{{Short description|Species of lizard}} {{pp-semi-indef}} {{Use dmy dates|date=June 2020}} {{Use Australian English|date = September 2011}} {{speciesbox | name = Thorny devil | image = Thornydevil.jpg | status = LC | status_system = IUCN3.1 | status_ref = <ref name="iucn status 19 November 2021">{{cite iucn |author1=Doughty, P. |author1-link=Paul Doughty |author2=Melville, J. |author2-link=Jane Melville |author3=Craig, M. |author4=Sanderson, C. |author4-link=species:Christopher Sanderson |date=2017 |title=''Moloch horridus'' |volume=2017 |article-number=e.T83492011A83492039 |doi=10.2305/IUCN.UK.2017-3.RLTS.T83492011A83492039.en |access-date=19 November 2021}}</ref> | display_parents = 2 | genus = Moloch | parent_authority = Gray, 1841 | species = horridus | authority = Gray, 1841 | synonyms = ''Acanthosaura gibbosus'' | range_map = Moloch_horridus_distribution_map.png | range_map_caption = Distribution of ''Moloch horridus'' }}
The '''thorny devil''' ('''''Moloch horridus'''''), also known commonly as the '''mountain devil''', '''thorny lizard''', '''thorny dragon''', and '''moloch''', is a species of lizard in the family Agamidae. The species is endemic to Australia. It is the sole species in the genus '''''Moloch'''''. It grows up to {{convert|21|cm|in|abbr=on}} in total length (including tail), with females generally larger than males.
==Taxonomy== The thorny devil was first described by the biologist John Edward Gray in 1841. While it is the only species contained in the genus ''Moloch'', many taxonomists suspect another species might remain to be found in the wild.<ref name="Browne-Cooper"/> The thorny devil is only distantly related to the morphologically similar North American horned lizards of the genus ''Phrynosoma''. This similarity is usually thought of as an example of convergent evolution.
The names given to this lizard reflect its appearance: the two large horned scales on its head complete the illusion of a dragon or devil. The name Moloch was used for a deity of the ancient Near East, usually depicted as a hideous beast.<ref>{{EponymDictionaryReptiles}}</ref>{{rp|82}} The thorny devil also has other nicknames people have given it such as the "devil lizard", "horned lizard", and the "thorny toad".<ref>[https://www.factzoo.com/reptiles/lizards/thorny-devil-lizard.html Thorny Devil Lizard – Prickly Desert Ant-Eater]. factzoo.com</ref>
==Description== The thorny devil grows up to {{convert|21|cm|in|abbr=on}} in total length (including tail),<ref>Boulenger GA (1885). ''Catalogue of the Lizards in the British Museum (Natural History). Second Edition Volume I. ... Agamidæ.'' London: Trustees of the British Museum (Natural History). (Taylor and Francis, printers). xii + 436 pp. + Plates I–XXXII.</ref>{{rp|411}} and can live for 15 to 20 years. The females are larger than the males. Most specimens are coloured in camouflaging shades of desert browns and tans. These colours change from pale colours during warm weather to darker colours during cold weather. The thorny devil is covered entirely with conical spines that are mostly uncalcified.
[[File:Thorny devil pale.jpg|thumb|left|A thorny devil in Western Australia]] An intimidating array of spikes covers the entire upper side of the body of the thorny devil. These thorny scales also help to defend it from predators. Camouflage and deception may also be used to evade predation. This lizard's unusual gait involves freezing and rocking as it moves about slowly in search of food, water, and mates.<ref name="Browne-Cooper"/>
The thorny devil also features a spiny "false head" on the back of its neck, and the lizard presents this to potential predators by dipping its real head. The "false head" is made of soft tissue.<ref>{{cite journal |last1=Bell |first1=Christopher |last2=Mead |first2=Jim |last3=Swift |first3=Sandra |author3-link=species:Sandra Swift |title=Cranial osteology of ''Moloch horridus'' (Reptilia: Squamata: Agamidae) |journal=Records of the Western Australian Museum |date=2009 |volume=25 |issue=Part 2 |pages=201–237 |doi=10.18195/issn.0312-3162.25(2).2009.201-237 |doi-access=free }}</ref>
