Editing Komodo dragon (section)

==Behaviour and ecology==
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The Komodo dragon prefers hot and dry places and typically lives in dry, open grassland, savanna, and tropical forest at low elevations. As an [[ectotherm]], it is most active in the day, although it exhibits some [[nocturnal]] activity. Komodo dragons are solitary, coming together only to breed and eat. There are some "personality" differences among the species, where some present as more "shy", particularly females.<ref>
Laver RJ, Purwandana D, Ariefiandy A, Imansyah J, Forsyth D, et al. (2012) Life-History and Spatial Determinants of Somatic Growth Dynamics in Komodo Dragon Populations. PLOS ONE 7(9): e45398. https://doi.org/10.1371/journal.pone.0045398</ref> They are capable of running rapidly in brief sprints up to {{cvt|20|km/h}}, diving up to {{cvt|4.5|m|ft}}, and climbing trees proficiently when young through use of their strong claws.<ref name="animal">{{cite book| last = Burnie | first = David |author2=Don E. Wilson | title = Animal | publisher = DK Publishing | year = 2001 | location = New York | pages = 417, 420 | isbn = 978-0-7894-7764-4}}</ref> To catch out-of-reach prey, the Komodo dragon may stand on its hind legs and use its tail as a support.<ref name="liz"/>{{rp|144}} As it matures, its claws are used primarily as weapons, as its great size makes climbing impractical.<ref name="location"/>

For shelter, the Komodo dragon digs holes that can measure from {{cvt|1|to|3|m|ft}} wide with its powerful forelimbs and claws.<ref name="cogger">{{cite book |editor1=Cogger, Harold G.|editor2=Zweifel, Richard G.|others=Illustrations by David Kirshner |title=Encyclopedia of Reptiles & Amphibians |publisher=Academic Press |location=Boston |year=1998 |pages=132, 157–58 |isbn=978-0-12-178560-4}}</ref> Because of its large size and habit of sleeping in these burrows, it is able to conserve body heat throughout the night and minimise its basking period the morning after.<ref>{{cite book |author1=Eric R. Pianka |author2=Laurie J. Vitt; with a foreword by Harry W. Greene |title=Lizards: Windows to the Evolution of Diversity |publisher=University of California Press |location=Berkeley |year=2003 |page=[https://archive.org/details/lizardswindowsto00pian/page/244 244] |isbn=978-0-520-23401-7 |url=https://archive.org/details/lizardswindowsto00pian/page/244 }}</ref> The Komodo dragon stays in the shade during the hottest part of the day and hunts in the afternoon.<ref name="gateway-faq"/> These special resting places, usually located on ridges with cool sea breezes, are marked with droppings and are cleared of vegetation. They serve as strategic locations from which to ambush deer.<ref name="southsea"/>

===Diet===
[[File:Komodo Dragon Eating Rinca.jpg|thumb|Komodo dragon on Rinca feeding on a [[water buffalo]] corpse]]
Komodo dragons are [[apex predator]]s.<ref name="firefly"/> They are carnivores; although they have been considered as eating mostly carrion,<ref name="world">{{cite book |last1=Mattison |first1=Chris |year=1992 |orig-year=1989 |title=Lizards of the World |publisher=Facts on File |location=New York |pages=16,57,99,175 |isbn=978-0-8160-5716-0}}</ref> they will frequently ambush live prey with a stealthy approach. When suitable prey arrives near a dragon's ambush site, it will suddenly charge at the animal at high speeds and go for the underside or the throat.<ref name="location"/> The majority of the extant Komodo dragon population's diet is made up of introduced ungulates, such as deer, pigs, and buffalo. <ref>Shine, Richard; Somaweera, Ruchira (April 2019). "Last lizard standing: The enigmatic persistence of the Komodo dragon". Global Ecology and Conservation. 18: e00624. Bibcode:2019GEcoC..1800624S. doi:10.1016/j.gecco.2019.e00624.</ref>

