View source for Australian water dragon

{{Taxobox
| name = Australian Water Dragon
| image = 1A B-DRAGON.JPG
| image_width = 
| image_caption = ''Physignathus lesueurii lesueurii''
| regnum = [[Animal]]ia
| phylum = [[Chordate|Chordata]]
| classis = [[Reptile|Reptilia]]
| ordo = [[Squamata]]
| subordo = [[Lacertilia]]
| familia = [[Agamidae]]
| subfamilia = [[Agaminae]]
| genus = ''[[Physignathus]]''
| species = '''''P. lesueurii'''''
| binomial = ''Physignathus lesueurii''
| binomial_authority = ([[John Edward Gray|Gray]], 1831)
| subdivision_ranks = Subspecies
| subdivision = 
''P. l. lesueurii'' (Eastern)<br/>
''P. l. howittii'' (Gippsland)
}}

The '''Australian Water Dragon''' ('''''Physignathus lesueurii'''''), which includes the '''Eastern Water Dragon''' ('''''P. l. lesueurii''''') and the '''Gippsland Water Dragon''' ('''''P. l. howittii'''''), is an [[arboreal]] [[agamid]] species native to Eastern [[Australia]] from [[Victoria (Australia)|Victoria]] north to [[Queensland]], there is also a small population in the south-east coast of the State of [[South Australia]].

== Description ==
Australian water dragons have long powerful limbs and claws for climbing, a long muscular laterally-compressed tail for swimming, and prominent [[nuchal]] and vertebral crests<ref name = JCUP>{{citation |last1=Maruyama |first1 =Kaori |last2=Langkilde|first2=Tracy| title= Physignathus lesueurii|url=http://www.jcu.edu.au/school/tbiol/zoology/herp/Physignathuslesueuri.pdf| publisher = [[James Cook University]]|accessdate=2009-05-21|author-link= Kaori Maruyama}}</ref> (A nuchal crest is a central row of spikes at the base of the head. These spikes continue down the spine, getting smaller as they reach the base of the tail.)<ref name = anbgD>[http://www.anbg.gov.au/anbg/reptiles/dragon.html Australian National Botanic Gardens: Research into Water Dragons]</ref>

Including their tails, which comprise about two-thirds of their total length, adult females grow to about 60&nbsp;cm (2 feet) long, and adult males can grow slightly longer than one metre (3 feet) and weigh about 1&nbsp;kg. Males show bolder colouration and have larger heads than females.<ref name="Willa">[http://calamvalecreek.awardspace.com/willa.html Critters of Calamvale Creek: Eastern Water Dragon]</ref><ref>[http://www.faunanet.gov.au/wos/factfile.cfm?Fact_ID=292 Australian Museum Online: Wildlife of Sydney]</ref> Colour is less distinct in juveniles.<ref name = Whispa>[http://calamvalecreek.awardspace.com/whispa.html Critters of Calamvale Creek: baby Eastern Water Dragon ]</ref>

=== Species variation ===
The Australian Water Dragon is the only species of the genus ''[[Physignathus]]'' in Australia. 

There are two subspecies; ''Physignathus lesueurii lesueurii'' (Eastern Water Dragon) and ''P. l. howitti'' ([[Gippsland]] Water Dragon). ''P. l. lesueurii'' tends towards white, yellow and red on the throat and possesses a dark band behind its eye; ''P. l. howitti'' lacks this and instead has dark bands on either side of its throat, which is blotched with yellow, orange, or blue. Both subspecies are light greenish grey in overall colour with black bands running across their back, tail and legs.

== Behavior ==
[[File:Water Dragon2.jpg|thumb|Eastern Water Dragon]]
[[File:Physignathus lesueurii howittii.jpg|right|thumb|''P. l. howitti'', Gippsland Water Dragon basking in [[Canberra]]]]

Australian water dragons are extremely shy in the wild, but readily adapt to continual human presence in suburban parks and gardens.  They are fast runners and strong climbers.  When presented with a potential predator, they seek cover in thick vegetation, or drop from an overhanging branch into water.  They are able to swim totally submerged, and rest on the bottom of shallow creeks or lakes for up to 90 minutes,<ref name = anbgD/> to avoid detection.  

Both males and females display typical [[agamid]] behaviour such as [[basking]], arm-waving and head-bobbing. Fast arm-waving signals dominance, while slow arm-waving signals submission. Males are territorial,<ref name= JCUP/> and in areas of higher population density, males exhibit displays of aggression toward other males including posturing and chasing.  

