Crocodile#Taxonomy of the Crocodylidae

The word crocodile (croc.) was derived during the Middle English period {{cite web|url=https://www.oed.com/dictionary/crocodile_n?tl=true|website=www.oed.com|title=crocodile noun|date=|publisher=Oxford University Press|access-date=|url-status=|archive-url=|archive-date=|via=Cresswell (2010) www.oxfordreference.com/display/10.1093/acref/9780199547920.001.0001/acref-9780199547920-e-1305: "ME"}} from the transliteration krokódilos of a Greek {{efn|The Ancient Greek words for croc. were: σοῦχος {{cite web|url=https://www.perseus.tufts.edu/hopper/definitionlookup?type=begin&q=crocodile&target=greek|website=www.perseus.tufts.edu|title=English-to-Greek Word Search Results for crocodile|publisher=LSJ: Perseus Project|access-date=14 April 2025|url-status=|archive-url=|archive-date=}} which was the Ancient Egyptian croc. {{cite web|url= https://lsj.gr/wiki/%CF%83%CE%BF%E1%BF%A6%CF%87%CE%BF%CF%82|website=lsj.gr|title=σοῦχος|date=|publisher=LSJ|access-date=14 April 2025|url-status=|archive-url=|archive-date=}} and, probably, {{cite web|url=https://lsj.gr/wiki/%E1%BD%80%CE%B4%CE%BF%CE%BD%CF%84%CE%BF%CF%84%CF%8D%CF%81%CE%B1%CE%BD%CE%BD%CE%BF%CF%82|website=lsj.gr|title=ὀδοντοτύραννος|date=|publisher=LSJ|access-date=14 April 2025|url-status=|archive-url=|archive-date=}} ὀδοντοτύραννος the Ancient Indian croc. }} word which translates as: "stones worm".{{cite web|url=https://www.oxfordreference.com/display/10.1093/acref/9780199547920.001.0001/acref-9780199547920-e-1305|website=www.oxfordreference.com|title=crocodile|editor= Julia Cresswell|date=2010|publisher=Oxford University Press|access-date=|url-status=|archive-url=https://archive.today/20250414114622/https://www.oxfordreference.com/display/10.1093/acref/9780199547920.001.0001/acref-9780199547920-e-1305|archive-date=14 April 2025}} {{efn|It has been suggested, {{cite book|last1=Wylie|first1=Dan |author-link1=|location=Rhodes University, Grahamstown, South Africa|date= 15 July 2013|chapter=|chapter-url=|editor-last1=|editor-first1= |editor-last2=|editor-first2=|title=Crocodile|url=https://books.google.com/books?id=VWDqAQAAQBAJ&q=crocodile+A+(further)+corrupted+form+cocodrille+is+found+in+Old+French|series=|language=|volume=|edition=|publisher=Reaktion Books|page=16|isbn=978-1780231235|issn=|url-status=|access-date=|via=}}{{cite web|author1=Giuliano Russini |url=https://www.monaconatureencyclopedia.com/crocodylus-cataphractus/?lang=en|website=www.monaconatureencyclopedia.com|title=Crocodylus cataphractus|date=26 April 2012|publisher=|access-date=|url-status=|archive-url=|archive-date=}}{{cite web|author= Adam Aleksic|url=https://www.etymologynerd.com/blog/pebble-worm|website=www.etymologynerd.com|title=

PEBBLE WORM|date=|publisher=|access-date=|url-status=|archive-url=|archive-date=|quote=degree from Harvard University, co-founded the Harvard Undergraduate Linguistics Society. poynter.yale.edu/events/2025-02-07-adam-aleksic-etymologynerd - The Poynter Fellowship in Journalism}}{{cite book|last1=Ikram|first1=Salima |author-link1=|year=2010|chapter=Crocodiles: Guardians of the Gateways|chapter-url=https://d1wqtxts1xzle7.cloudfront.net/36713843/Ikram_Crocodiles_Guardians_of_the_Gateways-libre.pdf?1424471010=&response-content-disposition=inline%3B+filename%3D2010_Crocodiles_Guardians_of_the_Gateway.pdf&Expires=1744727479&Signature=g3LWrL~Tu0FWtwHSK33KJxtbx7-gV1vZpqBCuZZfGHg7Sf5V3eHRkkvRBaiSIuVZPFj9S8botv1Etljh~VZ4A-TmPoGadOTOWLO8hwafinAZzVkRMYqi9b~8t6rTEzoeOaoy8QToIuVOKLcQyRDYBxwUOZtjziZhgKveQofAVIe9MI~g6VdHzen0JRs9nLME84tPxGjuYVZhfqVRbcN3VBnAIkwatufoviWcSh9GnIYk4MVKwUujdxtIBxRh0SbtF6fZfCjAmvSgOIGXJm2Z-zUAfYQCgWFdtEBmy1iD7qcY0W1eqOy5gv9T3bIuUIflv1f2krbK1eOAupativWFIA__&Key-Pair-Id=APKAJLOHF5GGSLRBV4ZA|editor-last1=Hawass |editor-first1=Z. |editor-last2=Ikram|editor-first2=S. |title=Thebes and Beyond: Studies in Honour of Kent R. Weeks|url=|series=|page=85 (1)|volume=|edition=|publication-place=Cairo|publisher=Supreme Council of Antiquities Press|publication-date=2010 |isbn=|issn=|url-status=|access-date=|via=Google scholar & www.academia.edu/10965872/2010_Crocodiles_Guardians_of_the_Gateways_In_Z_Hawass_and_S_Ikram_eds_Thebes_and_Beyond_Studies_in_Honour_of_Kent_R_Weeks_Cairo_Supreme_Council_of_Antiquities_Press_85_98}}

that the word parts croc. & dile are compounded from {{lang|grc-Latn|krokè}} ({{gloss|pebbles}}), and {{lang|grc-Latn|drilos / deilos }} ({{gloss|worm}}), although the former is only attested as a "a stripling" a colloquialism for a young man, or, a circumcised man {{cite web|url=https://lsj.gr/wiki/%CE%B4%CF%81%E1%BF%96%CE%BB%CE%BF%CF%82|website=lsj.gr|title=δρῖλος|date=|publisher=|access-date=|url-status=|archive-url=|archive-date=|via=dictionary.reference.com/browse/crocodile [access-date=26 April 2013]}} the latter in ancient sources infact is interpreted as: cowardly, vile, worthless, lowborn, mean {{cite web|url=https://lsj.gr/wiki/%CE%B4%CE%B5%CE%B9%CE%BB%CF%8C%CF%82|website=lsj.gr|title=δειλός|date=|publisher=LSJ|access-date=|url-status=|archive-url=|archive-date=|via= biblehub.com/greek/1169.htm}}}} Through Ancient Greece {{Cite web |url=http://perseus.mpiwg-berlin.mpg.de/cgi-bin/vor?lookup=krokodeilos&lang=greek |title=Perseus Lookup Tool |access-date=30 July 2008 |archive-url=https://web.archive.org/web/20160303205859/http://perseus.mpiwg-berlin.mpg.de/cgi-bin/vor?lookup=krokodeilos&lang=greek |archive-date=3 March 2016 |url-status=dead}} the English language word has developed from Grecian origination in Anatolia. {{Cite journal|last1= Grigoriev|first1=Stanislav|url=https://www.researchgate.net/publication/360291199|date=2022|location=Russian Academy of Sciences|title=ORIGINS OF THE GREEKS AND GREEK DIALECTS|journal=Journal of Ancient History and Archaeology|volume=9 |issue=1|pages=Abstract|doi=10.14795/j.v9i1.697|publisher=Editura Mega Print SRL - Universitatea Tehnică din Cluj-Napoca: Central and Eastern European Online Library & researchgate.net|issn=2360-266X|via=bmcr.brynmawr.edu/2025/2025.04.18/ - scholar.google.com/scholar?hl=en&as_sdt=0%2C5&q=how+Greek+formed+from+proto-greek&btnG=|doi-access=free}}

A very early extant Ancient Greek source is an Aesop's Fable named Ἀλώπηξ καὶ κροκόδειλος of the sixth century BCE. Herodotus a century after in consideration of the Greek word thought it was from the Ionic period.{{cite book|author1=Herodotus|author-link1=Herodotus |chapter=69|chapter-url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0126%3Abook%3D2%3Achapter%3D69%3Asection%3D3|editor-last1= Godley|editor-first1=A. D.|editor1-link=A. D. Godley|title=The Histories: Book 2 - Section 3|url=https://www.perseus.tufts.edu/hopper/text?doc=Perseus%3Atext%3A1999.01.0126%3Abook%3D1%3Achapter%3D1%3Asection%3D0|translator=A. D. Godley|volume=|edition=|publication-place=Cambridge|publisher=Harvard University Press|publication-date=1920 |access-date=|via=etymonline.com/index.php?search=crocodile [access-date=16 March 2010] & ijhth.journals.ekb.eg/article_194385_58a53f74295669c490be0d372bbca44c.pdf p.19 Moussa, WFI (Egypyt, 2021)|quote=The Egyptians do not call them crocodiles, but khampsae. The Ionians named them crocodiles, from their resemblance to the lizards which they have in their walls¹. 1. κροκόδειλος is Ionic for a lizard; the commoner word is σαύρα or σαῦρος. χάμψα is the Egyptian "em-suh," a name which survives in the Arabic "timsah," i.e. em-suh with the feminine article prefixed.}}

The Latin language word crocodilus existed in first century a.d. in the work Naturalis Historia of Pliny the Elder.{{cite book|author1=Pliny the Elder|author-link1=Pliny the Elder |date=1938|chapter=XXVIII|chapter-url=https://www.loebclassics.com/view/pliny_elder-natural_history/1938/pb_LCL418.77.xml|editor-last1=HENDERSON|editor-first1=JEFFREY|title=Natural Histories|url=https://www.loebclassics.com/view/pliny_elder-natural_history/1938/pb_LCL330.3.xml|series=Loeb Classical Library|language=Latin|publication-place=Harvard University|publisher=Harvard University Press|isbn=|issn=|doi=10.4159/DLCL.pliny_elder-natural_history.1938|access-date=|via=Luigi Prada (2023) www.degruyterbrill.com/document/doi/10.1515/zaes-2021-0024/html}} Examples in writing in the sixth and seventh century a.d., {{lang|la|crocodillorum}} and {{lang|la|crocodili}} existed, {{Cite journal|last1=Несторов (Nestorov)|first1=Маријана (Marijana)|date=2014|title=A Traveler's Guide to Crocodiles in the Middle Ages|journal=Lucida intervalla (www.klasicnenauke.rs/lucida-intervalla)|volume=43|issue=|pages=140, 145–6|doi=|issn=|url=https://www.klasicnenauke.rs/wp-content/uploads/2023/12/li43-nestorov.pdf|publisher=Одељење за класичне науке (Department of Classical Sciences): Univerzitet u Beogradu|s2cid=|doi-access=|quote= Cocodrillus igitur de subito excitans vivu[m] transglutit eum.}} though {{lang|la|corcodrillus}} {{Cite journal|last1=traulsen|first1=johannes|url=https://riviste.unimi.it/interfaces/article/download/9625/pdf/33468|date=2018|title=The Desert Fathers' Beasts Crocodiles in Medieval German Monastic Literature|journal=Interfaces|volume=5|issue=|pages=79|doi=10.13130/interfaces-05-07|publisher=Milano University Press (www.unimi.it/en/university/la-statale/milano-university-press-our-publishing-house)|doi-access=|via=(riviste.unimi.it/interfaces/article/download/9625/pdf/33468) www.dictionary.com/browse/crocodile: Dictionary.com}} and