Komodo dragons do not deliberately allow the prey to escape with fatal injuries but try to kill prey outright using a combination of lacerating damage and blood loss. They have been recorded as killing wild pigs within seconds,<ref name=auffenberg1>{{cite book|author=Auffenberg, Walter |title=The Behavioral Ecology of the Komodo Monitor |publisher=University Presses of Florida |location=Gainesville, Florida |year=1981 |isbn=978-0-8130-0621-5}}</ref> and observations of Komodo dragons tracking prey for long distances are likely misinterpreted cases of prey escaping an attack before succumbing to infection. Most prey attacked by a Komodo dragon reputedly suffer from said sepsis and will later be eaten by the same or other lizards.<ref>{{Cite journal |last1=Bull |first1=J. J. |last2=Jessop |first2=Tim S. |last3=Whiteley |first3=Marvin |date=2010-06-21 |title=Deathly Drool: Evolutionary and Ecological Basis of Septic Bacteria in Komodo Dragon Mouths |journal=PLOS ONE |language=en |volume=5 |issue=6 |pages=e11097 |doi=10.1371/journal.pone.0011097 |issn=1932-6203 |pmc=2888571 |pmid=20574514 |bibcode=2010PLoSO...511097B |doi-access=free }}</ref>

Komodo dragons eat by tearing large chunks of flesh and swallowing them whole while holding the carcass down with their forelegs. For smaller prey up to the size of a goat, their loosely articulated jaws, flexible skulls, and expandable stomachs allow them to swallow prey whole. The undigested vegetable contents of a prey animal's stomach and intestines are typically avoided.<ref name="southsea"/> Copious amounts of red saliva the Komodo dragons produce help to lubricate the food, but swallowing is still a long process (15–20&nbsp;minutes to swallow a goat). A Komodo dragon may attempt to speed up the process by ramming the carcass against a tree to force it down its throat, sometimes ramming so forcefully that the tree is knocked down.<ref name="southsea"/> A small tube under the tongue that connects to the lungs allows it to breathe while swallowing.<ref name="location"/>

After eating up to 80% of its body mass in one meal,<ref name="firefly">{{cite book |editor1-last=Halliday |editor1-first=Tim |editor1-link=Tim Halliday |editor2-last=Adler |editor2-first=Kraig |year=2002 |title=Firefly Encyclopedia of Reptiles and Amphibians |publisher=Firefly Books |location=Hove |isbn=978-1-55297-613-5 |pages=[https://archive.org/details/fireflyencyclope0000unse_p6l7/page/112 112–13, 144, 147, 168–69] |url=https://archive.org/details/fireflyencyclope0000unse_p6l7/page/112}}</ref> it drags itself to a sunny location to speed digestion, as the food could rot and poison the dragon if left undigested in its stomach for too long. Because of their slow metabolism, large dragons can survive on as few as 12&nbsp;meals a year.<ref name="location"/> After digestion, the Komodo dragon regurgitates a mass of horns, hair, and teeth known as the gastric pellet, which is covered in malodorous mucus. After regurgitating the gastric pellet, it rubs its face in the dirt or on bushes to get rid of the mucus.<ref name="location"/>

[[File:Komodo excrement.jpg|thumb|upright|Komodo excrement has a dark portion, which is stool, and a whitish portion, which is [[urate]], the nitrogenous end-product of their digestion process]]
The eating habits of Komodo dragons follow a hierarchy, with the larger animals generally eating before the smaller ones. The largest male typically asserts his dominance and the smaller males show their submission by use of body language and rumbling hisses. Dragons of equal size may resort to "wrestling". Losers usually retreat, though they have been known to be killed and eaten by victors.<ref name=auffenberg/><ref>{{cite book |last=Mader |first=Douglas R. |year=1996 |title=Reptile Medicine and Surgery |publisher=WB Saunders Co. |page=16 |isbn=0721652085}}</ref>

