Editing Monitor lizard (section)

==Biology==
{{Multiple image
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| footer            = A Bell's phase [[lace monitor]] in a tree
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[[File:Varanoid skulls.png|thumb|Skulls of various varanoids]]
Monitor lizards are considered unique among animals in that its members are relatively morphologically conservative, yet show a very large size range.<ref name=pianka1995>{{cite journal|author=Pianka, E.R. |title= Evolution of Body Size: Varanid Lizards as a Model System|journal= The American Naturalist|volume= 146|issue= 3|pages= 398–414|doi=10.1086/285806|url=http://www.zo.utexas.edu/courses/THOC/BodySize.pdf|year= 1995|bibcode= 1995ANat..146..398P|s2cid= 85237692}}</ref> However, finer morphological features such as the shape of the skull and limbs do vary, and are strongly related to the ecology of each species.<ref>{{cite journal|doi=    10.1371/journal.pone.0130625
|pmid=    26106889
|title=    The Relationship between Cranial Structure, Biomechanical Performance and Ecological Diversity in Varanoid Lizards
|journal=    PLOS ONE
|volume=    10
|issue=    6
|pages=    e0130625
|year=    2015
|last1=    McCurry
|first1=    Matthew R.
|last2=    Mahony
|first2=    Michael
|last3=    Clausen
|first3=    Phillip D.
|last4=    Quayle
|first4=    Michelle R.
|last5=    Walmsley
|first5=    Christopher W.
|last6=    Jessop
|first6=    Tim S.
|last7=    Wroe
|first7=    Stephen
|last8=    Richards
|first8=    Heather
|last9=    McHenry
|first9=    Colin R.
|pmc=4479569
|bibcode= 2015PLoSO..1030625M
|doi-access= free
}}</ref><ref>{{cite journal|doi=10.1111/j.1469-7998.2009.00559.x|title=Evolutionary relationships of sprint speed in Australian varanid lizards|journal=Journal of Zoology|volume=278|issue=4|pages=270–280|year=2009|last1=Clemente|first1=C. J.|last2=Thompson|first2=G. G.|last3=Withers|first3=P. C.|doi-access=free}}</ref>

Like snakes, monitor lizards have highly forked tongues that act as part of the "smell" sense, where the tips of the tongue carry molecules from the environment to the a sensory organ in the skull called the [[Vomeronasal organ|Jacobson's organ]]. The forked apparatus allows for these lizards to sense boundaries in the molecules they collect, almost smelling in "stereo".<ref>{{Cite journal |last=Sack |first=Jeffrey D. |date=2022-08-01 |title=True Facts: Snake and Lizard Tongues |url=https://online.ucpress.edu/abt/article/84/6/378/189894/True-Facts-Snake-and-Lizard-Tongues |journal=The American Biology Teacher |language=en |volume=84 |issue=6 |pages=378 |doi=10.1525/abt.2022.84.6.378 |s2cid=251407423 |issn=0002-7685 |doi-access=free}}</ref><ref>{{Cite journal |last1=Srichairat |first1=Nattawut |last2=Taksintum |first2=Wut |last3=Chumnanpuen |first3=Pramote |date=2017-07-11 |title=Gross Morphological Structure of Digestive System in Water Monitor Lizard Varanus salvator (Squamata: Varanidae) |url=http://wjst.wu.ac.th/index.php/wjst/article/view/3356 |journal=Walailak Journal of Science and Technology |volume=15 |issue=3 |pages=245–253 |doi=10.48048/wjst.2018.3356 |issn=2228-835X|doi-access=free }}</ref> While most reptiles possess [[Taste bud|taste buds]], monitor lizards and likely snakes as well completely lack taste buds.<ref>{{Cite journal |last=Young |first=Bruce A. |date=1997 |title=On the Absence of Taste Buds in Monitor Lizards (Varanus) and Snakes |url=https://www.jstor.org/stable/1565343 |journal=Journal of Herpetology |volume=31 |issue=1 |pages=130–137 |doi=10.2307/1565343 |jstor=1565343 |issn=0022-1511}}</ref> [[Mertens' water monitor|Merten's water monitor]], the most aquatically adapted monitor species, is uniquely capable of using its sense of smell underwater to locate and capture prey.<ref>{{Cite journal |last1=Mayes |first1=P. J. |last2=Thompson |first2=G. G. |last3=Withers |first3=P. C. |date=2005 |title=Diet and foraging behaviour of the semi-aquatic Varanus mertensi (Reptilia:Varanidae) |url=http://www.publish.csiro.au/?paper=WR04040 |journal=Wildlife Research |language=en |volume=32 |issue=1 |pages=67 |doi=10.1071/WR04040 |bibcode=2005WildR..32...67M |issn=1035-3712}}</ref>

