Editing Lizard (section)

===Reproduction and life cycle===
[[File:Trachylepis maculilabris mating.jpg|thumb|250px|''Trachylepis maculilabris'' [[skinks]] mating]]
As with all amniotes, lizards rely on internal fertilisation and copulation involves the male inserting one of his [[Hemipenis|hemipene]]s into the female's [[cloaca]].<ref>Pianka and Vitt, pp. 108.</ref> Female lizards also have
[[Hemipenis#Hemiclitoris|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.<ref name="Pianka-Vitt115"/> 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.<ref>Pianka and Vitt, pp. 110–111.</ref> 
[[File:EasternFenceLizard Egg.png|thumb|200px|left|Two pictures of an [[eastern fence lizard]] 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. [[Egg incubation|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 monitor]]s, the young hatch close to 300 days, and the female returns to help them escape the termite mound where the eggs were laid.<ref name="Pianka-Vitt115">Pianka and Vitt, pp. 115–116.</ref>

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.<ref>Pianka and Vitt, pp. 117–118.</ref> 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 lizard]]s.<ref name="Pianka-Vitt119">Pianka and Vitt, pp. 119.</ref> 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.<ref>{{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 }}</ref>

Sex determination in lizards can be [[Temperature-dependent sex determination|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 [[Heterogametic sex|heterogamety]] (XY and XXY) and female heterogamety (ZW) occur.<ref name="Pianka-Vitt119"/>