The Komodo dragon's diet varies depending on stage of growth. Young Komodo dragons will eat insects, birds and bird's eggs and small reptiles, while larger Komodo dragons (typically over {{cvt|20|kg|lb}}) prefer large [[ungulate]] prey, such as [[Javan rusa]] deer, [[Wild boar|wild pigs]] and [[water buffalo]].<ref>{{Cite journal |last1=Purwandana |first1=Deni |last2=Ariefiandy |first2=Achmad |last3=Imansyah |first3=M. Jeri |last4=Seno |first4=Aganto |last5=Ciofi |first5=Claudio |last6=Letnic |first6=Mike |last7=Jessop |first7=Tim S. |date=April 2016 |title=Ecological allometries and niche use dynamics across Komodo dragon ontogeny |url=http://link.springer.com/10.1007/s00114-016-1351-6 |journal=The Science of Nature |language=en |volume=103 |issue=3–4 |page=27 |doi=10.1007/s00114-016-1351-6 |pmid=26936625 |bibcode=2016SciNa.103...27P |s2cid=16570624 |issn=0028-1042}}</ref><ref>{{Cite journal |last1=Jessop |first1=Tim S. |last2=Madsen |first2=Thomas |last3=Sumner |first3=Joanna |last4=Rudiharto |first4=Heru |last5=Phillips |first5=John A. |last6=Ciofi |first6=Claudio |date=February 2006 |title=Maximum body size among insular Komodo dragon populations covaries with large prey density |url=https://onlinelibrary.wiley.com/doi/10.1111/j.0030-1299.2006.14371.x |journal=Oikos |language=en |volume=112 |issue=2 |pages=422–429 |doi=10.1111/j.0030-1299.2006.14371.x |bibcode=2006Oikos.112..422J |issn=0030-1299}}</ref> Occasionally, they attack and bite humans. Sometimes they consume human corpses, digging up bodies from shallow graves.<ref name="liz"/>{{rp|84}} This habit of raiding graves caused the villagers of Komodo to move their graves from sandy to clay ground, and pile rocks on top of them, to deter the lizards.<ref name="southsea">{{cite book |author1=Ballance, Alison |author2=Morris, Rod |title=South Sea Islands: A natural history |publisher=Firefly Books Ltd |location=Hove |year= 2003|isbn=978-1-55297-609-8}}</ref> Dwarf species of ''[[Stegodon]]'' (a proboscidean related to living elephants) are suggested to have been a primary prey item of the Komodo dragon during the [[Pleistocene]], prior to the introduction of their modern ungulate prey, which were only introduced to the islands in the [[Holocene]], around 10-7,000 years ago.<ref name="Diamond2">{{cite journal |last=Diamond |first=Jared M. |year=1987 |title=Did Komodo dragons evolve to eat pygmy elephants? |journal=[[Nature (journal)|Nature]] |volume=326 |issue=6116 |page=832 |bibcode=1987Natur.326..832D |doi=10.1038/326832a0 |s2cid=37203256}}</ref><ref>{{Cite journal |last1=Shine |first1=Richard |last2=Somaweera |first2=Ruchira |date=April 2019 |title=Last lizard standing: The enigmatic persistence of the Komodo dragon |journal=Global Ecology and Conservation |language=en |volume=18 |pages=e00624 |doi=10.1016/j.gecco.2019.e00624|doi-access=free |bibcode=2019GEcoC..1800624S }}</ref>

The Komodo dragon drinks by sucking water into its mouth via [[buccal pumping]] (a process also used for respiration), lifting its head, and letting the water run down its throat.<ref name=auffenberg1/>

