View source for Biology:Megalodon

{{Short description|Extinct giant shark species from 23 to 3.6 million years ago}}
{{Speciesbox
| name = Megalodon
| fossil_range = {{longitem|[[Earth:Aquitanian (stage)|Early Miocene]]–Early Pliocene, c. {{Geological range|23|3.6|earliest=28|latest=1.8}}}}
| image = Megalodon shark jaws museum of natural history 068.jpg
| image_upright = 1.15
| image_caption = Model of megalodon jaws at the [[Biology:American Museum of Natural History|American Museum of Natural History]]
| image_alt = Large black model of shark jaws with two visible rows of teeth, suspended by wires inside a room.
| genus = Otodus
| species = megalodon
| authority = (Agassiz, 1835)<ref name=Agassiz1843>{{cite book|author=Agassiz, L.|year=1843|title=Recherches sur les poissons fossiles|volume=3|language=French|doi=10.5962/bhl.title.4275|url=https://www.biodiversitylibrary.org/bibliography/4275}}</ref><ref name=Brignon2021>{{cite journal|author=Brignon, A.|year=2021|title=Historical and nomenclatural remarks on some megatoothed shark teeth (Elasmobranchii, Otodontidae) from the Cenozoic of New Jersey (U.S.A.)|journal=Rivista Italiana di Paleontologia e Stratigrafia|volume=127|issue=3|pages=595–625|doi=10.13130/2039-4942/16440|url=https://www.researchgate.net/publication/354765218}}</ref>
| synonyms = 
{{collapsible list|title=List of synonyms|
{{collapsible list|title=Genus ''Carcharias''|
* ''C. giganteus''
* ''C. grosseserratus''
* ''C. incidens''
* ''C. macrodon''
* ''C. megalodon''
* ''C. mexicanus''
* ''C. polygurus''
* ''C. polygyrus''
* ''C. productus''
* ''C.'' (''Prionodon'') ''incidens''
}}
{{collapsible list|title=Genus ''Carcharocles''|
* ''C. subauriculatus''
* ''C. megalodon''
* ''C. megalodon megalodon''
* ''C. productus''
}}
{{collapsible list|title=Genus ''Carcharodon''|
* ''C. arcuatus''
* ''C. branneri''
* ''C. brevis''
* ''C. costae''
* ''C. crassidens''
* ''C. crassirhadix''
* ''C. crassus''
* ''C. gibbesi''
* ''C. gigas''
* ''C. helveticus''
* ''C. humilis''
* ''C. intermedius''
* ''C. latissimus''
* ''C. leviathan''
* ''C. megalodon''
* ''C. megalodon indica''
* ''C. megalodon megalodon''
* ''C. megalodon polygyra''
* ''C. megalodon productus''
* ''C. megalodon siculus''
* ''C. megalodon yamanarii''
* ''C. morricei''
* ''C. polygurus''
* ''C. polygyrus''
* ''C. productus''
* ''C. quenstedti''
* ''C. rectidens''
* ''C. rectideus''
* ''C. semiserratus''
* ''C. subauriculatus''
* ''C. tumidissimus''
* ''C. turicensis''
}}
{{collapsible list|title=Genus ''Megaselachus''|
* ''M. arcuatus''
* ''M. auriculatus falciformis''
* ''M. branneri''
* ''M. brevis''
* ''M. crassidens''
* ''M. crassirhadix''
* ''M. crassus''
* ''M. gigas''
* ''M. heterodon''
* ''M. humilis''
* ''M. incidens''
* ''M. leviathan''
* ''M. megalodon''
* ''M. megalodon indicus''
* ''M. polygyrus''
* ''M. productus''
* ''M. rectidens''
* ''M. semiserratus''
* ''M. subauriculatus''
}}
{{collapsible list|title=Genus ''Procarcharodon''|
* ''P. megalodon''
* ''P. megalodon megalodon''
}}
{{collapsible list|title=Genus ''Otodus''|
* ''O. (Megaselachus) megalodon''
}}
{{collapsible list|title=Genus ''Selache''|
* ''S. manzonii''
}}
}}
| synonyms_ref = <ref>{{cite web|url=http://shark-references.com/species/view/Otodus-Megaselachus-megalodon|title=''Otodus'' (''Megaselachus'') ''megalodon'' (Agassiz, 1837)|website=SharkReferences.com|access-date=24 October 2017}}</ref><ref>{{cite book|url={{google books|plainurl=yes|id=8XNGAAAAYAAJ&pg=PA82}}|first=C. R.|last=Eastman|title=Maryland Geological Survey|volume=2|publisher= Johns Hopkins University|location=Baltimore, Maryland|year=1904|page=82}}</ref><ref name=cappetta /><ref>{{cite journal|url={{google books|plainurl=yes|id=ZmqWKhTAeqYC|page=308}}|first=O. P.|last=Hay|year=1901|title=Bibliography and Catalogue of the Fossil Vertebrata of North America|journal=Bulletin of the United States Geological Society|issue=179|page=308}}</ref><ref name="Shimada2016"/>
}}

'''''Otodus megalodon''''' ({{IPAc-en|ˈ|m|ɛ|g|əl|ə|d|ɒ|n}} {{Respell|MEG|əl|ə|don}}; meaning "big tooth"), [[Biology:Common name|commonly known]] as '''megalodon''', is an [[Biology:Extinction|extinct]] [[Biology:Species|species]] of giant mackerel shark that lived approximately 23 to 3.6 [[Physics:Mya (unit)|million years ago]] (Mya), from the [[Earth:Early Miocene|Early Miocene]] to the Pliocene epochs. '''''O. megalodon''''' was formerly thought to be a member of the family [[Biology:Lamnidae|Lamnidae]] and a close relative of the [[Biology:Great white shark|great white shark]] (''Carcharodon carcharias''), but has been reclassified into the extinct family [[Biology:Otodontidae|Otodontidae]], which [[Biology:Speciation|diverged]] from the great white shark during the [[Earth:Early Cretaceous|Early Cretaceous]].

While regarded as one of the largest and most powerful [[Earth:Predation|predators]] to have ever lived, megalodon is only known from fragmentary remains, and its appearance and maximum size are uncertain. Scientists differ on whether it would have more closely resembled a stockier version of the [[Biology:Great white shark|great white shark]] (Carcharodon carcharias), the [[Biology:Basking shark|basking shark]] (''Cetorhinus maximus'') or the [[Biology:Sand tiger shark|sand tiger shark]] (''Carcharias taurus''). The most recent estimate with the least error range suggests a maximum length estimate up to {{convert|20.3|m|ft|sp=us}}, although the modal lengths are estimated at {{convert|10.5|m|ft|sp=us}}. Extrapolation from a vertebral centra{{Fix|text=Possibly "vertebral centrum"; "centra" is plural.}} with dimensions based on the [[Biology:Great white shark|great white shark]] suggests that
* a megalodon about {{convert|16|m|ft|sp=us}} long weighs up to {{convert|48|t|ST LT|abbr=on}},
* one {{convert|17|m|ft|sp=us}} long weighs up to {{convert|59|t|ST LT|abbr=on}}, and
* one {{convert|20.3|m|ft|sp=us}} long (the maximum length) weighs up to {{convert|103|t|ST LT|abbr=on}}.

Extrapolating from a [[Biology:Vertebral column|vertebral column]] and reconstructing a 3D model with dimensions based on all extant [[Biology:Lamnidae|lamnid sharks]] suggests that a {{convert|16|m|ft|sp=us|adj=mid|-long}} individual may have been much larger than previous estimates, reaching an excess of {{convert|61.5|t|ST LT|abbr=on}} in body mass; an individual of this size would have needed to consume 98,175 kcal per day. Their [[Biology:Tooth|teeth]] were thick and robust, built for grabbing prey and breaking bone, and their large jaws could exert a bite force of up to {{convert|108,500|to|182,200|newtons|lbf|-1}}.

Megalodon probably had a major impact on the structure of [[Biology:Marine life|marine communities]]. The fossil record indicates that it had a [[Biology:Cosmopolitan distribution|cosmopolitan distribution]]. It probably targeted large prey, such as [[Biology:Cetacea|whales]], [[Biology:Pinniped|seals]] and [[Biology:Sea turtle|sea turtle]]s. Juveniles inhabited warm coastal waters and fed on fish and small whales. Unlike the great white, which attacks prey from the soft underside, megalodon probably used its strong jaws to break through the chest cavity and puncture the heart and lungs of its prey.

The animal faced competition from whale-eating [[Biology:Cetacea|cetacea]]ns, such as ''[[Biology:Livyatan|Livyatan]]'' and other [[Biology:Macroraptorial sperm whale|macroraptorial sperm whale]]s and possibly smaller ancestral [[Biology:Orca|killer whales]] (orcinus orca). As the shark preferred warmer waters, it is thought that oceanic cooling associated with the onset of the [[Earth:Quaternary glaciation|ice ages]], coupled with the lowering of sea levels and resulting loss of suitable nursery areas, may have also contributed to its decline. A reduction in the diversity of [[Biology:Baleen whale|baleen whale]]s and a shift in their distribution toward polar regions may have reduced megalodon's primary food source. The shark's extinction coincides with a [[Biology:Deep-sea gigantism|gigantism]] trend in baleen whales.

== Classification ==
===Prescientific and early research history===
{{multiple image
|align = right
|total_width = 450
|image1=Sharks Teeth HOCU - 2832 and 4222.webp
|image2=De Gloffopetris Differtatio (cropped).jpg
|footer = '''Left image:''' Chesapeake megalodon tooth (Fig. 7) excavated from a [[Place:Hopewell Culture National Historical Park|Hopewell burial mound]]. '''Right image:''' Colonna's 1616 comparison of a megalodon (top left) and [[Biology:Great white shark|great white]] tooth (right).
}}

Megalodon teeth have been excavated and used since ancient times. They were a valued artifact amongst [[History:Pre-Columbian era|pre-Columbian]] cultures in the [[Earth:Americas|Americas]] for their large sizes and serrated blades, from which they were modified into [[Engineering:Projectile point|projectile point]]s, knives, jewelry, and funeral accessories.<ref name=Loweryetal2011>{{cite journal|author1=Lowery, D.|author2=Godfrey, S.J.|author3=Eshelman, R.|year=2011|journal=Archaeology of Eastern North America|volume=9|pages=93–108|title=Integrated geology, paleontology, and archaeology: Native American use of fossil shark teeth in the Chesapeake Bay region|jstor=23265116 |url=https://www.jstor.org/stable/23265116}}</ref><ref name=FarrellMS>{{cite thesis|author=Farrell, A.D.|year=2021|title=A Use-Wear and Functional Analysis of Precontact Shark Teeth Assemblages from Florida |type=MS|publisher=Florida State University|url=https://diginole.lib.fsu.edu/islandora/object/fsu:781655}}</ref> At least some, such as the Panamanian Sitio Conte societies, seemed to have used them primarily for ceremonial purposes.<ref name=FarrellMS /> Mining<ref name=NPSHopewell>{{cite web|title=Hopewell Culture National Historical Park Sharks Teeth HOCU - 2832 and 4222|website=National Park Service|url=https://www.nps.gov/articles/000/inside-the-collections-hocu-2832-and-4222.htm|author=Jacobs, J.}}</ref> of megalodon teeth by the Algonquin peoples in the Chesapeake Bay and their selective trade with the Adena culture in Ohio occurred as early as 430 BC.<ref name=Loweryetal2011 /> The earliest written account of megalodon teeth was by Pliny the Elder in an AD 73 volume of ''Historia Naturalis'', who described them as resembling petrified human [[Biology:Tongue|tongue]]s that Roman folklorists believed to have fallen from the sky during [[Astronomy:Lunar eclipse|lunar eclipse]]s and called them ''glossopetrae'' ("tongue stones").<ref name=Duffin2017>{{cite book|chapter=Fossil Sharks' Teeth as Alexipharmics|author=Duffin, C.J.|title=Toxicology of the Middle Ages and Renaissance|pages=125–133|year=2017|editor=Philip Wexler|doi=10.1016/B978-0-12-809554-6.00012-3|isbn=9780128095546 }}</ref> The purported tongues were later thought in a 12th-century Maltese tradition to have belonged to serpents that [[Biography:Paul the Apostle|Paul the Apostle]] turned to stone while shipwrecked there, and were given antivenom powers by the saint.<ref name=ForliandGurreini>{{cite book|author1=Forli, M.|author2=Guerrini, A.|title=The History of Fossils over Centuries |chapter=Quaestio de Fossilibus: Glossopetres, Snake Tongues and Ceraunids |pages=41–83|year=2022|doi=10.1007/978-3-031-04687-2_6|isbn=978-3-031-04686-5 }}</ref> ''Glossopetrae'' reappeared throughout Europe in late 13th to 16th century literature, ascribed with more [[Philosophy:Supernatural|supernatural]] properties that cured a wider variety of [[Chemistry:Poison|poison]]s. Use of megalodon teeth for this purpose became widespread among medieval and [[Philosophy:Renaissance|Renaissance]] nobility, who fashioned them into protective amulets and tableware to purportedly detoxify poisoned liquids or bodies that touched the stones. By the 16th century, teeth were directly consumed as ingredients of European-made [[Chemistry:Goa stone|Goa stone]]s.<ref name=Duffin2017 />

{{multiple image
|align = left
|total_width = 300
|image1 = Stenoshark.jpg
|image2 = StenoFossilSharkTeeth.webp
|footer = Mercati's depictions of a great white's head and teeth (left) and fossil megalodon and great white teeth (right), reused by Steensen in 1667
|alt1 = An illustration of a shark head (sideview). Visible are wrinkles and an exaggerated nose and eyes, and at the bottom are two individual drawings of shark teeth
}}
The true nature of the ''glossopetrae'' as shark's teeth was held by some since at least 1554, when cosmographer André Thevet described it as hearsay, although he did not believe it. The earliest scientific argument for this view was made by Italian naturalist Fabio Colonna, who in 1616 published an illustration of a Maltese megalodon tooth alongside a [[Biology:Great white shark|great white shark]]'s and noted their striking similarities. He argued that the former and its likenesses were not petrified serpent's tongues but actually the teeth of similar sharks that washed up on shore. Colonna supported this thesis through an experiment of burning ''glossopetrae'' samples, from which he observed [[Chemistry:Carbon|carbon]] residue he interpreted as proving an organic origin.<ref name=ForliandGurreini /> However, interpretation of the stones as shark's teeth remained widely unaccepted. This was in part due the inability to explain how some of them are found far from the sea.<ref name=Bressan2016>{{cite web|title=How the Dissection Of A Shark's Head Revealed The True Nature Of Fossils|author=Bressan, D.|date=14 January 2016|website=Forbes|url=https://www.forbes.com/sites/davidbressan/2016/01/14/how-the-dissection-of-a-sharks-head-revealed-the-true-nature-of-fossils/?sh=428c61d4e8c0}}</ref> The shark tooth argument was academically raised again during the late 17th century by {{wipe|England}} scientists Robert Hooke, [[Biography:John Ray|John Ray]], and {{wipe|Denmark}} naturalist Niels Steensen (Latinized ''Nicholas Steno'').<ref name=StenoUCMP>{{cite web|url=https://ucmp.berkeley.edu/history/steno.html|title=Nicholas Steno|website=University of California Museum of Paleontology}}</ref> Steensen's argument in particular is most recognized as inferred from his dissection of the head of a great white caught in 1666. His 1667 report depicted engravings of a shark's head and megalodon teeth that became especially iconic. However, the illustrated head was not actually the head that Steensen dissected, nor were the fossil teeth illustrated by him. Both engravings were originally commissioned in the 1590s by Papal [[Medicine:Physician|physician]] Michele Mercati, who also had in possession the head of a great white, for his book ''Metallotheca''. The work remained unpublished in Steensen's time due to Mercati's premature death, and the former reused the two illustrations per suggestion by [[Company:Carlo Roberto Dati|Carlo Roberto Dati]], who thought a depiction of the actual dissected shark was unsuitable for readers.<ref name=DavidsonSteno>{{cite journal|author=Davidson, J.P.|title=Historical Point of View: Fish Tales: Attributing the First Illustration of a Fossil Shark's Tooth to Richard Verstegan (1605) and Nicolas Steno (1667)|journal=Proceedings of the Academy of Natural Sciences of Philadelphia|year=2000|volume=150|pages=329–344|jstor=4065077 |url=https://www.jstor.org/stable/4065077}}</ref> Steensen also stood out in pioneering a [[Earth:Stratigraphy|stratigraphic]] explanation for how similar stones appeared further inland. He observed that rock layers bearing megalodon teeth contained marine sediments and hypothesized that these layers correlated to a [[Religion:Genesis flood narrative|period of flood]] that was later covered by terrestrial layers and uplifted by geologic activity.<ref name=Bressan2016 />