{{lang|la|cocodrillus}} were forms in Medieval Latin. The Latin form is found as cocodrille c. the 13th century in the Old French work Li livres dou tresor, in which the croc. is jaune (yellow).{{cite web |author1=Paolo Acquaviva|url=https://rolinc.org/wp-content/uploads/2023/02/acquaviva-rolinc-21.2.23.pdf|location=University of Dublin|website=rolinc.org|title=Varieties of definiteness and constructionist interpretation|page=13|publisher=Romance Linguistics Circle - Università di Bergamo, University of Cambridge, Università di Messina, University of Newcastle, University of Oxford |access-date=|publication-date=21 February 2023|archive-url=|quote=The OF is found quoted from Mathieu (2009)}}

The earliest known source in the English language is within the work Kyng Alisaunder[https://archive.org/stream/metricalromances01webeiala#page/n93/mode/2up King Alisaunder] Weber edition (1810) from towards the beginning of the 14^th century, a magical romance poetry work of rhyming couplets, where the word is found line 5720:{{cite book|last1=|first1=|last2=|first2=|chapter=chapter III|editor-last1=Weber, ESQ.|editor-first1=Henry |editor1-link=Henry Weber|title=Metrical Romances of the Thirteenth, Fourteenth, and Fifteenth Centuries: published from ancient manuscripts with an introducton, notes, and a glossary - Kyng Asisaunder: Part II. |chapter-url=https://archive.org/stream/metricalromances01webeiala#page/n93/mode/2up|series=|language=|volume=|edition=|publication-place=Edinburgh; London|publisher=Archibald Constable and Co; John Murray, and Constable, Hunter, Park, and Hunter|publication-date=1810 |page=236|issn=|url-status=|access-date=15 April 2025|quote=To the Most Noble Elizabeth Marchioness of Stafford, Countess of Sutherland|via=University of California, Los Angeles}}

:Forth went the kyng wondres sekynde :

:A griselich hest he gonne fynde ;

:So mychel seigh he neuere, ne non swiche ;

:Two heudes it had wel ferlich

:To a cokedrill that on was liche,

:That others the monoceros selcouthliche. {{efn|The croc. in question was an Indian croc. The text tells the tale of Alexander of Macedonia:

:Weber p.226 - "Alexander returns into Upper India where he defeats the inhabitants - The host attacked by a monstrous beast, and by elephants," (text form: olifauntz, line 5734) "which are subdued";

commences line 5688:

:The kynge thennes went forth,

:Ayein into Ynde in the north,

:That is y-cleped, als I fynde

:In the book, the vpper Ynde.

}}

Writing sometime after 1483 on his visit to the Holy Lands Felix Fabri in German and Latin mentions the Cocodrillen and cocodrillos respectively. {{efn|The modern / current German term is: das Krokodil {{cite web|url=https://translate.google.com/?hl=es&sl=en&tl=de&text=crocodile&op=translate|website=translate.google.com|title=crocodile|date=|access-date=|url-status=|archive-url=|archive-date=}}}} By 1538 the exact same form of the modern word as the current English is found in French; {{efn|Is shown in Gessner, 1560, Historiæ animalium p. 54 as "GALLICE Crocodile" (i.e. French {{cite web|url=https://www.oed.com/dictionary/gallice_adv?tl=true|website=www.oed.com|title=† Gallice adverb|date=|publisher=Oxford University|access-date=|url-status=|archive-url=|archive-date=}}) - see: p.27^:{{cite web|author=Dirk HR Spennemann|url=https://www.bsanz.org/wp-content/uploads/2020/12/Spennemann-Merians-crocodile-supplementary-2.pdf|website=www.bsanz.org|title=Matthäus Merian's crocodile in the Historiae naturalis de quadrupetibus—Supplemental data—|date=|publisher=Institute for Land Water and Society; Charles Sturt University|access-date=|url-status=|archive-url=|archive-date=}}}} {{cite web|url=https://www.cnrtl.fr/etymologie/crocodile|website=www.cnrtl.fr|title=Étymol. et Hist. 1. a)|date=|publisher=CNRTL|publication-place= 44, avenue de la Libération BP 30687 54063 Nancy Cedex - France|access-date=|url-status=|archive-url=|archive-date=}} croc. is within a poem of Edmund Spenser,{{efn|

PROSOPOPOIA.Or Mother Hubberds Tale.

:Then vnto him all monstrous beasts resorted

:Bred of two kindes, as Griffons, Minotaures,

:Crocodiles, Dragons, Beauers, and Centaures:

:With those himselfe he strengthned mightelie,

:That feare he neede no force of enemie.}}{{cite journal|url=https://www.luminarium.org/renascence-editions/hubberd.html|website=www.luminarium.org|title=Spenser's Minor Poems|editor=Ernest de Sélincourt|editor-link=Ernest de Sélincourt|date=1910|doi=10.1086/SPSv23p153 |publication-place=Oxford|publication-date=1591|access-date=|url-status=|archive-url=|archive-date=|via=Sean Henry (2008) www.journals.uchicago.edu/doi/abs/10.1086/SPSv23p153|url-access=subscription}} thought written in 1579-80, {{cite web|url=https://rpo.library.utoronto.ca/content/prosopopoia-or-mother-hubbards-tale|website=rpo.library.utoronto.ca|title=Edmund Spenser, Complaints, containing sundry, small poems of the world's vanity (1591). Facs. edn. (Amsterdam: Theatrum Orbis Terrarum, 1970). PR 2357 A1 1591A Robarts Library|date=|publisher=University of Toronto|access-date=|url-status=|archive-url=|archive-date=|quote=Notes 479}} and in the works of William Shakespeare whose lifetime was 1564 - 1616.{{cite web|url=https://www.opensourceshakespeare.org/search/search-results.php|website=www.opensourceshakespeare.org|title=Antony and Cleopatra,; Hamlet; Henry VI, Part II; Othello|date=|publisher=George Mason University |access-date=|url-status=|archive-url=|archive-date=}} The similitude of the English word formation to a Latin source was caused at least by the transmission {{cite web|author=Richard Tarrant|url=https://www.oxfordbibliographies.com/display/document/obo-9780195389661/obo-9780195389661-0302.xml|website=www.oxfordbibliographies.com|title=Oxford Bibliographies Online: Transmission of Greek and Latin Literature|date=2018|publisher=Oxford University|access-date=|doi=10.1093/obo/9780195389661-0302|archive-url=|archive-date=}} of a relevant ancient science {{cite web|author=Aude Doody|url=https://www.oxfordbibliographies.com/display/document/obo-9780195389661/obo-9780195389661-0194.xml|website=|title=Oxford Bibliographies Online: Pliny the Elder|date=2019|publisher=Oxford University|access-date=|doi=10.1093/obo/9780195389661-0194|archive-url=|archive-date=|quote=The Natural History is a key document in the history of science }} from the influx of the publication of translations of Pliny the Elder some time towards the end of fourteenth and, or, beginning of fifteenth century. The publication of concrete realization in the anatomical work of Andreas Vesalius during 1543 inspired the creation of monographs and books of animals contributing to new science in zoology.{{Cite journal|last1= Egerton|first1=Frank N.|date=October 2003|url= https://www.jstor.org/stable/bullecosociamer.84.4.206|title=A History of the Ecological Sciences, Part 11: Emergence of Vertebrate Zoology During the 1500s|journal=Bulletin of the Ecological Society of America|volume=84|issue=4|pages=206–212|doi=10.1890/0012-9623(2003)84[206:AHOTES]2.0.CO;2|issn= |publisher=Wiley|doi-access=}}

{{See also|List of crocodilians}}

Crocodylidae was named as a family by Georges Cuvier in 1807. It belongs to the larger superfamily Crocodyloidea, which also includes additional extinct crocodile relatives. These all belong to the order Crocodilia, which also includes alligators and gharials.

Although crocodiles, alligators, and the gharial are similar in appearance, they belong to separate biological families. The gharial, with its narrow snout, is easier to distinguish, while morphological differences are more difficult to spot in crocodiles and alligators. The most obvious external differences are visible in the head, with crocodiles having narrower and longer heads, with a more V-shaped than a U-shaped snout compared to alligators and caimans. Another obvious trait is that the upper and lower jaws of the crocodiles are the same width, and the teeth in the lower jaw fall along the edge or outside the upper jaw when the mouth is closed; therefore, all teeth are visible, unlike an alligator, which possesses in the upper jaw small depressions into which the lower teeth fit. Also, when the crocodile's mouth is closed, the large fourth tooth in the lower jaw fits into a constriction in the upper jaw. For hard-to-distinguish specimens, the protruding tooth is the most reliable feature to define the species' family.{{cite web |url=http://www.flmnh.ufl.edu/cnhc/cbd-faq-q1.htm |title=Crocodilian Biology Database – FAQ – What's the difference between a crocodile and an alligator |publisher=Flmnh.ufl.edu |access-date=5 April 2009}} Crocodiles have more webbing on the toes of the hind feet and can better tolerate saltwater due to specialized salt glands for filtering out salt, which are present, but non-functioning, in alligators. Another trait that separates crocodiles from other crocodilians is their much higher levels of aggression.{{cite book | author = Guggisberg, C. A. W. | title = Crocodiles: Their Natural History, Folklore, and Conservation| year = 1972 | page = 195 | isbn = 978-0-7153-5272-4 | publisher = David & Charles | location = Newton Abbot, England}}

Crocodylidae is cladistically defined as a crown group composed of the last common ancestor of the Nile crocodile (Crocodylus niloticus), the Dwarf crocodile (Osteolaemus tetraspis), and all of its descendants.{{cite journal |last1=Rio |first1=Jonathan P. |last2=Mannion |first2=Philip D. |date=6 September 2021 |title=Phylogenetic analysis of a new morphological dataset elucidates the evolutionary history of Crocodylia and resolves the long-standing gharial problem |journal=PeerJ |volume=9 |pages=e12094 |doi=10.7717/peerj.12094 |pmid=34567843 |pmc=8428266 |doi-access=free}} It contains two subfamilies: Crocodylinae and Osteolaeminae.{{Cite journal|last1=Hekkala |first1=E. |last2=Gatesy |first2=J. |last3=Narechania |first3=A. |last4=Meredith |first4=R. |last5=Russello |first5=M. |last6=Aardema |first6=M. L. |last7=Jensen |first7=E. |last8=Montanari |first8=S. |last9=Brochu |first9=C. |last10=Norell |first10=M. |last11=Amato |first11=G. |date=27 April 2021 |title=Paleogenomics illuminates the evolutionary history of the extinct Holocene "horned" crocodile of Madagascar, Voay robustus |journal=Communications Biology |language=en |volume=4 |issue=1 |page=505 |doi=10.1038/s42003-021-02017-0 |pmid=33907305 |pmc=8079395 |issn=2399-3642 |doi-access=free}} Crocodylinae contains 13-14 living species, as well as 6 extinct species. Osteolaeminae was named by Christopher Brochu in 2003 as a subfamily of Crocodylidae separate from Crocodylinae,{{Cite journal | last1 = Brochu | first1 = C. A. | last2 = Storrs | first2 = G. W. | doi = 10.1080/02724634.2012.652324 | title = A giant crocodile from the Plio-Pleistocene of Kenya, the phylogenetic relationships of Neogene African crocodylines, and the antiquity of Crocodylus in Africa | journal = Journal of Vertebrate Paleontology | volume = 32 | issue = 3 | pages = 587–602 | year = 2012 | bibcode = 2012JVPal..32..587B | s2cid = 85103427 }} and contains the two extant genera Osteolaemus and Mecistops, along with several extinct genera. The number of extant species within Osteolaeminae is currently in question.