===Saliva===
Although previous studies proposed that Komodo dragon saliva contains a variety of highly septic bacteria that would help to bring down prey,<ref name="auffenberg">{{cite book |author=Auffenberg, Walter |title=The Behavioral Ecology of the Komodo Monitor |publisher=University Presses of Florida |location=Gainesville |year=1981 |page=406 |isbn=978-0-8130-0621-5 }}</ref><ref name="Aerobic">{{cite journal|pmid=12238371|year=2002|last1=Montgomery|first1=JM|last2=Gillespie|first2=D|last3=Sastrawan|first3=P|last4=Fredeking|first4=TM|last5=Stewart|first5=GL|title=Aerobic salivary bacteria in wild and captive Komodo dragons|volume=38|issue=3|pages=545–51|journal=Journal of Wildlife Diseases|url=http://www.jwildlifedis.org/cgi/reprint/38/3/545.pdf|archive-url=https://web.archive.org/web/20071214133444/http://www.jwildlifedis.org/cgi/reprint/38/3/545.pdf|url-status=dead|archive-date=14 December 2007|doi=10.7589/0090-3558-38.3.545|s2cid=9670009}}</ref> research in 2013 suggested that the bacteria in the mouths of Komodo dragons are ordinary and similar to those found in other carnivores. Komodo dragons have good mouth hygiene. To quote Bryan Fry: "After they are done feeding, they will spend 10 to 15 minutes lip-licking and rubbing their head in the leaves to clean their mouth&nbsp;... Unlike people have been led to believe, they do not have chunks of rotting flesh from their meals on their teeth, cultivating bacteria." They do have a slashing bite, which normally includes a dose of their neurotoxic venom and anticoagulant saliva.<ref>D’Amore, D. C., Moreno, K., McHenry, C. R., & Wroe, S. (2011). The effects of biting and pulling on the forces generated during feeding in the Komodo dragon (Varanus komodoensis). PloS One, 6(10), e26226–e26226. https://doi.org/10.1371/journal.pone.0026226</ref> Komodo dragons do not wait for prey to die and track it at a distance, as [[viper]]s do; observations of them hunting deer, boar and in some cases buffalo reveal that they kill prey in less than half an hour.<ref name="Goldstein paper">{{Cite journal|last1=Goldstein|first1=Ellie J. C.|last2=Tyrrell|first2=Kerin L.|last3=Citron|first3=Diane M.|last4=Cox|first4=Cathleen R.|last5=Recchio|first5=Ian M.|last6=Okimoto|first6=Ben|last7=Bryja|first7=Judith|last8=Fry|first8=Bryan G.|date=June 2013|title= Anaerobic and aerobic bacteriology of the saliva and gingiva from 16 captive Komodo dragons (Varanus komodoensis): new implications for the "bacteria as venom" model |journal=Journal of Zoo and Wildlife Medicine|volume=44|issue=2|pages=262–272|doi=10.1638/2012-0022R.1|issn=1042-7260|pmid=23805543|s2cid=9932073}}</ref>

The observation of prey dying of sepsis would then be explained by the natural instinct of [[water buffalo]]s, which are not native to the islands where the Komodo dragon lives, to run into water after escaping an attack. The warm, faeces-filled water would then cause the infections. The study used samples from 16 captive dragons (10 adults and six neonates) from three US zoos.<ref name="Goldstein paper"/>

===Antibacterial immune factor===
Researchers have isolated a powerful antibacterial [[peptide]], VK25, from the [[blood plasma]] of Komodo dragons. Based on their analysis of this peptide, they have synthesized a short peptide dubbed DRGN-1 and tested it against [[Multiple drug resistance|multidrug-resistant (MDR)]] pathogens. Preliminary results of these tests show that DRGN-1 is effective in killing drug-resistant bacterial strains and even some fungi. It has the added observed benefit of significantly promoting wound healing in both uninfected and mixed [[biofilm]] infected wounds.<ref>{{Cite journal|last1=Chung|first1=Ezra M. C.|last2=Dean|first2=Scott N.|last3=Propst|first3=Crystal N.|last4=Bishop|first4=Barney M.|last5=van Hoek|first5=Monique L.|date=11 April 2017|title=Komodo dragon-inspired synthetic peptide DRGN-1 promotes wound-healing of a mixed-biofilm infected wound|url= |journal=npj Biofilms and Microbiomes|language=en|volume=3|issue=1|page=9|doi=10.1038/s41522-017-0017-2|pmid=28649410|pmc=5445593|issn=2055-5008}}</ref>

===Disputed claims of venom===
[[File:Komodo dragon stalking deer.png|thumb|left|Komodo dragon stalking a [[Timor deer]]]]
In late 2005, researchers at the [[University of Melbourne]] speculated that the [[perentie]] (''Varanus giganteus''), other species of monitors, and [[agamids]] may be somewhat venomous. The team believes that the immediate effects of bites from these lizards were caused by mild envenomation. Bites on human digits by a [[lace monitor]] (''V. varius''), a Komodo dragon, and a [[Varanus timorensis|spotted tree monitor]] (''V. timorensis'') all produced similar effects: rapid swelling, localised disruption of blood clotting, and shooting pain up to the elbow, with some symptoms lasting for several hours.<ref name="Fry2006">{{cite journal|year = 2006|title = Early evolution of the venom system in lizards and snakes|journal = Nature|volume = 439|pages = 584–588|doi = 10.1038/nature04328|url = http://www.naherpetology.org/pdf_files/467.pdf|pmid = 16292255|last1 = Fry|first1 = BG|last2 = Vidal|first2 = N|last3 = Norman|first3 = JA|last4 = Vonk|first4 = FJ|last5 = Scheib|first5 = H|last6 = Ramjan|first6 = SF|last7 = Kuruppu|first7 = S|last8 = Fung|first8 = K|last9 = Hedges|first9 = SB|last10 = Richardson|first10 = Michael K.|last11 = Hodgson|first11 = Wayne. C.|last12 = Ignjatovic|first12 = Vera|last13 = Summerhayes|first13 = Robyn|last14 = Kochva|first14 = Elazar|issue = 7076|display-authors = 8|bibcode = 2006Natur.439..584F|s2cid = 4386245|access-date = 14 March 2008|archive-date = 10 October 2017|archive-url = https://web.archive.org/web/20171010191815/http://www.naherpetology.org/pdf_files/467.pdf|url-status = usurped}}</ref>