[[File:Recherches sur les poissons fossiles (Tab 29) (7267241882).jpg|thumb|right|[[Biology:Holotype|Holotype]] tooth (Fig. 2-3) in Agassiz (1835), cataloged as TE-PLI 18]]
{{wipe|Switzerland}} naturalist Louis Agassiz gave megalodon its [[Biology:Binomial nomenclature|scientific name]] in his seminal 1833-1843 work ''Recherches sur les poissons fossiles'' (Research on fossil fish). He named it ''[[Biology:Carcharias|Carcharias]] megalodon'' in an 1835 illustration of the [[Biology:Holotype|holotype]] and additional teeth, congeneric with the modern [[Biology:Sand tiger shark|sand tiger shark]].<ref name=Agassiz1843 /><ref name=Brignon2021 /> The specific name is a portmanteau of the [[Social:Ancient Greek|Ancient Greek]] words μεγάλος (''megálos'', meaning "big") and ὀδών (''odṓn'', meaning "tooth"),<ref>{{LSJ|mega/los|μεγάλος|ref}}</ref><ref>{{LSJ|o)dw/n|ὀδών|ref}}</ref> combined meaning "big tooth." Agassiz referenced the name as early as 1832, but because specimens were not referenced they are not [[Biology:Nomen nudum|taxonomically recognized uses]].<ref name=Brignon2021 /> Formal description of the species was published in an 1843 volume, where Agassiz revised the name to ''[[Biology:Carcharodon|Carcharodon]] megalodon'' as its teeth were far too large for the former [[Biology:Genus|genus]] and more alike to the great white shark.<ref name=Agassiz1843 /> He also erroneously identified several megalodon teeth as belonging to additional species eventually named ''Carcharodon rectidens'', ''Carcharodon subauriculatus'', ''Carcharodon productus'', and ''Carcharodon polygurus''.<ref name=Agassiz1843 /><ref name=Woodward1899>{{cite book|author=Woodward, A.S.|year=1899|title=Catalogue of the fossil fishes in the British Museum (Natural History), Part I. Containing the Elasmobranchii|pages=415–420|publisher=British Museum (Natural History)|doi=10.5962/bhl.title.61854|url=https://www.biodiversitylibrary.org/item/211828#page/461/mode/1up}}</ref> Because ''Carcharodon megalodon'' appeared first in the 1835 illustration, the remaining names are considered junior synonyms under the [[Biology:Principle of priority|principle of priority]].<ref name=Brignon2021/><ref name=Woodward1899 />

=== Evolution ===
[[File:Otodus evolution.webp|thumb|right|Diagram of the chronospecies evolution of megalodon]]

While the earliest megalodon remains have been reported from the Late Oligocene, around 28 [[Physics:Mya (unit)|million years ago]] (Mya),<ref>{{Cite journal|last1= Yabe|first1= H.|last2= Goto|first2= M.|last3= Kaneko|first3= N.|title=Age of ''Carcharocles megalodon'' (Lamniformes: Otodontidae): A review of the stratigraphic records|journal=The Palaeontological Society of Japan|volume= 75|pages= 7–15|year= 2004}}</ref><ref name="CA">{{Cite journal|last1=Gottfried|first1=M. D.|last2=Fordyce|first2=R. E.|title=An associated specimen of ''Carcharodon angustidens'' (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on ''Carcharodon'' interrelationships|year=2001|journal=Journal of Vertebrate Paleontology|volume=21|issue=4|pages=730–739|doi=10.1671/0272-4634(2001)021[0730:AASOCA]2.0.CO;2|s2cid=86092645|url=http://www.thefossilforum.com/applications/core/interface/file/attachment.php?id=270846|access-date=6 November 2017|archive-date=17 December 2019|archive-url=https://web.archive.org/web/20191217041232/http://webcache.googleusercontent.com/search?q=cache%3AMgxUX8ckLrYJ%3Awww.thefossilforum.com%2Fapplications%2Fcore%2Finterface%2Ffile%2Fattachment.php%3Fid%3D270846+&cd=13&hl=en&ct=clnk&gl=us|url-status=dead}}</ref> there is disagreement as to when it appeared, with dates ranging to as young as 16 mya.<ref name="Pimiento2016">{{cite journal|last1= Pimiento|first1= C.|last2= MacFadden|first2=B. J.|last3=Clements|first3=C. F.|last4=Varela|first4= S.|last5= Jaramillo|first5= C.|last6= Velez-Juarbe|first6= J.|last7= Silliman|first7=B. R.|title=Geographical distribution patterns of ''Carcharocles megalodon'' over time reveal clues about extinction mechanisms|journal=Journal of Biogeography|year=2016|pages= 1645–1655|doi=10.1111/jbi.12754|volume=43|issue= 8|bibcode= 2016JBiog..43.1645P|s2cid= 55776834}}</ref> It has been thought that megalodon became extinct around the end of the Pliocene, about 2.6&nbsp;Mya;<ref name="Pimiento2016" /><ref name="Pimiento2014">{{Cite journal | doi = 10.1371/journal.pone.0111086| pmid = 25338197| title = When Did ''Carcharocles megalodon'' Become Extinct? A New Analysis of the Fossil Record| journal = PLOS ONE| volume = 9| issue = 10| pages = e111086|year=2014| last1 = Pimiento | first1 = C. | last2 = Clements | first2 = C. F.| bibcode = 2014PLoSO...9k1086P | pmc=4206505| doi-access = free}}</ref> claims of [[Earth:Pleistocene|Pleistocene]] megalodon teeth, younger than 2.6 million years old, are considered unreliable.<ref name="Pimiento2014" /> A 2019 assessment moves the extinction date back to earlier in the Pliocene, 3.6&nbsp;Mya.<ref name="Boessenecker2019" /><ref>{{cite AV media|title=Giant 'megalodon' shark extinct earlier than previously thought |url=https://www.sciencedaily.com/releases/2019/02/190213081637.htm |website=Science Daily |date=13 February 2019}}</ref>

Megalodon is considered to be a member of the family Otodontidae, genus ''Otodus'', as opposed to its previous classification into Lamnidae, genus ''Carcharodon''.<ref name="Pimiento2016" /><ref name="Pimiento&Balk2015"/><ref name="Pimiento2014" /><ref name="Shimada2016">{{cite journal|last1= Shimada|first1=K.|last2= Chandler|first2=R. E.|last3= Lam|first3=O. L. T.|last4= Tanaka|first4=T.|last5= Ward|first5=D. J.|title=A new elusive otodontid shark (Lamniformes: Otodontidae) from the lower Miocene, and comments on the taxonomy of otodontid genera, including the 'megatoothed' clade|journal= Historical Biology|volume=29|issue=5|year=2016|pages= 1–11|doi= 10.1080/08912963.2016.1236795|s2cid=89080495}}</ref><ref name="Shimada2019">{{Cite journal|last=Shimada|first=Kenshu|year=2019|title=The size of the megatooth shark, ''Otodus megalodon'' (Lamniformes: Otodontidae), revisited|journal=Historical Biology|volume=33|issue=7|pages=1–8|doi=10.1080/08912963.2019.1666840|s2cid=208570844|issn=0891-2963}}</ref> Megalodon's classification into ''Carcharodon'' was due to dental similarity with the great white shark, but most authors believe that this is due to [[Biology:Convergent evolution|convergent evolution]]. In this model, the great white shark is more closely related to the extinct broad-toothed mako (''Isurus hastalis'') than to megalodon, as evidenced by more similar dentition in those two sharks; megalodon teeth have much finer serrations than great white shark teeth. The great white shark is more closely related to the mako shark (''Isurus'' spp.), with a [[Biology:Most recent common ancestor|common ancestor]] around 4&nbsp;Mya.<ref name="A">{{Cite journal|last=Nyberg|first=K. G. |title=Tracing the ancestry of the great white shark, ''Carcharodon carcharias'', using morphometric analyses of fossil teeth |author2=Ciampaglio C. N. |author3=Wray G. A. |year= 2006|journal= Journal of Vertebrate Paleontology|volume=26|issue=4|pages=806–814|doi=10.1671/0272-4634(2006)26[806:TTAOTG]2.0.CO;2|s2cid=53640614 }}</ref><ref name="FSP">{{Cite journal|author1=Ehret D. J. |author2=Hubbell G. |author3=Macfadden B. J. |title=Exceptional preservation of the white shark ''Carcharodon'' from the early Pliocene of Peru|journal=Journal of Vertebrate Paleontology|volume= 29|issue=1|pages= 1–13|doi= 10.1671/039.029.0113|year=2009|jstor=20491064|s2cid=129585445 }}</ref> Proponents of the former model, wherein megalodon and the great white shark are more closely related, argue that the differences between their dentition are minute and obscure.<ref name="G">{{Cite book|last1=Klimley|first1=Peter|last2=Ainley|first2=David|title=Great White Sharks: The Biology of Carcharodon carcharias|publisher=Academic Press|year=1996|chapter-url={{google books|plainurl=yes|id=2My8M5tL-KIC|page=9}}|isbn=978-0-12-415031-7|chapter=Evolution|location=San Diego, California|oclc=212425118}}</ref>{{rp|23–25}}
[[File:Megalodon tooth with great white sharks teeth-3-2.jpg|thumb|left|Megalodon tooth with two great white shark teeth|alt=A black megalodon tooth and two white great white shark teeth above a centimeter scale, the megalodon tooth extends between the zero and thirteen-and-a-half centimeter marks. One great white tooth extends between the eleven and thirteen centimeter marks, and the other extends between from the thirteen and sixteen centimeter marks.]]

The genus ''Carcharocles'' contains four species: ''[[Biology:Carcharocles auriculatus|C. auriculatus]]'', ''[[Biology:Carcharocles angustidens|C. angustidens]]'', ''[[Biology:Carcharocles chubutensis|C. chubutensis]]'', and ''C. megalodon''.<ref name="H" />{{rp|30–31}} The evolution of this lineage is characterized by the increase of serrations, the widening of the crown, the development of a more triangular shape, and the disappearance of the lateral cusps.<ref name="H" />{{rp|28–31}}<ref name="C" /> The evolution in tooth morphology reflects a shift in predation tactics from a tearing-grasping bite to a cutting bite, likely reflecting a shift in prey choice from fish to cetaceans.<ref name="Perez2019" /> Lateral cusplets were finally lost in a gradual process that took roughly 12 million years during the transition between ''C. chubutensis'' and ''C. megalodon''.<ref name="Perez2019">{{cite journal|last1= Perez|first1=V. J.|last2= Godfrey|first2=S. J.|last3= Kent|first3=B. W.|last4= Weems|first4=R. E.|last5= Nance|first5=J. R.|title=The transition between ''Carcharocles chubutensis'' and ''Carcharocles megalodon'' (Otodontidae, Chondrichthyes): lateral cusplet loss through time|journal= Journal of Vertebrate Paleontology|volume=38|issue=6|year= 2019|pages= e1546732|doi= 10.1080/02724634.2018.1546732|doi-access= free}}</ref> The genus was proposed by D. S. Jordan and H. Hannibal in 1923 to contain ''C. auriculatus''. In the 1980s, megalodon was assigned to ''Carcharocles''.<ref name="A" /><ref name="H" />{{rp|30}} Before this, in 1960, the genus ''Procarcharodon'' was erected by French ichthyologist Edgard Casier, which included those four sharks and was considered separate from the great white shark. It is since considered a junior synonym of ''Carcharocles''.<ref name="H" />{{rp|30}} The genus ''[[Biology:Palaeocarcharodon|Palaeocarcharodon]]'' was erected alongside ''Procarcharodon'' to represent the beginning of the lineage, and, in the model wherein megalodon and the great white shark are closely related, their last common ancestor. It is believed to be an evolutionary dead-end and unrelated to the ''Carcharocles'' sharks by authors who reject that model.<ref name="G" />{{rp|70}}
[[File:White shark.jpg|thumb|The great white shark (''Carcharodon carcharias'') and megalodon were previously thought to be close relatives.<ref name="A" /><ref name="FSP" />|alt=A great white shark swimming a few meters below the surface, above a school of much smaller fish.]]

Another model of the evolution of this genus, also proposed by Casier in 1960, is that the direct ancestor of the ''Carcharocles'' is the shark ''Otodus obliquus'', which lived from the [[Earth:Paleocene|Paleocene]] through the Miocene epochs, 60 to 13&nbsp;Mya.<ref name="FSP" /><ref name="C" /> The genus ''Otodus'' is ultimately derived from ''[[Biology:Cretolamna|Cretolamna]]'', a shark from the [[Earth:Cretaceous|Cretaceous]] period.<ref name="Shimada2016" /><ref name="otodusmegalodon">{{cite journal|last1= Siverson |first1= M.|last2= Lindgren |first2= J.|last3= Newbrey |first3= M.G.|last4= Cederström |first4= P.|last5= Cook |first5= T.D.|title= Late Cretaceous (Cenomanian-Campanian) mid-palaeolatitude sharks of ''Cretalamna appendiculata'' type |journal=Acta Palaeontologica Polonica |year=2013 |doi=10.4202/app.2012.0137 |page=2 |s2cid= 58906204|url= http://www.app.pan.pl/archive/published/app58/app20120137_acc.pdf |url-status=dead |archive-url= https://web.archive.org/web/20131019193239/http://www.app.pan.pl/archive/published/app58/app20120137_acc.pdf |archive-date=19 October 2013|doi-access= free }}</ref> In this model, ''O. obliquus'' evolved into ''O. aksuaticus'', which evolved into ''C. auriculatus'', and then into ''C. angustidens'', and then into ''C. chubutensis'', and then finally into ''C. megalodon''.

Another model of the evolution of ''Carcharocles'', proposed in 2001 by paleontologist Michael Benton, is that the three other species are actually a single species of shark that gradually changed over time between the Paleocene and the Pliocene, making it a [[Biology:Chronospecies|chronospecies]].<ref name="H" />{{rp|17}}<ref name="CA" /><ref>{{cite journal|last1=Benton|first1=M. J.|last2=Pearson|first2=P. N.|year=2001|title=Speciation in the fossil record|journal=Trends in Ecology and Evolution|volume=16|issue=7|pages=405–411|pmid=11403874|doi=10.1016/s0169-5347(01)02149-8}}</ref> Some authors suggest that ''C. auriculatus'', ''C. angustidens'', and ''C. chubutensis'' should be classified as a single species in the genus ''Otodus'', leaving ''C. megalodon'' the sole member of ''Carcharocles''.<ref name="CA" /><ref name="AN" />

The genus ''Carcharocles'' may be invalid, and the shark may actually belong in the genus ''Otodus'', making it ''Otodus megalodon''.<ref name=cappetta /> A 1974 study on Paleogene sharks by Henri Cappetta erected the [[Biology:Subgenus|subgenus]] ''Megaselachus'', classifying the shark as ''Otodus'' (''Megaselachus'') ''megalodon'', along with ''O. (M.) chubutensis''. A 2006 review of Chondrichthyes elevated ''Megaselachus'' to genus, and classified the sharks as ''Megaselachus megalodon'' and ''M. chubutensis''.<ref name=cappetta>{{cite book|last=Cappetta|first=H.|year=1987|title=Handbook of Paleoichthyology|publisher=Friedrich Pfeil|chapter=Mesozoic and Cenozoic Elasmobranchii|volume=3B|location=München, Germany|isbn=978-3-89937-046-1|oclc=829906016}}</ref> The discovery of fossils assigned to the genus ''[[Biology:Megalolamna|Megalolamna]]'' in 2016 led to a re-evaluation of ''Otodus'', which concluded that it is [[Biology:Paraphyly|paraphyletic]], that is, it consists of a [[Biology:Most recent common ancestor|last common ancestor]] but it does not include all of its descendants. The inclusion of the ''Carcharocles'' sharks in ''Otodus'' would make it [[Biology:Monophyly|monophyletic]], with the [[Biology:Sister group|sister clade]] being ''Megalolamna''.<ref name="Shimada2016" />

The cladogram below represents the hypothetical relationships between megalodon and other sharks, including the great white shark. Modified from Shimada et al. (2016),<ref name="Shimada2016" /> Ehret et al., (2009),<ref name="FSP" /> and the findings of Siversson et al. (2013).<ref name=Siverssonetal2015>{{cite journal|author1=Siversson, M.|author2=Lindgren, J.|author3=Newbrey, M.G.|author4=Cederström, P.|author5=Cook, T.D.|title=Cenomanian–Campanian (Late Cretaceous) mid-palaeolatitude sharks of ''Cretalamna appendiculata'' type|journal=Acta Palaeontologica Polonica|volume=60|issue=2|year=2015|pages=339–384|doi=10.4202/app.2012.0137|s2cid=58906204|url=http://www.app.pan.pl/archive/published/app60/app20120137.pdf|doi-access=free}}</ref><ref name=Austra>{{cite web|author=Vivian, G.|year=2013|title=Research debunks Great White lineage|url=http://www.australasianscience.com.au/news/august-2013/research-debunks-great-white-lineage.html}}</ref><ref name=AustralianMuseum2013>{{cite web|title=Palaeontological detective work unravels evolution of megatooth sharks|year=2013|url=http://museum.wa.gov.au/about/latest-news/palaeontological-detective-work-unravels-evolution-megatooth-sharks}}</ref>
{{clade
  |label1=[[Biology:Lamniformes|Lamniformes]]
  |1={{clade
     |1={{clade
        |label1=[[Biology:Otodontidae|Otodontidae]]
        |1={{clade
           |1=''[[Biology:Kenolamna|Kenolamna gunsoni]]''
           |2={{clade
              |1={{clade
                 |1=''[[Biology:Cretalamna|Cretalamna appendiculata]]''
                 |2=''[[Biology:Cretalamna|Cretalamna aschersoni]]''
                 }}
              |2={{clade
                 |1=''Megalolamna paradoxodon'' <span style="{{MirrorH}}">[[File:Megalolamna SW.png|70 px]]</span>
                 |2={{clade
                    |1=''Otodus obliquus''
                    |2='''''Otodus megalodon''''' [[File:Megalodon restoration.png|70 px]]
                    }}
              }}
}}}}
        |label2=[[Biology:Lamnidae|Lamnidae]]
        |2={{clade
           |1=''Isurus oxyrinchus'' <span style="{{MirrorH}}">[[File:Shortfin mako shark (Duane Raver).png|70 px]]</span>
           |2=''[[Biology:Great white shark|Carcharodon carcharias]]'' <span style="{{MirrorH}}">[[File:White shark (Duane Raver).png|70 px]]</span>
}}}}}}}}

