclopedia of Curious and Unusual Animals|url=https://archive.org/details/extraordinaryani0000pipe|url-access=registration|publisher=[[Greenwood Press]]|location=Westport, Conn.|isbn=978-0-313-33922-6|page=[https://Archive.org/details/extraordinaryani0000pipe/page/143 143]}}</ref>

== Etymology ==
The [[Neo-Latin]] ''gekko'' and [[English language|English]] 'gecko' stem from [[Indonesian language|Indonesian]]-[[Malaysian language|Malaysian]] ''gēkoq'',<ref name="OED">{{Cite OED|term=gecko|id=77283|access-date=7 February 2024}} Earlier version first published in New English Dictionary, 1898.</ref> a [[Malay language|Malay]] word borrowed from [[Javanese language|Javanese]],<ref name="Wilkinson">{{Cite encyclopedia |url=https://nla.gov.au/nla.obj-60272771/view?partId=nla.obj-435905740#page/n346/ |title=ge'kok |dictionary=A Malay-English dictionary (romanised) |last=Wilkinson |first=Richard James |publisher=Salavopoulos & Kinderlis |location=Mytilene, Greece |date=1932 |volume=I |page=337 |via=TROVE, [[National Library of Australia]] |access-date=2022-12-10 |archive-date=2022-12-10 |archive-url=https://web.archive.org/web/20221210165431/https://nla.gov.au/nla.obj-60272771/view?partId=nla.obj-435905740#page/n346/ |url-status=live }}</ref> from ''tokek'', which [[onomatopoeia|imitates]] the sounds that some species like ''[[Tokay gecko]]'' make.<ref name=OED/><ref>{{cite journal |author1=Siti Zaleha Mat Diah<!-- exactly as written in journal --> |author2=Rosli Hashim<!-- exactly as written in journal --> |author3=Yong Hoi Sen<!-- exactly as written in journal --> |author4=Daicus Belabut<!-- exactly as written in journal --> |author5=Syuhadah Dzarawi N.<!-- exactly as written in journal --> |author6=Lim Boo Liat<!-- exactly as written in journal --> |title=Preliminary Survey of Lizards of Pantai Melawi, Bachok, Kelantan, Malaysia |journal=Malaysian Journal of Science |date=2010 |volume=29 |issue=special issue |pages=117–120 |doi=10.22452/mjs.vol29nosp.13 |url=https://ejournal.um.edu.my/index.php/MJS/article/view/7338 |access-date=11 December 2022 |language=en |issn=2600-8688 |doi-access=free |archive-date=10 December 2022 |archive-url=https://web.archive.org/web/20221210165426/https://ejournal.um.edu.my/index.php/MJS/article/view/7338 |url-status=live }}</ref>{{rp|120}}<ref>{{cite journal |last1=Marcellini |first1=Dale |title=Acoustic and Visual Display Behavior of Gekkonid Lizards |url=https://academic.oup.com/icb/article/17/1/251/172256 |journal=American Zoologist |date=February 1977 |volume=17 |issue=1 |pages=251–260 |doi=10.1093/icb/17.1.251 |doi-access=free |access-date=2023-01-07 |archive-date=2023-01-27 |archive-url=https://web.archive.org/web/20230127025130/https://academic.oup.com/icb/article/17/1/251/172256 |url-status=live }}</ref>{{rp|253}}

==Common traits==
Like other reptiles, geckos are [[ectotherm]]ic,<ref name="nzetc.victoria.ac.nz">{{Cite web|last=Girons|first=Hubert|date=August 1980|url=http://nzetc.victoria.ac.nz/tm/scholarly/tei-Bio24Tuat02-t1-body-d2.html|title=Thermoregulation in Reptiles with Special Reference to the Tuatara and Its Ecophysiology Tuatara|volume=24|issue=2|website=nzetc.Victoria.ac.nz|publisher=[[Victoria University of Wellington]] Library|access-date=31 May 2014|archive-date=30 July 2014|archive-url=https://web.archive.org/web/20140730021654/http://nzetc.victoria.ac.nz/tm/scholarly/tei-Bio24Tuat02-t1-body-d2.html|url-status=live}}</ref> producing very little metabolic heat. Essentially, a gecko's body temperature is dependent on its environment. To accomplish bodily functions such as locomotion, feeding or reproduction, geckos must maintain an elevated body temperature.<ref name="nzetc.victoria.ac.nz"/>

===Shedding or molting===
[[File:Leopard Gecko Shedding Skin.ogv|thumb|Video of leopard gecko shedding skin|left]]
All geckos shed their skin at fairly regular intervals, with species differing in timing and method. [[Leopard gecko]]s shed at about two- to four-week intervals. The presence of moisture aids in the shedding. When shedding begins, the gecko speeds the process by detaching the loose skin from its body and eating it.<ref>{{Cite web|url=http://www.GeckoCare.net/shedding.php|title=GeckoCare - shedding|website=www.GeckoCare.net|access-date=19 April 2013|archive-url=https://web.archive.org/web/20130529170233/http://www.geckocare.net/shedding.php|archive-date=29 May 2013}}</ref> For young geckos, shedding occurs more frequently, once a week, but when they are fully grown, they shed once every one to two months.<ref>{{Cite web|url=https://buddygenius.com/crested-geckos-shed/|title=Crested geckos shedding|website=BuddyGenius.com|date=5 July 2020|publisher=Buddy Genius|access-date=1 February 2022|archive-date=16 January 2018|archive-url=https://web.archive.org/web/20180116140204/https://buddygenius.com/crested-geckos-shed/|url-status=live}}</ref>