File:Crocfarm.jpging in Australia]]

File:Crocadiles.jpg]]

File:Crocodylus acutus mexico 01.jpg at La Manzanilla, Jalisco, Mexico]]

File:Voay robustus.JPG]]

• Subfamily Crocodylinae
• Genus Crocodylus
• Crocodylus acutus, American crocodile
• Crocodylus halli, Hall's New Guinea crocodile found South of the New Guinea Highlands{{cite journal | last1 = Murray | first1 = Christopher M. | last2 = Russo | first2 = Peter | last3 = Zorrilla | first3 = Alexander | last4 = McMahan | first4 = Caleb D. | year = 2019 | title = Divergent Morphology among Populations of the New Guinea Crocodile, Crocodylus novaeguineae (Schmidt, 1928) Diagnosis of An Independent Lineage and Description of A New Species. | journal = Copeia | volume = 107 | issue = 3| pages = 517–523 | doi = 10.1643/CG-19-240 | doi-access = free }}
• Crocodylus intermedius, Orinoco crocodile
• Crocodylus johnsoni, freshwater crocodile, or Johnstone's crocodile
• Crocodylus mindorensis, Philippine crocodile
• Crocodylus moreletii, Morelet's crocodile or Mexican crocodile
• Crocodylus niloticus, Nile crocodile or African crocodile (the subspecies found in Madagascar is sometimes called the black crocodile)
• Crocodylus novaeguineae, New Guinea crocodile found North of the New Guinea Highlands
• Crocodylus palustris, mugger, marsh or Indian crocodile
• Crocodylus porosus, saltwater crocodile or estuarine crocodile
• Crocodylus raninus, the Borneo crocodile, is currently considered to be a synonym of Crocodylus porosus; whether or not it is a distinct species remains unclear.{{Cite web|url=http://reptile-database.reptarium.cz/species?genus=Crocodylus&species=raninus|title = Species | the Reptile Database}}
• Crocodylus rhombifer, Cuban crocodile
• Crocodylus siamensis, Siamese crocodile (may be extinct in the wild)
• Crocodylus suchus, West African crocodile, desert or sacred crocodile
• Crocodylus anthropophagus{{extinct}}
• Crocodylus checchiai{{extinct}}
• Crocodylus falconensis{{extinct}}
• Crocodylus palaeindicus{{extinct}}
• Crocodylus thorbjarnarsoni{{extinct}}
• Genus Voay{{extinct}}
• Voay robustus{{extinct}} (formerly Crocodylus robustus)
• Subfamily Osteolaeminae
• Genus Osteolaemus
• Osteolaemus tetraspis, dwarf crocodile (There has been controversy as to whether or not this is actually two species; recent (2010) DNA analysis indicate three distinct species: O. tetraspis, O. osborni and a third, currently unnamed.)
• Genus Mecistops
• Mecistops cataphractus West African slender-snouted crocodile
• Mecistops leptorhynchus Central African slender-snouted crocodile
• Genus Brochuchus{{extinct}}
• Brochuchus pigotti{{extinct}} (formerly Crocodylus pigotti)
• Brochuchus parvidens{{extinct}}
• Genus Euthecodon{{extinct}}
• Euthecodon nitriae{{extinct}}
• Euthecodon brumpti{{extinct}}
• Euthecodon arambourgi{{extinct}}
• Genus Rimasuchus{{extinct}}
• Rimasuchus lloydi{{extinct}} (formerly Crocodylus lloydi)

Recent molecular studies using DNA sequencing have shown crocodiles to be more closely related to the gavialids rather than to alligators, contrary to prior theories based on morphological studies alone.{{cite journal |pmid=12775527 |year=2003 |last1=Harshman |first1=J. |title=True and false gharials: A nuclear gene phylogeny of crocodylia |journal=Systematic Biology |volume=52|issue=3|pages=386–402|last2=Huddleston|first2=C. J. |last3=Bollback |first3=J. P. |last4=Parsons|first4=T. J.|last5=Braun|first5=M. J.|doi=10.1080/10635150309323 |url=http://si-pddr.si.edu/bitstream/handle/10088/6275/2003C_Harshman_et_al.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://si-pddr.si.edu/bitstream/handle/10088/6275/2003C_Harshman_et_al.pdf |archive-date=2022-10-09 |url-status=live|doi-access=free }}{{cite journal|last1=Gatesy |first1=J. |last2=Amato |first2=G. |year=2008 |title=The rapid accumulation of consistent molecular support for intergeneric crocodylian relationships |journal=Molecular Phylogenetics and Evolution|volume=48 |issue=3 |pages=1232–1237 |doi=10.1016/j.ympev.2008.02.009|pmid=18372192|bibcode=2008MolPE..48.1232G }}{{cite journal| author=Erickson, G. M.| author2=Gignac, P. M.| author3=Steppan, S. J.| author4=Lappin, A. K.| author5=Vliet, K. A.| author6=Brueggen, J. A.| author7=Inouye, B. D.| author8=Kledzik, D.| author9=Webb, G. J. W. | year=2012 | title=Insights into the ecology and evolutionary success of crocodilians revealed through bite-force and tooth-pressure experimentation | journal=PLOS ONE | volume=7 |issue=3 |page=e31781 |doi=10.1371/journal.pone.0031781|editor1-last=Claessens|editor1-first=Leon|bibcode = 2012PLoSO...731781E | pmid=22431965 | pmc=3303775| doi-access=free}}{{cite journal | author=Michael S. Y. Lee |author2=Adam M. Yates |date=27 June 2018 |title=Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil |journal=Proceedings of the Royal Society B |volume=285 |issue=1881 |doi=10.1098/rspb.2018.1071 |pmid=30051855 |pmc=6030529 |doi-access=free}}

Below is a cladogram showing the relationships of the major extant crocodile groups based on molecular studies, excluding separate extinct taxa:

{{clade| style=font-size:85%;line-height:85%

|label1=Crocodilia

|1={{clade

|label1=Alligatoridae

|1={{clade

|label1=Caimaninae

|1={{clade

|1={{clade

|1=Caiman 90 px

|2=Melanosuchus 120 px }}

|2=Paleosuchus 90 px }}

|label2=Alligatorinae

|2=Alligator 100 px }}

|label2=Longirostres

|2={{clade

|label1=Crocodylidae

|1={{clade

|1=Crocodylus 90 px

|2={{clade

|1=Mecistops 90 px

|2=Osteolaemus 90 px }} }}

|label2=Gavialidae

|2={{clade

|1=Gavialis 110 px

|2=Tomistoma 90 px

}} }} }} }}

Below is a more detailed cladogram of Crocodylidae, based on a 2021 study using paleogenomics that extracted DNA from the extinct Voay.

{{clade| style=font-size:85%;line-height:85%

|label1=Crocodylidae

|sublabel1=(crown group)

|1={{clade

|label1=Osteolaeminae

|1={{clade

|1={{clade

|1=Mecistops cataphractus West African slender-snouted crocodile

|2=Euthecodon{{extinct}} }}

|2={{clade

|1=Brochuchus{{extinct}}

|2={{clade

|1=Rimasuchus{{extinct}}

|2={{clade

|1=Osteolaemus osborni Osborn's dwarf crocodile

|2=Osteolaemus tetraspis Dwarf crocodile }} }} }} }}

|label2=Crocodylinae

|2={{clade

|1=Voay{{extinct}}

|label2=Crocodylus

|2={{clade

|1={{clade

|1={{clade

|1=Crocodylus anthropophagus{{extinct}}

|2=Crocodylus thorbjarnarsoni{{extinct}} }}

|2={{clade

|1=Crocodylus palaeindicus{{extinct}}

|2=Crocodylus Tirari Desert{{extinct}} }} }}

|2={{clade

|1={{clade

|1={{clade

|1=Crocodylus johnstoni Freshwater crocodile

|2={{clade

|1=Crocodylus novaeguineae New Guinea crocodile

|2=Crocodylus mindorensis Philippine crocodile }} }}

|2={{clade

|1=Crocodylus porosus Saltwater crocodile

|2={{clade

|1=Crocodylus siamensis Siamese crocodile

|2=Crocodylus palustris Mugger crocodile }} }} }}

|2={{clade

|1={{clade

|1=Crocodylus checchiai{{extinct}}

|2=Crocodylus falconensis{{extinct}} }}

|2={{clade

|1=Crocodylus suchus West African crocodile

|2={{clade

|1=Crocodylus niloticus Nile crocodile

|2={{clade

|1={{clade

|1=Crocodylus moreletii Morelet's crocodile

|2=Crocodylus rhombifer Cuban crocodile }}

|2={{clade

|1=Crocodylus intermedius Orinoco crocodile

|2=Crocodylus acutus American crocodile }} }} }} }} }} }} }} }} }} }}

Alternatively, some morphological studies have recovered Mecistops as a basal member of Crocodylinae, more closely related to Crocodylus than to Osteolaemus and the other members of Osteolaeminae,{{cite journal |last1=Azarra |first1=Beatrice |last2=Boschian |first2=Giovanni |last3=Brochu |first3=Christopher |last4=Delfino |first4=Massimo |last5=Iurino |first5=Dawid Adam |last6=Kimambo |first6=Jackson Stanley |last7=Manzi |first7=Giorgio |last8=Masao |first8=Fidelis T. |last9=Menconero |first9=Sofia |last10=Njau |first10=Jackson K |last11=Cherin |first11=Marco |year=2021 |title=A new cranium of Crocodylus anthropophagus from Olduvai Gorge, northern Tanzania |journal=Rivista Italiana di Paleontologia e Stratigrafia (Research in Paleontology and Stratigraphy) |volume=127 |issue=2 |pages=275–295 |url=https://www.researchgate.net/publication/352560805 |doi=10.13130/2039-4942/15771 |s2cid=237962496 }} as shown in the cladogram below.

{{clade| style=font-size:85%;line-height:85%

|grouplabel1={{clade labels |width=10em; |label1=Paleoafrican Crocodylus |top1=40% |color1=red |label2=Neotropical Crocodylus |top2=60% |color2=black |style2=background-color:#ffffee; |label3=Indo-Pacific Crocodylus |top3=85% |color3=green}}

|label1=Crocodylidae

|1={{clade

|label1=Osteolaeminae

|1={{clade

|1=Rimasuchus lloydi{{extinct}}

|2={{clade

|1=Voay robustus{{extinct}}

|2={{clade

|1=Osteolaemus osborni Osborn's dwarf crocodile

|2=Osteolaemus tetraspis Dwarf crocodile }} }}

|3={{clade

|1="Crocodylus" gariepensis{{extinct}}

|2={{clade

|1={{clade

|1=Brochuchus parvidens{{extinct}}

|2=Brochuchus pigotti{{extinct}} }}

|2={{clade

|1=Euthecodon arambourgi{{extinct}}

|2=Euthecodon brumpti{{extinct}} }} }} }} }}

|label2=Crocodylinae

|2={{clade

|1=Mecistops cataphractus West African slender-snouted crocodile

|2={{clade

|style1=background-color:#ffdddd;

|1={{clade

|1=Crocodylus thorbjarnarsoni{{extinct}} |barbegin1=red

|2=Crocodylus anthropophagus{{extinct}} |barend2=red }}

|2={{clade

|1=Crocodylus niloticus Nile crocodile

|2={{clade

|1=Crocodylus checchiai{{extinct}}

|style2=background-color:#ffffee;

|2=Crocodylus moreletii Morelet's crocodile |barbegin2=yellow

|style3=background-color:#ffffee;

|3=Crocodylus intermedius Orinoco crocodile |bar3=yellow

|style4=background-color:#ffffee;

|4=Crocodylus acutus American crocodile |bar4=yellow

|style5=background-color:#ffffee;

|5=Crocodylus rhombifer Cuban crocodile |barend5=yellow }}

|style3=background-color:#ddffdd;

|3=Crocodylus palaeindicus{{extinct}} |barbegin3=lightgreen |barend3=lightgreen

|style4=background-color:#ccffcc;

|4={{clade

|1=Crocodylus palustris Mugger crocodile |barbegin1=green

|2={{clade

|1={{clade

|1=Crocodylus ossifragus{{extinct}} |bar1=green

|2=Crocodylus siamensis Siamese crocodile |bar2=green }}

|2={{clade

|1=Crocodylus mindorensis Philippine crocodile |bar1=green

|2=Crocodylus johnstoni Freshwater crocodile |bar2=green

|3=Crocodylus porosus Saltwater crocodile |bar3=green

|4={{clade

|1=Crocodylus raninus Borneo crocodile |bar1=green

|2=Crocodylus novaeguineae New Guinea crocodile  |barend2=green }} }} }} }} }} }} }} }} }}

File:Crocodylidae Distribution.png{{Clear}}

A total of 18 extant species have been recognized. Further genetic study is needed for the confirmation of proposed species under the genus Osteolaemus.