Monitor lizards are [[oviparous]],<ref name="piankavitt2003" /> laying from seven to 38 [[Egg (biology)|eggs]],<ref>https://indonesiaindonesia.com/f/37477-sejarah-pulau-komodo/ (in [[Indonesian language|Indonesian]])</ref> which they often cover with soil or protect in a hollow tree stump. Some species, including the Komodo dragon, are capable of [[parthenogenesis]].<ref>{{cite journal |last=Smith |first=Kerri |year=2006 |title=Dragon virgin births startle zoo keepers |url=http://www.nature.com/news/2006/061218/full/061218-7.html |journal=Nature |doi=10.1038/news061218-7 |s2cid=191590714 |access-date=2006-12-20 |doi-access=free}}</ref>

=== Venom ===
Anatomical and molecular studies indicate that most if not all [[Varanidae|varanids]] are [[venom]]ous.<ref name="Fry2009">
{{cite journal |vauthors=Fry BG, Wroe S, Teeuwisse W, van Osch JP, Moreno K, Ingle J, McHenry C, Ferrara T, Clausen P, Scheib H, Winter KL, Greisman L, Roelants K, van der Weerd L, Clemente CJ, Giannakis E, Hodgson WC, Luz S, Martelli P, Krishnasamy K, Kochva E, Kwok HF, Scanlon D, Karas J, Citron DM, Goldstein EJ, Mcnaughtan JE, Norman JA |date=June 2009 |title= A central role for venom in predation by ''Varanus komodoensis'' (Komodo dragon) and the extinct giant ''Varanus (Megalania) priscus''. |journal= PNAS |volume= 106 |pages= 8969–8974 |doi = 10.1073/pnas.0810883106 |pmid = 19451641 |issue = 22 |pmc = 2690028|bibcode=2009PNAS..106.8969F |doi-access=free }}</ref><ref name="Fry2006">
{{cite journal |vauthors=Fry BG, Vidal N, Norman JA, Vonk FJ, Scheib H, Ramjan SF, Kuruppu S, Fung K, Hedges B, Richardson MK, Hodgson WC, Ignjatovic V, Summerhays R, Kochva E |date=February 2006 |title= Early evolution of the venom system in lizards and snakes |journal= Nature |volume= 439 |pages= 584–588 |doi = 10.1038/nature04328 |pmid = 16292255 |issue = 7076|bibcode=2006Natur.439..584F |s2cid=4386245 }}</ref> Unlike snakes, monitor lizard venom glands are situated in their lower jaw.<ref>{{Cite journal |last1=Fry |first1=Bryan G. |last2=Wroe |first2=Stephen |last3=Teeuwisse |first3=Wouter |last4=van Osch |first4=Matthias J. P. |last5=Moreno |first5=Karen |last6=Ingle |first6=Janette |last7=McHenry |first7=Colin |last8=Ferrara |first8=Toni |last9=Clausen |first9=Phillip |last10=Scheib |first10=Holger |last11=Winter |first11=Kelly L. |last12=Greisman |first12=Laura |last13=Roelants |first13=Kim |last14=van der Weerd |first14=Louise |last15=Clemente |first15=Christofer J. |date=2009-06-02 |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 |language=en |volume=106 |issue=22 |pages=8969–8974 |doi=10.1073/pnas.0810883106 |issn=0027-8424 |pmc=2690028 |pmid=19451641 |bibcode=2009PNAS..106.8969F |doi-access=free }}</ref> The venom of monitor lizards is diverse and complex, as a result of the diverse ecological niches monitor lizards occupy.<ref>{{Cite journal|last1=Dobson|first1=James S.|last2=Zdenek|first2=Christina N.|last3=Hay|first3=Chris|last4=Violette|first4=Aude|last5=Fourmy|first5=Rudy|last6=Cochran|first6=Chip|last7=Fry|first7=Bryan G.|date=May 2019|title=Varanid Lizard Venoms Disrupt the Clotting Ability of Human Fibrinogen through Destructive Cleavage|journal=Toxins|language=en|volume=11|issue=5|pages=255|doi=10.3390/toxins11050255|pmid=31067768|pmc=6563220|doi-access=free}}</ref> 