===Adhesion ability===
{{See also|Synthetic setae|Gecko feet}}
[[File:Gecko foot on glass.JPG|thumb|Close-up of the underside of a gecko's foot as it walks on vertical glass|left]]
About 60% of gecko species have adhesive toepads which allow them to [[Adhesion|adhere]] to most surfaces without the use of liquids or [[surface tension]]. Such pads have been gained and lost repeatedly over the course of gecko evolution.<ref name="plosone.org">{{Cite journal|last1=Gamble|first1=Tony|last2=Greenbaum|first2=Eli|last3=Jackman|first3=Todd R.|last4=Russell|first4=Anthony P.|last5=Bauer|first5=Aaron M.|date=27 June 2012|title=Repeated Origin and Loss of Adhesive Toepads in Geckos|journal=PLOS ONE|volume=7|issue=6|article-number=e39429|doi=10.1371/journal.pone.0039429|pmid=22761794|pmc=3384654|bibcode=2012PLoSO...739429G|doi-access=free}}</ref> Adhesive toepads evolved independently in about eleven different gecko lineages, and were lost in at least nine lineages.<ref name="plosone.org"/>

It was previously thought that the spatula-shaped [[seta]]e arranged in [[Lamella (anatomy)|lamellae]] on gecko footpads enable attractive [[van der Waals' force]]s (the weakest of the weak chemical forces) between the [[Beta-keratin|β-keratin]] lamellae / setae / spatulae structures and the surface.<ref>{{Cite web|url=http://www.nisenet.org/scientific-images/gecko_toe|title=Scientific image – gecko toe|website=www.NISEnet.org|publisher=NISE Network|access-date=2022-02-01|archive-date=2013-05-09|archive-url=https://web.archive.org/web/20130509025409/http://www.nisenet.org/scientific-images/gecko_toe|url-status=live}}</ref><ref name=Santos2007>{{Cite journal|last1=Santos|first1=Daniel|first2=Matthew|last2=Spenko|first3=Aaron|last3=Parness|first4=Kim|last4=Sangbae|first5=Mark|last5=Cutkosky|date=2007|url=http://www.brill.nl/journal-adhesion-science-and-technology|title=Directional adhesion for climbing: Theoretical and practical considerations|journal=[[Journal of Adhesion Science and Technology]]|volume=21|issue=12–13|pages=1317–1341|quote=''Gecko "feet and toes are a hierarchical system of complex structures consisting of lamellae, setae, and spatulae. The distinguishing characteristics of the gecko adhesion system have been described [as] (1) anisotropic attachment, (2) high pulloff force to preload ratio, (3) low detachment force, (4) material independence, (5) self-cleaning, (6) antiself sticking and (7) nonsticky default state. ... The gecko's adhesive structures are made from ß-keratin (modulus of elasticity [about] 2 GPa). Such a stiff material is not inherently sticky; however, because of the gecko adhesive's hierarchical nature and extremely small distal features (spatulae are [about] 200 nm in size), the gecko's foot is able to intimately conform to the surface and generate significant attraction using [[van der Waals force]]s.''|doi=10.1163/156856107782328399|s2cid=53470787|access-date=2012-02-04|archive-date=2012-01-15|archive-url=https://web.archive.org/web/20120115143737/http://www.brill.nl/journal-adhesion-science-and-technology|url-status=live|url-access=subscription}}</ref> These van der Waals interactions involve no fluids; in theory, a boot made of [[synthetic setae]] would adhere as easily to the surface of the [[International Space Station]] as it would to a living-room wall, although adhesion varies with humidity.<ref name="Puthoff"/><ref name="Prowse"/> However, a 2014 study suggests that gecko adhesion is in fact mainly determined by electrostatic interaction (caused by contact electrification), not van der Waals or capillary forces.<ref name=RSI-2014>{{Cite journal|last1=Izadi|first1=H.|last2=Stewart|first2=K.M.E.|last3=Penlidis|first3=A.|date=9 July 2014|title=Role of contact electrification and electrostatic interactions in gecko adhesion|journal=[[Journal of the Royal Society Interface]]|volume=11|issue=98|article-number=20140371|doi=10.1098/rsif.2014.0371|pmid=25008078|pmc=4233685|quote=We have demonstrated that it is the CE-driven electrostatic interactions which dictate the strength of gecko adhesion, and not the van der Waals or capillary forces which are conventionally considered as the main source of gecko adhesion.}}</ref>

The setae on the feet of geckos are also self-cleaning, and usually remove any clogging dirt within a few steps.<ref name="Hansen"/><ref>{{Cite web|url=http://www.lclark.edu/~autumn/dept/geckostory.html|title=How geckos stick to walls|website=www.lclark.edu|access-date=2007-09-22|archive-date=2007-09-25|archive-url=https://web.archive.org/web/20070925041306/http://www.lclark.edu/~autumn/dept/geckostory.html}}</ref><ref name=SpatulaeNature>{{Cite journal|last1=Xu|first1=Quan|last2=Wan|first2=Yiyang|last3=Hu|first3=Travis Shihao|last4=Liu|first4=Tony X.|last5=Tao|first5=Dashuai|last6=Niewiarowski|first6=Peter H.|last7=Tian|first7=Yu|last8=Liu|first8=Yue|last9=Dai|first9=Liming|last10=Yang|first10=Yanqing|last11=Xia|first11=Zhenhai|date=20 November 2015|title=Robust self-cleaning and micromanipulation capabilities of gecko spatulae and their bio-mimics|journal=[[Nature Communications]]|volume=6|page=8949|doi=10.1038/ncomms9949|pmid=26584513|pmc=4673831|bibcode=2015NatCo...6.8949X}}</ref> [[Polytetrafluoroethylene]] (PTFE), which has very low surface energy,<ref>{{Cite web|url=http://www.JustAnswer.com/questions/bwl6-feet-gecko-lizard-not-stick|title=Why do the gecko's feet not stick to a teflon surface?|website=www.JustAnswer.com}}{{Unreliable source?|date=February 2022}}</ref> is more difficult for geckos to adhere to than many other surfaces.