In 2009, the same researchers published further evidence demonstrating that Komodo dragons possess a venomous bite. [[Magnetic resonance imaging|MRI]] scans of a preserved [[skull]] showed the presence of two [[Salivary gland|glands]] in the lower jaw. The researchers extracted one of these glands from the head of a terminally ill dragon in the [[Singapore Zoological Gardens]], and found it secreted several different toxic [[protein]]s. The known functions of these proteins include inhibition of blood clotting, lowering of blood pressure, muscle paralysis, and the induction of hypothermia, leading to shock and loss of consciousness in envenomated prey.<ref>[https://web.archive.org/web/20110312125153/http://www.google.com/hostednews/afp/article/ALeqM5hVmc_PKzCdhfs-dEi2kE0CS2CybA ''Scientists discover deadly secret of Komodo's bite''], AFP, 19 May 2009</ref><ref name=fry>{{cite journal |vauthors=Fry BG, Wroe S, Teeuwisse W, etal |title=A central role for venom in predation by ''Varanus komodoensis'' (Komodo Dragon) and the extinct giant ''Varanus'' (''Megalania'') ''priscus'' |journal=Proceedings of the National Academy of Sciences of the United States of America |volume=106 |issue=22 |pages=8969–74 |year=2009|pmid=19451641 |pmc=2690028 |doi=10.1073/pnas.0810883106 |bibcode=2009PNAS..106.8969F |doi-access=free }}</ref> As a result of the discovery, the previous theory that bacteria were responsible for the deaths of Komodo victims was disputed.<ref>Staff. "[http://www.cnn.com/2009/TECH/science/05/20/komodo.dragon.bite/index.html Komodo dragons kill with venom, not bacteria, study says]". [[CNN]]. 20 May 2009. Retrieved on 25 May 2009.</ref>

Other scientists have stated that this allegation of venom glands "has had the effect of underestimating the variety of complex roles played by oral secretions in the biology of reptiles, produced a very narrow view of oral secretions and resulted in misinterpretation of reptilian evolution." According to these scientists "reptilian oral secretions contribute to many biological roles other than to quickly dispatch prey." These researchers concluded, "Calling all in this clade venomous implies an overall potential danger that does not exist, misleads in the assessment of medical risks, and confuses the biological assessment of squamate biochemical systems."<ref name="Mackessy2009">{{cite book|last1=Weinstein|first1=Scott A.|last2=Smith|first2=Tamara L.|last3=Kardong|first3=Kenneth V.|editor=Stephen P. Mackessy|title=Handbook of Venoms and Toxins of Reptiles|chapter-url=https://books.google.com/books?id=x_vME799de4C&pg=PA84|access-date=18 July 2013|date=14 July 2009|publisher=Taylor & Francis |isbn=978-1-4200-0866-1|pages=76–84|chapter=Reptile Venom Glands Form, Function, and Future }}</ref> Evolutionary biologist Schwenk says that even if the lizards have venom-like proteins in their mouths they may be using them for a different function, and he doubts venom is necessary to explain the effect of a Komodo dragon bite, arguing that shock and blood loss are the primary factors.<ref name="Schwenk">{{cite news|author=Zimmer, Carl|date=May 2009|title=Venom Might Boost Dragons Bite|work=San Diego Tribune|url=http://www3.signonsandiego.com/stories/2009/may/25/1c25komodo183628-venom-may-be-boost-dragons-bite/?uniontrib|access-date=26 September 2009|archive-date=6 June 2009|archive-url=https://web.archive.org/web/20090606045519/http://www3.signonsandiego.com/stories/2009/may/25/1c25komodo183628-venom-may-be-boost-dragons-bite/?uniontrib|url-status=dead}}</ref><ref>{{cite news|author=Zimmer, Carl|date=18 May 2009|title=Chemicals in Dragon's Glands Stir Venom Debate|work=[[The New York Times]] |page=D2|url=https://www.nytimes.com/2009/05/19/science/19komo.html|access-date=23 March 2012}}</ref> As of 2023, no clear unambiguous evidence of Komodo dragon bites being venomous has been presented.<ref>{{Cite journal |last1=Friedman |first1=Nathan A |last2=Seltzer |first2=Justin A |last3=Winkler |first3=Garret A |last4=Noste |first4=Erin |last5=Montilla |first5=Henry |last6=Clark |first6=Richard F. |date=February 2023 |title=Crouching Zookeeper, Hidden Dragon: A Case of a Komodo Dragon Bite |url=https://linkinghub.elsevier.com/retrieve/pii/S0736467922007818 |journal=The Journal of Emergency Medicine |language=en |volume=64 |issue=2 |pages=186–189 |doi=10.1016/j.jemermed.2022.12.001|pmid=36813645 }}</ref>