=== Breeding ===
Australian water dragons hibernate over winter. During spring, usually in early October, the female excavates a burrow about 10–15&nbsp;cm (4-6 inches) deep and lays between 6 and 18 eggs.<ref name = JCUP/> The nest is usually in sandy or soft soil, in an area open to sun. When the mother has laid the eggs, she backfills the chamber with soil and scatters loose debris over it.  Australian water dragons exhibit temperature-dependant sex determination; the sex of the hatchlings is determined by the temperature of the nest site.<ref name = anbgD/>

When the young are born they stay near the entrance of the burrow for some time before leaving home. When they finally leave the nest, they tend to group together away from the adult population.<ref name="Willa" />

== Habitat ==
As its name suggests, the Australian water dragon is associated with water and is semi-aquatic. It can be found near creeks, rivers, lakes and other water bodies that also have basking sites such as overhanging branches or rocks in open or filtered sun. The species is so common in the rainforest section of [[Brisbane Botanic Gardens, Mount Coot-tha]] in Queensland that a monument has been built to them there.

There are anecdotal reports of a small colony living on the Sixth Creek in the Forest Range area of South Australia, which were probably introduced there during the 1980s by a local reptile enthusiast. This is many hundreds of miles outside their natural range.

== Predators, threats and diet ==
Australian water dragons are prey to snakes, cats, dogs and foxes. Nestlings and smaller juvenile water dragons are vulnerable to predation by kookaburras, currawongs, butcherbirds and other carnivorous birds.<ref name = Pred>[http://www.anbg.gov.au/anbg/reptiles/dragon-predators.html Australian National Botanic Gardens: Predators of Water Dragons]</ref> They are also prone to becoming road kill due to the attraction of warm bitumen and concrete for basking.<ref name = Pred/>
The Australian water dragon's diet depends on its size. Juveniles and yearlings tend to feed on small insects such as ants, spiders, crickets, and caterpillars. When they get bigger, so does their prey. An adult diet includes small rodents such as baby mice, although insects are still the most commonly consumed.

==Gallery==
<gallery>
Image:Gippsland-Water-Dragon---Physignathus-lesueurii-howittii.jpg|Swimming across river in Melbourne
Image:Eastern Water Dragon Clontarf.jpg|Head detail of the Eastern subspecies
Image:Physignathus lesueurii lesueurii (Sydney, 2010-03-24).jpg|''P. l. lesueurii'' (Eastern Water Dragon) basking on a log in suburban [[Sydney]]
Image:Eastern_water_dragon.jpg|''P. l. lesueurii'' swimming, [[Shoalhaven River]], [[New South Wales]]
Image:Water Dragon Sydney Harbour.JPG|Australian Water Dragon surveying [[Port Jackson|Sydney Harbour]]
</gallery>

== References ==
{{reflist}}

== External links ==
{{commons|Physignathus lesueurii}}
{{wikispecies|Physignathus lesueurii}}
*{{eol|791059}}
* [http://www.anbg.gov.au/anbg/reptiles/dragon-research-results.html Australian National Botanic Gardens Research]
*{{citeweb|url=http://www.jcu.edu.au/school/tbiol/zoology/herp/Physignathuslesueuri.pdf|title= ''Physignathus lesueurii'' |author= Maruyama, K., Langkilde, T.|date= 1999}}
* {{citeweb|url=http://cms.jcu.edu.au/discovernature/herpscommon/JCUDEV_009994|title= ''Physignathus lesueurii'' |publisher= James Cook University - Discover Nature}}
* {{citeweb|url=http://lamington.nrsm.uq.edu.au/documents/Rept/eastwater.htm|title= ''Physignathus lesueurii''|author= Reptiles of Lamington National Park}}
* {{citeweb|url=http://www.ozanimals.com/Reptile/Gippsland-Water-Dragon/Physignathus/lesueurii%20howittii.html|title= ''Physignathus lesueurii howittii''|publisher= ozanimals.com }}
*{{NRDB species|genus=Physignathus|species=lesueurii}}

[[Category:Agamidae]]
[[Category:Reptiles of Australia]]

[[bg:Австралийски воден дракон]]
[[de:Australische Wasseragame]]
[[fr:Physignathus lesueurii]]
[[hu:Barna víziagáma]]
[[nl:Lesueurs wateragame]]
[[ja:ヒガシウォータードラゴン]]
[[pl:Agama wodna]]
[[ru:Водяная ящерица]]
[[zh:横纹长鬣蜥]]