Gecko adhesion is typically improved by higher humidity,<ref name="Puthoff">{{Cite journal|last1=Puthoff|first1=J.B.|last2=Prowse|first2=M.|last3=Wilkinson|first3=M.|last4=Autumn|first4=K.|date=2010|title=Changes in materials properties explain the effects of humidity on gecko adhesion|journal=[[Journal of Experimental Biology]]|volume=213|pages=3699–3704|doi=10.1242/jeb.047654|issue=21|pmid=20952618|doi-access=free|bibcode=2010JExpB.213.3699P }}</ref><ref name="Prowse">{{Cite journal|last1=Prowse|first1=M.S.|last2=Wilkinson|first2=Matt|last3=Puthoff|first3=Jonathan B.|last4=Mayer|first4=George|last5=Autumn|first5=Kellar|date=2011|title=Effects of humidity on the mechanical properties of gecko setae|journal=[[Acta Biomaterialia]]|volume=7|pages=733–738|doi=10.1016/j.actbio.2010.09.036|pmid=20920615|issue=2}}</ref><ref name="Huber, G., et al. 2005 16293–6">{{Cite journal|last1=Huber|first1=G.|last2=Mantz|first2=H.|last3=Spolenak|first3=R.|last4=Mecke|first4=K.|last5=Jacobs|first5=K.|last6=Gorb|first6=S.N.|last7=Arzt|first7=E.|date=2005|title=Evidence for capillarity contributions to gecko adhesion from single spatula nanomechanical measurements|journal=[[Proceedings of the National Academy of Sciences]]|volume=102|pages=16293–6|doi=10.1073/pnas.0506328102|pmid=16260737|pmc=1283435|issue=45|bibcode=2005PNAS..10216293H|doi-access=free}}</ref><ref name="Chen, B. 2010 1–9">{{Cite journal|last1=Chen|first1=B.|last2=Gao|first2=H.|date=2010|title=An alternative explanation of the effect of humidity in gecko adhesion: stiffness reduction enhances adhesion on a rough surface|journal=[[International Journal of Applied Mechanics]]|volume=2|issue=1|pages=1–9|doi=10.1142/s1758825110000433|bibcode=2010IJAM....2....1C}}</ref><ref name="Loskill, P. 20120587">{{Cite journal|last1=Loskill|first1=P.|last2=Puthoff|first2=J.|last3=Wilkinson|first3=M.|last4=Mecke|first4=K.|last5=Jacobs|first5=K.|last6=Autumn|first6=K.|date=September 2012|title=Macroscale adhesion of gecko setae reflects nanoscale differences in subsurface composition|journal=[[Journal of the Royal Society Interface]]|volume=10|issue=78|article-number=20120587|doi=10.1098/rsif.2012.0587|pmid=22993246|pmc=3565786}}</ref> even on hydrophobic surfaces, yet is reduced under conditions of complete immersion in water. The role of water in that system is under discussion, yet recent experiments agree that the presence of molecular water layers (water molecules carry a very large dipole moment) on the setae, as well as on the surface, increase the surface energy of both, therefore the energy gain in getting these surfaces in contact is enlarged, which results in an increased gecko adhesion force.<ref name="Puthoff"/><ref name="Prowse"/><ref name="Huber, G., et al. 2005 16293–6"/><ref name="Chen, B. 2010 1–9"/><ref name="Loskill, P. 20120587"/> Moreover, the elastic properties of the b-keratin change with water uptake.<ref name="Puthoff"/><ref name="Prowse"/><ref name="Huber, G., et al. 2005 16293–6"/>

Gecko toes seem to be [[double jointed|double-jointed]], but this is a misnomer, and is properly called digital hyperextension.<ref name="Russell, A.P. 1975">{{Cite journal|last=Russell|first=A.P.|date=1975|title=A contribution to the functional analysis of the foot of the Tokay, ''Gekko gecko'' (Reptilia: Gekkonidae)|journal=[[Journal of Zoology]]|volume=176|issue=4|pages=437–476|doi=10.1111/j.1469-7998.1975.tb03215.x}}</ref> Gecko toes can hyperextend in the opposite direction from human fingers and toes. This allows them to overcome the van der Waals force by peeling their toes off surfaces from the tips inward. In essence, by this peeling action, the gecko separates spatula by spatula from the surface, so for each spatula separation, only some force necessary. (The process is similar to removing [[Scotch Tape]] from a surface.)

Gecko toes operate well below their full attractive capabilities most of the time, because the margin for error is great depending upon the [[surface roughness]], and therefore the number of setae in contact with that surface.

Use of small van der Waals force requires very large surface areas; every square millimetre of a gecko's footpad contains about 14,000&nbsp;hair-like setae. Each seta has a diameter of 5&nbsp;[[micrometer (unit)|μm]]. Human hair varies from 18 to 180&nbsp;μm, so the cross-sectional area of a human hair is equivalent to 12 to 1300 setae. Each seta is in turn tipped with between 100 and 1,000 spatulae.<ref name="Hansen">{{Cite journal|last1=Hansen|first1=W.R.|last2=Autumn|first2=K.|date=2005|title=Evidence for self-cleaning in gecko setae|journal=[[Proceedings of the National Academy of Sciences]]|volume=102|issue=2|pages=385–389|doi=10.1073/pnas.0408304102|quote=Setae occur in uniform arrays on overlapping lamellar pads at a density of 14,400 per mm<sup>2</sup>|pmid=15630086|pmc=544316|bibcode=2005PNAS..102..385H|doi-access=free}}</ref> Each spatula is 0.2&nbsp;μm long<ref name=Hansen/> (one five-millionth of a metre), or just below the wavelength of visible light.<ref name="Autumn">{{Cite journal|last1=Autumn|first1=Kellar|last2=Sitti|first2=M.|last3=Liang|first3=Y.A.|last4=Peattie|first4=A.M.|last5=Hansen|first5=W.R.|last6=Sponberg|first6=S.|last7=Kenny|first7=T.W.|last8=Fearing|first8=R.|last9=Israelachvili|first9=J.N.|last10=Full|first10=R.J.|date=2002|title=Evidence for van der Waals adhesion in gecko setae|journal=[[Proceedings of the National Academy of Sciences]]|volume=99|issue=19|pages=12252–12256|doi=10.1073/pnas.192252799|pmid=12198184|pmc=129431|bibcode=2002PNAS...9912252A|doi-access=free}}</ref>