The thorny devil's scales are ridged, enabling the animal to collect water by simply touching it with any part of the body, usually the limbs; capillary action transports the water to the mouth through channels in its skin.<ref name="Browne-Cooper">{{cite book|author1=Browne-Cooper, Robert|author1-link=species:Robert Browne-Cooper|author2=Bush, Brian|author2-link=species:Brian Gordon Bush|author3=Maryan, Brad|author3-link=species:Brad Maryan|author4=Robinson, David|author4-link=species:David Robinson|title=Reptiles and Frogs in the Bush: Southwestern Australia|year=2007|publisher=University of Western Australia Press|location=Perth|isbn= 978-1-920694-74-6|pages=46, 65, 158}}</ref> The thorny devil is also equipped to harvest moisture in the dry desert following nighttime's extremely low temperatures and the subsequent condensation of dew. The process involves moisture contact, their hydrophilic skin surface structures with capillaries, and an internal transport mechanism.<ref name="Comanns3">{{cite journal |last1=Comanns |first1=Philipp |last2=Esser |first2=Falk J. |last3=Kappel |first3=Peter H. |last4=Baumgartner |first4=Werner |last5=Shaw |first5=Jeremy |last6=Withers |first6=Philip C. |title=Adsorption and movement of water by skin of the Australian thorny devil (Agamidae: ''Moloch horridus'') |journal=Royal Society Open Science |date=September 2017 |volume=4 |issue=9 |article-number=170591 |doi=10.1098/rsos.170591 |doi-access=free|pmid=28989762 |pmc=5627102 |bibcode=2017RSOS....470591C }}</ref> *The lizard rubs its body against the moist substrate and shovels damp sand onto its back, the outer epidermis layer equipped to draw in cutaneous moisture. *The keratinous fibered epidermis is hydrophilic with hexagonal microstructures on the scale surfaces. When trace amounts of water contact its skin (pre-wetting) these microstructures fill with water, the skin surface becoming superhydrophilic. This allows moisture to spread across wider surface areas, yielding faster uptake, as water is collected via capillary action in small channels located between its scales. *Captured water is transported passively via capillary action in semi-tubular channels located beneath the partially overlapping scales, in an asymmetric and interconnected system that extends over the lizard's entire body surface. The channels terminate at the mouth where active ingestion (drinking) is observable by jaw movements when moisture is plentiful, e.g. water puddles.
The same hydrophilic moisture-harvesting physiology is characteristic in the Texas horned lizard (''Phrynosoma cornutum''), roundtail horned lizard (''Phrynosoma modestum''), desert horned lizard (''Phrynosoma platyrhinos''), Arabian toad-headed agama (''Phrynocephalus arabicus''), sunwatcher toadhead agama (''Phrynocephalus helioscopus''), ''Phrynocephalus horvathi'', yellow-spotted agama (''Trapelus flavimaculatus''), ''Trapelus pallidus'' and desert agama (''Trapelus mutabilis'').<ref name="Comanns2b">{{cite journal |last1=Comanns |first1=Philipp |title=Passive water collection with the integument: mechanisms and their biomimetic potential |journal=Journal of Experimental Biology |date=May 2018 |volume=221 |issue=10 |page=Table 1 |doi=10.1242/jeb.153130|pmid=29789349 |doi-access=free |bibcode=2018JExpB.221B3130C }}</ref>
==Distribution and habitat== [[Image:MolochLyd.jpg|thumb|Illustration from Lydekker's ''The Royal Natural History'']] thumb|upright|Thorny devil underside, Western Australia The thorny devil usually lives in the arid scrubland and desert that covers most of central Australia, sandplain and sandridge desert in the deep interior and the mallee belt.
The habitat of the thorny devil coincides more with the regions of sandy loam soils than with a particular climate in Western Australia.<ref>{{cite journal|author=Pianka ER, Pianka HD|year=1970|title=The ecology of ''Moloch horridus'' (Lacertilia: Agamidae) in Western Australia|journal=Copeia|volume=1970|issue=1|pages=90–103|doi=10.2307/1441978|jstor=1441978}}</ref>
==Self-defense== The thorny devil is covered in hard, rather sharp spines that dissuade attacks by predators by making it difficult to swallow. It also has a false head on its back. When it feels threatened by other animals, it lowers its head between its front legs, and then presents its false head. Predators that consume the thorny devil include wild birds and goannas.