== Biology ==
=== Appearance ===
[[File:Lateral view of otouds megalodon.png|thumb|Lateral view of an ''Otodus megalodon'' restoration based on ''[[Biology:Cretalamna|Cretalamna]]'' and modern lamnids]]
One interpretation on how megalodon appeared was that it was a robust-looking shark, and may have had a similar build to the great white shark. The jaws may have been blunter and wider than the great white, and the fins would have also been similar in shape, though thicker due to its size. It may have had a pig-eyed appearance, in that it had small, deep-set eyes.<ref name="Gottfried1996"/>

Another interpretation is that megalodon bore a similarity to the [[Biology:Whale shark|whale shark]] (''Rhincodon typus'') or the [[Biology:Basking shark|basking shark]] (''Cetorhinus maximus''). The tail fin would have been crescent-shaped, the anal fin and second dorsal fin would have been small, and there would have been a caudal keel present on either side of the tail fin (on the caudal peduncle). This build is common in other large aquatic animals, such as whales, tuna, and other sharks, in order to reduce [[Physics:Drag|drag]] while swimming. The head shape can vary between species as most of the drag-reducing adaptations are toward the tail-end of the animal.<ref name="H" />{{rp|35–36}}

One associated set of megalodon remains was found with placoid scales, which are {{Convert|0.3 to 0.8|mm|in}} in maximum width, and have broadly spaced keels.<ref>{{Cite journal |last1=Shimada |first1=Kenshu |last2=Yamaoka |first2=Yuta |last3=Kurihara |first3=Yukito |last4=Takakuwa |first4=Yuji |last5=Maisch |first5=Harry M. |last6=Becker |first6=Martin A. |last7=Eagle |first7=Robert A. |last8=Griffiths |first8=Michael L. |date=23 June 2023 |title=Tessellated calcified cartilage and placoid scales of the Neogene megatooth shark, Otodus megalodon (Lamniformes: Otodontidae), offer new insights into its biology and the evolution of regional endothermy and gigantism in the otodontid clade |journal=Historical Biology |language=en |pages=1–15 |doi=10.1080/08912963.2023.2211597 |s2cid=259597157 |issn=0891-2963|doi-access=free }}</ref>

=== Size ===
{{Multiple image
| direction = vertical
| image1 = Megalodon-Carcharodon-Scale-Chart-SVG.svg
| caption1 = Size comparison of the great white and whale shark to estimates for megalodon
| image2 = Megalodon size chart.png
| caption2 = Proportions of megalodon at lengths of {{cvt|3|m|ft|0}}, {{cvt|8|m}}, and {{cvt|16|m}}, extrapolated from extant relatives, with a {{cvt|1.65|m}} diver
| align = left
| total_width = 
| alt1 = 
}}
Due to fragmentary remains, there have been many contradictory size estimates for megalodon, as they can only be drawn from fossil teeth and vertebrae.<ref name="H2">{{Cite book|last=Renz|first=Mark|url={{google books|plainurl=yes|id=cMRe5GmDXmUC}}|title=Megalodon: Hunting the Hunter|publisher=PaleoPress|year=2002|isbn=978-0-9719477-0-2|location=Lehigh Acres, Florida|pages=1–159|oclc=52125833}}</ref>{{rp|87}}<ref>{{cite journal|last1=Portell|first1=Roger|last2=Hubell|first2=Gordon|last3=Donovan|first3=Stephen|last4=Green|first4=Jeremy|last5=Harper|first5=David|last6=Pickerill|first6=Ron|year=2008|title=Miocene sharks in the Kendeace and Grand Bay formations of Carriacou, The Grenadines, Lesser Antilles|url=http://caribjsci.org/Dec08/44_279-286.pdf|url-status=dead|journal=Caribbean Journal of Science|volume=44|issue=3|pages=279–286|doi=10.18475/cjos.v44i3.a2|archive-url=https://web.archive.org/web/20110720034621/http://caribjsci.org/Dec08/44_279-286.pdf|archive-date=20 July 2011|s2cid=87154947}}</ref> The great white shark has been the basis of reconstruction and size estimation, as it is regarded as the best analogue to megalodon. Several total length estimation methods have been produced from comparing megalodon teeth and vertebrae to those of the great white.<ref name="Gottfried1996">{{cite book|last1=Gottfried|first1=MD|url=https://books.google.com/books?id=2My8M5tL-KIC&q=Gottfried|title=Great White Sharks: The Biology of ''Carcharodon carcharias''|last2=Compagno|first2=LJV|last3=Bowman|first3=SC|publisher=Academic Press|year=1996|isbn=978-0124150317|editor1-last=Klimley|location=San Diego, California|pages=55–89|chapter=Size and skeletal anatomy of the giant megatooth shark ''Carcharodon megalodon''|editor2-last=Ainley}}</ref><ref name="AN2">{{Cite journal|last1=Pimiento|first1=Catalina|last2=Ehret|first2=Dana J.|last3=MacFadden|first3=Bruce J.|last4=Hubbell|first4=Gordon|year=2010|editor1-last=Stepanova|editor1-first=Anna|title=Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama|journal=PLOS ONE|volume=5|issue=5|pages=e10552|bibcode=2010PLoSO...510552P|doi=10.1371/journal.pone.0010552|pmc=2866656|pmid=20479893|doi-access=free}}</ref><ref name="Perezetal2021">{{Cite journal|last1=Perez|first1=Victor|last2=Leder|first2=Ronny|last3=Badaut|first3=Teddy|date=2021|title=Body length estimation of Neogene macrophagous lamniform sharks (Carcharodon and Otodus) derived from associated fossil dentitions|url=https://palaeo-electronica.org/content/2021/3284-estimating-lamniform-body-size|journal=Palaeontologia Electronica|volume=24|issue=1|pages=1–28|doi=10.26879/1140|doi-access=free}}</ref><ref name="Shimada2019"/>

Megalodon size estimates vary depending on the method used, with maximum total length estimates ranging from {{convert|14.2|-|20.3|m|ft|sp=us}}.<ref name="Gottfried1996"/><ref name="Perezetal2021"/><ref name="Shimada2019"/> A 2015 study estimated the average total body length at {{convert|10.5|m|ft|sp=us}}, calculated from 544 megalodon teeth, found throughout geological time and geography, including adults and juveniles.<ref name="Pimiento201622">{{cite journal|last1=Pimiento|first1=C.|last2=MacFadden|first2=B. J.|last3=Clements|first3=C. F.|last4=Varela|first4=S.|last5=Jaramillo|first5=C.|last6=Velez-Juarbe|first6=J.|last7=Silliman|first7=B. R.|year=2016|title=Geographical distribution patterns of ''Carcharocles megalodon'' over time reveal clues about extinction mechanisms|journal=Journal of Biogeography|volume=43|issue=8|pages=1645–1655|doi=10.1111/jbi.12754|bibcode=2016JBiog..43.1645P |s2cid=55776834}}</ref><ref name="Pimiento&Balk2015">{{cite journal|last1=Pimiento|first1=C.|last2=Balk|first2=M. A.|year=2015|title=Body-size trends of the extinct giant shark ''Carcharocles megalodon'': a deep-time perspective on marine apex predators|journal=Paleobiology|volume=41|issue=3|pages=479–490|doi=10.1017/pab.2015.16|pmc=4541548|pmid=26321775|bibcode=2015Pbio...41..479P }}</ref> In comparison, large great white sharks are generally around {{convert|6|m|ft|sp=us}} in length, with a few contentious reports suggesting larger sizes.<ref name="McClainetal2015">{{Cite journal|last1=McClain|first1=Craig R.|last2=Balk|first2=Meghan A.|last3=Benfield|first3=Mark C.|last4=Branch|first4=Trevor A.|last5=Chen|first5=Catherine|last6=Cosgrove|first6=James|last7=Dove|first7=Alistair D.M.|last8=Gaskins|first8=Lindsay C.|last9=Helm|first9=Rebecca R.|last10=Hochberg|first10=Frederick G.|last11=Lee|first11=Frank B.|date=13 January 2015|title=Sizing ocean giants: patterns of intraspecific size variation in marine megafauna|journal=PeerJ|language=en|volume=3|pages=e715|doi=10.7717/peerj.715|issn=2167-8359|pmc=4304853|pmid=25649000 |doi-access=free }}</ref><ref>{{Cite book|last=I.|first=Castro, Jose|url=http://worldcat.org/oclc/958576172|title=Sharks of North America.|date=2011|publisher=Oxford University Press, USA|isbn=978-0-19-978097-6|oclc=958576172}}</ref><ref name="Gottfried1996"/> The whale shark is the largest living fish, with one large female reported with a precaudal length of {{convert|15|m|ft|sp=us}} and an estimated total length of {{convert|18.8|m|ft|sp=us}}.<ref name="McClainetal2015" /><ref>{{Cite journal|last1=Borrell|first1=Asunción|last2=Aguilar|first2=Alex|last3=Gazo|first3=Manel|last4=Kumarran|first4=R. P.|last5=Cardona|first5=Luis|date=1 December 2011|title=Stable isotope profiles in whale shark (Rhincodon typus) suggest segregation and dissimilarities in the diet depending on sex and size|url=https://doi.org/10.1007/s10641-011-9879-y|journal=Environmental Biology of Fishes|language=en|volume=92|issue=4|pages=559–567|doi=10.1007/s10641-011-9879-y|bibcode=2011EnvBF..92..559B |s2cid=37683420|issn=1573-5133}}</ref> It is possible that different populations of megalodon around the globe had different body sizes and behaviors due to different ecological pressures.<ref name="Pimiento&Balk2015"/> Megalodon is thought to have been the largest macropredatory shark that ever lived.<ref name="Gottfried1996"/>

{{blockquote| "A C. megalodon about 16 meters long would have weighed about 48 metric tons (53 tons). A 17-meter (56-foot) C. megalodon would have weighed about 59 metric tons (65 tons), and a 20.3-meter (67 foot) monster would have topped off at 103 metric tons (114 tons)."<ref name = "Prothero"/> 
}}

In his 2015 book, ''The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution'', Donald Prothero proposed the body mass estimates for different individuals of different length by extrapolating from a vertebral centra based on the dimensions of the great white,<ref name = "Prothero">{{cite book |last=Prothero |first=Donald R. |chapter=09. Mega-Jaws: The Largest Fish. Carcharocles |title=The Story of Life in 25 Fossils: Tales of Intrepid Fossil Hunters and the Wonders of Evolution |date=25 August 2015 |pages= 96–110 |publisher=Columbia University Press |location=New York Chichester, West Sussex |isbn=978-0-231-53942-5 |doi=10.7312/prot17190-010 |language=en}}</ref> a methodology also used for the 2008 study which supports the maximum mass estimate.<ref name="Wroeetal2008">{{cite journal|last=Wroe|first=S.|author2=Huber, D. R.|author3=Lowry, M.|author4=McHenry, C.|author5=Moreno, K.|author6=Clausen, P.|author7=Ferrara, T. L.|author8=Cunningham, E.|author9=Dean, M. N.|author10=Summers, A. P.|year=2008|title=Three-dimensional computer analysis of white shark jaw mechanics: how hard can a great white bite?|url=http://www.bio-nica.info/Biblioteca/Wroe2008GreatWhiteSharkBiteForce.pdf|journal=Journal of Zoology|volume=276|issue=4|pages=336–342|doi=10.1111/j.1469-7998.2008.00494.x}}</ref>

In 2020, Cooper and his colleagues reconstructed a 2D model of megalodon based on the dimensions of all the extant [[Biology:Lamnidae|lamnid sharks]] and suggested that a {{convert|16|m|ft|sp=us}} long megalodon would have had a {{cvt|4.65|m}} long head, {{cvt|1.41|m}} tall gill slits, a {{cvt|1.62|m}} tall dorsal fin, {{cvt|3.08|m|ftin}} long pectoral fins, and a {{cvt|3.85|m|ftin}} tall tail fin.<ref name="Cooper2020">{{cite journal|last1=Cooper|first1=J. A.|last2=Pimiento|first2=C.|last3=Ferrón|first3=H. G.|last4=Benton|first4=M. J.|year=2020|title=Body dimensions of the extinct giant shark ''Otodus megalodon'': a 2D reconstruction|journal=Scientific Reports|volume=10|issue=14596|page=14596|doi=10.1038/s41598-020-71387-y|pmc=7471939|pmid=32883981|bibcode=2020NatSR..1014596C|doi-access=free}}</ref> In 2022, Cooper and his colleagues also reconstructed a 3D model with the same basis as the 2020 study, resulting in a body mass estimate of {{convert|61.56|t|ST LT|abbr=on}} for a {{convert|16|m|ft|sp=us}} long megalodon (higher than the previous estimates); a [[Biology:Vertebral column|vertebral column]] specimen named IRSNB P 9893 (formerly IRSNB 3121), belonging to a 46 year old individual from Belgium, was used for extrapolation. An individual of this size would have required 98,175 kcal per day, 20 times more than what the adult great white requires.<ref name=Cooperetal2022>{{cite journal|year=2022|last1=Cooper|first1=J.A.|last2=Hutchinson|first2=J.R.|last3=Bernvi|first3=D.C.|last4=Cliff|first4=G.|last5=Wilson|first5=R.P.|last6=Dicken|first6=M.L.|last7=Menzel|first7=J.|last8=Wroe|first8=S.|last9=Pirlo|first9=J.|last10=Pimiento|first10=C.|title=The extinct shark ''Otodus megalodon'' was a transoceanic superpredator: Inferences from 3D modeling|journal=Science Advances|volume=8|issue=33|pages=eabm9424|doi=10.1126/sciadv.abm9424|doi-access=free|pmid=35977007|pmc=9385135 |bibcode=2022SciA....8M9424C |issn=2375-2548}}</ref>

Mature male megalodon may have had a body mass of {{convert|12.6|to|33.9|t|ST LT|abbr=on}}, and mature females may have been {{convert|27.4|to|59.4|t|ST LT|abbr=on}}, assuming that males could range in length from {{convert|10.5|to|14.3|m|ft|sp=us}} and females {{convert|13.3|to|17|m|ft|sp=us}}.<ref name="Gottfried1996"/>

A 2015 study linking shark size and typical swimming speed estimated that megalodon would have typically swum at {{convert|18|kph|mph|sp=us}}–assuming that its body mass was typically {{convert|48|t|ST LT|abbr=on}}–which is consistent with other aquatic creatures of its size, such as the [[Biology:Fin whale|fin whale]] (''Balaenoptera physalus'') which typically cruises at speeds of {{convert|14.5|to|21.5|kph|mph|abbr=on}}.<ref>{{cite journal|first1=D. M. P.|last1=Jacoby|first2=P.|last2=Siriwat|first3=R.|last3=Freeman|first4=C.|last4=Carbone|year=2015|title=Is the scaling of swim speed in sharks driven by metabolism?|journal=Biology Letters|volume=12|issue=10|pages=20150781|doi=10.1098/rsbl.2015.0781|pmc=4707698|pmid=26631246}}</ref> In 2022, Cooper and his colleagues converted this calculation into relative cruising speed (body lengths per second), resulting in an mean absolute cruising speed of {{convert|5|kph|mph|sp=us}} and a mean relative cruising speed of 0.09 body lengths per second for a {{convert|16|m|ft|sp=us}} long megalodon; the authors found their mean absolute cruising speed to be faster than any extant lamnid sharks and their mean relative cruising speed to be slower, consistent with previous estimates.<ref name=Cooperetal2022/>
[[File:2016 megalodon.jpg|thumb|Sculpture in the Museum of Evolution in Puebla, Mexico|alt=Sculpture of a giant shark mounted on display in a museum next to a mounted shark jawbone]]
Its large size may have been due to climatic factors and the abundance of large prey items, and it may have also been influenced by the evolution of [[Biology:Mesotherm|regional endothermy]] (mesothermy) which would have increased its [[Metabolic rate|metabolic rate]] and swimming speed. The otodontid sharks have been considered to have been [[Biology:Ectotherm|ectotherm]]s, so on that basis megalodon would have been ectothermic. However, the largest contemporary ectothermic sharks, such as the whale shark, are filter feeders, while lamnids are regional endotherms, implying some metabolic correlations with a predatory lifestyle. These considerations, as well as tooth oxygen isotopic data and the need for higher burst swimming speeds in macropredators of endothermic prey than ectothermy would allow, imply that otodontids, including megalodon, were probably regional endotherms.<ref name="Ferrón2017">{{cite journal|first=H. G.|last= Ferrón|year= 2017|title= Regional endothermy as a trigger for gigantism in some extinct macropredatory sharks|journal= PLOS ONE|volume= 12|issue= 9|pages= e0185185|doi= 10.1371/journal.pone.0185185|pmid= 28938002|pmc= 5609766|bibcode= 2017PLoSO..1285185F|doi-access= free}}</ref>