The setae of a typical mature {{Convert|70|g|oz|abbr=off|adj=on|lk=on}} gecko would be capable of supporting a weight of {{Convert|133|kg|lb|abbr=off}}:<ref>{{Cite web|title=Geckos can hang upside down carrying 40kg|url=http://www.physics.org/facts/gecko-really.asp|website=www.Physics.org|access-date=2 November 2012|archive-date=21 May 2008|archive-url=https://web.archive.org/web/20080521015041/http://www.physics.org/facts/gecko-really.asp|url-status=live}}</ref><ref name=Autumn_SciAmer>{{Cite magazine|last=Autumn|first=Kellar|date=29 September 2003|url=http://www.scientificamerican.com/article.cfm?id=how-do-gecko-lizards-unst|title=How do gecko lizards unstick themselves as they move across a surface?|magazine=[[Scientific American]]|access-date=23 March 2013|archive-date=23 October 2012|archive-url=https://web.archive.org/web/20121023131852/http://www.scientificamerican.com/article.cfm?id=how-do-gecko-lizards-unst|url-status=live}}</ref> each spatula could exert an adhesive force of 5 to 25&nbsp;nN.<ref name="Huber, G., et al. 2005 16293–6"/><ref name="Lee">{{Cite journal|last1=Lee|first1=Haeshin|last2=Lee|first2=Bruce P.|last3=Messersmith|first3=Phillip B.|year=2007|title=A reversible wet / dry adhesive inspired by mussels and geckos|journal=[[Nature (journal)|Nature]]|volume=448|issue=7151|pages=338–341|doi=10.1038/nature05968|pmid=17637666|bibcode=2007Natur.448..338L|s2cid=4407993}}</ref> The exact value of the adhesion force of a spatula varies with the surface energy of the substrate to which it adheres. Recent studies<ref name="Loskill, P. 20120587"/><ref>{{Cite journal|last1=Loskill|first1=P.|last2=Haehl|first2=H.|last3=Grandthyll|first3=S.|last4=Faidt|first4=T.|last5=Mueller|first5=F.|last6=Jacobs|first6=K.|date=November 2012|title=Is adhesion superficial? Silicon wafers as a model system to study van der Waals interactions|journal=[[Advances in Colloid and Interface Science]]|volume=179–182|pages=107–113|doi=10.1016/j.cis.2012.06.006|pmid=22795778|arxiv=1202.6304|s2cid=5406490}}</ref> have moreover shown that the component of the surface energy derived from long-range forces, such as van der Waals forces, depends on the material's structure below the outermost atomic layers (up to 100&nbsp;nm beneath the surface); taking that into account, the adhesive strength can be inferred.

Apart from the [[seta]]e, [[phospholipids]]; fatty substances produced naturally in their bodies, also come into play.<ref name=Hsu_Phospholipids>{{Cite journal|last1=Hsu|first1=P.Y.|last2=Ge|first2=L.|last3=Li|first3=X.|last4=Stark|first4=A.Y.|last5=Wesdemiotis|first5=C.|last6=Niewiarowski|first6=P.H.|last7=Dhinojwala|first7=A.|date=24 August 2011|title=Direct evidence of phospholipids in gecko footprints and spatula-substrate contact interface detected using surface-sensitive spectroscopy|journal=[[Journal of the Royal Society Interface]]|volume=9|issue=69|pages=657–664|doi=10.1098/rsif.2011.0370|pmid=21865250|pmc=3284128}}</ref> These lipids lubricate the setae and allow the gecko to detach its foot before the next step.

The origin of gecko adhesion likely started as simple modifications to the epidermis on the underside of the toes. This was recently discovered in the genus ''[[Gonatodes]]'' from South America.<ref name="Higham, T.E. 2016">{{Cite journal|last1=Higham|first1=T.E.|last2=Gamble|first2=T.|last3=Russell|first3=A.P.|date=2017|title=On the origin of frictional adhesion in geckos: small morphological changes lead to a major biomechanical transition in the genus ''Gonatodes''|journal=[[Biological Journal of the Linnean Society]]|doi=10.1111/bij.12897|volume=120|issue=3|pages=503–517|doi-access=free}}</ref><ref>{{Cite journal|last1=Russell|first1=A.P.|last2=Baskerville|first2=J.|last3=Gamble|first3=T.|last4=Higham|first4=T.|date=November 2015|title=The evolution of digit form in Gonatodes (Gekkota: Sphaerodactylidae) and its bearing on the transition from frictional to adhesive contact in gekkotans|journal=[[Journal of Morphology]]|volume=276|issue=11|pages=1311–1332|pmid=26248497|doi=10.1002/jmor.20420|s2cid=20296012}}</ref> Simple elaborations of the epidermal spinules into setae have enabled ''Gonatodes humeralis'' to climb smooth surfaces and sleep on smooth leaves.

[[Biomimetic]] technologies designed to [[Synthetic setae|mimic gecko adhesion]] could produce reusable self-cleaning dry adhesives with many applications. Development effort is being put into these technologies, but manufacturing synthetic setae is not a trivial material design task.

