Pogona: Difference between revisions

'''''Pogona''''' is a [[genus]] of [[reptiles]] containing eight [[lizard]] [[species]], which are often known by the [[common name]] '''bearded dragons'''. The name "bearded dragon" refers to the underside of the throat (or "beard") of the lizard, which can turn black and puffbecome upinflated for a number of reasons, most often as a result of [[Stress (biology)|stress]], if they feel threatened,<ref name="https://beardeddragontank.com/8-reasons-for-your-bearded-dragons-black-beard">{{cite web |title=8 Reasons For Your Bearded Dragonś Black Beard |url=https://beardeddragontank.com/8-reasons-for-your-bearded-dragons-black-beard |website=beardeddragontank.com}}</ref> or are trying to entice a mate. They are a semiarboreal species, spending significant amounts of time on branches, in bushes, and near human habitation.<ref>{{Cite web|url=http://beardeddragoncaresheet.weebly.com/housing.html|title=Housing|website=Care of Bearded Dragons (Pogona vitticeps)|access-date=2019-12-19}}</ref> ''Pogona'' species bask on rocks and exposed branches in the mornings and afternoons and sleep at night, making them a [[Diurnality|diurnal species]]. Their diet consists primarily of vegetation and some insects. They are found throughout much of Australia and inhabit environments such as [[desert]]s, and [[shrubland]]s.<ref name="Browne-Cooper">{{cite book |last=Browne-Cooper |first= Robert|author2=Brian Bush |author3=Brad Maryan |author4=David Robinson |title= Reptiles and Frogs in the Bush: Southwestern Australia|year= 2007|publisher= [[University of Western Australia]] Press|isbn= 978-1-920694-74-6 |page=160|quote=''Pogona minor minor'', Abrolhos Bearded Dragon }}</ref>

[[File:Bearded Dragon South Australia.jpg|thumb|leftupright=0.5|right|Captive adult measuring over 30 cm (1 ft)]]

The genus ''Pogona'' is in the [[subfamily]] [[Amphibolurinae]] of the lizard group [[Agamidae]]. Bearded dragons are characterized by their broad, triangular heads, flattened bodies, and rows and clusters of spiny scales covering their entire bodies. When threatened, bearded dragons puff up their bodies and beards to ward off predators and make their somewhat dull spikes seem somewhat more dangerous. Bearded dragons display a hand-waving gesture to show submission (most often when acknowledging another bearded dragon's territory), and a head-bobbing display to show dominance<ref>{{Cite web |last=Pets |first=Lizard |date=May 23, 2023 |title=Why do bearded dragons bob their heads at humans? |url=https://lizard-pets.com/behaviour/why-do-bearded-dragons-bob-their-heads-at-humans/ |url-status=live |website=Lizard Pets}}</ref> between dragons. Some have the ability to slightly change color duringin response to certain stimuli including rivalry challenges between males, in response toand ambient temperature changes such as(e.g., turning black to absorb heat, and other stimuli). Bearded dragons occur in a variety of colors and morphs and can range from being all dark to completely white under controlled breeding conditions. Males grow up to {{convert|60|cm|in|abbr=on}} long, and females up to {{convert|51|cm|in|abbr=on}}.

Adult bearded dragons are very territorial. As they grow, they establish territories in which displays of aggression and appeasement form a normal part of their social interactions. A dominant male adopts a dominant stance and sometimes readies himself for a fight to attack a male aggressor to defend territory or food sources, or in competition for a female. Any male approaching without displaying submissive behavior is seen as a challenge for territory. Aggressive males have even been known to attack females that do not display submissive gestures in return.<ref>{{Cite web |date=2019-06-20 |title=Bearded dragons |url=https://www.nationalgeographic.com/animals/reptiles/facts/bearded-dragon |access-date=2024-02-29 |website=Animals |language=en}}</ref>

Correspondingly, adult male bearded dragons can bite more forcefully than adult females, which is associated with greater head dimensions.<ref name="Jonesetal2020a">{{cite journal | title = Reproductive phenotype predicts adult bite-force performance in sex reversed dragons (''Pogona vitticeps'') | journal = Journal of Experimental Zoology A | volume = 333 | pages = 252‒263 | year=2020 | author= Jones MEH, Pistevos JC, Cooper N, Lappin, AK, Georges A Hutchinson MN, Holleley CE. | issue = 4 | doi=10.1002/jez.2353 | pmid = 32061035 | hdl = 10141/622643 | s2cid = 211122728 | hdl-access = free }}</ref>