===Reproduction===
[[File:Komodo-mating.JPG|thumb|Komodo dragons mating]]
[[Mating]] occurs between May and August, with the eggs laid in September.<ref name="sciam"/><ref name="ciofi2004"/> During this period, males fight over females and territory by grappling with one another upon their hind legs, with the loser eventually being pinned to the ground. These males may vomit or defecate when preparing for the fight.<ref name="liz"/> The winner of the fight will then flick his long tongue at the female to gain information about her receptivity.<ref name="firefly" /> Females are [[wikt:Special:Search/antagonism|antagonistic]] and resist with their claws and teeth during the early phases of courtship. Therefore, the male must fully restrain the female during coitus to avoid being hurt. Other courtship displays include males rubbing their chins on the female, hard scratches to the back, and licking.<ref name="library">{{cite web |publisher=[[San Diego Zoo]] |url=http://library.sandiegozoo.org/factsheets/komodo_dragon/komodo.htm |title=Komodo Dragon, ''Varanus komodoensis'' |access-date=27 October 2009 |archive-url=https://web.archive.org/web/20100117100540/http://library.sandiegozoo.org/factsheets/komodo_dragon/komodo.htm |archive-date=17 January 2010 |url-status=dead }}</ref> Copulation occurs when the male inserts one of his [[hemipenes]] into the female's [[cloaca]].<ref name="nzpfactsheet"/> Komodo dragons may be monogamous and form "pair bonds", a rare behavior for lizards.<ref name="liz"/> In order to avoid inbreeding, females actively select distantly related male sperm.<ref>M. Olsson, R. Shine, A. Gullberg, T. Madsen, H. TegelströmFemale lizards control paternity of their offspring by selective use of sperm. Nature, 383 (1996), p. 585
</ref>