==Skin==
Gecko skin does not generally bear scales, but appears at a macro scale as a papillose surface, which is made from hair-like protuberances developed across the entire body. These confer [[Ultrahydrophobicity|superhydrophobicity]], and the unique design of the hair confers a profound antimicrobial action. These protuberances are very small, up to 4&nbsp;microns in length, and tapering to a point.<ref>{{Cite journal|last1=Green|first1=DW|last2=Lee|first2=KK|last3=Watson|first3=JA|last4=Kim|first4=HY|last5=Yoon|first5=KS|last6=Kim|first6=EJ|last7=Lee|first7=JM|last8=Watson|first8=GS|last9=Jung|first9=HS|date=25 January 2017|title=High quality bioreplication of intricate nanostructures from a fragile Gecko skin surface with bactericidal properties|journal=[[Scientific Reports]]|volume=7|article-number=41023|doi=10.1038/srep41023|pmid=28120867|pmc=5264400|bibcode=2017NatSR...741023G}}</ref> Gecko skin has been observed to have an anti-bacterial property, killing [[gram-negative bacteria]] when they come in contact with the skin.<ref>{{Cite journal|last1=Watson|first1=Gregory S.|last2=Green|first2=David W.|last3=Schwarzkopf|first3=Lin|last4=Li|first4=Xin|last5=Cribb|first5=Bronwen W.|last6=Myhra|first6=Sverre|last7=Watson|first7=Jolanta A.|date=2015|title=A gecko skin micro/Nano structure – A low adhesion, superhydrophobic, anti-wetting, self-cleaning, biocompatible, antibacterial surface|journal=[[Acta Biomaterialia]]|volume=21|pages=109–122|doi=10.1016/j.actbio.2015.03.007|pmid=25772496}}</ref>

The [[Uroplatus sikorae|mossy leaf-tailed gecko]] of Madagascar, ''U. sikorae'', has coloration developed as [[camouflage]], most being greyish brown to black, or greenish brown, with various markings meant to resemble [[tree]] bark; down to the [[lichen]]s and moss found on the bark. It also has flaps of skin, running the length of its body, head and limbs, known as the ''dermal flap'', which it can lay against the tree during the day, scattering shadows, and making its outline practically invisible.<ref>{{Cite book|last=Pianka|first=Eric R.|date=2006|title=Lizards: Windows to the Evolution of Diversity|url=https://Archive.org/details/lizardswindowsto00pian|url-access=registration|publisher=[[University of California Press]]|location=Berkeley, CA|pages=[https://Archive.org/details/lizardswindowsto00pian/page/247 247]|isbn=0-520-24847-3}}</ref>

==Teeth==
As [[polyphyodont]]s, geckos can replace each of their 100&nbsp;teeth every 3 to 4 months.<ref>{{Cite web|url=http://www.DevBio.Biology.gatech.edu/?page_id=3229|title=Mechanism of Tooth Replacement in Leopard Geckos – Developmental Biology Interactive|archive-url=https://web.archive.org/web/20150312094002/http://www.devbio.biology.gatech.edu/?page_id=3229|archive-date=2015-03-12}}</ref> Next to the full grown tooth there is a small replacement tooth developing from the [[Animal tooth development|odontogenic]] [[stem cell]] in the [[dental lamina]].<ref>{{cite journal |title=Identification of putative dental epithelial stem cells in a lizard with life-long tooth replacement |author1=Gregory R. Handrigan |author2=Kelvin J. Leung |author3=Joy M. Richman |journal=Development |year=2010 |volume=137 |issue=21 |pages=3545–3549 |doi=10.1242/dev.052415 |pmid=20876646|doi-access=free }}</ref> The formation of the teeth is [[pleurodont]]; they are fused (ankylosed) by their sides to the inner surface of the jaw bones.
This formation is common in all species in the order [[Squamata]].
{{clear left}}

==Taxonomy and classification==
[[File:LizardFemoralPoresRooij.png|thumb|Pores on the skin are often used in classification.]]

The suborder<ref>{{Cite journal |last=Rech |first=Inna |last2=Ginal |first2=Philipp |last3=Rauhaus |first3=Anna |last4=Ziegler |first4=Thomas |last5=Rödder |first5=Dennis |date=2023-10-01 |title=Geckos in zoos: A global approach on distribution patterns of threatened geckos (Gekkota) in zoological institutions |url=https://www.sciencedirect.com/science/article/pii/S1617138123001383 |journal=Journal for Nature Conservation |volume=75 |article-number=126467 |doi=10.1016/j.jnc.2023.126467 |issn=1617-1381|url-access=subscription }}</ref> [[Gekkota]] is divided into seven families, containing about 125 [[genus|genera]] of geckos, including the snake-like (legless) pygopods.<ref name="plosone.org"/><ref>{{cite journal |last1=Han |first1=D. |last2=Zhou |first2=K. |last3=Bauer |first3=A.M. |year=2004 |title=Phylogenetic relationships among gekkotan lizards inferred from c-mos nuclear DNA sequences and a new classification of the Gekkota |journal=Biological Journal of the Linnean Society |volume=83 |issue=3 |pages=353–368 |doi=10.1111/j.1095-8312.2004.00393.x|doi-access=free }}</ref><ref>{{cite journal |last1=Gamble |first1=T. |last2=Bauer |first2=A.M. |last3=Greenbaum |first3=E. |last4=Jackman |first4=T.R. |date=July 2008 |title=Out of the blue: A novel, trans-Atlantic clade of geckos (Gekkota, Squamata) |journal=Zoologica Scripta |volume=37 |issue=4 |pages=355–366 |doi=10.1111/j.1463-6409.2008.00330.x |s2cid=83706826 |url=https://epublications.marquette.edu/bio_fac/872 |doi-access=free |access-date=2023-08-18 |archive-date=2023-11-01 |archive-url=https://web.archive.org/web/20231101035638/https://epublications.marquette.edu/bio_fac/872/ |url-status=live }}</ref><ref name=Gamble_Gondwana>{{cite journal |last1=Gamble |first1=Tony |last2=Bauer |first2=Aaron M. |last3=Greenbaum |first3=Eli |last4=Jackman |first4=Todd R. |title=Evidence for Gondwanan vicariance in an ancient clade of gecko lizards |journal=Journal of Biogeography |volume=35 |date=21 August 2007 |doi=10.1111/j.1365-2699.2007.01770.x |pages=88–104 |s2cid=29974883 |url=https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1758&context=bio_fac |access-date=30 September 2020 |archive-date=6 May 2020 |archive-url=https://web.archive.org/web/20200506224757/https://epublications.marquette.edu/cgi/viewcontent.cgi?article=1758&context=bio_fac |url-status=live |url-access=subscription }}</ref><ref>{{cite journal |last1=Gamble |first1=T. |last2=Bauer |first2=A.M. |last3=Colli |first3=G.R. |last4=Greenbaum |first4=E. |last5=Jackman | first5=T.R. |last6=Vitt |first6=L.J. |last7=Simons |first7=A.M. |date=February 2011 |title=Coming to America: Multiple Origins of New World Geckos |journal=Journal of Evolutionary Biology |volume=24 |issue=2 |pages=231–244 |doi=10.1111/j.1420-9101.2010.02184.x |pmid=21126276 |pmc=3075428}}</ref><ref name="Into the light: Diurnality has evol"/><ref>{{cite journal |last=Gamble |first=Tony |author2=Greenbaum, Eli |author3=Jackman, Todd R. |author4=Russell, Anthony P. |author5=Bauer, Aaron M. |title=Repeated Origin and Loss of Adhesive Toepads in Geckos |journal=PLOS ONE |date=June 27, 2012 |volume=7 |issue=6 |article-number=e39429 |doi=10.1371/journal.pone.0039429 |pmid=22761794 |pmc=3384654|bibcode=2012PLoSO...739429G |doi-access=free }}</ref>