In 2020, Shimada and colleagues suggested large size was instead due to intrauterine cannibalism, where the larger fetus eats the smaller fetus, resulting in progressively larger and larger fetuses, requiring the mother to attain even greater size as well as caloric requirements which would have promoted endothermy. Males would have needed to keep up with female size in order to still effectively copulate (which probably involved latching onto the female with [[Biology:Clasper|clasper]]s, like modern cartilaginous fish).<ref>{{cite journal|first1=K.|last1=Shimada|first2=M. A.|last2=Becker|first3=M. L.|last3=Griffiths|year=2020|title=Body, jaw, and dentition lengths of macrophagous lamniform sharks, and body size evolution in Lamniformes with special reference to 'off-the-scale' gigantism of the megatooth shark, ''Otodus megalodon''|journal=Historical Biology|volume=33 |issue=11 |pages=1–17|doi=10.1080/08912963.2020.1812598|doi-access=free}}</ref>

==== Maximum estimates ====
The first attempt to reconstruct the jaw of megalodon was made by Bashford Dean in 1909, displayed at the [[Biology:American Museum of Natural History|American Museum of Natural History]]. From the dimensions of this jaw reconstruction, it was hypothesized that megalodon could have approached {{convert|30|m|ft|sp=us}} in length. Dean had overestimated the size of the cartilage on both jaws, causing it to be too tall.<ref name="prothero" /><ref>{{cite book|url={{google books|plainurl=yes|id=miZ8AwAAQBAJ|page=19}}|first1=G.|last1=Helfman|first2=G. H.|last2=Burgess|year=2014|title=Sharks: The Animal Answer Guide|publisher=Johns Hopkins University Press|location=Baltimore, Maryland|page=19 |isbn=978-1-4214-1310-5|oclc=903293986}}</ref>{{multiple image
| direction = 
| width = 
| image1 = Carcharodon megalodon.jpg
| alt1 = Black-and-white photo of a man sitting inside a megalodon jaw reconstruction.
| caption1 = Reconstruction by Bashford Dean in 1909
| image2 = Megalodon.jpg
| width2 = 155
| alt2 = A white megalodon tooth on the palms of a person. On the right side of the image is a ruler. The tip of the tooth starts at zero and ends at the seventeen centimeter marker on the ruler.
| caption2 = Tooth compared to hand
}}

In 1973, John E. Randall, an [[Biology:Ichthyology|ichthyologist]], used the [[Biology:Tooth enamel|enamel]] height (the vertical distance of the blade from the base of the enamel portion of the tooth to its tip) to measure the length of the shark, yielding a maximum length of about {{convert|13|m|ft|sp=us}}.<ref name="W">{{cite journal|last=Randall|first=John E.|title=Size of the Great White Shark (''Carcharodon'')|journal=Science Magazine|pages=169–170|year=1973|bibcode=1973Sci...181..169R|volume=181|doi=10.1126/science.181.4095.169|pmid=17746627|issue=4095|s2cid=36607712}}</ref> However, tooth enamel height does not necessarily increase in proportion to the animal's total length.<ref name="G" />{{rp|99}}

In 1994, marine biologists Patrick J. Schembri and Stephen Papson opined that ''O. megalodon'' may have approached a maximum of around {{convert|24|to|25|m|ft|sp=us}} in total length.<ref>{{Cite journal|last=Schembri|first=Patrick|title=Malta's Natural Heritage|journal=Natural Heritage. In|pages=105–124|year=1994|url=https://www.researchgate.net/publication/242261710}}</ref><ref>{{Cite journal|last=Papson|first=Stephen|title=Copyright: Cross the Fin Line of Terror|journal=Journal of American Culture|volume=15|issue=4|pages=67–81|year=1992|doi=10.1111/j.1542-734X.1992.1504_67.x}}</ref>

In 1996, shark researchers Michael D. Gottfried, Leonard Compagno, and S. Curtis Bowman proposed a linear relationship between the great white shark's total length and the height of the largest upper anterior tooth. The proposed relationship is: total length in meters = − (0.096) × [UA maximum height ([[Millimetre|mm]])]-(0.22).<ref name="CA2">{{Cite journal|last1=Gottfried|first1=M. D.|last2=Fordyce|first2=R. E.|year=2001|title=An associated specimen of ''Carcharodon angustidens'' (Chondrichthyes, Lamnidae) from the Late Oligocene of New Zealand, with comments on ''Carcharodon'' interrelationships|url=http://www.thefossilforum.com/applications/core/interface/file/attachment.php?id=270846|journal=Journal of Vertebrate Paleontology|volume=21|issue=4|pages=730–739|doi=10.1671/0272-4634(2001)021[0730:AASOCA]2.0.CO;2|s2cid=86092645|access-date=6 November 2017|archive-date=17 December 2019|archive-url=https://web.archive.org/web/20191217041232/http://webcache.googleusercontent.com/search?q=cache%3AMgxUX8ckLrYJ%3Awww.thefossilforum.com%2Fapplications%2Fcore%2Finterface%2Ffile%2Fattachment.php%3Fid%3D270846+&cd=13&hl=en&ct=clnk&gl=us|url-status=dead}}</ref><ref name="Gottfried1996"/> Using this tooth height regression equation, the authors estimated a total length of {{convert|15.9|m|ft|sp=us}} based on a tooth {{convert|16.8|cm|in|sp=us}} tall, which the authors considered a conservative maximum estimate. They also compared the ratio between the tooth height and total length of large female great whites to the largest megalodon tooth. A {{convert|6|m|ft|sp=us|abbr=|adj=on}} long female great white, which the authors considered the largest 'reasonably trustworthy' total length, produced an estimate of {{convert|16.8|m|ft|sp=us}}. However, based on the largest female great white reported, at {{convert|7.1|m|ft|sp=us}}, they estimated a maximum estimate of {{convert|20.2|m|ft|sp=us}}.<ref name="Gottfried1996"/>

In 2002, shark researcher Clifford Jeremiah proposed that total length was proportional to the root width of an upper anterior tooth. He claimed that for every {{convert|1|cm|in|sp=us}} of root width, there are approximately {{convert|1.4|m|ft|sp=us}} of shark length. Jeremiah pointed out that the jaw perimeter of a shark is directly proportional to its total length, with the width of the roots of the largest teeth being a tool for estimating jaw perimeter. The largest tooth in Jeremiah's possession had a root width of about {{convert|12|cm|in|sp=us}}, which yielded {{convert|16.5|m|ft|sp=us}} in total length.<ref name="H" />{{rp|88}}

In 2002, paleontologist Kenshu Shimada of DePaul University proposed a linear relationship between tooth crown height and total length after conducting anatomical analysis of several specimens, allowing any sized tooth to be used. Shimada stated that the previously proposed methods were based on a less-reliable evaluation of the dental [[Biology:Homology|homology]] between megalodon and the great white shark, and that the growth rate between the crown and root is not [[Isometry|isometric]], which he considered in his model. Using this model, the upper anterior tooth possessed by Gottfried and colleagues corresponded to a total length of {{convert|15|m|ft|sp=us}}.<ref name="Shimada">{{Cite journal|last=Shimada|first=Kenshu|title=The relationship between the tooth size and total body length in the white shark, ''Carcharodon carcharias'' (Lamniformes: Lamnidae) |journal=Journal of Fossil Research |volume=35 |issue=2 |pages=28–33 |year= 2002}}</ref> Among several specimens found in the Gatún Formation of Panama, one upper lateral tooth was used by other researchers to obtain a total length estimate of {{convert|17.9|m|ft|sp=us}} using this method.<ref name="AN" /><ref name="SAR">{{cite journal|last=Pimiento|first=Catalina|author2=Gerardo González-Barba|author3=Dana J. Ehret|author4=Austin J. W. Hendy|author5=Bruce J. MacFadden|author6=Carlos Jaramillo|title=Sharks and Rays (Chondrichthyes, Elasmobranchii) from the Late Miocene Gatun Formation of Panama|journal=Journal of Paleontology|year=2013|doi=10.1666/12-117|volume=87|issue=5|pages=755–774|bibcode=2013JPal...87..755P |s2cid=45662900|url=http://stri.si.edu/sites/publications/PDFs/STRI-W_Pimiento_et_al_2013_Sharks_and_Rays_from_Gatun.pdf|url-status=dead|archive-url=https://web.archive.org/web/20131029205612/http://stri.si.edu/sites/publications/PDFs/STRI-W_Pimiento_et_al_2013_Sharks_and_Rays_from_Gatun.pdf|archive-date=29 October 2013}}</ref>

In 2019, Shimada revisited the size of megalodon and discouraged using non-anterior teeth for estimations, noting that the exact position of isolated non-anterior teeth is difficult to identify. Shimada provided maximum total length estimates using the largest anterior teeth available in museums. The tooth with the tallest crown height known to Shimada, NSM PV-19896, produced a total length estimate of {{convert|14.2|m|ft|sp=us}}. The tooth with the tallest total height, FMNH PF 11306, was reported at {{convert|16.8|cm|in|sp=us}}. However, Shimada remeasured the tooth and found it actually to measure {{convert|16.2|cm|in|sp=us}}. Using the total height tooth regression equation proposed by Gottfried and colleagues produced an estimate of {{convert|15.3|m|ft|sp=us}}.<ref name="Shimada2019"/><ref name="Perezetal2021"/>

In 2021, Victor J. Perez, Ronny M. Leder, and Teddy Badaut proposed a method of estimating total length of megalodon from the sum of the tooth crown widths. Using more complete megalodon dentitions, they reconstructed the dental formula and then made comparisons to living sharks. The researchers noted that the 2002 Shimada crown height equations produce wildly varying results for different teeth belonging to the same shark (range of error of ± {{convert|9|m|ft}}), casting doubt on some of the conclusions of previous studies using that method. Using the largest tooth available to the authors, GHC 6, with a crown width of {{convert|13.3|cm|in|sp=us}}, they estimated a maximum body length of approximately {{convert|20|m|ft|sp=us}}, with a range of error of approximately ± {{convert|3.5|m|ft}}.<ref name="Perezetal2021"/> This maximum length estimate was also supported by Cooper and his colleagues in 2022.<ref name=Cooperetal2022/>

There are anecdotal reports of teeth larger than those found in museum collections.<ref name="Shimada2019"/> Gordon Hubbell from Gainesville, Florida, possesses an upper anterior megalodon tooth whose maximum height is {{convert|7.25|in|cm|sp=us|order=flip}}, one of the largest known tooth specimens from the shark.<ref>{{cite magazine|last=Crane|first=B.|year=2017|title=A Prehistoric Killer, Buried in Muck|url=https://www.newyorker.com/tech/elements/a-prehistoric-killer-buried-in-muck|access-date=10 December 2017|magazine=The New Yorker}}</ref> In addition, a {{convert|9|by|11|ft|m|order=flip|adj=on|sp=us|sigfig=2}} megalodon jaw reconstruction developed by fossil hunter Vito Bertucci contains a tooth whose maximum height is reportedly over {{convert|18|cm|in|sp=us|sigfig=1}}.<ref>{{cite web|last=Mustain|first=A.|year=2011|title=For Sale: World's Largest Shark Jaws|url=https://www.livescience.com/14255-shark-jaws-worlds-largest-auction.html|access-date=31 August 2017|publisher=LiveScience}}</ref>

=== Teeth and bite force ===
[[File:Megalodon teeth.jpg|thumb|left|Reconstruction showing the position of the [[Biology:Shark tooth|replacement teeth]]|alt=A sideview of the inside of a megalodon jaw reconstruction showing five rows of teeth. Each row is more horizontal than the last, with the last row essentially resting on the jaw.]]
The most common fossils of megalodon are its teeth. Diagnostic characteristics include a triangular shape, robust structure, large size, fine serrations, a lack of lateral denticles, and a visible V-shaped neck (where the [[Medicine:Root canal|root]] meets the [[Medicine:Crown (tooth)|crown]]).<ref name="G" />{{rp|55}}<ref name="AN" /> The tooth met the jaw at a steep angle, similar to the great white shark. The tooth was anchored by [[Biology:Collagen|connective tissue fibers]], and the roughness of the base may have added to mechanical strength.<ref name="Den" /> The lingual side of the tooth, the part facing the tongue, was convex; and the labial side, the other side of the tooth, was slightly convex or flat. The anterior teeth were almost perpendicular to the jaw and symmetrical, whereas the posterior teeth were slanted and asymmetrical.<ref>{{cite journal|first1=M.|last1=Reolid|first2=J. M.|last2=Molina|year=2015|title=Record of ''Carcharocles megalodon'' in the Eastern Guadalquivir Basin (Upper Miocene, South Spain)|journal=Estudios Geológicos|volume=71|issue=2|doi=10.3989/egeol.41828.342|page=e032|doi-access=free}}</ref>

Megalodon teeth can measure over {{convert|180|mm|in|sp=us|sigfig=2}} in slant height (diagonal length) and are the largest of any known shark species,<ref name="H">{{Cite book|last=Renz|first=Mark|title=Megalodon: Hunting the Hunter|publisher= PaleoPress|year= 2002|pages=1–159|url = {{google books|plainurl=yes|id=cMRe5GmDXmUC}}|location=Lehigh Acres, Florida|isbn=978-0-9719477-0-2|oclc=52125833}}</ref>{{rp|33}} implying it was the largest of all macropredatory sharks.<ref name="Gottfried1996"/> In 1989, a nearly complete set of megalodon teeth was discovered in Saitama, Japan. Another nearly complete associated megalodon dentition was excavated from the Yorktown Formations in the United States, and served as the basis of a jaw reconstruction of megalodon at the National Museum of Natural History (USNM). Based on these discoveries, an artificial dental formula was put together for megalodon in 1996.<ref name="G" />{{rp|55}}<ref>{{cite journal|last1=Uyeno|first1=T.|last2=Sakamoto|first2=O.|last3=Sekine|first3=H.|year=1989|title=The Description of an Almost Complete Tooth Set of ''Carcharodon megalodon'' from a Middle Miocene Bed in the Saitama Prefecture, Japan|journal=Saitama Museum of Natural History Bulletin|volume=7|pages=73–85}}</ref>

The dental formula of megalodon is: {{DentalFormula|upper=2.1.7.4|lower=3.0.8.4}}. As evident from the formula, megalodon had four kinds of teeth in its jaws: anterior, intermediate, lateral, and posterior. Megalodon's intermediate tooth technically appears to be an upper anterior and is termed as "A3" because it is fairly symmetrical and does not point mesially (side of the tooth toward the midline of the jaws where the left and right jaws meet). Megalodon had a very robust dentition,<ref name="G" />{{rp|20–21}} and had over 250 teeth in its jaws, spanning 5 rows.<ref name="H" />{{rp|iv}} It is possible that large megalodon individuals had jaws spanning roughly {{convert|2|m|ft|sp=us|sigfig=2}} across.<ref name="H" />{{rp|129}} The teeth were also serrated, which would have improved efficiency in cutting through flesh or bone.<ref name="A" /><ref name="H" />{{rp|1}} The shark may have been able to open its mouth to a 75° angle, though a reconstruction at the USNM approximates a 100° angle.<ref name="Gottfried1996"/>
[[File:Megalodon jaws on display at the National Baltimore Aquarium.jpg|thumb|right|Reconstructed jaws on display at the National Aquarium in Baltimore|alt=A dark-yellow megalodon jaw reconstruction with two rows of white teeth stained black on the top.]]