{{For|information on Tomistoma or false gharial, that is recently not considered as a true crocodile|False gharial}}

{{Hatnote|Crocodiles are similar to alligators and caimans; for their common characteristics and differences among them, see Crocodilia.}}

File:Skull & scutes - Crocodylinae.jpg, Nile and Saltwater crocodiles, with post-occipital scutes highlighted in red, nuchal shield in blue and dorsal scutes in green]]

File:Crocodilelyd5.png.]]

Apart from the advantage conferred by its sufficiently large size relative to other animals in the ecosystem,{{Cite journal|last1=Somaweera |first1=Ruchira |last2= Brien|first2=Matthew|last3= Shine|first3=Richard|location=Australia|date=1 December 2013|url=https://meridian.allenpress.com/herpetological-monographs/article-abstract/27/1/23/33006/The-Role-of-Predation-in-Shaping-Crocodilian|title=The Role of Predation in Shaping Crocodilian Natural History|journal=Herpetological Monographs|volume=27 |issue=1|pages=Abstract|issn=0733-1347|doi=10.1655/HERPMONOGRAPHS-D-11-00001 |url-access=subscription}} other physical traits contribute a crocodile's position as predator. Its external morphology is a sign of its aquatic and predatory lifestyle. Its streamlined body enables it to swim swiftly; it also tucks its feet to the side while swimming, making it faster by decreasing water resistance. Crocodiles have webbed feet which, though not used to propel them through the water, allow them to make fast turns and sudden moves in the water or initiate swimming. Webbed feet are an advantage in shallow water, where the animals sometimes move around by walking. Crocodiles have a palatal flap, a rigid tissue at the back of the mouth that blocks the entry of water. The palate has a special path from the nostril to the glottis that bypasses the mouth. The nostrils are closed during submergence.

Like other archosaurs, crocodilians are diapsid, although their post-temporal fenestrae are reduced. The walls of the braincase are bony but lack supratemporal and postfrontal bones.Grigg, Gordon and Gans, Carl (1993) [http://eprint.uq.edu.au/archive/00002011/02/croc.pdf Morphology And Physiology Of The Crocodylia] {{webarchive|url=https://web.archive.org/web/20050720011236/http://eprint.uq.edu.au/archive/00002011/02/croc.pdf |date=20 July 2005 }}, in Fauna of Australia Vol 2A Amphibia and Reptilia, chapter 40, pp. 326–336. Australian Government Publishing Service, Canberra. Their tongues are not free, but held in place by a membrane that limits movement; as a result, crocodiles are unable to stick out their tongues.{{cite book | last = Huchzermeyer | first = Fritz | year = 2003 | title = Crocodiles: Biology, Husbandry and Diseases | publisher = CABI Publishing | isbn =978-0-85199-656-1 | url = https://books.google.com/books?id=4Arv-IUFnuoC| page = 13 }} Crocodiles have smooth skin on their bellies and sides, while their dorsal surfaces are armoured with large osteoderms. The armoured skin has scales and is thick and rugged, providing some protection. They are still able to absorb heat through this armour, as a network of small capillaries allows blood through the scales to absorb heat. The osteoderms are highly vascularised and aid in calcium balance, both to neutralize acids while the animal cannot breathe underwater{{Cite web|last=Wednesday|first=25 April 2012 Anna SallehABC|date=25 April 2012|title=Antacid armour key to tetrapod survival|url=http://www.abc.net.au/science/articles/2012/04/25/3488040.htm|access-date=26 July 2020|website=www.abc.net.au|language=en-AU}} and to provide calcium for eggshell formation.{{Cite journal|last1=Dacke|first1=C.|last2=Elsey|first2=R.|last3=Trosclair|first3=P.|last4=Sugiyama|first4=T.|last5=Nevarez|first5=Javier|last6=Schweitzer|first6=Mary|date=1 September 2015|title=Alligator osteoderms as a source of labile calcium for eggshell formation|url=https://www.researchgate.net/publication/280973901|journal=Journal of Zoology|volume=297|issue=4|pages=255–264|doi=10.1111/jzo.12272}} Crocodilian tegument have pores believed to be sensory in function, analogous to the lateral line in fishes. They are particularly seen on their upper and lower jaws. Another possibility is that they are secretory, as they produce an oily substance which appears to flush mud off.

File:Large Crocodylus porosus.jpg in captivity]]

Size greatly varies among species, from the dwarf crocodile to the saltwater crocodile. Species of the dwarf crocodile Osteolaemus grow to an adult size of just {{convert|1.5|to|1.9|m|ft|abbr=on}},[http://crocodilian.com/cnhc/csp_otet.htm]. Crocodilian Species List. Retrieved on 14 April 2012 whereas the saltwater crocodile can grow to sizes over {{convert|6|m|ft|abbr=on}} and weigh over {{convert|1000|kg|lb|abbr=on}}.Guinness Book of World Records. Retrieved on 8 April 2013. Several other large species can reach over {{convert|5.2|m|ft|abbr=on}} long and weigh over {{convert|900|kg|lb|abbr=on}}. Crocodilians show pronounced sexual dimorphism, with males growing much larger and more rapidly than females. Despite their large adult sizes, crocodiles start their lives at around {{convert|20|cm|in|abbr=on}} long. The largest species of crocodile is the saltwater crocodile, found in eastern India, northern Australia, throughout South-east Asia, and in the surrounding waters.

The brain volume of two adult crocodiles was 5.6 cm³ for a spectacled caiman and 8.5 cm³ for a larger Nile crocodile.{{Cite journal | doi=10.1371/journal.pone.0178491| pmid=28614349| pmc=5470673|bibcode = 2017PLoSO..1278491J|title = Volume of the crocodilian brain and endocast during ontogeny| journal=PLOS ONE| volume=12| issue=6| pages=e0178491|last1 = Jirak|first1 = Daniel| last2=Janacek| first2=Jiri| year=2017| doi-access=free}}

The largest crocodile ever held in captivity is a saltwater–Siamese hybrid named Yai ({{langx|th|ใหญ่}}, meaning big; born 10 June 1972) at the Samutprakarn Crocodile Farm and Zoo, Thailand. This animal measures {{convert|6|m|abbr=on}} in length and weighs {{convert|1200|kg|abbr=on}}.[http://www.worldcrocodile.com/centerfarm.swf The Guinness Book of Records. Largest Captive Crocodile] {{Webarchive|url=https://web.archive.org/web/20101105124058/http://www.worldcrocodile.com/centerfarm.swf |date=5 November 2010 }}, Worldcrocodile.com

The longest crocodile captured alive was Lolong, a saltwater crocodile which was measured at {{convert|6.17|m|ft|abbr=on}} and weighed at {{convert|1075|kg|abbr=on}} by a National Geographic team in Agusan del Sur Province, Philippines.{{cite web|last=Britton|first=Adam|title=Lolong officially the world's largest crocodile in captivity|url=http://crocodilian.blogspot.com/2012/06/lolong-officially-worlds-largest.html|publisher=Crocodilian.com|access-date=12 July 2012|date=23 June 2012|archive-date=18 December 2013|archive-url=https://web.archive.org/web/20131218183151/http://crocodilian.blogspot.com/2012/06/lolong-officially-worlds-largest.html|url-status=dead}}{{cite news|title=Displaced Species|url=http://www.philstar.com/Article.aspx?articleId=824855&publicationSubCategoryId=64|archive-url=https://archive.today/20130131170445/http://www.philstar.com/Article.aspx?articleId=824855&publicationSubCategoryId=64|url-status=dead|archive-date=31 January 2013|newspaper=PhilStar|access-date=12 July 2012}}{{cite web|author=GMA News with Ben Serrano|author2=Paterno Esmaquel|name-list-style=amp|title=NatGeo team confirms Lolong the croc is world's longest|url=http://www.gmanews.tv/story/237992/nation/natgeo-team-confirms-lolong-the-croc-is-worlds-longest|work=GMA News Online Top Stories|date=9 November 2011 |publisher=GMA Network Inc.|access-date=15 November 2011}}

Crocodiles are polyphyodonts; they are able to replace each of their 80 teeth up to 50 times in their 35- to 75-year lifespan.{{cite web|url=http://blogs.smithsonianmag.com/science/2013/05/solving-an-alligator-mystery-may-help-humans-regrow-lost-teeth/#ixzz2jeiA3qon|title=Solving an Alligator Mystery May Help Humans Regrow Lost Teeth|first=Rachel|last=Nuwer|author-link=Rachel Nuwer |access-date=4 November 2013|archive-date=25 June 2013|archive-url=https://web.archive.org/web/20130625153648/http://blogs.smithsonianmag.com/science/2013/05/solving-an-alligator-mystery-may-help-humans-regrow-lost-teeth/#ixzz2jeiA3qon|url-status=dead}}{{cite journal|title=Specialized stem cell niche enables repetitive renewal of alligator teeth|first1=Ping|last1=Wu|first2=Xiaoshan|last2=Wu|first3=Ting-Xin|last3=Jiang|first4=Ruth M.|last4=Elsey|first5=Bradley L.|last5=Temple|first6=Stephen J.|last6=Divers|first7=Travis C.|last7=Glenn|first8=Kuo|last8=Yuan|first9=Min-Huey|last9=Chen|first10=Randall B.|last10=Widelitz|first11=Cheng-Ming|last11=Chuong|author-link11=Cheng-Ming Chuong|date=28 May 2013|journal=PNAS|volume=110|issue=22|pages=E2009–E2018|doi=10.1073/pnas.1213202110|pmid=23671090|pmc=3670376|bibcode=2013PNAS..110E2009W|doi-access=free}} Next to each full-grown tooth, there is a small replacement tooth and an odontogenic stem cell in the dental lamina in standby that can be activated if required.[http://www-hsc.usc.edu/~cmchuong/2013AllTooth.pdf Specialized stem cell niche enables repetitive renewal of alligator teeth] {{webarchive |url=https://web.archive.org/web/20131104212952/http://www-hsc.usc.edu/~cmchuong/2013AllTooth.pdf |date=4 November 2013 }}

Crocodilians are more closely related to birds and dinosaurs than to most animals classified as reptiles, the three families being included in the group Archosauria ('ruling reptiles'). Despite their prehistoric look, crocodiles are among the more biologically complex reptiles. Unlike other reptiles, a crocodile has a cerebral cortex and a four-chambered heart. Crocodilians also have the functional equivalent of a diaphragm by incorporating muscles used for aquatic locomotion into respiration.{{cite journal|vauthors=Uriona TJ, Farmer CG |year=2008|title=Recruitment of the diaphragmaticus, ischiopubis and other respiratory muscles to control pitch and roll in the American alligator (Alligator mississippiensis) |journal=Journal of Experimental Biology|volume=211|pages=1141–1147|pmid=18344489|doi=10.1242/jeb.015339|issue=Pt 7|doi-access=free|bibcode=2008JExpB.211.1141U }} Salt glands are present in the tongues of crocodiles and they have a pore opening on the surface of the tongue, a trait that separates them from alligators. Salt glands are dysfunctional in Alligatoridae. Their function appears to be similar to that of salt glands in marine turtles. Crocodiles do not have sweat glands and release heat through their mouths. They often sleep with their mouths open and may pant like a dog.{{cite web | author= Anitai, Stefan | title = 14 Amazing Facts About Crocodiles – Living dinosaurs | date = 3 November 2007 | url=http://news.softpedia.com/news/14-Amazing-Facts-About-Crocodiles-69931.shtml | publisher= Softpedia | access-date = 1 April 2008}} Four species of freshwater crocodile climb trees to bask in areas lacking a shoreline.{{cite journal | url=http://www.herpetologynotes.seh-herpetology.org/Volume7_PDFs/Dinets_HerpetologyNotes_volume7_pages3-7.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.herpetologynotes.seh-herpetology.org/Volume7_PDFs/Dinets_HerpetologyNotes_volume7_pages3-7.pdf |archive-date=2022-10-09 |url-status=live | title=Climbing behaviour in extant crocodilians |author1=Dinets, Vladimir |author2=Britton, Adam |author3=Shirley, Matthew | journal=Herpetology Notes | year=2013 | volume=7 | pages=3–7}}

File:A crocodiles eye (7825799462).jpg

Crocodiles have acute senses, an evolutionary advantage that makes them successful predators. The eyes, ears and nostrils are located on top of the head, allowing the crocodile to lie low in the water, almost totally submerged and hidden from prey.