For example, many species have [[anticoagulant]] venom, disrupting clotting through a combination of [[fibrinogenolysis]] and blocking [[platelet]] aggregation. Amongst them, arboreal species, such as the [[Varanus (Hapturosaurus)|tree monitors]] and the [[Banded tree monitor|banded monitor]], have by far the strongest fibrinogenolytic venom. As a result, wounds from monitor lizard bites often bleed more than they would if they were simply lacerations. Venom may also cause [[hypotension]].<ref>{{Cite journal |last1=Dobson |first1=James S. |last2=Zdenek |first2=Christina N. |last3=Hay |first3=Chris |last4=Violette |first4=Aude |last5=Fourmy |first5=Rudy |last6=Cochran |first6=Chip |last7=Fry |first7=Bryan G. |date=2019-05-07 |title=Varanid Lizard Venoms Disrupt the Clotting Ability of Human Fibrinogen through Destructive Cleavage |journal=Toxins |language=en |volume=11 |issue=5 |pages=255 |doi=10.3390/toxins11050255 |issn=2072-6651 |pmc=6563220 |pmid=31067768 |doi-access=free }}</ref> 

In some species such as the [[Komodo dragon]] and the [[desert monitor]], venom also induces a powerful neurotoxic effect. In the latter species for instance, envenomation causes immediate paralysis in rodents (but not birds) and lesser effects of the same nature in humans.<ref>{{Cite journal |last=Zima |first=Yuliya |date=December 2019 |title=On the Toxicity of the Bite of the Caspian Gray Monitor Lizard (Varanus griseus caspius) |journal=Biawak |volume=13 |issue=2 |pages=115–118 |via=ResearchGate}}</ref>

=== Metabolism ===
Monitor lizards maintain large territories and employ active-pursuit hunting techniques that are reminiscent of similar-sized mammals.<ref name="kinggreenknight1999">King, D., Green, B., Knight, F. (1999). ''Monitors: The Biology of Varanid Lizards.'' Florida. Krieger Publishing Company.</ref> The highly active nature of monitor lizards has led to numerous studies on the metabolic capacities of these lizards. The general consensus is that monitor lizards have the highest standard metabolic rates of all [[Extant taxon|extant]] reptiles.<ref name="piankavitt2003">Pianka, E.R., Vitt, L.J. (2003). ''Lizards: Windows to the Evolution of Diversity.'' California. University of California Press.</ref>

Monitor lizards have a high aerobic scope<ref name=piankavitt2003 /><ref name=wood1978>{{cite journal|vauthors=Wood SC, Johansen K, Glass ML, ((Maloiy GMO)) |title= Aerobic Metabolism of the Lizard ''Varanus exanthematicus'': Effects of Activity, Temperature, and Size|journal= Journal of Comparative Physiology B|volume= 127|issue= 4|pages= 331–336|doi=10.1007/BF00738417|year= 1978|s2cid= 19320799}}</ref> that is afforded, in part, by their heart anatomy. Whereas most reptiles are considered to have three-chambered hearts, the hearts of monitor lizards – as with those of [[Boidae|boas]] and [[Pythonidae|pythons]] – have a well developed [[Ventricle (heart)|ventricular]] septum that completely separates the [[Lung|pulmonary]] and [[Systemic circulation|systemic]] sides of the circulatory system during [[systole]].<ref name=wang2003>{{cite journal|vauthors=Wang T, Altimiras J, Klein W, Axelsson M |title= Ventricular Haemodynamics in ''Python molurus'': Separation of Pulmonary and Systemic Pressures|journal= The Journal of Experimental Biology|volume= 206|issue= Pt 23|pages= 4241–5|pmid=14581594|year= 2003|doi=10.1242/jeb.00681 |doi-access= free|bibcode= 2003JExpB.206.4241W}}</ref> This allows monitor lizards to create mammalian-equivalent pressure differentials between the pulmonary and systemic circuits,<ref name=wang2003 /> which in turn ensure that oxygenated blood is quickly distributed to the body without also flooding the lungs with high-pressure blood.