*Family [[Carphodactylidae]]
*Family [[Diplodactylidae]]
*Family [[Eublepharidae]]
*Family [[Gekkonidae]]
*Family [[Phyllodactylidae]]
*Family [[Pygopodidae]]
*Family [[Sphaerodactylidae]]

Legless lizards of the family [[Dibamidae]], also referred to as blind lizards,<ref>{{cite web |url=http://animaldiversity.ummz.umich.edu/site/accounts/classification/Gekkota.html |title=Infraorder GekkotaInfraorder Gekkota (blind lizards, geckos, and legless lizards) |last=Myers |first=P. |author2=R. Espinosa |author3=C. S. Parr |author4=T. Jones |author5=G. S. Hammond |author6=T. A. Dewey |year=2008 |publisher=The Animal Diversity Web (online) |access-date=2009-04-04 |archive-url=https://web.archive.org/web/20090513023543/http://animaldiversity.ummz.umich.edu/site/accounts/classification/Gekkota.html |archive-date=2009-05-13 }}</ref> have occasionally been counted as gekkotans, but recent molecular phylogenies suggest otherwise.<ref>{{cite journal |last1=Townsend |first1=Ted M. |last2=Larson |first2=Allan |last3=Louis |first3=Edward |last4=Macey |first4=J. Robert |title=Molecular Phylogenetics of Squamata: The Position of Snakes, Amphisbaenians, and Dibamids, and the Root of the Squamate Tree |journal=Systematic Biology |date=1 October 2004 |volume=53 |issue=5 |pages=735–757 |doi=10.1080/10635150490522340|pmid=15545252 |doi-access=free }}</ref><ref>{{cite journal |last1=Vidal |first1=Nicolas |last2=Hedges |first2=S. Blair |title=The phylogeny of squamate reptiles (lizards, snakes, and amphisbaenians) inferred from nine nuclear protein-coding genes |journal=Comptes Rendus Biologies |date=October 2005 |volume=328 |issue=10–11 |pages=1000–1008 |doi=10.1016/j.crvi.2005.10.001|pmid=16286089 |url=https://comptes-rendus.academie-sciences.fr/biologies/articles/10.1016/j.crvi.2005.10.001/ |url-access=subscription }}</ref>

{{clade
|label1='''Gekkota'''
|1={{clade
   |1={{clade
      |1=[[Diplodactylidae]]
      |2={{clade
         |1=[[Carphodactylidae]]
         |2=[[Pygopodidae]]
       }}
    }}
   |2={{clade
      |1=[[Eublepharidae]]
      |2={{clade
         |1=[[Sphaerodactylidae]]
         |2={{clade
            |1=[[Phyllodactylidae]]
            |2=[[Gekkonidae]]
          }}
        }}
     }}
 }}
}}