In 2008, a team of scientists led by S. Wroe conducted an experiment to determine the bite force of the great white shark, using a {{convert|2.5|m|ft|sp=us|adj=on|sigfig=2}} long specimen, and then isometrically scaled the results for its maximum size and the conservative minimum and maximum body mass of megalodon. They placed the bite force of the latter between {{convert|108,514|to|182,201|N|lbf}} in a posterior bite, compared to the {{convert|18,216|N|lbf}} bite force for the largest confirmed great white shark, and {{convert|7,495|N|lbf}} for the [[Biology:Placodermi|placoderm]] fish ''[[Biology:Dunkleosteus|Dunkleosteus]]''. In addition, Wroe and colleagues pointed out that sharks shake sideways while feeding, amplifying the force generated, which would probably have caused the total force experienced by prey to be higher than the estimate.<ref name="Wroeetal2008"/><ref name=Anderson&Westneat2009>{{cite journal|last=Anderson|first=P.S.L.|author2=Westneat, M.|title=A biomechanical model of feeding kinematics for ''Dunkleosteus terrelli'' (Arthrodira, Placodermi)|journal=Paleobiology|date=2009|volume=35|issue=2|pages=251–269|doi=10.1666/08011.1|bibcode=2009Pbio...35..251A |s2cid=86203770}}</ref>

In 2021, Antonio Ballell and Humberto Ferrón used [[Finite element method|Finite Element Analysis]] modeling to examine the stress distribution of three types of megalodon teeth and closely related mega-toothed species when exposed to anterior and lateral forces, the latter of which would be generated when a shark shakes its head to tear through flesh. The resulting simulations identified higher levels of stress in megalodon teeth under lateral force loads compared to its precursor species such as ''O. obliquus'' and ''O. angusteidens'' when tooth size was removed as a factor. This suggests that megalodon teeth were of a different functional significance than previously expected, challenging prior interpretations that megalodon's dental morphology was primarily driven by a dietary shift towards marine mammals. Instead, the authors proposed that it was a byproduct of an increase in body size caused by [[Biology:Heterochrony|heterochronic selection]].<ref name=BallellandFerron>{{cite journal|author1=Ballell, A.|author2=Ferrón, H.G.|year=2021|title=Biomechanical insights into the dentition of megatooth sharks (Lamniformes: Otodontidae)|journal=Scientific Reports|volume=11|issue=1232|page=1232|doi=10.1038/s41598-020-80323-z|pmid=33441828|pmc=7806677|doi-access=free}}</ref>

=== Internal anatomy ===
[[File:Otodus megalodon skeleatal.png|thumb| Restoration of the skeleton of ''O. megalodon'' based on modern lamniforms, with known elements highlighted]]
Megalodon is represented in the fossil record by teeth, [[Biology:Vertebral column|vertebral centra]], and coprolites.<ref name="Gottfried1996"/><ref name="Stringer%King"/> As with all sharks, the [[Biology:Skeleton|skeleton]] of megalodon was formed of [[Biology:Cartilage|cartilage]] rather than [[Biology:Bone|bone]]; consequently most fossil specimens are poorly preserved.<ref>{{cite web|url=http://www.fossilguy.com/gallery/vert/fish-shark/carcharocles/carcharocles.htm|title=Megalodon Shark Facts and Information: The Details| publisher=fossilguy.com|access-date=18 September 2017}}</ref> To support its large dentition, the jaws of megalodon would have been more massive, stouter, and more strongly developed than those of the great white, which possesses a comparatively gracile dentition. Its [[Biology:Chondrocranium|chondrocranium]], the cartilaginous skull, would have had a blockier and more robust appearance than that of the great white. Its fins were proportional to its larger size.<ref name="Gottfried1996"/>

Some fossil [[Biology:Vertebra|vertebra]]e have been found. The most notable example is a partially preserved vertebral column of a single specimen, excavated in the Antwerp Basin, Belgium, in 1926. It comprises 150 vertebral centra, with the centra ranging from {{convert|55|mm|in|sp=us}} to {{convert|155|mm|in|sp=us|sigfig=1}} in diameter. The shark's vertebrae may have gotten much bigger, and scrutiny of the specimen revealed that it had a higher vertebral count than specimens of any known shark, possibly over 200 centra; only the great white approached it.<ref name="Gottfried1996"/> Another partially preserved vertebral column of a megalodon was excavated from the Gram Formation in Denmark in 1983, which comprises 20 vertebral centra, with the centra ranging from {{convert|100|mm|in|sp=us|sigfig=1}} to {{convert|230|mm|in|sp=us|sigfig=1}} in diameter.<ref name="Den">{{cite journal |last1=Almgreen |first1=S. E. Bendix |title=''Carcharodon megalodon'' from the Upper Miocene of Denmark, with comments on elasmobranch tooth enameloid: coronoïn |journal=Bulletin of the Geological Society of Denmark |date=15 November 1983 |volume=32 |pages=1–32 |id={{NAID|10012345550}} |citeseerx=10.1.1.514.1782 |doi=10.37570/bgsd-1983-32-01 |doi-access=free |s2cid=53311833 }}</ref>
[[File:Giant white shark coprolite (Miocene; coastal waters of South Carolina, USA).jpg|thumb|Coprolite attributed to megalodon|alt=Smmothly rounded dark brown rock-like coprolite]]
The coprolite remains of megalodon are spiral-shaped, indicating that the shark may have had a [[Biology:Spiral valve|spiral valve]], a corkscrew-shaped portion of the lower intestines, similar to extant lamniform sharks. Miocene coprolite remains were discovered in Beaufort County, South Carolina, with one measuring {{convert|14|cm|in|abbr=on}}.<ref name="Stringer%King">{{cite journal|url={{google books|plainurl=yes|id=C_MoCgAAQBAJ|page=301}}|first1=G. L.|last1=Stringer|first2=L.|last2=King|year=2012|title=Late Eocene Shark Coprolites from the Yazoo Clay in Northeastern Louisiana|journal=New Mexico Museum of Natural History and Science, Bulletin |volume=57|series=Vertebrate Corpolites|page=301}}</ref>

Gottfried and colleagues reconstructed the entire skeleton of megalodon, which was later put on display at the Calvert Marine Museum in the United States and the [[Organization:Iziko South African Museum|Iziko South African Museum]].<ref name="Gottfried1996"/><ref name="C">{{cite web|last=Andres|first=Lutz|title=''C. megalodon'' — Megatooth Shark, ''Carcharodon'' versus ''Carcharocles''|url=http://www.fossilguy.com/topics/megshark/megshark.htm|year=2002|publisher=fossilguy.com|access-date=16 January 2008}}</ref> This reconstruction is {{convert|11.3|m|ft|sp=us}} long and represents a mature male,<ref name="Gottfried1996"/>{{rp|61}} based on the ontogenetic changes a great white shark experiences over the course of its life.<ref name="Gottfried1996"/>{{rp|65}}

== Paleobiology ==

=== Range and habitat ===
Megalodon had a [[Biology:Cosmopolitan distribution|cosmopolitan distribution]];<ref name="Pimiento2016" /><ref name="SAR" /> its fossils have been excavated from many parts of the world, including Europe, Africa, the Americas, and Australia.<ref name="G" />{{rp|67}}<ref>{{Cite journal|last=Fitzgerald|first=Erich|title=A review of the Tertiary fossil Cetacea (Mammalia) localities in Australia|journal=Memoirs of Museum Victoria|volume=61|issue=2|pages=183–208|year=2004|doi=10.24199/j.mmv.2004.61.12|doi-access=free}}</ref> It most commonly occurred in [[Earth:Subtropics|subtropical]] to temperate latitudes.<ref name="Pimiento2016" /><ref name="G" />{{rp|78}} It has been found at latitudes up to 55° N; its inferred tolerated temperature range was {{convert|1|–|24|C|F}}.{{refn |Carbonated bio[[Chemistry:Apatite|apatite]] from a megalodon tooth (of unknown source location) dated to 5.75 ± 0.9 Ma in age has been analyzed for isotope ratios of oxygen (<sup>18</sup>O/<sup>16</sup>O) and carbon (<sup>13</sup>C/<sup>12</sup>C), using a [[Physics:Clumped isotopes|carbonate clumped-isotope thermometer]] methodology to yield an estimate of the ambient temperature in that individual's environment of 19 ± 4 °C.<ref name="Löffler2019">{{cite journal|last1= Löffler|first1= N.|last2= Fiebig|first2= J.|last3= Mulch|first3= A.|last4= Tütken|first4= T.|last5= Schmidt|first5= B.C.|last6= Bajnai|first6= D.|last7= Conrad|first7= A.C.|last8= Wacker|first8= U.|last9= Böttcher|first9= M.E.|title= Refining the temperature dependence of the oxygen and clumped isotopic compositions of structurally bound carbonate in apatite|journal= Geochimica et Cosmochimica Acta|volume= 253|year= 2019|pages= 19–38|doi= 10.1016/j.gca.2019.03.002|bibcode= 2019GeCoA.253...19L|s2cid= 107992832}}</ref> | group = note}} It arguably had the capacity to endure such low temperatures due to mesothermy, the physiological capability of large sharks to maintain a higher body temperature than the surrounding water by conserving [[Basal metabolic rate|metabolic heat]].<ref name="Pimiento2016" />

Megalodon inhabited a wide range of marine environments (i.e., shallow coastal waters, areas of coastal [[Earth:Upwelling|upwelling]], swampy coastal [[Earth:Lagoon|lagoon]]s, sandy littorals, and offshore deep water environments), and exhibited a transient lifestyle. Adult megalodon were not abundant in shallow water environments, and mostly inhabited offshore areas. Megalodon may have moved between coastal and oceanic waters, particularly in different stages of its life cycle.<ref name="H" />{{rp|33}}<ref name="GTWT" />

Fossil remains show a trend for specimens to be larger on average in the Southern Hemisphere than in the Northern, with mean lengths of {{convert|11.6|and|9.6|m|ft|sp=us}}, respectively; and also larger in the Pacific than the Atlantic, with mean lengths of {{convert|10.9|and|9.5|m|ft|sp=us}} respectively. They do not suggest any trend of changing body size with absolute latitude, or of change in size over time (although the ''Carcharocles'' lineage in general is thought to display a trend of increasing size over time). The overall [[Mode (statistics)|modal]] length has been estimated at {{convert|10.5|m|ft|sp=us}}, with the length distribution skewed towards larger individuals, suggesting an ecological or competitive advantage for larger body size.<ref name="Pimiento&Balk2015"/>

==== Locations of fossils ====
Megalodon had a global distribution and fossils of the shark have been found in many places around the world, bordering all oceans of the [[Earth:Neogene|Neogene]].<ref name=fossilworks>{{fossilworks|id=202672|title=''Carcharocles megalodon''|date=28 August 2017}}</ref>
{| class="wikitable sortable mw-collapsible mw-collapsed"
!scope="col"|Epoch
!scope="col"|Formation
!scope="col"|State
!scope="col"|Continent
|-
| rowspan=25 style="background-color: {{period color|pliocene}};" | Pliocene
| Luanda Formation || {{ANG}} || Africa
|-
| || {{flag|Libya}} || Africa
|-
| || {{RSA}} || Africa
|-
| Castell'Arquato Formation || {{ITA}} || Europe
|-
| Arenas de Huelva Formation || {{ESP}} || Europe
|-
| Esbarrondadoiro Formation || {{POR}} || Europe
|-
| Touril Complex Formation || {{POR}} || Europe
|-
| [[Earth:Red Crag Formation|Red Crag Formation]] || {{UK}} || Europe
|-
| San Mateo Formation || {{USA}} || North America
|-
| Towsley Formation || {{USA}} || North America
|-
| Bone Valley Formation || {{USA}} || North America
|-
| [[Earth:Tamiami Formation|Tamiami Formation]] || {{USA}} || North America
|-
| Yorktown Formation || {{USA}} || North America
|-
| [[Earth:Highlands Formation|Highlands Formation]] || {{flag|Antigua and Barbuda}} || North America
|-
| Refugio Formation || {{MEX}} || North America
|-
| [[Earth:San Diego Formation|San Diego Formation]] || {{MEX}} || North America
|-
| [[Earth:Tirabuzon Formation|Tirabuzon Formation]] || {{MEX}} || North America
|-
| [[Earth:Onzole Formation|Onzole Formation]] || {{ECU}} || South America
|-
| Paraguaná Formation || {{VEN}} || South America
|-
| Black Rock Sandstone || {{AUS}} || [[Earth:Oceania|Oceania]]
|-
| Cameron Inlet Formation || {{AUS}} || [[Earth:Oceania|Oceania]]
|-
| Grange Burn Formation || {{AUS}} || [[Earth:Oceania|Oceania]]
|-
| Loxton Sand Formation || {{AUS}} || [[Earth:Oceania|Oceania]]
|-
| Whaler's Bluff Formation || {{AUS}} || [[Earth:Oceania|Oceania]]
|-
| [[Earth:Tangahoe Formation|Tangahoe Formation]] || {{NZL}} || [[Earth:Oceania|Oceania]]
|-
| rowspan=87 style="background-color: #CEE0F2;" | Miocene
|-
| || {{flag|Egypt}} || Africa
|-
| Madagascar Basin || {{flag|Madagascar}} || Africa
|-
| || {{flag|Nigeria}} || Africa
|-
| Varswater Formation || {{RSA}} || Africa
|-
| Baripada Limestone || {{flag|India}} || Asia
|-
| Arakida Formation || {{flag|Japan}} || Asia
|-
| Bihoku Group || {{flag|Japan}} || Asia
|-
| Fujina Formation || {{flag|Japan}} || Asia
|-
| Hannoura Formation || {{flag|Japan}} || Asia
|-
| Hongo Formation || {{flag|Japan}} || Asia
|-
| Horimatsu Formation || {{flag|Japan}} || Asia
|-
| Ichishi Formation || {{flag|Japan}} || Asia
|-
| Kurahara Formation || {{flag|Japan}} || Asia
|-
| Maenami Formation || {{flag|Japan}} || Asia
|-
| Matsuyama Group || {{flag|Japan}} || Asia
|-
| Sekinobana Formation || {{flag|Japan}} || Asia
|-
| Suso Formation || {{flag|Japan}} || Asia
|-
| Takakubo Formation || {{flag|Japan}} || Asia
|-
| Tonokita Formation || {{flag|Japan}} || Asia
|-
| Tsurushi Formation || {{flag|Japan}} || Asia
|-
| Wajimazaki Formation || {{flag|Japan}} || Asia
|-
| Yoshii Formation || {{flag|Japan}} || Asia
|-
| || {{flag|Myanmar}} || Asia
|-
| Burgeschleinitz Formation || {{flag|Austria}} || Europe
|-
| Melker Sand Formation || {{flag|Austria}} || Europe
|-
| Rzehakia Formation || {{flag|Austria}} || Europe
|-
| [[Earth:Weissenegg Formation|Weissenegg Formation]] || {{flag|Austria}} || Europe
|-
| Antwerpen Sands Member || {{flag|Belgium}} || Europe
|-
| || {{flag|Cyprus}} || Europe
|-
| Hrušky Formation || {{flag|Czech Republic}} || Europe
|-
| [[Earth:Gram Formation|Gram Formation]] || {{flag|Denmark}} || Europe
|-
| Aquitaine Basin || {{flag|France}} || Europe
|-
| || {{flag|Germany}} || Europe
|-
| Libano Sandstone || {{flag|Italy}} || Europe
|-
| Blue Clay Formation || {{flag|Malta}} || Europe
|-
| Globigerina Limestone<ref>{{cite news |title=Young Prince George gifted 23m-year-old tooth from extinct shark found in Malta |url=https://timesofmalta.com/articles/view/young-prince-george-gifted-23m-year-old-tooth-from-extinct-shark-found.820588 |access-date=28 September 2020 |work=Times of Malta |date=27 September 2020}}</ref> || {{flag|Malta}} || Europe
|-
| Aalten Member || {{flag|Netherlands}} || Europe
|-
| [[Earth:Breda Formation|Breda Formation]] || {{flag|Netherlands}} || Europe
|-
| Korytnica Clays || {{flag|Poland}} || Europe
|-
| [[Earth:Leitha Limestone|Leitha Limestone]] || {{flag|Poland}} || Europe
|-
| Esbarrondadoiro Formation || {{flag|Portugal}} || Europe
|-
| Filakovo Formation || {{flag|Slovakia}} || Europe
|-
| Arjona Formation || {{flag|Spain}} || Europe
|-
| Calcarenites of Sant Elm || {{flag|Spain}} || Europe
|-
| || {{flag|Turkey}} || Europe
|-
| [[Earth:Monterey Formation|Monterey Formation]] || {{USA}} || North America
|-
| Puente Formation || {{USA}} || North America
|-
| [[Earth:Purisima Formation|Purisima Formation]] || {{USA}} || North America
|-
| San Mateo Formation || {{USA}} || North America
|-
| [[Earth:Santa Margarita Formation|Santa Margarita Formation]] || {{USA}} || North America
|-
| [[Earth:Temblor Formation|Temblor Formation]] || {{USA}} || North America
|-
| Topanga Formation || {{USA}} || North America
|-
| Bone Valley Formation || {{USA}} || North America
|-
| Calvert Formation || {{USA}} || North America
|-
| Kirkwood Formation || {{USA}} || North America
|-
| || {{flag|Barbados}} || North America
|-
| Cojímar Formation || {{flag|Cuba}} || North America
|-
| Kendance Formation || {{flag|Grenada}} || North America
|-
| || {{flag|Jamaica}} || North America
|-
| [[Earth:Aymamón Limestone|Aymamón Limestone]] || {{flag|Puerto Rico}} || North America
|-
| [[Earth:Almejas Formation|Almejas Formation]] || {{flag|Mexico}} || North America
|-
| [[Earth:Carrillo Puerto Formation|Carrillo Puerto Formation]] || {{flag|Mexico}} || North America
|-
| [[Earth:Chagres Formation|Chagres Formation]] || {{flag|Panama}} || North America
|-
| Chucunaque Formation || {{flag|Panama}} || North America
|-
| [[Earth:Gatún Formation|Gatún Formation]] || {{flag|Panama}} || North America
|-
| Paraná Formation || {{flag|Argentina}} || South America
|-
| [[Earth:Bahía Inglesa Formation|Bahía Inglesa Formation]] || {{flag|Chile}} || South America
|-
| [[Earth:Coquimbo Formation|Coquimbo Formation]] || {{flag|Chile}} || South America
|-
| [[Earth:Castilletes Formation|Castilletes Formation]] || {{flag|Colombia}} || South America
|-
| Miramar Formation || {{flag|Peru}} || South America
|-
| [[Earth:Pisco Formation|Pisco Formation]] || {{flag|Peru}} || South America
|-
| Camacho Formation || {{flag|Uruguay}} || South America
|-
| Cantaure Formation || {{flag|Venezuela}} || South America
|-
| Caujarao Formation || {{flag|Venezuela}} || South America
|-
| Socorro Formation || {{flag|Venezuela}} || South America
|-
| [[Earth:Urumaco Formation|Urumaco Formation]] || {{flag|Venezuela}} || South America
|-
| Batesford Limestone || {{flag|Australia}} || [[Earth:Oceania|Oceania]]
|-
| Black Rock Sandstone || {{flag|Australia}} || [[Earth:Oceania|Oceania]]
|-
| Gippsland Limestone || {{flag|Australia}} || [[Earth:Oceania|Oceania]]
|-
| Mannum Formation || {{flag|Australia}} || [[Earth:Oceania|Oceania]]
|-
| Morgan Limestone || {{flag|Australia}} || [[Earth:Oceania|Oceania]]
|-
| Port Campbell Limestone || {{flag|Australia}} || [[Earth:Oceania|Oceania]]
|-
| || {{flag|Fiji}} || [[Earth:Oceania|Oceania]]
|-
| || {{flag|French Polynesia}} || [[Earth:Oceania|Oceania]]
|-
| Duho Formation<ref>{{cite journal|last1=Yun|first1=C.|year=2020|title=New example of ''Cosmopolitodus hastalis'' (Lamniformes, Lamnidae) from the Miocene South Korea|journal=Zoodiversity|volume=54|issue=5|pages=433–438|doi=10.15407/zoo2020.05.433|s2cid=229274996 |doi-access=free}}</ref> || {{flag|South Korea}} || Asia
|-
| Seogwipo Formation<ref>{{Cite journal |last1=Choi |first1=Seung |last2=Lee |first2=Yuong-Nam |date=2017 |title=A review of vertebrate body fossils from the Korean Peninsula and perspectives |url=http://link.springer.com/10.1007/s12303-017-0040-6 |journal=Geosciences Journal |language=en |volume=21 |issue=6 |pages=867–889 |doi=10.1007/s12303-017-0040-6 |bibcode=2017GescJ..21..867C |s2cid=133835817 |issn=1226-4806}}</ref> || {{flag|South Korea}} || Asia
|-
|}