Crocodiles have very good night vision, and are mostly nocturnal hunters. They use the disadvantage of most prey animals' poor nocturnal vision to their advantage. The light receptors in crocodilians' eyes include cones and numerous rods, so it is assumed all crocodilians can see colours.{{cite web|url=http://wikis.evergreen.edu/m2o1112/index.php/Reptiles|title=Reptiles|author=evergreen|access-date=29 April 2013|archive-url=https://web.archive.org/web/20130615152003/http://wikis.evergreen.edu/m2o1112/index.php/Reptiles|archive-date=15 June 2013|url-status=dead}} Crocodiles have vertical-slit shaped pupils, similar to those of domestic cats. One explanation for the evolution of slit pupils is that they exclude light more effectively than a circular pupil, helping to protect the eyes during daylight.{{cite journal | last1 = Land | first1 = M.F. | year = 2006 | title = Visual optics: the shapes of pupils | journal = Current Biology | volume = 16 | issue = 5| pages = R167–R168 | doi=10.1016/j.cub.2006.02.046 | pmid=16527734| doi-access = free | bibcode = 2006CBio...16.R167L }} On the rear wall of the eye is a tapetum lucidum, which reflects incoming light back onto the retina, thus utilizing the small amount of light available at night to best advantage. In addition to the protection of the upper and lower eyelids, crocodiles have a nictitating membrane (sometimes called a "third eye-lid") that can be drawn over the eye from the inner corner while the lids are open. The eyeball surface is thus protected under the water while a certain degree of vision is still possible.{{cite web|url=https://www.britannica.com/EBchecked/topic/143679/crocodile/38424/Form-and-function|title=Crocodile|author=Encyclopædia Britannica|access-date=29 April 2013}}

Crocodilian sense of smell is also very well developed, aiding them to detect prey or animal carcasses that are either on land or in water, from far away. It is possible that crocodiles use olfaction in the egg prior to hatching.

Chemoreception in crocodiles is especially interesting because they hunt in both terrestrial and aquatic surroundings. Crocodiles have only one olfactory chamber and the vomeronasal organ is absent in the adults{{cite journal | last1 = Hansen | first1 = A | year = 2007 | title = Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis | journal = BMC Neuroscience | volume = 8 | page = 64 | doi = 10.1186/1471-2202-8-64 | pmid = 17683564 | pmc = 1950884 | doi-access = free }} indicating all olfactory perception is limited to the olfactory system. Behavioural and olfactometer experiments indicate that crocodiles detect both air-borne and water-soluble chemicals and use their olfactory system for hunting. When above water, crocodiles enhance their ability to detect volatile odorants by gular pumping, a rhythmic movement of the floor of the pharynx.{{cite journal | last1 = Gans | first1 = C. | last2 = Clark | first2 = B. | year = 1976 | title = Studies on ventilation of Caiman crocodilus (Crocodilia: Reptilia) | url =https://deepblue.lib.umich.edu/bitstream/2027.42/21779/1/0000173.pdf | journal = Respir. Physiol | volume = 26 | issue = 3| pages = 285–301 | doi=10.1016/0034-5687(76)90001-3| pmid = 951534 | hdl = 2027.42/21779 | hdl-access = free }}{{cite journal | last1 = Putterill | first1 = J.F. | last2 = Soley | first2 = J.T. | year = 2006 | title = Morphology of the gular valve of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768) | journal = J. Morphol. | volume = 267 | issue = 8| pages = 924–939 | doi=10.1002/jmor.10448| pmid = 16634086 | s2cid = 21995436 }} Crocodiles close their nostrils when submerged, so olfaction underwater is unlikely. Underwater food detection is presumably gustatory and tactile.Schwenk, K. (2008). Comparative anatomy and physiology of chemical senses in nonavian aquatic reptiles. In, Sensory Evolution on the Threshold: Adaptations in Secondarily Aquatic Vertebrates. J.G.M Thewissen and S. Nummels (Eds). University of California Press, Berkeley. pp. 65–81

Crocodiles can hear well; their tympanic membranes are concealed by flat flaps that may be raised or lowered by muscles.

The touch sensors, concentrated in crocodile skin, can be thicker than those in human fingerprints.{{Cite web|date=9 November 2012|title=Croc Jaws More Sensitive Than Human Fingertips|url=https://www.nationalgeographic.com/animals/article/121108-nile-crocodile-duncan-leitch-science-human-sensitive-touch|archive-url=https://web.archive.org/web/20210325143141/https://www.nationalgeographic.com/animals/article/121108-nile-crocodile-duncan-leitch-science-human-sensitive-touch|url-status=dead|archive-date=25 March 2021|access-date=31 January 2022|website=Animals|language=en}} Crocodiles can feel the touch on their skin.{{Cite web|date=14 October 2021|title=Do Crocodiles Feel Pain? (Surprising Answer) {{!}}|url=https://wildexplained.com/do-crocodiles-feel-pain/|access-date=31 January 2022|language=en-us}}

Cranial: The upper and lower jaws are covered with sensory pits, visible as small, black speckles on the skin, the crocodilian version of the lateral line organs seen in fish and many amphibians, though arising from a completely different origin. These pigmented nodules encase bundles of nerve fibers innervated beneath by branches of the trigeminal nerve. They respond to the slightest disturbance in surface water, detecting vibrations and small pressure changes as small as a single drop.{{cite news|url=https://www.cbc.ca/news/science/alligators-detect-silent-ripples-when-hunting-1.320458|title=Alligators detect silent ripples when hunting|author=CBCnews|year=2002|access-date=29 April 2013|work=CBC News}} This makes it possible for crocodiles to detect prey, danger and intruders, even in total darkness. These sense organs are known as domed pressure receptors (DPRs).{{cite journal | last1 = Jackson | first1 = K. | last2 = Brooks | first2 = D.R. | year = 2007 | title = Do crocodiles co-opt their sense of "touch" to "taste"? A possible new type of vertebrate sensory organ | url = http://people.whitman.edu/~jacksok/AMRE2447.pdf | journal = Amphibia-Reptilia | volume = 28 | issue = 2 | pages = 277–285 | doi = 10.1163/156853807780202486 | access-date = 29 April 2013 | archive-url = https://web.archive.org/web/20130730091857/http://people.whitman.edu/~jacksok/AMRE2447.pdf | archive-date = 30 July 2013 | url-status = dead }}

Post-Cranial: While alligators and caimans have DPRs only on their jaws, crocodiles have similar organs on almost every scale on their bodies. The function of the DPRs on the jaws is clear; to catch prey, but it is still not clear what the function is of the organs on the rest of the body. The receptors flatten when exposed to increased osmotic pressure, such as that experienced when swimming in sea water hyperosmotic to the body fluids. When contact between the integument and the surrounding sea water solution is blocked, crocodiles are found to lose their ability to discriminate salinities. It has been proposed that the flattening of the sensory organ in hyperosmotic sea water is sensed by the animal as "touch", but interpreted as chemical information about its surroundings. This might be why in alligators they are absent on the rest of the body.{{cite web|url=http://crocodilian.com/cnhc/cbd-gb1.htm |title=Crocodilian Biology Database – Integumentary Sense Organs |publisher=Crocodilian.com |access-date=26 April 2013}}

File:Crocodile attack during Mara River crossing - frame 1 - Flickr - Lip Kee.jpg

File:Human Crocodile Conflict.jpg

File:Crocodile at Ranganathittu, Mysore, Karnataka.JPG

Crocodiles are ambush predators, waiting for fish or land animals to come close, then rushing out to attack. Crocodiles mostly eat fish, amphibians, crustaceans, molluscs, birds, reptiles, and mammals, and they occasionally cannibalize smaller crocodiles. What a crocodile eats varies greatly with species, size and age. From the mostly fish-eating species, like the slender-snouted and freshwater crocodiles, to the larger species like the Nile crocodile and the saltwater crocodile that prey on large mammals, such as buffalo, deer and wild boar, diet shows great diversity. Diet is also greatly affected by the size and age of the individual within the same species. All young crocodiles hunt mostly invertebrates and small fish, gradually moving on to larger prey. Being ectothermic (cold-blooded) predators, they have a very slow metabolism, so they can survive long periods without food. Despite their appearance of being slow, crocodiles have a very fast strike and are top predators in their environment, and various species have been observed attacking and killing other predators such as sharks and big cats.{{cite web|url=https://www.nationalgeographic.com/animals/?nav=A-Z |title=Saltwater Crocodile, Saltwater Crocodile Profile, Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, News – National Geographic |publisher=Animals.nationalgeographic.com |access-date=16 March 2010}}{{cite web |url=http://crocodilian.com/cnhc/csp_cnil.htm |title=Crocodilian Species – Nile Crocodile (Crocodylus niloticus) |publisher=Crocodilian.com |access-date=26 April 2013 |archive-date=25 October 2011 |archive-url=https://web.archive.org/web/20111025183255/http://crocodilian.com/cnhc/csp_cnil.htm |url-status=dead }} Crocodiles are also known to be aggressive scavengers who feed upon carrion and steal from other predators.{{cite web|url=http://www.australiananimallearningzone.com/saltwater-crocodile-crocodylus-porosus.htm|title=Saltwater Crocodile Profile|work=Australian Animal|date=22 December 2012 }} Evidence suggests that crocodiles also feed upon fruits, based on the discovery of seeds in stools and stomachs from many subjects as well as accounts of them feeding.{{cite magazine|url=http://www.popsci.com/article/science/are-crocodiles-secret-fruit-lovers|title=ARE CROCODILES SECRET FRUIT-LOVERS?|magazine=Popular Science|author=Jon Tennant}} 13 November 2013{{cite web|url=http://www.livescience.com/39198-crocodiles-alligators-eat-fruit.html?li_source=LI&li_medium=more-from-livescience|title=Crikey! Crocodiles and Alligators Snack on Fruit|work=Live Science|author=Charles Q. Choi|date=27 August 2013}} 27 August 2013