=== Evolutionary history ===
[[File:Eichstaettisaurus schroederi 398858 (cropped).jpg|thumb|Skeleton of ''[[Eichstaettisaurus]],'' thought to be an early member of the gecko lineage]]
[[File:Deutsches Bernsteinmuseum 04 (cropped).jpg|thumb|Fossil of ''[[Yantarogekko]]'' preserved in Baltic amber]]
Several species of lizard from the late Jurassic have been considered early relatives of geckos, the most prominent and most well supported being the arboreal ''[[Eichstaettisaurus]]'' from the late Jurassic of Germany. ''[[Norellius]]'' from the early Cretaceous of Mongolia is also usually placed as a close relative of geckos.<ref>{{Cite journal |last=Tałanda |first=Mateusz |date=September 2018 |editor-last=Benson |editor-first=Roger |title=An exceptionally preserved Jurassic skink suggests lizard diversification preceded fragmentation of Pangaea |url=https://onlinelibrary.wiley.com/doi/10.1111/pala.12358 |journal=Palaeontology |language=en |volume=61 |issue=5 |pages=659–677 |doi=10.1111/pala.12358 |bibcode=2018Palgy..61..659T |s2cid=134878128 |access-date=2022-06-17 |archive-date=2022-06-17 |archive-url=https://web.archive.org/web/20220617042556/https://onlinelibrary.wiley.com/doi/10.1111/pala.12358 |url-status=live |url-access=subscription }}</ref> The oldest known fossils of modern geckos are from the mid-Cretaceous [[Burmese amber]] of Myanmar (including ''[[Cretaceogekko]]''), around 100 million years old, which have adhesive pads on the feet similar to those of living geckos.<ref>{{cite web |author=Arnold, E.N. |author-link=:fr:Edwin Nicholas Arnold |author2=Poinar, G. |author2-link=George Poinar |name-list-style=amp |date=2008 |title=A 100 million year old gecko with sophisticated adhesive toe pads, preserved in amber from Myanmar (abstract) |url=https://www.mapress.com/zootaxa/2008/f/z01847p068f.pdf |publisher=[[Zootaxa]] |access-date=August 12, 2009 |archive-date=April 23, 2021 |archive-url=https://web.archive.org/web/20210423164342/https://www.mapress.com/zootaxa/2008/f/z01847p068f.pdf |url-status=live }}</ref><ref>{{Cite journal |last1=Fontanarrosa |first1=Gabriela |last2=Daza |first2=Juan D. |last3=Abdala |first3=Virginia |date=April 2018 |title=Cretaceous fossil gecko hand reveals a strikingly modern scansorial morphology: Qualitative and biometric analysis of an amber-preserved lizard hand |journal=Cretaceous Research |volume=84 |pages=120–133 |doi=10.1016/j.cretres.2017.11.003 |bibcode=2018CrRes..84..120F |issn=0195-6671|hdl=11336/64819 |hdl-access=free }}</ref><ref>{{Cite journal |last=Bauer |first=A M |date=2019-07-01 |title=Gecko Adhesion in Space and Time: A Phylogenetic Perspective on the Scansorial Success Story |journal=Integrative and Comparative Biology |volume=59 |issue=1 |pages=117–130 |doi=10.1093/icb/icz020 |pmid=30938766 |issn=1540-7063|doi-access=free }}</ref>

==Species==
[[File:Mediterranean house gecko.JPG|thumb|[[Mediterranean house gecko]]]]More than 1,850 species of geckos occur worldwide,<ref>{{Cite web|url=http://www.reptile-database.org/|title=THE REPTILE DATABASE|website=www.reptile-database.org|access-date=2016-09-20|archive-date=2021-10-29|archive-url=https://web.archive.org/web/20211029024411/http://www.reptile-database.org/|url-status=live}}</ref> including these familiar species:
*''[[Coleonyx variegatus]]'', the western banded gecko, is native to the southwestern [[United States]] and northwest [[Mexico]].
*''[[Cyrtopodion brachykolon]]'', the bent-toed gecko, is found in northwestern [[Pakistan]]; it was first described in 2007.
*''[[Leopard gecko|Eublepharis macularius]]'', the leopard gecko, is the most common gecko kept as a pet; it does not have adhesive toe pads and cannot climb the glass of a [[vivarium]].
*''[[Gehyra mutilata]]'' (''Pteropus mutilatus''), the stump-toed gecko, is able to vary its color from very light to very dark to camouflage itself; this gecko is at home in the wild, as well as in residential areas.
*''[[Tokay gecko|Gekko gecko]]'', the Tokay gecko, is a large, common, [[Southeast Asia]]n gecko known for its aggressive temperament, loud mating calls, and bright markings.
*''[[Hemidactylus]]'' is genus of geckos with many varieties.
**''[[Common house gecko|Hemidactylus frenatus]]'', the common house gecko, thrives around people and human habitation structures in the tropics and subtropics worldwide.
**''[[Indo-Pacific gecko|Hemidactylus garnotii]]'', the Indo-Pacific gecko, is found in houses throughout the tropics, and has become an invasive species of concern in [[Florida]] and [[Georgia (U.S. state)|Georgia]] in the US.
**''[[Hemidactylus mabouia]]'', the tropical house gecko, Afro-American house gecko, or cosmopolitan house gecko, is a species of house gecko native to sub-Saharan Africa and also currently found in North, Central, and South America and the Caribbean.
**''[[Mediterranean house gecko|Hemidactylus turcicus]]'', the Mediterranean house gecko, is frequently found in and around buildings, and is an [[introduced species]] in the US.
*''[[Lepidodactylus lugubris]]'', the mourning gecko, is originally an East Asian and Pacific species; it is equally at home in the wild and residential neighborhoods.
*''[[Bibron's thick-toed gecko|Pachydactylus bibroni]]'', Bibron's gecko, is native to southern Africa; this hardy [[arboreal locomotion|arboreal]] gecko is considered a household pest.
*''[[Gold dust day gecko|Phelsuma laticauda]]'', the gold dust day gecko, is diurnal; it lives in northern [[Madagascar]] and on the [[Comoros]]. It is also an introduced species in [[Hawaiian Islands|Hawaii]].
*''[[Ptychozoon]]'' is a genus of arboreal geckos from Southeast Asia also known as flying or parachute geckos; they have wing-like flaps from the neck to the upper leg to help them conceal themselves on trees and provide lift while jumping.
*''[[Rhacodactylus]]'' is genus native to [[New Caledonia]].
**''[[Crested gecko|Rhacodactylus ciliatus]]'' (now assigned to the genus ''Correlophus''), the crested gecko, was believed extinct until rediscovered in 1994, and is gaining popularity as a pet.
**''[[Rhacodactylus leachianus]]'', the New Caledonian giant gecko, was first described by Cuvier in 1829; it is the largest living species of gecko.
*''[[Sphaerodactylus ariasae]]'', the dwarf gecko, is native to the Caribbean Islands; it is the world's smallest lizard.
*''[[Tarentola mauritanica]]'', the crocodile or Moorish gecko, is commonly found in the [[Mediterranean Sea|Mediterranean]] region from the [[Iberian Peninsula]] and southern [[France]] to [[Greece]] and [[North Africa|northern Africa]]; their most distinguishing characteristics are their pointed heads, spiked skin, and tails resembling those of a [[crocodile]].