Female Komodos lay their eggs from August to September and may use several types of locality; in one study, 60% laid their eggs in the nests of [[orange-footed scrubfowl]] (a moundbuilder or [[megapode]]), 20% on ground level and 20% in hilly areas.<ref name="Jakarta" /> The females make many camouflage nests/holes to prevent other dragons from eating the eggs.<ref>{{cite journal|url=http://www.komodonationalpark.org/downloads/jessop%20et%20al.%202004e.pdf|title=Distribution, use and selection of nest type by Komodo dragons |doi=10.1016/j.biocon.2003.08.005 |year=2004 |last1=Jessop|first1=Tim S. |last2=Sumner |first2=Joanna |last3=Rudiharto |first3=Heru|last4=Purwandana|first4=Deni|last5=Imansyah|first5=M.Jeri|last6=Phillips|first6=John A. |journal=Biological Conservation |volume=117|issue=5|page=463|bibcode=2004BCons.117..463J |url-status=dead|archive-url=https://web.archive.org/web/20111209095216/http://www.komodonationalpark.org/downloads/jessop%20et%20al.%202004e.pdf|archive-date=9 December 2011}}</ref> Nests typically house one female, however a study found evidence of two females occasionally occupying the same den.<ref>{{Cite journal |last1=Jessop |first1=Tim S. |last2=Sumner |first2=Joanna |last3=Rudiharto |first3=Heru |last4=Purwandana |first4=Deni |last5=Imansyah |first5=M. Jeri |last6=Phillips |first6=John A. |date=2004 |title=Distribution, use and selection of nest type by Komodo Dragons |url=https://www.sciencedirect.com/science/article/pii/S0006320703003434 |journal=Biological Conservation |volume=117 |issue=5|pages=463–470 |doi=10.1016/j.biocon.2003.08.005 |bibcode=2004BCons.117..463J }}</ref> Clutches contain an average of 20 eggs, which have an incubation period of 7–8 months.<ref name="liz"/> Hatching is an exhausting effort for the neonates, which break out of their eggshells with an [[egg tooth]] that falls off before long. After cutting themselves out, the hatchlings may lie in their eggshells for hours before starting to dig out of the nest. They are born quite defenseless and are vulnerable to predation.<ref name=auffenberg/> Sixteen youngsters from a single nest were on average 46.5&nbsp;cm long and weighed 105.1&nbsp;grams.<ref name="Jakarta">{{cite news|url=http://www.thejakartapost.com/news/2015/03/11/wotong-bird-nests-help-komodos-survive-study.html |title='Wotong' bird nests help Komodos survive: Study |author=Markus Makur|year=2015|access-date=11 March 2015|newspaper=The Jakarta Post}}</ref>

Young Komodo dragons spend much of their first few years in trees, where they are relatively safe from predators, including cannibalistic adults, as juvenile dragons make up 10% of their diets.<ref name="liz"/> The habit of cannibalism may be advantageous in sustaining the large size of adults, as medium-sized prey on the islands is rare.<ref name="coldblood">{{cite book |author=Attenborough, David |author-link=David Attenborough|title=Life in Cold Blood |url=https://archive.org/details/lifeincoldblood0000atte |url-access=registration |publisher=Princeton University Press |location=Princeton, N.J. |year=2008 |isbn=978-0-691-13718-6}}</ref> When the young approach a kill, they roll around in faecal matter and rest in the intestines of eviscerated animals to deter these hungry adults.<ref name="liz"/> Komodo dragons take approximately 8 to 9 years to mature, and may live for up to 30 years.<ref name="ciofi2004">{{cite book |last=Ciofi |first=Claudio |year=2004 |chapter=''Varanus komodoensis'' |title=Varanoid Lizards of the World |publisher=Indiana University Press |location=Bloomington & Indianapolis |isbn=978-0-253-34366-6 |pages=197–204}}</ref>

====Parthenogenesis====
{{Main|Parthenogenesis}}
[[File:Parthkomodo.jpg|thumb|right|[[Parthenogenetic]] baby Komodo dragon, [[Chester Zoo]], England]]
A Komodo dragon at [[London Zoo]] named Sungai laid a clutch of eggs in late 2005 after being separated from male company for more than two years. Scientists initially assumed she had been able to store [[spermatozoon|sperm]] from her earlier encounter with a male, an [[adaptation]] known as [[superfecundation]].<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 |url-status=dead |archive-url=https://web.archive.org/web/20071008112514/http://www.bloomberg.com/apps/news?pid=20601082 |archive-date=8 October 2007 }}</ref> On 20 December 2006, it was reported that Flora, a captive Komodo dragon living in the [[Chester Zoo]] in England, was the second known Komodo dragon to have laid unfertilised eggs: she laid 11 eggs, and seven of them hatched, all of them male.<ref>Notice by her cage in [[Chester Zoo]] in England</ref> Scientists at [[Liverpool University]] in England performed genetic tests on three eggs that collapsed after being moved to an incubator, and verified Flora had never been in physical contact with a male dragon. After Flora's eggs' condition had been discovered, testing showed Sungai's eggs were also produced without outside fertilization.<ref>{{cite news |url=https://www.timesonline.co.uk/tol/news/uk/article759338.ece |title=Wise men testify to Dragon's virgin birth |access-date=26 November 2007 |work=[[The Times]] | location=London | first=Mark | last=Henderson | date=21 December 2006}}</ref> On 31 January 2008, the [[Sedgwick County Zoo]] in [[Wichita, Kansas]], became the first zoo in the Americas to document [[parthenogenesis]] in Komodo dragons. The zoo has two adult female Komodo dragons, one of which laid about 17 eggs on 19–20 May 2007. Only two eggs were incubated and hatched due to space issues; the first hatched on 31 January 2008, while the second hatched on 1 February. Both hatchlings were males.<ref>{{cite web |publisher=[[Sedgwick County Zoo]] |url=http://www.scz.org/n_recent.html |archive-url=https://web.archive.org/web/20080211184900/http://www.scz.org/n_recent.html |archive-date=11 February 2008 |title=Recent News – Sedgwick County Zoo |access-date=12 February 2008}}</ref><ref>{{cite web |publisher=[[NBC News]] |url=https://www.nbcnews.com/id/wbna23058689 |title=Komodo dragons hatch with no male involved |access-date=12 February 2008|date=8 February 2008 }}</ref>