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=== Prey relationships ===
[[File:Meg bitten cetacean vertebra.jpg|thumb|[[Biology:Vertebra|Vertebra]] of a whale bitten in half by a megalodon with visible gashes from teeth.|alt=A square piece of fossil bone with some roughly parallel grooves across it.]]
Though sharks are generally opportunistic feeders, megalodon's great size, high-speed swimming capability, and powerful jaws, coupled with an impressive feeding apparatus, made it an [[Biology:Apex predator|apex predator]] capable of consuming a broad spectrum of animals. Otodus megalodon was probably one of the most powerful predators to have existed.<ref name=Cooperetal2022/> A study focusing on [[Physics:Isotopes of calcium|calcium isotopes]] of extinct and extant [[Biology:Elasmobranchii|elasmobranch]] sharks and rays revealed that megalodon fed at a higher [[Earth:Trophic level|trophic level]] than the contemporaneous great white shark ("higher up" in the food chain.)<ref name="Martin2015">{{cite journal|last1= Martin|first1= J. E.|last2= Tacail|first2=T.|last3=Sylvain|first3=A.|last4=Catherine|first4= G.|last5= Vincent|first5= B.|title=Calcium isotopes reveal the trophic position of extant and fossil elasmobranchs|journal=Chemical Geology|year=2015|pages= 118–125 |doi=10.1016/j.chemgeo.2015.09.011|volume=415|bibcode= 2015ChGeo.415..118M}}</ref>

Fossil evidence indicates that megalodon preyed upon many cetacean species, such as dolphins, small whales, [[Biology:Cetotheriidae|cetotheres]], [[Biology:Squalodontidae|squalodontids]] (shark toothed dolphins), sperm whales, [[Biology:Bowhead whale|bowhead whale]]s, and [[Biology:Rorqual|rorqual]]s.<ref name=prothero /><ref name="collareta" /><ref name="WGWS">{{cite journal|last=Morgan|first=Gary S.|title=Whither the giant white shark?|url=https://www.priweb.org/files/pubtext/item_pdf_289.pdf|journal=Paleontology Topics|year=1994|volume=2|issue=3|pages=1–2|url-status=dead|archive-url=https://web.archive.org/web/20160722045756/https://www.priweb.org/files/pubtext/item_pdf_289.pdf|archive-date=22 July 2016}}</ref> In addition to this, they also targeted seals, sirenians, and sea turtles.<ref name="GTWT" /> The shark was an opportunist and piscivorous, and it would have also gone after smaller fish and other sharks.<ref name=prothero>{{cite book|chapter-url={{google books|plainurl=yes|id=QjkjBQAAQBAJ|page=96}}|first=D. R.|last=Prothero|year=2015|title=The Story of Life in 25 Fossils|chapter=Mega-Jaws|publisher=Columbia University Press|location=New York, New York|pages=96–110|isbn=978-0-231-17190-8|oclc=897505111}}</ref> Many whale bones have been found with deep gashes most likely made by their teeth.<ref name="G" />{{rp|75}} Various excavations have revealed megalodon teeth lying close to the chewed remains of whales,<ref name="G" />{{rp|75}}<ref name="C" /> and sometimes in direct association with them.<ref name="GWS">{{cite journal |last1=Augilera |first1=Orangel A. |last2=García |first2=Luis |last3=Cozzuol |first3=Mario A. |year=2008 |title=Giant-toothed white sharks and cetacean trophic interaction from the Pliocene Caribbean Paraguaná Formation |journal=Paläontologische Zeitschrift |volume=82 |issue=2 |pages=204–208 |doi=10.1007/BF02988410 |bibcode=2008PalZ...82..204A |issn=0038-2353 |s2cid=84251638}}</ref>

The feeding ecology of megalodon appears to have varied with age and between sites, like the modern [[Biology:Great white shark|great white shark]]. It is plausible that the adult megalodon population off the coast of Peru targeted primarily [[Biology:Cetotheriidae|cetothere whales]] {{convert|2.5|to|7|m|ft|sp=us|sigfig=2}} in length and other prey smaller than itself, rather than large whales in the same size class as themselves.<ref name="collareta">{{cite journal | first1 = A. | last1 = Collareta | first2 = O. | last2 = Lambert | first3 = W. | last3 = Landini | first4 = C. | last4 = Di Celma | first5 = E. | last5 = Malinverno | first6 = R. | last6 = Varas-Malca | first7 = M. | last7 = Urbina | first8 = G. | last8 = Bianucci | title = Did the giant extinct shark ''Carcharocles megalodon'' target small prey? Bite marks on marine mammal remains from the late Miocene of Peru | journal = Palaeogeography, Palaeoclimatology, Palaeoecology | volume = 469 | pages = 84–91 | doi = 10.1016/j.palaeo.2017.01.001 | year = 2017 | bibcode = 2017PPP...469...84C| hdl = 10281/151854 | hdl-access = free }}</ref> Meanwhile, juveniles likely had a diet that consisted more of fish.<ref name="AN" /><ref name="landini">{{cite journal | first1 = W. | last1 = Landini | first2 = A. | last2 = Altamirano-Sera | first3 = A. | last3 = Collareta | first4 = C. | last4 = Di Celma | first5 = M. | last5 = Urbina | first6 = G. | last6 = Bianucci | title = The late Miocene elasmobranch assemblage from Cerro Colorado (Pisco Formation, Peru) | year = 2017 | volume = 73 | pages = 168–190 | journal = Journal of South American Earth Sciences | doi = 10.1016/j.jsames.2016.12.010 | bibcode = 2017JSAES..73..168L}}</ref>

=== Competition ===
[[File:Physeteroidea - Livyatan melvillei.JPG|thumb|left|Megalodon may have faced [[Biology:Competition|competition]] from macroraptorial sperm whales, such as ''Livyatan'' (above).<ref name=LV />|alt=A skull of an extinct sperm whale, with large smooth conical teeth, and a depression on the top front of the skull. The jaw is open.]]
Megalodon faced a highly [[Biology:Interspecific competition|competitive]] environment.<ref name="LV">{{Cite journal|doi= 10.1038/nature09067|last1=Lambert|first1=O.|last2=Bianucci|first2=G.|last3=Post|first3= P.|last4=de Muizon|first4=C.|last5=Salas-Gismondi|first5=R.|last6=Urbina|first6=M.|last7=Reumer|first7=J.|title=The giant bite of a new raptorial sperm whale from the Miocene epoch of Peru|journal= Nature|volume= 466|issue= 7302|pages=105–108|year=2010|pmid=20596020|bibcode = 2010Natur.466..105L |s2cid=4369352}}</ref> Its position at the top of the food chain<ref name="LHS">{{Cite journal|doi=10.1007/BF00751027|last=Compagno|first=Leonard J. V.|title = Alternative life-history styles of cartilaginous fishes in time and space|journal=Environmental Biology of Fishes|volume=28|issue=1–4|pages=33–75|year=1989|s2cid=22527888}}</ref> probably had a significant impact on the structuring of marine communities.<ref name="LV" /><ref>{{Cite journal|last=Ferretti |first=Francesco |author2=Boris Worm |author3=Gregory L. Britten |author4=Michael R. Heithaus |author5=Heike K. Lotze1 |title=Patterns and ecosystem consequences of shark declines in the ocean |journal=Ecology Letters |volume=13 |issue=8 |pages=1055–1071 |year=2010 |url=http://wormlab.biology.dal.ca/ramweb/papers-total/Ferretti%20et%20al%202010_Ecol_Lett.pdf |doi=10.1111/j.1461-0248.2010.01489.x |access-date=19 February 2011 |pmid=20528897 |bibcode=2010EcolL..13.1055F |url-status=dead |archive-url=https://web.archive.org/web/20110706174653/http://wormlab.biology.dal.ca/ramweb/papers-total/Ferretti%20et%20al%202010_Ecol_Lett.pdf |archive-date=6 July 2011 }}</ref> Fossil evidence indicates a correlation between megalodon and the [[Biology:Evolution of cetaceans|emergence]] and diversification of cetaceans and other marine mammals.<ref name="G" />{{rp|78}}<ref name="LV" /> Juvenile megalodon preferred habitats where small cetaceans were abundant, and adult megalodon preferred habitats where large cetaceans were abundant. Such preferences may have developed shortly after they appeared in the Oligocene.<ref name="G" />{{rp|74–75}}

Megalodon were contemporaneous with whale-eating [[Biology:Toothed whale|toothed whale]]s (particularly [[Biology:Macroraptorial sperm whale|macroraptorial sperm whale]]s and [[Biology:Squalodontidae|squalodontidae]]), which were also probably among the era's apex predators, and provided competition.<ref name="LV" /> Some attained gigantic sizes, such as ''[[Biology:Livyatan|Livyatan]]'', estimated between {{convert|13.5|to|17.5|m|ft|sp=us}}. Fossilized teeth of an undetermined species of such physeteroids from Lee Creek Mine, North Carolina, indicate it had a maximum body length of {{convert|8|to|10|m|abbr=on}} and a maximum lifespan of about 25 years. This is very different from similarly sized modern killer whales that live to 65 years, suggesting that unlike the latter, which are apex predators, these physeteroids were subject to predation from larger species such as megalodon or ''Livyatan''.<ref name="Gilbert2018">{{cite journal|last1=Gilbert|first1=K.N.|last2=Ivany|first2=L.C.|last3=Uhen|first3=M.D.|year=2018|title=Living fast and dying young: life history and ecology of a Neogene sperm whale|journal=Journal of Vertebrate Paleontology|volume=38|issue=2|pages=e1439038|doi=10.1080/02724634.2018.1439038|bibcode=2018JVPal..38E9038G |s2cid=89750852}}</ref> By the Late Miocene, around 11&nbsp;Mya, macroraptorials experienced a significant decline in abundance and diversity. Other species may have filled this niche in the Pliocene,<ref name="LV" /><ref name="OO">{{Cite journal|last1=Heyning|first1=John|last2=Dahlheim|first2=Marilyn|title=Orcinus orca|journal=Mammalian Species|issue=304|pages=1–9|year=1988|url=http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-304-01-0001.pdf|doi=10.2307/3504225|jstor=3504225|s2cid=253914153 |url-status=dead|archive-url=https://web.archive.org/web/20101205083613/http://www.science.smith.edu/departments/Biology/VHAYSSEN/msi/pdf/i0076-3519-304-01-0001.pdf|archive-date=5 December 2010}}</ref> such as the fossil killer whale ''[[Biology:Orcinus citoniensis|Orcinus citoniensis]]'' which may have been a [[Biology:Pack hunter|pack predator]] and targeted prey larger than itself,<ref name="C" /><ref>{{Cite journal|last1=Bianucci|first1=Giovanni|last2=Walter|first2=Landini|title=Killer sperm whale: a new basal physeteroid (Mammalia, Cetacea) from the Late Miocene of Italy|journal=Zoological Journal of the Linnean Society|volume=148|issue=1|pages=103–131|year=2006|doi=10.1111/j.1096-3642.2006.00228.x|doi-access=free}}</ref><ref>{{cite book|first1=D. R.|last1=Lindberg|first2=N. D.|last2=Pyenson|year=2006|chapter=Evolutionary Patterns in Cetacea: Fishing Up Prey Size through Deep Time|title=Whales, Whaling, and Ocean Ecosystems|chapter-url={{google books|plainurl=yes|id=daY_utPoJGAC|page=77}}|publisher=University of California Press|page=77|isbn=978-0-520-24884-7}}</ref><ref>{{cite journal|first=R. W.|last=Boessenecker|year=2013|title=A new marine vertebrate assemblage from the Late Neogene Purisima Formation in Central California, part II: Pinnipeds and Cetaceans|journal=Geodiversitas|volume=35|issue=4|pages=815–940|doi=10.5252/g2013n4a5|s2cid=85940452|url=https://zenodo.org/record/4538200}}</ref> but this inference is disputed,<ref name="Boessenecker2019" /> and it was probably a generalist predator rather than a marine mammal specialist.<ref name = "Bianucci1997">{{cite journal|url=https://www.researchgate.net/publication/244994854|first= G.|last= Bianucci|year= 1997|title= ''Hemisyntrachelus cortesii'' (Cetacea, Delphinidae) from the Pliocene Sediments of Campore Quarry (Salsomaggiori Terme, Italy|journal= Bollettino della Societa Paleontologica Italiana|volume= 36|issue= 1|pages= 75–83)}}</ref>

Megalodon may have subjected contemporaneous white sharks to competitive exclusion, as the fossil records indicate that other shark species avoided regions it inhabited by mainly keeping to the colder waters of the time.<ref name="Antunes2015">{{Cite journal|last1=Antunes|first1=M.T.|last2=Legoinha|first2=P.|last3=Balbing|first3=A.|title=Megalodon, mako shark and planktonic foraminifera from the continental shelf off Portugal and their age|journal=Geologica Acta|volume=13|pages=181–190|year=2015|url=http://dspace.uevora.pt/rdpc/handle/10174/17685}}</ref><ref name="G" />{{rp|77}} In areas where their ranges seemed to have overlapped, such as in Pliocene Baja California, it is possible that megalodon and the great white shark occupied the area at different times of the year while following different migratory prey.<ref name="G" />{{rp|77}}<ref>{{cite web|title=Paleoecology of Megalodon and the White Shark|url=http://www.elasmo-research.org/education/evolution/paleoecology.htm|publisher=Biology of Sharks and Rays|access-date=1 October 2017}}</ref> Megalodon probably also had a tendency for [[Biology:Cannibalism|cannibalism]], much like contemporary sharks.<ref>{{Cite journal|last1=Tanke|first1=Darren|last2=Currie|first2=Philip|title=Head-Biting Behaviour in Theropod Dinosaurs: Paleopathological Evidence|journal=Gaia |issue=15|pages=167–184|year= 1998|url=http://www.arca.museus.ul.pt/ArcaSite/obj/gaia/MNHNL-0000781-MG-DOC-web.PDF}}</ref>

=== Feeding strategies ===
[[File:VMNH megalodon.jpg|thumb|Artistic impression of a megalodon pursuing two ''[[Biology:Eobalaenoptera|Eobalaenoptera]]'' whales|alt=A painting of a megalodon about to eat two small whales. The mouth is open, and two rows of teeth are visible only on the bottom jaw. There are two other sharks in the background.]]
Sharks often employ complex hunting strategies to engage large prey animals. Great white shark hunting strategies may be similar to how megalodon hunted its large prey.<ref name=godfrey2005>{{cite journal|url=http://www.vmnh.net/content/File/Research_and_Collections/Jeffersoniana_Number_16.pdf|first1=S. J.|last1=Godfrey|first2=J.|last2=Altman|year=2005|title=A Miocene Cetacean Vertebra Showing a Partially Healed Compression Factor, the Result of Convulsions or Failed Predation by the Giant White Shark, ''Carcharodon megalodon''|journal=Jeffersoniana|number=16|pages=1–12|access-date=1 October 2017|archive-date=31 January 2014|archive-url=https://web.archive.org/web/20140131163724/http://www.vmnh.net/content/File/Research_and_Collections/Jeffersoniana_Number_16.pdf|url-status=dead}}</ref> Megalodon bite marks on whale fossils suggest that it employed different hunting strategies against large prey than the great white shark.<ref name=prothero />

One particular specimen–the remains of a {{convert|9|m|ft|sp=us|adj=on}} long undescribed Miocene baleen whale–provided the first opportunity to quantitatively analyze its attack behavior. Unlike great whites which target the underbelly of their prey, megalodon probably targeted the heart and lungs, with their thick teeth adapted for biting through tough bone, as indicated by bite marks inflicted to the rib cage and other tough bony areas on whale remains.<ref name=prothero /> Furthermore, attack patterns could differ for prey of different sizes. Fossil remains of some small cetaceans, for example cetotheres, suggest that they were rammed with great force from below before being killed and eaten, based on [[Medicine:Vertebral compression fracture|compression fractures]].<ref name=godfrey2005 />