==Reproduction==
{{See also|Parthenogenesis in squamata#Lizards}}
{{Expand section|date=February 2020}}
Most geckos lay a small clutch of eggs. Some are live-bearing, and a few can [[Asexual reproduction|reproduce asexually]] via [[parthenogenesis]]. Geckos also have a large diversity of sex-determining mechanisms, including [[temperature-dependent sex determination]] and both XX/XY and ZZ/ZW [[sex chromosome]]s with multiple transitions among them over evolutionary time.<ref>{{cite journal |last1=Gamble |first1=Tony |author2=Coryell, J. |author3=Ezaz, T. | author4=Lynch, J. |author5=Scantlebury, D. |author6=Zarkower, D. |title=Restriction site-associated DNA sequencing (RAD-seq) reveals an extraordinary number of transitions among gecko sex-determining systems |journal=Molecular Biology and Evolution |volume=32 |issue=5 |pages=1296–1309 |year=2015 |pmid=25657328  |doi=10.1093/molbev/msv023|doi-access=free }}</ref>
Madagascar day geckos engage in a mating ritual in which sexually mature males produce a waxy substance from pores on the back of their legs. Males approach females with a head swaying motion along with rapid tongue flicking in the female.<ref>{{Cite web |last1=Fry |first1=Courtney |last2=Roycroft |first2=Carl |title=Phelsuma madagascariensis (Madagascar Day Gecko) |url=https://animaldiversity.org/accounts/Phelsuma_madagascariensis/ |url-status=live |archive-url=https://web.archive.org/web/20231001011236/https://animaldiversity.org/accounts/Phelsuma_madagascariensis/ |archive-date=2023-10-01 |access-date=2024-02-07 |website=Animal Diversity Web |language=en}}</ref>

Obligate [[parthenogenesis]] as a reproductive system has evolved multiple times in the family Gekkonidae.<ref name="Dedukh2022">{{Cite journal |last1=Dedukh |first1=Dmitrij |last2=Altmanová |first2=Marie |last3=Klíma |first3=Jiří |last4=Kratochvíl |first4=Lukáš |date=2022-04-01 |title=Premeiotic endoreplication is essential for obligate parthenogenesis in geckos |url=https://journals.biologists.com/dev/article/149/7/dev200345/275038/Premeiotic-endoreplication-is-essential-for |journal=Development |volume=149 |issue=7 |pages=dev200345 |doi=10.1242/dev.200345 |issn=1477-9129 |pmid=35388415|s2cid=248001402 }}</ref> It has been shown that [[oocyte]]s are able to undergo [[meiosis]] in three different obligate parthenogenetic complexes of geckos. An extra premeiotic endoreplication of [[chromosome]]s is essential for obligate parthenogenesis in these geckos.<ref name = Dedukh2022/> Appropriate segregation during meiosis to form viable progeny is facilitated by the formation of [[bivalent (genetics)|bivalents]] made from copies of identical chromosomes.

==References==
{{Reflist}}

==Further reading==
* Forbes, Peter (4th Estate, London 2005) ''The Gecko's Foot—Bio Inspiration: Engineered from Nature'' {{ISBN|0-00-717990-1}} in H/B
* Zug, George. [http://www.sil.si.edu/smithsoniancontributions/Zoology/sc_RecordSingle.cfm?filename=SCtZ-0631 ''Speciation and Dispersal in a Low Diversity Taxon: The Slender Geckos'' Hemiphyllodactylus ''(Reptilia, Gekkonidae)'']. Smithsonian Contributions to Zoology, no. 631. Washington, D.C.: Smithsonian Institution Scholarly Press, 2010.
* {{cite journal | last1 = Gamble | first1 = T. | last2 = Greenbaum | first2 = E. | last3 = Jackman | first3 = T.R. | last4 = Russell | first4 = A.P. | last5 = Bauer | first5 = A.M. | year = 2012 | title = Repeated origin and loss of adhesive toepads in geckos | journal = PLOS ONE | volume = 7 | issue = 6| article-number = e39429 | doi=10.1371/journal.pone.0039429 | pmid=22761794 | pmc=3384654 | bibcode = 2012PLoSO...739429G| doi-access = free }}

==External links==
{{Commons category|Gekkonidae}}
{{Wikispecies}}
{{wiktionary|gecko}}
* [http://www.theinformationarchives.com/Gecko/ Gecko gallery and information]
* [https://web.archive.org/web/20090214232218/http://lclark.edu/~autumn/dept/geckostory.html ''How Geckos Stick to Walls'']
* [http://www.geckocare.net/ Comprehensive gecko care information]
* [https://www.gekkota.com Global gecko association site with pictures, caresheets, species list]
* [https://www.flickr.com/photos/thirtypounces/54014101/ Gecko anatomy picture]
* [https://www.null-hypothesis.co.uk/science/reviews/books/geckos_foot_peter_forbes_reviewed ''The Gecko's Foot'']
* [https://news.bbc.co.uk/2/hi/science/nature/6967474.stm Artificial gecko feet for a Spiderman suit (BBC 2007-08-28)]
* [https://www.geckotime.com/ Gecko Time Online ''Gecko Magazine'']

{{Squamata families}}
{{Taxonbar|from1=Q16546828|from2=Q1008888}}

{{DEFAULTSORT:Gecko}}
[[Category:Geckos| ]]
[[Category:Lizards of Asia]]
[[Category:Articles containing video clips]]
[[Category:Extant Cenomanian first appearances]]
[[Category:Vertebrate suborders]]