Crocodiles have the most acidic stomach of any vertebrate. They can easily digest bones, hooves and horns. The BBC TVBBC channel 1 program Inside The Perfect Predator, Thursday 25 March 2010 reported that a Nile crocodile that has lurked a long time underwater to catch prey builds up a large oxygen debt. When it has caught and eaten that prey, it closes its right aortic arch and uses its left aortic arch to flush blood loaded with carbon dioxide from its muscles directly to its stomach; the resulting excess acidity in its blood supply makes it much easier for the stomach lining to secrete more stomach acid to quickly dissolve bulks of swallowed prey flesh and bone. Many large crocodilians swallow stones (called gastroliths or stomach stones), which may act as ballast to balance their bodies or assist in crushing food, similar to grit ingested by birds. Herodotus claimed that Nile crocodiles had a symbiotic relationship with certain birds, such as the Egyptian plover, which enter the crocodile's mouth and pick leeches feeding on the crocodile's blood; with no evidence of this interaction actually occurring in any crocodile species, it is most likely mythical or allegorical fiction.{{cite web |author=Adam Britton |url=http://crocodilian.blogspot.com/2009/09/crocodile-myths-1-curious-trochilus.html |title=Croc Blog: Crocodile myths #1 – the curious trochilus |publisher=Crocodilian.blogspot.com |date=6 September 2009 |access-date=26 April 2013 |archive-date=11 March 2013 |archive-url=https://web.archive.org/web/20130311082746/http://crocodilian.blogspot.com/2009/09/crocodile-myths-1-curious-trochilus.html |url-status=dead }}

File:Nile Crocodile (Crocodylus niloticus) trying to swallow a big Tilapia (Oreochromis sp.)... (16818888756).jpg in Kruger National Park, South Africa]]

Since they feed by grabbing and holding onto their prey, they have evolved sharp teeth for piercing and holding onto flesh, and powerful muscles to close the jaws and hold them shut. The teeth are not well-suited to tearing flesh off of large prey items as are the dentition and claws of many mammalian carnivores, the hooked bills and talons of raptorial birds, or the serrated teeth of sharks. However, this is an advantage rather than a disadvantage to the crocodile since the properties of the teeth allow it to hold onto prey with the least possibility of the prey animal escaping. Cutting teeth, combined with the exceptionally high bite force, would pass through flesh easily enough to leave an escape opportunity for prey. The jaws can bite down with immense force, by far the strongest bite of any animal. The force of a large crocodile's bite is more than {{convert|5000|lbf|N|abbr=on}}, which was measured in a {{convert|5.5|m|ft|abbr=on}} Nile crocodile, in the field;National Geographic documentary; "Bite Force", Brady Barr. comparing to {{convert|335|lbf|N|abbr=on}} for a Rottweiler, {{convert|800|lbf|N|abbr=on}} for a hyena, {{convert|2200|lbf|N|abbr=on}} for an American alligator,{{cite web|url=http://dogfacts.wordpress.com/2008/02/03/national-geographics-dr-brady-barrs-bite-pressure-tests/ |title=National Geographic's Dr. Brady Barr's Bite Pressure Tests | Dog Facts |publisher=Dogfacts.wordpress.com |access-date=26 April 2013|date=3 February 2008 }}{{failed verification|date=October 2014}} and {{convert|4095|lbf|N|abbr=on}} for the largest confirmed great white shark.{{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.|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 |archive-url=https://ghostarchive.org/archive/20221009/http://www.bio-nica.info/Biblioteca/Wroe2008GreatWhiteSharkBiteForce.pdf |archive-date=2022-10-09 |url-status=live|journal=Journal of Zoology|volume=276|issue=4|pages=336–342|year= 2008|doi=10.1111/j.1469-7998.2008.00494.x}}

A {{convert|5.2|m|ft|abbr=on}} long saltwater crocodile has been confirmed as having the strongest bite force ever recorded for an animal in a laboratory setting. It was able to apply a bite force value of {{convert|3700|lbf|N|abbr=on}}, and thus surpassed the previous record of {{convert|2125|lbf|N|abbr=on}} made by a {{convert|3.9|m|ft|abbr=on}} long American alligator.{{cite journal|title=The ontogeny of bite-force performance in American alligator (Alligator mississippiensis)|journal=Journal of Zoology|volume=260|issue=3|pages=317–327|url=http://www.alligatorfarm.us/images/Research/Erickson%20et%20al.%202003.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.alligatorfarm.us/images/Research/Erickson%20et%20al.%202003.pdf |archive-date=2022-10-09 |url-status=live|doi=10.1017/S0952836903003819|year=2003|last1=Erickson|first1=Gregory M.|last2=Lappin|first2=A. Kristopher|last3=Vliet|first3=Kent A.}}{{cite journal|url=https://www.sciencedaily.com/releases/2012/03/120316093427.htm|title=Australian saltwater crocodiles are world's most powerful biters |journal=PLOS ONE |volume=7 |issue=3 |pages=e31781 |doi=10.1371/journal.pone.0031781 |pmid=22431965 |pmc=3303775 |date=16 March 2012 |access-date=26 April 2013|bibcode=2012PLoSO...731781E|last1=Erickson |first1=Gregory M. |last2=Gignac |first2=Paul M. |last3=Steppan |first3=Scott J. |last4=Lappin |first4=A. Kristopher |last5=Vliet |first5=Kent A. |last6=Brueggen |first6=John D. |last7=Inouye |first7=Brian D. |last8=Kledzik |first8=David |last9=Webb |first9=Grahame J. W. |doi-access=free }} Taking the measurements of several {{convert|5.2|m|ft|abbr=on}} crocodiles as reference, the bite forces of 6-m individuals were estimated at {{convert|7700|lbf|N|abbr=on}}.{{cite web|url=http://news.nationalgeographic.com/news/2012/03/120315-crocodiles-bite-force-erickson-science-plos-one-strongest/ |archive-url=https://web.archive.org/web/20120317064400/http://news.nationalgeographic.com/news/2012/03/120315-crocodiles-bite-force-erickson-science-plos-one-strongest/ |url-status=dead |archive-date=17 March 2012 |title=Crocodiles Have Strongest Bite Ever Measured, Hands-on Tests Show |publisher=News.nationalgeographic.com |date=15 March 2012 |access-date=26 April 2013}} The study, led by Dr. Gregory M. Erickson, also shed light on the larger, extinct species of crocodilians. Since crocodile anatomy has changed only slightly over the last 80 million years, current data on modern crocodilians can be used to estimate the bite force of extinct species. An {{convert|11|to(-)|12|m|ft|adj=on}} Deinosuchus would apply a force of {{convert|23100|lbf|N|abbr=on}}, nearly twice that of the latest, higher bite force estimations of Tyrannosaurus ({{convert|12814|lbf|N|abbr=on}}).{{cite web|url=http://www.smithsonianmag.com/science-nature/The-Tyrannosaurus-Rexs-Dangerous-and-Deadly-Bite-37252918/|title=The Tyrannosaurus Rex's Dangerous and Deadly Bite|website=Smithsonian|date=October 2012|first=Riley|last=Black|access-date=6 June 2021}}{{Cite journal|last1=Bates|first1=K. T.|last2=Falkingham|first2=P.L.|date=29 February 2012|title=Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics|journal=Biology Letters|volume=8|issue=4|pages=660–664|doi=10.1098/rsbl.2012.0056|pmid=22378742|pmc=3391458}}Crispian Scully, (2002) Oxford Handbook of Applied Dental Sciences, Oxford University Press –{{ISBN|978-0-19-851096-3}} P156 The extraordinary bite of crocodilians is a result of their anatomy. The space for the jaw muscle in the skull is very large, which is easily visible from the outside as a bulge at each side. The muscle is so stiff, it is almost as hard as bone to touch, as if it were the continuum of the skull. Another trait is that most of the muscle in a crocodile's jaw is arranged for clamping down. Despite the strong muscles to close the jaw, crocodiles have extremely small and weak muscles to open the jaw. Crocodiles can thus be subdued for study or transport by taping their jaws or holding their jaws shut with large rubber bands cut from automobile inner tubes.

File:Crocodile farm in Mexico.JPG

Crocodiles can move quickly over short distances, even out of water. The land speed record for a crocodile is {{convert|17|km/h|0|abbr=on}} measured in a galloping Australian freshwater crocodile.{{cite web | last = Britton | first = Adam | title = Crocodilian Biology Database FAQ, "How fast can a crocodile run?" | url=http://www.flmnh.ufl.edu/cnhc/cbd-faq-q4.htm | access-date = 2 February 2008}} Maximum speed varies between species. Some species can gallop, including Cuban crocodiles, Johnston's crocodiles, New Guinea crocodiles, African dwarf crocodiles, and even small Nile crocodiles. The fastest means by which most species can move is a "belly run", in which the body moves in a snake-like (sinusoidal) fashion, limbs splayed out to either side paddling away frantically while the tail whips to and fro. Crocodiles can reach speeds of {{convert|10|-|11|km/h|0|abbr=on}} when they "belly run", and often faster if slipping down muddy riverbanks. When a crocodile walks quickly, it holds its legs in a straighter and more upright position under its body, which is called the "high walk". This walk allows a speed of up to 5 km/h.{{cite book|last1=Walters|first1=Martin|last2=Johnson|first2=Jinny|title=Encyclopedia of Animals|publisher=Marks and Spencer p.l.c|isbn=978-1-84273-964-8|page=145}}

Crocodiles may possess a homing instinct. In northern Australia, three rogue saltwater crocodiles were relocated {{convert|400|km|0|abbr=on}} by helicopter, but returned to their original locations within three weeks, based on data obtained from tracking devices attached to them.{{cite journal|author=Read M. A.|author2=Grigg G. C.|author3=Irwin S. R.|author4=Shanahan D.|author5=Franklin C. E. |year=2007 |title=Satellite Tracking Reveals Long Distance Coastal Travel and Homing by Translocated Estuarine Crocodiles, Crocodylus porosus |journal= PLOS ONE |volume=2 |issue=9 |page=e949 |doi=10.1371/journal.pone.0000949 |editor1-last=Lusseau |editor1-first=David |pmid=17895990 |pmc=1978533|bibcode=2007PLoSO...2..949R|doi-access=free}}

Measuring crocodile age is unreliable, although several techniques are used to derive a reasonable guess. The most common method is to measure lamellar growth rings in bones and teeth—each ring corresponds to a change in growth rate which typically occurs once a year between dry and wet seasons.{{cite web|url=http://www.flmnh.ufl.edu/cnhc/cbd-faq-q3.htm |title=Crocodilian Biology Database, FAQ. "How long do crocodiles live for?" |publisher=Flmnh.ufl.edu |access-date=26 April 2013}} Bearing these inaccuracies in mind, it can be safely said that all crocodile species have an average lifespan of at least 30–40 years, and in the case of larger species an average of 60–70 years. The oldest crocodiles appear to be the largest species. C. porosus is estimated to live around 70 years on average, with limited evidence of some individuals exceeding 100 years.{{cite web |url=http://crocodilian.com/cnhc/cbd-faq-q3.htm |title=Crocodilian Biology Database – FAQ – How long do crocodiles live for? |publisher=Crocodilian.com |access-date=26 April 2013 |archive-date=21 March 2015 |archive-url=https://web.archive.org/web/20150321151949/http://crocodilian.com/cnhc/cbd-faq-q3.htm |url-status=dead }}