There is also evidence that a possible separate hunting strategy existed for attacking raptorial sperm whales; a tooth belonging to an undetermined {{convert|4|m|ft|abbr=on}} physeteroid closely resembling those of ''[[Biology:Acrophyseter|Acrophyseter]]'' discovered in the Nutrien Aurora Phosphate Mine in North Carolina suggests that a megalodon or ''O. chubutensis'' may have aimed for the head of the sperm whale in order to inflict a fatal bite, the resulting attack leaving distinctive bite marks on the tooth. While scavenging behavior cannot be ruled out as a possibility, the placement of the bite marks is more consistent with predatory attacks than feeding by scavenging, as the jaw is not a particularly nutritious area to for a shark feed or focus on. The fact that the bite marks were found on the tooth's roots further suggest that the shark broke the whale's jaw during the bite, suggesting the bite was extremely powerful. The fossil is also notable as it stands as the first known instance of an antagonistic interaction between a sperm whale and an otodontid shark recorded in the fossil record.<ref>{{cite journal|url=http://app.pan.pl/archive/published/app66/app008202020.pdf|title=Otodus-bitten sperm whale tooth from the Neogene of the Coastal Eastern United States|author1=Stephen J. Godfrey |author2=John R. Nance |author3=Norman L. Riker |journal=Acta Palaeontologica Polonica|volume=66|pages=599–603|date=2021|issue=3 }}</ref>

During the Pliocene, larger cetaceans appeared.<ref name="Deméré 2005">{{cite journal|last1=Deméré|first1=Thomas A.|last2=Berta| first2=Annalisa|last3=McGowen|first3=Michael R.|year=2005|title=The taxonomic and evolutionary history of fossil and modern balaenopteroid mysticetes| journal=Journal of Mammalian Evolution|volume=12|issue=1/2|pages=99–143|doi=10.1007/s10914-005-6944-3|s2cid=90231}}</ref> Megalodon apparently further refined its hunting strategies to cope with these large whales. Numerous fossilized flipper bones and tail vertebrae of large whales from the Pliocene have been found with megalodon bite marks, which suggests that megalodon would immobilize a large whale before killing and feeding on it.<ref name="Wroeetal2008"/><ref name=prothero />

=== Growth and reproduction ===
[[File:Megalodon teeth.png|thumb|Collection of teeth of juvenile megalodon and ''C. chubutensis'' from a probable nursery area in the Gatún Formation of Panama|alt=Several triangular fossil shark teeth on a white background.]]
In 2010, Ehret estimated that megalodon had a fast growth rate nearly two times that of the extant great white shark. He also estimated that the slowing or cessation of somatic growth in megalodon occurred around 25 years of age, suggesting that this species had an extremely delayed sexual maturity.<ref>{{cite book|author=Ehret D.J.|year=2010|chapter=Chapter 5 – Macroevolution, Age, and Growth of the Megatoothed Sharks (Lamniformes Otodonridae)|title=Paleobiology and taxonomy of extinct lamnid and otodontid sharks (Chondrichthyes, Elasmobranchii, Lamniformes)|pages=100–136|url=https://ufdcimages.uflib.ufl.edu/UF/E0/04/23/97/00001/ehret_d.pdf}}</ref> In 2021, Shimada and colleagues calculated the growth rate of an approximately {{cvt|9.2|m}} individual based on the Belgian vertebrate column specimen that presumably contains annual growth rings on three of its vertebrae. They estimated the individual died at 46 years of age, with a growth rate of {{cvt|16|cm}} per year, and a length of {{cvt|2|m}} at birth. For a {{cvt|15|m}} individual{{snd}}which they considered to have been the maximum size attainable{{snd}}this would equate to a lifespan of 88 to 100 years.<ref>{{Cite journal|title=Ontogenetic growth pattern of the extinct megatooth shark Otodus megalodon{{snd}}implications for its reproductive biology, development, and life expectancy|first1=Kenshu|last1=S.|first2=M. F.|last2=Bonnan|first3=M. A.|last3=Becker|first4=M. L.|last4=Griffiths|year= 2021|journal=Historical Biology|volume=33 |issue=12 |pages=3254–3259|doi=10.1080/08912963.2020.1861608|bibcode=2021HBio...33.3254S |doi-access=free}}</ref> However, Cooper and his colleagues in 2022 estimated the length of this 46 year old individual at nearly {{cvt|16|m|ft}} based on the 3D reconstruction which resulted in the complete vertebral column to be {{cvt|11.1|m|ft}} long; the researchers claimed that this size estimate difference occurred due to the fact that Shimada and his colleagues extrapolated its size only based on the vertebral centra.<ref name=Cooperetal2022/>

Megalodon, like contemporaneous sharks, made use of nursery areas to birth their young in, specifically warm-water coastal environments with large amounts of food and protection from predators.<ref name="AN" /> Nursery sites were identified in the Gatún Formation of Panama, the Calvert Formation of Maryland, Banco de Concepción in the Canary Islands,<ref name="europapress.es">{{cite web|url=http://www.europapress.es/islas-canarias/noticia-identifican-canarias-fosiles-megalodon-tiburon-mas-grande-mayor-depredador-marino-existido-20130902152010.html|publisher=Europa Press Noticias SA|title=Identifican en Canarias fósiles de 'megalodón', el tiburón más grande que ha existido|trans-title=Identifying Canary fossils of 'megalodon', the largest shark that ever lived|language=es|year=2013|access-date=29 August 2017 }}</ref> and the [[Earth:Bone Valley|Bone Valley]] Formation of Florida. Given that all extant [[Biology:Lamniformes|lamniform]] sharks give birth to live young, this is believed to have been true of megalodon also.<ref name="Dulvy1997">{{cite journal|last1= Dulvy|first1=N. K.|last2= Reynolds|first2=J. D.|title= Evolutionary transitions among egg-laying, live-bearing and maternal inputs in sharks and rays|journal= Proceedings of the Royal Society B: Biological Sciences|volume= 264|issue= 1386|year=1997|pages= 1309–1315|doi= 10.1098/rspb.1997.0181|pmc=1688595|bibcode=1997RSPSB.264.1309D}}</ref> Infant megalodons were around {{convert|3.5|m|ft|sp=us|sigfig=2}} at their smallest,<ref name="Gottfried1996"/>{{rp|61}} and the pups were vulnerable to predation by other shark species, such as the great hammerhead shark (''Sphyrna mokarran'') and the [[Biology:Hemipristis serra|snaggletooth shark]] (''Hemipristis serra'').<ref name="AN" /> Their dietary preferences display an [[Biology:Ontogenetic niche shift|ontogenetic shift]]:<ref name="Gottfried1996"/>{{rp|65}} Young megalodon commonly preyed on fish,<ref name="AN">{{Cite journal|last1=Pimiento|first1=Catalina|first2=Dana J.|last2=Ehret|first3=Bruce J.|last3=MacFadden |first4=Gordon|last4=Hubbell |title=Ancient Nursery Area for the Extinct Giant Shark Megalodon from the Miocene of Panama|journal=PLOS ONE|volume=5|issue=5|pages=e10552|year= 2010|pmid=20479893|pmc=2866656|doi=10.1371/journal.pone.0010552|editor1-last=Stepanova|editor1-first=Anna|bibcode = 2010PLoSO...510552P |doi-access=free}}</ref> sea turtles,<ref name="GTWT">{{cite journal|author1=Aguilera O. |author2=Augilera E. R. D. |title=Giant-toothed White Sharks and Wide-toothed Mako (Lamnidae) from the Venezuela Neogene: Their Role in the Caribbean, Shallow-water Fish Assemblage|journal=Caribbean Journal of Science|volume=40|issue=3|pages=362–368|year= 2004|url= https://www.researchgate.net/publication/228741311}}</ref> [[Biology:Dugong|dugong]]s,<ref name="H" />{{rp|129}} and small cetaceans; mature megalodon moved to off-shore areas and consumed large cetaceans.<ref name="G" />{{rp|74–75}}

An exceptional case in the fossil record suggests that juvenile megalodon may have occasionally attacked much larger [[Biology:Balaenoptera|balaenopterid]] whales. Three tooth marks apparently from a {{convert|4|to|7|m|ft|adj=on|sp=us}} long Pliocene shark were found on a rib from an ancestral blue or humpback whale that showed evidence of subsequent healing, which is suspected to have been inflicted by a juvenile megalodon.<ref name="Ecphora">{{cite journal|last=Godfrey |first=Stephen|year=2004|title=The Ecphora|journal=The Newsletter of Calvert Marine Museum Fossil Club|volume=19|number=1|pages=1–13|url=http://calvertmarinemuseum.com/cmmfc/newsletter/CMMFC_Newsletter_2004-04.pdf|url-status=dead |archive-url=https://web.archive.org/web/20101210010152/http://calvertmarinemuseum.com/cmmfc/newsletter/CMMFC_Newsletter_2004-04.pdf |archive-date=10 December 2010}}</ref><ref name="Kallal">{{cite journal|last=Kallal|first=R. J.|author2=Godfrey, S. J. |author3=Ortner, D. J. |title=Bone Reactions on a Pliocene Cetacean Rib Indicate Short-Term Survival of Predation Event|journal=International Journal of Osteoarchaeology|volume=22|issue=3|pages=253–260|date=27 August 2010|doi=10.1002/oa.1199}}</ref>

== Extinction ==
=== Climate change ===
The Earth experienced a number of changes during the time period megalodon existed which affected marine life. A cooling trend starting in the Oligocene 35&nbsp;Mya ultimately led to glaciation at the poles. Geological events changed currents and precipitation; among these were the closure of the [[Earth:Central American Seaway|Central American Seaway]] and changes in the [[Earth:Tethys Ocean|Tethys Ocean]], contributing to the cooling of the oceans. The stalling of the [[Earth:Gulf Stream|Gulf Stream]] prevented nutrient-rich water from reaching major marine ecosystems, which may have negatively affected its food sources. The largest fluctuation of sea levels in the Cenozoic era occurred in the [[Earth:Plio-Pleistocene|Plio-Pleistocene]], between around 5 million to 12 thousand years ago, due to the expansion of glaciers at the poles, which negatively impacted coastal environments, and may have contributed to its extinction along with those of several other marine megafaunal species.<ref name=griffin2017 /> These oceanographic changes, in particular the sea level drops, may have restricted many of the suitable shallow warm-water nursery sites for megalodon, hindering reproduction.<ref name=elasmo /> Nursery areas are pivotal for the survival of many shark species, in part because they protect juveniles from predation.<ref name="NA">{{Cite news|last=Reilly|first=Michael|title=Prehistoric Shark Nursery Spawned Giants|publisher=Discovery News|date=29 September 2009|url=http://news.discovery.com/animals/megalodon-nursery-prehistoric-sharks.html|access-date=23 November 2013| archive-url= https://web.archive.org/web/20120310015215/http://news.discovery.com/animals/megalodon-nursery-prehistoric-sharks.html |archive-date= 10 March 2012}}</ref><ref name="AN" />

As its range did not apparently extend into colder waters, megalodon may not have been able to retain a significant amount of metabolic heat, so its range was restricted to shrinking warmer waters.<ref name=elasmo>{{cite web|url=http://www.elasmo-research.org/education/evolution/megalodon_extinction.htm|title=The Extinction of Megalodon|publisher=Biology of Sharks and Rays|access-date=31 August 2017}}</ref><ref name="WGWS" /><ref name="LNOC" /> Fossil evidence confirms the absence of megalodon in regions around the world where water temperatures had significantly declined during the Pliocene.<ref name="G" />{{rp|77}} However, an analysis of the distribution of megalodon over time suggests that temperature change did not play a direct role in its extinction. Its distribution during the Miocene and Pliocene did not correlate with warming and cooling trends; while abundance and distribution declined during the Pliocene, megalodon did show a capacity to inhabit colder latitudes. It was found in locations with a mean temperature ranging from {{convert|12|to|27|C|F}}, with a total range of {{convert|1|to|33|C|F}}, indicating that the global extent of suitable habitat should not have been greatly affected by the temperature changes that occurred.<ref name="Pimiento2016" /> This is consistent with evidence that it was a [[Biology:Mesotherm|mesotherm]].<ref name="Ferrón2017" />

=== Changing ecosystem ===
[[File:Piscobalaena nana.jpg|thumb|Megalodon may have become coextinct with smaller baleen whale species, such as ''Piscobalaena nana''.<ref name=collareta2017 />|alt=A whale skull behind a glass wall]]
Marine mammals attained their greatest diversity during the Miocene,<ref name="G" />{{rp|71}} such as with baleen whales with over 20 recognized Miocene genera in comparison to only six extant genera.<ref>{{Cite journal|author1=Dooly A.C. |author2=Nicholas C. F. |author3=Luo Z. X. |title=The earliest known member of the rorqual–gray whale clade (Mammalia, Cetacea)|year= 2006|journal=Journal of Vertebrate Paleontology|volume=24|issue=2|pages=453–463|jstor=4524731|doi=10.1671/2401|s2cid=84970052 }}</ref> Such diversity presented an ideal setting to support a super-predator such as megalodon.<ref name="G" />{{rp|75}} By the end of the Miocene, many species of mysticetes had gone extinct;<ref name="LV" /> surviving species may have been faster swimmers and thus more elusive prey.<ref name="H" />{{rp|46}} Furthermore, after the closure of the [[Earth:Central American Seaway|Central American Seaway]], tropical whales decreased in diversity and abundance.<ref name="LNOC">{{Cite journal|last=Allmon|first=Warren D.|author2=Steven D. Emslie |author3=Douglas S. Jones |author4=Gary S. Morgan |title=Late Neogene Oceanographic Change along Florida's West Coast: Evidence and Mechanisms|journal=The Journal of Geology|volume= 104|issue=2|pages= 143–162|year=2006|doi= 10.1086/629811|bibcode=1996JG....104..143A|s2cid=128418299}}</ref> The extinction of megalodon correlates with the decline of many small mysticete lineages, and it is possible that it was quite dependent on them as a food source.<ref name="collareta" /> Additionally, a marine megafauna extinction during the Pliocene was discovered to have eliminated 36% of all large marine species including 55% of marine mammals, 35% of seabirds, 9% of sharks, and 43% of sea turtles. The extinction was selective for [[Biology:Endotherm|endotherm]]s and mesotherms relative to [[Biology:Poikilotherm|poikilotherm]]s, implying causation by a decreased food supply<ref name=griffin2017>{{cite journal|first1=C.|last1=Pimiento|first2=J. N.|last2=Griffin|first3=C. F.|last3=Clements|first4=D.|last4=Silvestro|first5=S.|last5=Varela|first6=M. D.|last6=Uhen|first7=C.|last7=Jaramillo|year=2017|title=The Pleistocene Marine Megafauna Extinction and its Impact on Functional Diversity|journal=Nature Ecology and Evolution|volume=1|issue=8|pages=1100–1106|doi=10.1038/s41559-017-0223-6|pmid=29046566|bibcode=2017NatEE...1.1100P |s2cid=3639394|url=https://cronfa.swan.ac.uk/Record/cronfa34515}}</ref> and thus consistent with megalodon being mesothermic.<ref name="Ferrón2017" /> Megalodon may have been too large to sustain itself on the declining marine food resources.<ref name=elasmo /> The cooling of the oceans during the Pliocene might have restricted the access of megalodon to the polar regions, depriving it of the large whales which had migrated there.<ref name="LNOC" />