Komodo dragons have the [[ZW sex-determination system|ZW]] chromosomal [[sex-determination system]], as opposed to the [[XY sex-determination system|mammalian XY system]]. Male progeny prove Flora's unfertilized eggs were [[haploid]] (n) and doubled their chromosomes later to become [[diploid]] (2n) (by being fertilized by a [[polar body]], or by chromosome duplication without [[cell division]]), rather than by her laying diploid eggs by one of the [[meiosis]] reduction-divisions in her [[ovaries]] failing. When a female Komodo dragon (with ZW sex chromosomes) reproduces in this manner, she provides her progeny with only one chromosome from each of her pairs of chromosomes, including only one of her two sex chromosomes. This single set of chromosomes is duplicated in the egg, which develops parthenogenetically. Eggs receiving a Z [[chromosome]] become ZZ (male); those receiving a W chromosome become WW and fail to develop,<ref name="ZW">{{cite news |work=BBC News |url=http://news.bbc.co.uk/2/hi/science/nature/6196225.stm |title=Virgin births for giant lizards |access-date=13 March 2008 |date=20 December 2006}}</ref><ref>{{cite magazine |magazine=Scientific American |url=http://www.sciam.com/article.cfm?id=strange-but-true-komodo-d |title=Strange but True: Komodo Dragons Show that "Virgin Births" Are Possible: Scientific American |access-date=24 March 2008}}</ref> meaning that only males are produced by parthenogenesis in this species.[[File:COLLECTIE TROPENMUSEUM Varanus komodoensis die geplaagd wordt TMnr 10006427.jpg|thumb|Humans handling a komodo dragon]]It has been hypothesised that this reproductive adaptation allows a single female to enter an isolated [[ecological niche]] (such as an island) and by [[parthenogenesis]] produce male offspring, thereby establishing a sexually reproducing population (via reproduction with her offspring that can result in both male and female young).<ref name="ZW" /> Despite the advantages of such an adaptation, zoos are cautioned that parthenogenesis may be detrimental to genetic diversity.<ref name="pmid">{{cite journal |vauthors=Watts PC, Buley KR, Sanderson S, Boardman W, Ciofi C, Gibson R |title=Parthenogenesis in Komodo Dragons |journal=Nature |volume=444 |issue=7122 |pages=1021–22 |date=December 2006 |pmid=17183308 |doi=10.1038/4441021a |issn=0028-0836|bibcode=2006Natur.444.1021W |s2cid=4311088 }}</ref>

===Encounters with humans===
Attacks on humans are rare, but Komodo dragons have been responsible for several human fatalities, both in the wild and in captivity. According to data from [[Komodo National Park]] spanning a 38-year period between 1974 and 2012, there were 24 reported attacks on humans, five of them fatal. Most of the victims were local villagers living around the national park.<ref>{{cite news | title = 5 Kasus keganasan komodo liar menyerang manusia | date = 22 April 2014 | author = Fariz Fardianto | work = Merdeka.com | url = https://www.merdeka.com/peristiwa/5-kasus-keganasan-komodo-liar-menyerang-manusia/selama-34-tahun-komodo-terkam-24-orang.html | language = id}}</ref>