==Diet== The thorny devil mainly subsists on ants, especially ''Ochetellus flavipes'' and other species in the ''Camponotus'', ''Ectatomma'',<ref name="animaldiversity.org">{{Cite web|url=https://animaldiversity.org/accounts/Moloch_horridus/|title = ''Moloch horridus'' (Thorny Devil, Mountain Devil)| website=Animal Diversity Web }}</ref> ''Iridomyrmex'' (especially ''Iridomyrmex rufoniger''),<ref name="animaldiversity.org"/> ''Monomorium'',<ref name="animaldiversity.org"/> ''Ochetellus'', ''Pheidole'', or ''Polyrhachis''<ref name="animaldiversity.org"/> genera.<ref>{{citation |url=http://uts.cc.utexas.edu/~varanus/moloch.html |title=Australia's Thorny Devil |access-date=2007-10-31 |archive-date=10 October 2011 |archive-url=https://web.archive.org/web/20111010180520/http://uts.cc.utexas.edu/%7Evaranus/moloch.html }}</ref> Thorny devils often eat thousands of ants in one day.<ref name="Browne-Cooper"/>
The thorny devil collects moisture in the dry desert by the condensation of dew. This dew forms on its skin in the early morning as it begins to warm outside. Then the dew is channeled to its mouth by gravity and capillary action via the channels between its spines. During rainfalls, capillary action allows the thorny devil to absorb water from all over its body. Capillary action also allows the thorny devil to absorb water from damp sand. Absorption through sand is the thorny devil's main source of water intake.<ref>{{cite journal|doi=10.1242/jeb.151407|title=How thorny devils tap damp sand to slake thirst|year=2016|last1=Knight|first1=Kathryn|s2cid=89521720|journal=The Journal of Experimental Biology|volume=219|issue=21|pages=3309.1–3309|doi-access=free|bibcode=2016JExpB.219Q3309K }}</ref>
==Reproduction== The female thorny devil lays a clutch of three to ten eggs between September and December. She puts these in a nesting burrow about 30 cm underground. The eggs hatch after about three to four months.<ref>{{cite journal|author=Pianka ER|year=1997|title=Australia's thorny devil|journal=Reptiles|volume=5|issue=11|pages=14–23}}</ref>
==Popular reference== The popular appeal of the thorny devil is the basis of an anecdotal petty scam. American servicemen stationed in Southwest Australia decades ago (such as during World War II) were supposedly sold the thorny fruits of a species of weeds, the so-called "double gee" (''Emex australis''), but those were called "thorny devil eggs" as a part of the scam.{{citation needed|date=July 2015}} Thorny devils have been kept in captivity.<ref name="Browne-Cooper"/>
==References== {{Reflist}}
==Further reading== *{{cite journal|last1=Clemente|first1=Christofer|last2=Thompson|first2=Graham G.|last3=Withers|first3=Philip C|last4=Lloyd|first4=David|title=Kinematics, maximal metabolic rate, sprint and endurance for a slow-moving lizard, the thorny devil (''Moloch horridus'')|journal=Australian Journal of Zoology|date=2004|volume=52|issue=5|pages=487–503|doi=10.1071/ZO04026}} *{{cite journal|last1=Meyers|first1=Jay|title=Prey capture kinematics of ant-eating lizards|journal=Journal of Experimental Biology|date=2005|volume=208|issue=Pt 1|pages=115–127|doi=10.1242/jeb.01345|pmid=15601883|id={{ProQuest|13293724}}|doi-access=free|bibcode=2005JExpB.208..113M }} *Cogger HG (2014). ''Reptiles and Amphibians of Australia, Seventh Edition''. Clayton, Victoria, Australia: CSIRO Publishing. xxx + 1,033 pp. {{ISBN|978-0643100350}}. *Gray JE (1841). "Description of some new Species and four Genera of Reptiles from Western Australia discovered by John Gould, Esq." ''The Annals and Magazine of Natural History'', [''First Series'' ] '''7''': 86–91. (''Moloch'', new genus pp. 88–89; ''M. horridus'', new species, p. 89). *Wilson, Steve; Swan, Gerry (2013). ''A Complete Guide to Reptiles of Australia, Fourth Edition''. Sydney: New Holland Publishers. 522 pp. {{ISBN|978-1921517280}}. *{{cite book |last1=Wilson |first1=Steve |last2=Swan |first2=Gerry |title=A Complete Guide to Reptiles of Australia, Sixth Edition |date=2023 |publisher=Reed New Holland Publishers |location=Sydney |isbn=978-1-92554-671-2}} 688 pp. (''Moloch horridus'', pp. 482–483).
==External links== {{Commons category|Moloch horridus}} *[https://digimorph.org/specimens/Moloch_horridus/head/ Digimorph: ''Moloch horridus'', thorny dragon body structure] *[http://uts.cc.utexas.edu/~varanus/moloch.html Australia's Thorny Devil by Eric R. Pianka] {{Webarchive|url=https://web.archive.org/web/20111010180520/http://uts.cc.utexas.edu/%7Evaranus/moloch.html |date=10 October 2011 }} *[https://web.archive.org/web/20091025153154/http://www.kidcyber.com.au/topics/thornydev.htm Thorny Devil], www.kidcyber.com.au
{{Taxonbar|from=Q320665}}
Category:Agamidae Category:Reptiles of Western Australia Category:Reptiles described in 1841 Category:Agamid lizards of Australia Category:Taxa named by John Edward Gray Category:Moloch