In captivity, some individuals are claimed to have lived for over a century. A male crocodile lived to an estimated age of 110–115 years in a Russian zoo in Yekaterinburg. Named Kolya, he joined the zoo around 1913 to 1915, fully grown, after touring in an animal show, and lived until 1995.{{cite news | agency=Associated Press | title=Crocodile at Russian zoo dies; on display since czars | date=16 February 1995 | work=The News–Journal | location=Daytona Beach, Florida | volume=70 | issue=47 | publisher=News–Journal Corporation | url=https://news.google.com/newspapers?nid=1901&dat=19950216&id=MqgtAAAAIBAJ&pg=2827,36264 }} A male freshwater crocodile lived to an estimated age of 120–140 years at the Australia Zoo.{{cite news | title=Freshie the croc dies at age 140 | first=Kieran | last=Campbell | date=24 March 2010 | url=http://www.sunshinecoastdaily.com.au/news/freshie-the-croc-dies-at-age-140/494141/ | work=Sunshine Coast Daily }} Known affectionately as "Mr. Freshie", he was rescued around 1970 by Bob Irwin and Steve Irwin, after being shot twice by hunters and losing an eye as a result, and lived until 2010. Crocworld Conservation Centre, in Scottburgh, South Africa, claims to have a male Nile crocodile that was born in 1900. Named Henry, the crocodile is said to have lived in Botswana along the Okavango River, according to centre director Martin Rodrigues.{{cite web|url=http://ibnlive.in.com/news/johannesburg-worlds-oldest-crocodile-turns-114/518422-2.html |archive-url=https://web.archive.org/web/20141217215908/http://ibnlive.in.com/news/johannesburg-worlds-oldest-crocodile-turns-114/518422-2.html |url-status=dead |archive-date=17 December 2014 |title=Johannesburg: World's oldest crocodile turns 114 |publisher=IBN Live |date=16 December 2014| access-date=19 December 2014}}{{cite news |url=http://www.elnuevodia.com/celebrancumpleanosdelcocodrilomaslongevodelmundo-1911287.html |title=Celebran cumpleaños del cocodrilo más longevo del mundo |newspaper=El Nuevo Día |date=16 December 2014 |access-date=19 December 2014 |archive-date=21 December 2014 |archive-url=https://web.archive.org/web/20141221220518/http://www.elnuevodia.com/celebrancumpleanosdelcocodrilomaslongevodelmundo-1911287.html |url-status=dead }}

File:Crocodiles resting together.jpeg

Crocodiles are the most social of reptiles. Even though they do not form social groups, many species congregate in certain sections of rivers, tolerating each other at times of feeding and basking. Most species are not highly territorial, with the exception of the saltwater crocodile, which is a highly territorial and aggressive species: a mature, male saltwater crocodile will not tolerate any other males at any time of the year, but most other species are more flexible. There is a certain form of hierarchy in crocodiles: the largest and heaviest males are at the top, having access to the best basking site, while females are priority during a group feeding of a big kill or carcass. A good example of the hierarchy in crocodiles would be the case of the Nile crocodile. This species clearly displays all of these behaviours. Studies in this area are not thorough, however, and many species are yet to be studied in greater detail.{{cite web |url=http://crocodilian.com/cnhc/csp_cnil.htm |title=Crocodilian Species List |publisher=Crocodilian.com |access-date=26 April 2013 |archive-date=25 October 2011 |archive-url=https://web.archive.org/web/20111025183255/http://crocodilian.com/cnhc/csp_cnil.htm |url-status=dead }} Mugger crocodiles are also known to show toleration in group feedings and tend to congregate in certain areas. However, males of all species are aggressive towards each other during mating season, to gain access to females.

Crocodiles are also the most vocal of all reptiles, producing a wide variety of sounds during various situations and conditions, depending on species, age, size and sex. Depending on the context, some species can communicate over 20 different messages through vocalizations alone.{{cite web|url=http://crocodilian.com/cnhc/croccomm.html |title=Crocodilian Communication |publisher=Crocodilian.com |access-date=29 April 2013}} Some of these vocalizations are made during social communication, especially during territorial displays towards the same sex and courtship with the opposite sex; the common concern being reproduction. Therefore most conspecific vocalization is made during the breeding season, with the exception being year-round territorial behaviour in some species and quarrels during feeding. Crocodiles also produce different distress calls and in aggressive displays to their own kind and other animals; notably other predators during interspecific predatory confrontations over carcasses and terrestrial kills.

Specific vocalisations include —

• Chirp: When about to hatch, the young make a "peeping" noise, which encourages the female to excavate the nest. The female then gathers the hatchlings in her mouth and transports them to the water, where they remain in a group for several months, protected by the female{{cite web|url=http://www.arkive.org/nile-crocodile/crocodylus-niloticus/|archive-url=https://web.archive.org/web/20090123041108/http://www.arkive.org/nile-crocodile/crocodylus-niloticus/|url-status=dead|archive-date=23 January 2009|author=Arkive|title=Nile crocodile (Crocodylus niloticus)|access-date=29 April 2013}}
• Distress call: A high-pitched call used mostly by younger animals to alert other crocodiles to imminent danger or an animal being attacked.
• Threat call: A hissing sound that has also been described as a coughing noise.
• Hatching call: Emitted by a female when breeding to alert other crocodiles that she has laid eggs in her nest.
• Bellowing: Male crocodiles are especially vociferous. Bellowing choruses occur most often in the spring when breeding groups congregate, but can occur at any time of year. To bellow, males noticeably inflate as they raise the tail and head out of water, slowly waving the tail back and forth. They then puff out the throat and with a closed mouth, begin to vibrate air. Just before bellowing, males project an infrasonic signal at about 10 Hz through the water, which vibrates the ground and nearby objects. These low-frequency vibrations travel great distances through both air and water to advertise the male's presence and are so powerful they result in the water's appearing to "dance".{{cite web |url=http://factsanddetails.com/Asian.php?itemid=2435&subcatid=434 |archive-url=https://archive.today/20130629045148/http://factsanddetails.com/Asian.php?itemid=2435&subcatid=434 |url-status=dead |archive-date=29 June 2013 |author=Hays, J. |title=Crocodiles: Their history, characteristics and behavior |year=2008 |access-date=31 May 2013 }}

File:Nile crocodile eggs.jpg

Courtship takes place in a series of behavioural interactions that include a variety of snout rubbing and submissive display that can take a long time. Mating always takes place in water, where the pair can be observed mating several times.

Egg-laying usually takes place at night and about 30–40 minutes, which are laid in either holes or mound nests, depending on species. The eggs are hard shelled, but translucent at the time of egg-laying. Depending on the species of crocodile, 7 to 95 eggs are laid. Scutes may play a role in calcium storage for eggshell formation.

Nesting periods range from a few weeks up to six months. A hole nest is usually excavated in sand and a mound nest is usually constructed out of vegetation. Females can build or dig several trial nests which appear incomplete and abandoned later. {{cite book |author1=K. Richardson |author2=G. Webb |author3=C. Manolis |title = Crocodiles: Inside and Out |year = 2000}} Females are highly protective of their nests and young. Crocodile embryos do not have sex chromosomes, and unlike humans, sex is not determined genetically. Sex is determined by temperature, where at {{convert|30|°C|0|abbr=on}} or less most hatchlings are females and at {{convert|31|°C|0|abbr=on}}, offspring are of both sexes. A temperature of {{convert|32|to|33|°C|0|abbr=on}} gives mostly males whereas above {{convert|33|°C|0|abbr=on}} in some species continues to give males, but in other species resulting in females, which are sometimes called high-temperature females.{{cite book |author1=G. Webb |author2=C. Manolis |title = Crocodiles of Australia |year = 1989}} Temperature also affects growth and survival rate of the young, which may explain the sexual dimorphism in crocodiles. The average incubation period is around 80 days, and also is dependent on temperature and species that usually ranges from 65 to 95 days. The eggshell structure is very conservative through evolution but there are enough changes to tell different species apart by their eggshell microstructure.{{cite journal | last1 = Marzola | first1 = M. | last2 = Russo | first2 = J. | last3 = Mateus | first3 = O. | year = 2015 | title = Identification and comparison of modern and fossil crocodilian eggs and eggshell structures | journal = Historical Biology | volume = 27 | issue = 1| pages = 115–133 | doi=10.1080/08912963.2013.871009| bibcode = 2015HBio...27..115M | s2cid = 85685470 }}

At the time of hatching, the young start calling within the eggs. They have an egg-tooth at the tip of their snouts, which is developed from the skin, and that helps them pierce out of the shell. Hearing the calls, the female usually excavates the nest and sometimes takes the unhatched eggs in her mouth, slowly rolling the eggs to help the process. The young is usually carried to the water in the mouth. She would then introduce her hatchlings to the water and even feed them.{{cite web|url=http://scienceblogs.com/tetrapodzoology/2008/11/08/crocs-feed-their-babies/|title=Do crocodilians (sometimes) feed their young?|publisher=Science Blogs|author=Darren Naish}} 8 November 2008 The mother would then take care of her young for over a year before the next mating season. In the absence of the mother crocodile, the father would act in her place to take care of the young.{{cite web|url=http://oddstuffmagazine.com/10-delightful-baby-animals-that-grow-up-to-be-fatal-predators.html|title=10 Delightful Baby Animals that Grow up to Be Fatal Predators|date=3 February 2012|publisher=Odd Stuff}} 3 February 2012 However, even with a sophisticated parental nurturing, young crocodiles have a very high mortality rate due to their vulnerability to predation.{{cite web|url=http://animals.mom.me/life-cycle-alligators-crocodiles-8058.html|title=THE LIFE CYCLE OF ALLIGATORS AND CROCODILES|publisher=Demand Media|author= Jasey Kelly}} A group of hatchlings is called a pod or crèche and may be protected for months.

Crocodiles possess some advanced cognitive abilities.{{cite news|url=https://www.latimes.com/science/sciencenow/la-sci-sn-clever-crocodiles-alligators-sticks-twigs-birds-lure-prey-20131206-story.html|title=Scary smart! Clever crocodiles, alligators use sticks to lure prey|author=Amina Khan|newspaper=Los Angeles Times|date=6 December 2013}} 6 December 2013{{cite news|url=https://www.washingtonpost.com/national/health-science/crocodiles-and-their-ilk-may-be-smarter-than-they-look/2013/12/06/1084cf28-5d2c-11e3-bc56-c6ca94801fac_story.html|title=Crocodiles and their ilk may be smarter than they look|newspaper=The Washington Post|author=Jason G. Goldman}} 9 December 2013 Crocodiles cooperatively hunt. {{cite web|url=http://www.oneworldmagazine.org/tales/crocs/smart.html|archive-url=https://web.archive.org/web/20000930224445/http://www.oneworldmagazine.org/tales/crocs/smart.html|url-status=dead|archive-date=30 September 2000|title=The Crocodile Files|work=One World Magazine}} Large numbers of crocodiles swim in circles to trap fish and take turns snatching them. In hunting larger prey, crocodiles swarm in, with one holding the prey down as the others rip it apart.

Vladimir Dinets of the University of Tennessee, observing crocodile's use of twigs as bait was inconclusive. {{Cite journal|last1=Dinets|first1=Vladimir |last2=Brueggen

|first2=J.C. |last3=Brueggen

|first3=J.D. |url=https://www.researchgate.net/publication/271994159|date=December 2013|title=Crocodilians use tools for hunting|journal=Ethology Ecology & Evolution|volume=27|issue=1|pages=74–78|publisher= www.researchgate.net|doi=10.1080/03949370.2013.858276}}

{{Main|Crocodile attacks}}

File:Marine Stingers Sign Cairns.JPG, Australia]]

The larger species of crocodiles are very dangerous to humans, mainly because of their ability to strike before the person can react.{{cite web|title=Crocodilian Attacks|url=http://www.iucncsg.org/pages/Crocodilian-Attacks.html|publisher=IUCN Crocodile Specialist Group (iucncsg.org)|access-date=3 February 2013}} The saltwater crocodile and Nile crocodile are the most dangerous, killing hundreds of people each year in parts of Southeast Asia and Africa. The mugger crocodile and American crocodile are also dangerous to humans.{{citation needed|date=August 2023}}

{{Further|Crocodile farm|Crocodile skin}}

File:Crocodile wallets.jpg crocodile farm]]

File:Teriyaki CrocTail.jpg in Helsinki, Finland]]