Bearded dragons exhibit temperature sex determination; while the embryo is developing, higher temperatures cause dragons with a male genotype to experience sex reversal and express a female phenotype. This produces a bearded dragon that is a female, but still has a male genotype. Incubation temperatures above {{Convert|31°|C}} can cause sex reversal, and the likelihood of sex reversal has a positive correlation with temperature up to 36°C. Incubation temperatures below 31°C cannot trigger sex reversal.<ref>{{cite journal |last1=Castelli |first1=Megan |last2=Georges |first2=Arthur |title=Evolving thermal thresholds explain the distribution of temperature sex reversal in an Australian dragon lizard |journal=Diversity and Distributions |date=4 November 2020 |volume=27 |issue=3 |pages=427–438 |doi=10.1111/ddi.13203 |doi-access=free |hdl=1885/274579 |hdl-access=free }}</ref> Surprisingly, female bearded dragons with a male genotype do not have many differences from genotypic females. According to one study done on bite force, male bearded dragons have a higher bite force than genotypic females, and sex-reversed females, but no difference was seen between genotypic females and sex-reversed females.<ref>{{cite journal |last1=Jones |first1=Marc |last2=Pistavos |first2=Jennifer |last3=Cooper |first3=Natalie |last4=Lappin |first4=AK |last5=Georges |first5=Arthur |title=Reproductive phenotype predicts adult bite-force performance in sex-reversed dragons (Pogona vitticeps) |journal=Journal of Experimental Zoology A |date=April 2020 |volume=333 |issue=4 |pages=252–263 |doi=10.1002/jez.2353|pmid=32061035 |doi-access=free |hdl=10141/622643 |hdl-access=free }}</ref>

* Bicephalism is when a bearded dragon is born with two heads and one body.<ref name=":0Brown">Brown, Danny. ''A Guide to Australian Dragons in Captivity''. ABK Publications, 2012</ref>

* Anasarca is when a bearded dragon is swollen within the egg. Observing eggs in the incubator, an anasarca egg appears to be sweating. The cause of this is not known.<ref name=":0Brown" />

* Shistosomus reflexa is when the organs of a bearded dragon develop outside of the body.<ref name=":0Brown" />

* Spinal and limb defects are abnormalities in the spine, tail, limbs, or toes. This occurs with nutritional deficiencies, trauma, or temperature issues during the development of the affected area.<ref name=":0Brown" />

* MicropthalmiaMicrophthalmia/anopthalmiaanophthalmia is when a bearded dragon is born with small or no eye(s). The cause of this defect is a traumatic event or an environmental event that occurred during the development of the eyes.<ref name=":0Brown" />

* Hermaphroditism is when the reproductive organs of both male and female are present. Bearded dragons born with both reproductive organs are infertile.<ref name=":0Brown" />

Atadenovirus (ADV), also referred to as adenovirus, is a viral disease that can be deadly. ADV can be spread between reptiles through contact alone. Most juvenile ADV-positive bearded dragons do not live past 90 days. While ADV-positive adults will live longer, they eventually contract liver diseases.<ref>{{Cite web|url=http://www.reptilesmagazine.com/Reptile-Health/Habitats-Care/Atadenovirus-This-Disease-Can-Be-Deadly-To-Your-Bearded-Dragon/|title=Atadenovirus – This Disease Can Be Deadly To Your Bearded Dragon|website=www.reptilesmagazine.com|date=27 January 2012 |language=en|access-date=2017-05-05|archive-url=https://web.archive.org/web/20170522032024/http://www.reptilesmagazine.com/Reptile-Health/Habitats-Care/Atadenovirus-This-Disease-Can-Be-Deadly-To-Your-Bearded-Dragon/|archive-date=22 May 2017}}</ref> Common symptoms of ADV-positive bearded dragons include stunted growth and slow weight gain. Because of their compromised immune systems, ADV-positive bearded dragons may be infected with intestinal parasites.<ref>{{Cite web|url=http://azeah.com/lizards/atadenovirus-bearded-dragons|title=Atadenovirus in Bearded Dragons|last=Bjornebo|first=Heather|date=2016-08-11|website=azeah.com|access-date=2017-05-05}}</ref>

The following six species are recognised as being valid.<ref name="IUCN">{{cite iucnweb|title="IUCN search Pogona – Genus"|url=https://www.iucnredlist.org/search?taxonomies=170418&searchType=species}}</ref>