Competition from large odontocetes, such as macropredatory sperm whales which appeared in the Miocene, and a member of [[Biology:Orcinus|genus ''Orcinus'']] (i.e., ''[[Biology:Orcinus citoniensis|Orcinus citoniensis]]'') in the Pliocene,<ref name="LV" /><ref name="OO" /> is assumed to have contributed to the decline and extinction of megalodon.<ref name="Pimiento2016" /><ref name="H" />{{rp|46–47}}<ref name=elasmo /><ref name ="McCor">{{Cite journal|last1=McCormack|first1=Jeremy|last2=Griffiths|first2=Michael L.|last3=Kim|first3=Sora L.|last4=Shimada|first4=Kenshu|last5=Karnes|first5=Molly|last6=Maisch|first6=Harry|last7=Pederzani|first7=Sarah|last8=Bourgon |first8=Nicolas|last9=Jaouen|first9=Klervia|last10=Becker|first10=Martin A.|last11=Jöns|first11=Niels|date=31 May 2022|title=Trophic position of Otodus megalodon and great white sharks through time revealed by zinc isotopes|journal=Nature Communications|language=en|volume=13|issue=1|pages=2980|doi=10.1038/s41467-022-30528-9|pmid=35641494|pmc=9156768 |bibcode=2022NatCo..13.2980M |s2cid=249235478|issn=2041-1723}}</ref> But this assumption is disputed:<ref name="Boessenecker2019">{{cite journal|last1=Boessenecker|first1=R. W.|last2=Ehret|first2=D. J.|last3=Long|first3=D. J.|last4= Churchill|first4= M.|last5= Martin|first5= E.|last6= Boessenecker|first6=S. J.|title=The Early Pliocene extinction of the mega-toothed shark ''Otodus megalodon'': a view from the eastern North Pacific|journal= PeerJ|volume= 7|year= 2019|pages= e6088|doi= 10.7717/peerj.6088|pmid=30783558|pmc=6377595 |doi-access=free }}</ref> The Orcininae emerged in Mid-Pliocene with [[Biology:Orcinus citoniensis|''O. citoniensis'']] reported from the
Pliocene of Italy,<ref name="OO" /><ref name="Citron">{{Cite journal|last1=Citron|first1=Sara|last2=Geisler|first2=Jonathan H.|last3=Alberto|first3=Collareta|last4=Giovanni |first4=Bianucci|date=2022|title=Systematics, phylogeny and feeding behavior of the oldest killer whale: a reappraisal of Orcinus citoniensis (Capellini, 1883) from the Pliocene of Tuscany (Italy)|journal=Bollettino della Società Paleontologica Italiana|volume=61|issue=2|pages=167–186|doi=10.4435/BSPI.2022.13}}</ref> and similar forms reported from the Pliocene of England and South Africa,<ref name="OO" /> indicating the capacity of these dolphins to cope with increasingly prevalent cold water temperatures in high latitudes.<ref name="OO" /> These dolphins were assumed to have been macrophagous in some studies,<ref name="Pimiento2016" /> but on closer inspection, these dolphins are not found to be macrophagous and fed on small fishes instead.<ref name="Citron" /> On the other hand, gigantic macropredatory sperm whales such as ''[[Biology:Livyatan|Livyatan]]''-like forms are last reported from Australia and South Africa circa 5 million years ago.<ref name=beaumaris>{{Cite web|url=http://www.australasianscience.com.au/article/issue-april-2016/huge-tooth-reveals-prehistoric-moby-dick-melbourne.html|title=Huge Tooth Reveals Prehistoric Moby Dick in Melbourne|publisher=Australasian Science Magazine|access-date=24 April 2016}}</ref><ref name="SMH">{{cite web|date=21 April 2016|publisher=The Sydney Morning Herald|title=Move over Moby Dick: Meet Melbourne's own mega whale|url=https://www.smh.com.au/technology/move-over-moby-dick-meet-melbournes-own-mega-whale-20160421-gobhl6.html}}</ref><ref name="Gov">{{Cite journal|last=Govender|first=R|title=Early Pliocene fossil cetaceans from Hondeklip Bay, Namaqualand, South Africa|journal=Historical Biology|year=2021|volume=33|issue=4|pages=574–593|doi=10.1080/08912963.2019.1650273|bibcode=2021HBio...33..574G|s2cid=202019648}}</ref> Others, such as ''[[Biology:Hoplocetus|Hoplocetus]]'' and ''[[Biology:Scaldicetus|Scaldicetus]]'' also occupied a niche similar to that of modern killer whales but the last of these forms disappeared during the Pliocene.<ref name="Hampe2006">{{cite journal|last1= Hampe|first1= O.|title= Middle/late Miocene hoplocetine sperm whale remains (Odontoceti: Physeteridae) of North Germany with an emended classification of the Hoplocetinae|journal= Fossil Record|volume= 9|issue= 1|year= 2006|pages= 61–86|doi= 10.1002/mmng.200600002|bibcode= 2006FossR...9...61H|doi-access= free}}</ref><ref name="Citron" /> Members of [[Biology:Orcinus|genus ''Orcinus'']] became large and macrophagous in the [[Earth:Pleistocene|Pleistocene]].<ref name="Citron" />

Paleontologist Robert Boessenecker and his colleagues rechecked the fossil record of megalodon for carbon dating errors and concluded that it disappeared circa 3.5 million years ago.<ref name="Boessenecker2019" /> Boessenecker and his colleagues further suggest that megalodon suffered range fragmentation due to climatic shifts,<ref name="Boessenecker2019" /> and competition with white sharks might have contributed to its decline and extinction.<ref name="Boessenecker2019" /> Competition with white sharks is assumed to be a factor in other studies as well,<ref name="Portugal">{{Cite journal|last1=Antunes|first1=Miguel Telles|first2=Ausenda Cáceres|last2=Balbino|title=The Great White Shark ''Carcharodon carcharias'' (Linne, 1758) in the Pliocene of Portugal and its Early Distribution in Eastern Atlantic|journal=Revista Española de Paleontología|volume=25|issue=1|pages=1–6|year=2010|url=http://recyt.fecyt.es/index.php/REP/article/viewFile/11488/7741}}</ref><ref name="Pimiento2016" /><ref name ="McCor" /> but this hypothesis warrants further testing.<ref name="Kast2022">{{cite journal|last1=Kast|first1=Emma R.|last2=Griffiths|first2=Michael L.|last3=Kim|first3=Sora. L.|last4=Rao|first4=Zixuan C.|last5=Shimada|first5=Kensu|last6=Becker|first6=Martin A.|last7=Maisch|first7=Harry M.|last8=Eagle|first8=Robert A.|last9=Clarke|first9=Chelesia A.|last10=Neumann|first10=Allison N.|last11=Karnes|first11=Molly E.|last12=Lüdecke|first12=Tina|last13=Leichliter|first13=Jennifer N.|last14=Martínez-García|first14=Alfredo|last15=Akhtar|first15=Alliya A.|last16=Wang|first16=Xingchen T.|last17=Haug|first17=Gerald H.|last18=Sigman|first18=Daniel M.|date=22 June 2022|title=Cenozoic megatooth sharks occupied extremely high trophic positions|journal=Science Advances|volume=8|issue=25|pages=eabl6529 |doi=10.1126/sciadv.abl6529|pmid=35731884 |pmc=9217088 |bibcode=2022SciA....8L6529K }}</ref> Multiple compounding environmental and ecological factors including climate change and thermal limitations, collapse of prey populations and resource competition with white sharks are believed to have contributed to decline and extinction of megalodon.<ref name ="McCor" />

The extinction of megalodon set the stage for further changes in marine communities. The average body size of baleen whales increased significantly after its disappearance, although possibly due to other, climate-related, causes.<ref name="Slater2017">{{cite journal|last1= Slater|first1=G. J.|last2= Goldbogen|first2=J. A.|last3= Pyenson|first3=N. D.|title= Independent evolution of baleen whale gigantism linked to Plio-Pleistocene ocean dynamics|journal= Proceedings of the Royal Society B: Biological Sciences|volume= 284|issue= 1855|year= 2017|page= 20170546|doi= 10.1098/rspb.2017.0546|pmc=5454272|pmid=28539520}}</ref> Conversely the increase in baleen whale size may have contributed to the extinction of megalodon, as they may have preferred to go after smaller whales; bite marks on large whale species may have come from scavenging sharks. Megalodon may have simply become coextinct with smaller whale species, such as ''[[Biology:Piscobalaena|Piscobalaena nana]]''.<ref name=collareta2017>{{cite journal|first1=A.|last1=Collareta|first2=O.|last2=Lambert|first3=W.|last3=Landini|first4=G.|last4=Bianucci|year=2017|title=Did the giant extinct shark ''Carcharocles megalodon'' target small prey? Bite marks on marine mammal remains from the late Miocene of Peru|journal=Palaeogeography, Palaeoclimatology, Palaeoecology|volume=469|pages=84–91|doi=10.1016/j.palaeo.2017.01.001|bibcode=2017PPP...469...84C|hdl=10281/151854 |hdl-access=free}}</ref> The extinction of megalodon had a positive impact on other apex predators of the time, such as the great white shark, in some cases spreading to regions where megalodon became absent.<ref name="Pimiento2016" /><ref name="Portugal" /><ref name="Sylvain2010">{{Cite journal|last=Sylvain|first= Adnet|author2=A. C. Balbino |author3=M. T. Antunes|author4=J. M. Marín-Ferrer|title=New fossil teeth of the White Shark (''Carcharodon carcharias'') from the Early Pliocene of Spain. Implication for its paleoecology in the Mediterranean |journal=Neues Jahrbuch für Geologie und Paläontologie|volume= 256|issue=1|pages= 7–16|year=2010|doi= 10.1127/0077-7749/2009/0029}}</ref>

== In popular culture ==
[[File:HMS challenger William Frederick Mitchell.jpg|thumb|left|{{HMS|Challenger|1858|6}} discovered megalodon teeth which were erroneously [[Physics:Radiometric dating|dated]] to be around 11,000 to 24,000 years old.|alt=Painting of a three-masted ship sailing in the ocean]]

Megalodon has been portrayed in many works of fiction, including films and novels, and continues to be a popular subject for fiction involving sea monsters.<ref name="weinstock">{{cite book|url={{google books|plainurl=yes|id=PHbeCwAAQBAJ|page=107}}|first=J. A.|last=Weinstock|year=2014|title=The Ashgate Encyclopedia of Literary and Cinematic Monsters|publisher=[[Company:Routledge|Routledge]]|pages=107–108|location=Farnham, United Kingdom|isbn=978-1-4094-2562-5|oclc=874390267}}</ref> Reports of supposedly fresh megalodon teeth, such as those found by {{HMS|Challenger|1858|6}} in 1873 which were dated in 1959 by the zoologist Wladimir Tschernezky to be around 11,000 to 24,000 years old, helped popularise claims of recent megalodon survival amongst [[Biology:Cryptozoology|cryptozoologists]].<ref name=":0">{{Cite journal |last=Guimont |first=Edward |date=5 October 2021 |title=The Megalodon: A Monster of the New Mythology |url=https://journal.media-culture.org.au/index.php/mcjournal/article/view/2793 |journal=M/C Journal |language=en |volume=24 |issue=5 |doi=10.5204/mcj.2793 |s2cid=241813307 |issn=1441-2616|doi-access=free }}</ref> These claims have been discredited, and are probably teeth that were well-preserved by a thick mineral-crust precipitate of [[Chemistry:Manganese dioxide|manganese dioxide]], and so had a lower [[Physics:Radioactive decay|decomposition rate]] and retained a white color during [[Biology:Fossil|fossil]]ization. Fossil megalodon teeth can vary in color from off-white to dark browns, greys, and blues, and some fossil teeth may have been redeposited into a younger [[Earth:Stratum|stratum]]. The claims that megalodon could remain elusive in the depths, similar to the [[Biology:Megamouth shark|megamouth shark]] which was discovered in 1976, are unlikely as the shark lived in warm coastal waters and probably could not survive in the cold and nutrient-poor [[Earth:Deep sea community|deep sea environment]].<ref>{{cite journal |last=Roesch |first=B. S. |year=1998 |title=A Critical Evaluation of the Supposed Contemporary Existence of ''Carcharocles megalodon'' |url=http://web.ncf.ca/bz050/megalodon.html |journal=The Cryptozoology Review |volume=3 |issue=2 |pages=14–24 |access-date=11 November 2014 |archive-date=21 October 2013 |archive-url=https://web.archive.org/web/20131021005820/http://web.ncf.ca/bz050/megalodon.html |url-status=dead }}</ref><ref>{{cite web |title=Does Megalodon Still Live? |url=http://www.elasmo-research.org/education/evolution/megalodon_lives.htm |access-date=2 October 2017 |publisher=Biology of Sharks and Rays}}</ref>

Contemporary fiction about megalodon surviving into modern times was pioneered by the 1997 novel ''Meg: A Novel of Deep Terror'' by Steve Alten and its subsequent sequels. Megalodon subsequently began to feature in films, such as the 2003 direct to video ''Shark Attack 3: Megalodon'', and later ''The Meg,'' a 2018 film based on the 1997 book which grossed over $500 million at the box office.<ref name=":0" /><ref>{{cite web |title=The Meg (2018) |url=https://www.boxofficemojo.com/movies/?id=wbeventfilm2018.htm |access-date=22 December 2017 |website=Box Office Mojo}}</ref>

Animal Planet's pseudo-documentary ''[[Unsolved:Mermaids: The Body Found|Mermaids]]'' included an encounter 1.6 mya between a pod of [[Unsolved:Mermaid|mermaid]]s and a megalodon.<ref>{{cite AV media|title=[[Unsolved:Mermaids: The Body Found|Mermaids]]| publisher=Animal Planet|medium=Motion picture|people=Sid Bennett (director)|date=27 May 2012}}</ref> Later, in August 2013, the Discovery Channel opened its annual Shark Week series with another film for television, ''Megalodon: The Monster Shark Lives'',<ref>{{cite web| url=http://www.huffingtonpost.com/2013/08/05/shark-week-megalodon-monster-shark-video_n_3706120.html?ir=Green |title=Shark Week 'Megalodon: The Monster Shark Lives' Tries To Prove Existence Of Prehistoric Shark (VIDEO) |publisher=Huff Post Green |date=5 August 2013 |access-date=11 August 2013}}</ref> a controversial docufiction about the creature that presented alleged evidence in order to suggest that megalodons still lived. This program received criticism for being completely fictional and for inadequately disclosing its fictional nature; for example, all of the supposed scientists depicted were paid actors, and there was no disclosure in the documentary itself that it was fictional. In a poll by Discovery, 73% of the viewers of the documentary thought that megalodon was not extinct. In 2014, Discovery re-aired ''The Monster Shark Lives'', along with a new one-hour program, ''Megalodon: The New Evidence'', and an additional fictionalized program entitled ''Shark of Darkness: Wrath of Submarine'', resulting in further backlash from media sources and the scientific community.<ref name="prothero" /><ref>{{cite book|chapter-url={{google books|plainurl=y|id=9yZ7DQAAQBAJ|page=27}}|first1=B.|last1=Winston|first2=G.|last2=Vanstone|first3=W.|last3= Chi|year=2017|title=The Act of Documenting: Documentary Film in the 21st Century|chapter=A Walk in the Woods|publisher=Bloomsbury Publishing|location=New York, New York|isbn=978-1-5013-0918-2|oclc=961183719}}</ref><ref name="nytimesop">{{cite news|url=http://op-talk.blogs.nytimes.com/2014/08/15/sorry-fans-discovery-has-jumped-the-shark-week|first=J.|last=Flanagin|year=2014|title=Sorry, Fans. Discovery Has Jumped the Shark Week. |newspaper=New York Times|access-date=16 August 2014}}</ref><ref>{{Cite web |last=Shiffman |first=David |date=15 August 2014 |title=Shark Week Is Lying Again About Monster Megalodon Sharks |url=https://slate.com/technology/2014/08/shark-week-megalodon-films-discovery-channel-lies-about-extinct-monster-sharks.html |access-date=31 July 2022 |website=Slate Magazine |language=en}}</ref> Despite the criticism from scientists, ''Megalodon: The Monster Shark Lives'' was a huge ratings success, gaining 4.8 million viewers, the most for any Shark Week episode up to that point.<ref>{{Cite web |last1=O'Connell |first1=Mikey |date=5 August 2013 |title=TV Ratings: Shark Week Hits Record Highs With Fake 'Megalodon' Doc |url=https://www.hollywoodreporter.com/tv/tv-news/tv-ratings-shark-week-hits-599707/ |access-date=31 July 2022 |website=The Hollywood Reporter |language=en-US}}</ref>

Megalodon teeth are the state fossil of North Carolina.<ref>{{Cite web|url=https://ncpedia.org/fossil-fossilized-teeth-megalodon|title=Fossil, Fossilized Teeth of the Megalodon Shark {{!}} NCpedia|website=ncpedia.org|access-date=17 October 2019}}</ref>

== See also ==
{{Outline|Outline of sharks}}
* List of prehistoric cartilaginous fish
* Prehistoric fish
* Largest prehistoric organisms
{{clear}}

== Notes ==
{{Reflist
| group = note
}}

== References ==
{{Reflist}}

== Further reading ==
* {{cite journal |last1=Dickson |first1=K. A. |last2=Graham |first2=J. B. |date=November–December 2004 |title=Evolution and consequences of endothermy in fishes |journal=Physiological and Biochemical Zoology |pmid=15674772 |volume=77 |issue=6 |pages=998–1018 |doi=10.1086/423743|s2cid=40104003}}
* {{cite book |first=Bretton W. |last=Kent |year=1994 |title=Fossil Sharks of the Chesapeake Bay Region |location=Columbia, Md. |publisher=Egan Rees & Boyer |url=https://books.google.com/books?id=7cFJAQAAMAAJ |isbn=978-1-881620-01-3 |oclc=918266672}}

== External links ==
* [https://web.archive.org/web/20110303141026/http://www.biodiversity2010.org.au/2010/10/the-rise-of-super-predatory-sharks-2/ The rise of super predatory sharks]
* [http://www.elasmo.com/frameMe.html?file=genera/cenozoic/sharks/carcharocles.html&menu=bin/menu_genera-alt.html ''Carcharocles'': Extinct Megatoothed shark]

;Paleontological videos
* {{YouTube|5N3EjR7_vks|Shark Week Special on megalodon with Pat McCarthy and John Babiarz}} with comments on its extinction.
* {{YouTube|85clp1k_sms|Expert view: information about megalodon}} (featuring expert Dana Ehret)
* {{YouTube|e4p9EWuVxYQ|Lamniform sharks: 110 million years of ocean supremacy}} (featuring expert Mikael Siverson)
* {{YouTube|suC2vQQz1Ak|The Rise and Fall of the Neogene Giant Sharks}} (featuring expert Bretton Kent)

{{Taxonbar |from=Q163873}}

[[Category:Carcharocles]]
[[Category:Miocene first appearances]]
[[Category:Pisco Formation]]

{{Sourceattribution|Megalodon}}