Crocodiles are protected in many parts of the world, but are also farmed commercially. Their hides are tanned and used to make leather goods such as shoes and handbags; crocodile meat is also considered a delicacy.{{cite news |url=https://www.nytimes.com/1998/11/30/us/anahuac-journal-alligator-farmer-feeds-demand-for-all-the-parts.html |title=Anahuac Journal; Alligator Farmer Feeds Demand for All the Parts |work=The New York Times |date=30 November 1998 |last=Lyman |first=Rick |access-date=13 November 2013}} The most commonly farmed species are the saltwater and Nile crocodiles, while a hybrid of the saltwater and the rare Siamese crocodile is also bred in Asian farms. Farming has resulted in an increase in the saltwater crocodile population in Australia, as eggs are usually harvested from the wild, so landowners have an incentive to conserve their habitat. Crocodile leather can be made into goods such as wallets, briefcases, purses, handbags, belts, hats, and shoes. Crocodile oil has been used for various purposes.{{cite book|author=Elisabeth Janos|title=Country Folk Medicine: Tales of Skunk Oil, Sassafras Tea and Other Old-Time Remedies|url=https://books.google.com/books?id=FUaaDBFsYFEC&pg=PA56|year=2004|publisher=Globe Pequot Press|isbn=978-1-59228-178-7|page=56}} Crocodiles were eaten by Vietnamese while they were taboo and off limits for Chinese. Vietnamese women who married Chinese men adopted the Chinese taboo.{{cite book |author=Erica J. Peters |title=Appetites and Aspirations in Vietnam: Food and Drink in the Long Nineteenth Century |url=https://books.google.com/books?id=o_P1ig12re4C&pg=PA142 |year=2012 |publisher=Rowman Altamira |isbn=978-0-7591-2075-4 |pages=142–}}

Crocodile meat is consumed in some countries, such as Australia, Ethiopia, Thailand, South Africa, China, and Cuba (in pickled form). It is also occasionally eaten as an "exotic" delicacy in the western world.{{cite news| last1=Armstrong| first1=Hilary|title=Best exotic restaurants in London|url=https://www.standard.co.uk/goingout/restaurants/best-exotic-restaurants-in-london-6863561.html|newspaper=London Evening Standard|access-date=4 September 2016|date=8 April 2009}} Cuts of meat include backstrap and tail fillet.{{citation needed|date=August 2023}}

Due to high demand for crocodile products, TRAFFIC states that 1,418,487 Nile Crocodile skins were exported from Africa between 2006 and 2015.{{Cite web|url=https://www.traffic.org/what-we-do/species/reptiles-and-amphibians/|title=Reptiles and amphibians – Species we work with at TRAFFIC|website=www.traffic.org|access-date=10 January 2019}}

Aboriginal Australians harvested eggs and hunted crocodiles in a sustainable way for many thousands of years. The Brinkin people (aka Marrithiyal) of the Daly River in the Northern Territory (NT) used harpoons and bamboo, and even their own hands to capture crocodiles for food.{{cite web | last=Ryall | first=Jenni | title=Incredible video shows how crocodiles were hunted in Australia in 1949 |format=text + video, 10m.| website=Mashable | date=29 October 2021 | url=https://mashable.com/article/crocodile-hunters-australia | access-date=29 August 2023}} After settlement of northern Australia, in the late-19th and early 20th centuries, non-Indigenous people killed individual crocodiles, mostly by locals to protect the population, or novelty-seeking visitors, or just opportunistically, so numbers were not noticeably reduced. From the 1930s, commercial hunting began, with Aboriginal people often employed to kill the crocodiles using traditional methods. From the 1940s to the 1960s, hunting began on a larger scale using .303 rifles.{{cite web | title=Crocodile hunting | website=Queensland Historical Atlas | date=21 August 2013 | url=https://www.qhatlas.com.au/crocodile-hunting | access-date=29 August 2023}} They were hunted for leather, with the skins shipped to plants in capital cities. Western Australia banned hunting freshwater crocodiles in 1962 and saltwater crocodiles in 1970, while NT bans were brought in 1964 and 1971; Queensland did not pass such legislation. The federal government later banned the export of crocodile skins, which brought commercial hunting to an end in Queensland. They have been a protected species since the 1970s, when numbers were down to approximately 3,000 in the NT at the lowest estimate. In 2021, after several attacks on humans by the "salties" and an estimated population of around 200,000 had been reached, Queensland politician Bob Katter called for the reintroduction of hunting.{{cite web | last=Vidler | first=Adam | title=With more big crocs than ever, should hunting be allowed? | website=9News | date=29 March 2021 | url=https://www.9news.com.au/national/crocodile-populations-rising-protected-hunting-bob-katter/023d28c2-ee46-436c-a790-a5c952efe160 | access-date=29 August 2023}}

{{Further|Crocodilia#Cultural depictions}}

File:Sobek Oxford.jpg from the mortuary temple of Amenemhat III {{circa}} 1810 BC. Ashmolean Museum, Oxford.]]

File:Plaque with Crocodile Deity, ca. 700-900.,33.448.12.jpg

Crocodiles have appeared in various forms in religions across the world. Ancient Egypt had Sobek, the crocodile-headed god, with his cult-city Crocodilopolis, as well as Taweret, the goddess of childbirth and fertility, with the back and tail of a crocodile.{{cite web|url=http://www.touregypt.net/featurestories/sobek.htm|title=Egypt: The Crocodile God, Sobek|publisher=Tour Egypt|author=Catherine C. Harris}} The Jukun shrine in the Wukari Federation, Nigeria is dedicated to crocodiles in thanks for their aid during migration.{{cite news|url=http://allafrica.com/stories/200906240052.html|title=Nigeria: How Giant Crocodiles Guided Jukun to Kwararafa|work=All Africa|author=Fidelis Mac-Leva}} 24 June 2009 In Madagascar various peoples such as the Sakalava and Antandroy see crocodiles as ancestor spirits and under local fady often offer them food;Campbell, Gwyn (2012). David Griffiths and the Missionary "History of Madagascar". Leiden, The Netherlands: Brill. {{ISBN|978-90-04-19518-9}}.Marty Crump, Livros no Google Play

Eye of Newt and Toe of Frog, Adder's Fork and Lizard's Leg: The Lore and Mythology of Amphibians and Reptiles, University of Chicago Press, 16 November 2015 in the case of the latter at least a crocodile features prominently as an ancestor deity.An Athenæum article [https://books.google.com/books?id=-t8RAAAAYAAJ&pg=PA247 makes a claim] of a specific crocodile deity named textually as "Jacaret", but less biased sources do not mention this theonym in any capacity.

Crocodiles appear in different forms in Hinduism. Varuna, a Vedic and Hindu god, rides a part-crocodile makara; his consort Varuni rides a crocodile. Similarly the goddess personifications of the Ganga and Yamuna rivers are often depicted as riding crocodiles.{{cite web | title = Holy Rivers, Lakes, and Oceans | work = Heart of Hinduism | publisher = ISKCON Educational Services | year = 2004 | url = http://hinduism.iskcon.org/practice/504.htm | quote = Most rivers are considered female and are personified as goddesses. Ganga, who features in the Mahabharata, is usually shown riding on a crocodile (see right). | access-date = 16 September 2014 | archive-url = https://web.archive.org/web/20141014184216/http://hinduism.iskcon.org/practice/504.htm | archive-date = 14 October 2014 | url-status = dead}}{{cite web | title = Ganga The River Goddess – Tales in Art and Mythology | date = August 2003 | first = Nitin | last = Kumar | url = http://www.exoticindiaart.com/article/ganga/ | quote = The second distinguishing aspect of Ganga's iconography is her animal mount, which is often shown serving as a pedestal for her. This is the makara, a hybrid creature having the body of a crocodile and the tail of a fish. The makara in Hindu thought corresponds to the star sign of Capricorn in western astrology. The crocodile is a unique animal in that it can live on both land and sea. It thus denotes the wisdom of both the earth and waters.}}{{cite web | title = Hindu gods and their holy mounts | publisher = Sri.Venkateswara Zoological Park | url = http://svzoo.org/html/anicult2.htm | quote = The river goddesses, Ganga and Yamuna, were appropriately mounted on a tortoise and a crocodile respectively. | url-status = dead | archive-url = https://web.archive.org/web/20140623165912/http://svzoo.org/html/anicult2.htm | archive-date = 23 June 2014}} Also in India, in Goa, crocodile worship is practised, including the annual Mannge Thapnee ceremony.{{cite journal |author= |title=The Crocodile is God in Goa |journal=Crocodile Specialist Group Newsletter |date=January–March 1995 |volume=14 |issue=1 |page=8 |url=http://www.iucncsg.org/365_docs/attachments/protarea/CSG%20-96e3654b.pdf |archive-url=https://ghostarchive.org/archive/20221009/http://www.iucncsg.org/365_docs/attachments/protarea/CSG%20-96e3654b.pdf |archive-date=2022-10-09 |url-status=live }}

Sikh warriors known as nihang also have connections with crocodiles. Nihang may come from the Persian word for a mythical sea creature ({{langx|fa|نهنگ}}).{{cite book | last=Taba| first= David| year=2011| title= Iranian Character of The Armenian Language | page=9}} The term owes its origin to Mughal historians, who compared the ferocity of the Akali with that of crocodiles.{{cite web | title=Explainer Nihang Sikh sect in spotlight again after Singhu killing | website=The Federal | date=15 October 2021 | url=https://thefederal.com/videos/explainers/explainer-nihang-sikh-sect-in-spotlight-again-after-singhu-killing/ | access-date=29 August 2023}}{{cite web | title=The Nihang | website=Sikh Heritage | url=http://www.sikh-heritage.co.uk/movements/Nihangs/Nihangs.htm | access-date=29 August 2023}} In Sikhism however, Akali refers to the immortal army of Akal (god).{{cite book | last=Singh | first=Khushwant | year=1999 | title=A History of the Sikhs Voghzlume I:1469–1839 | publisher=Oxford University Press | location=India | isbn = 0-19-562643-5 | page=215}}

In Latin America, Cipactli was the giant earth crocodile of the Aztec and other Nahua peoples.{{citation needed|date=September 2021}}

File:City of Surabaya Logo.svg

The name of Surabaya, Indonesia, is locally believed to be derived from the words "suro" (shark) and "boyo" (crocodile), two creatures which, in a local myth, fought each other in order to gain the title of "the strongest and most powerful animal" in the area. It was said that the two powerful animals agreed for a truce and set boundaries; that the shark's domain would be in the sea while the crocodile's domain would be on the land. However one day the shark swam into the river estuary to hunt; this angered the crocodile, who declared it his territory. The Shark argued that the river was a water-realm which meant that it was shark territory, while the crocodile argued that the river flowed deep inland, so it was therefore crocodile territory. The two animals bit each other and a ferocious fight ensued. Finally the shark, badly bitten, fled to the open sea, and in the end the crocodile ruled the estuarine area that today is the city.{{cite book|author1=Irwan Rouf|author2=Shenia Ananda|title=Rangkuman 100 Cerita Rakyat Indonesia: Dari Sabang Sampai Merauke|url=https://books.google.com/books?id=cPJqcwuSOUkC&pg=PA64| year=2013| publisher=AnakKita |isbn=978-602-9003-82-6 |page=60}} Another source alludes to a Jayabaya prophecy—a 12th-century psychic king of Kediri Kingdom—as he foresaw a fight between a giant white shark and a giant white crocodile taking place in the area. This is sometimes interpreted as a foretelling of the Mongol invasion of Java, a major conflict between the forces of the Kublai Khan, Mongol ruler of China, and those of Raden Wijaya's Majapahit in 1293.{{cite web|title=Welcome to Surabaya City, East Java|publisher=Surabaya Tourism, EastJava.com| url=http://www.eastjava.com/tourism/surabaya/|access-date=17 November 2014}} The two animals are now used as the city's symbol, with the two facing and circling each other, as depicted in a statue appropriately located near the entrance to the city zoo (see photo on the Surabaya page).{{citation needed|date=August 2023}}

File:The American River Ganges (Thomas Nast cartoon).jpg depicting Roman Catholic bishops as crocodiles attacking public schools, with the connivance of Irish Catholic politicians]]

{{Main|Crocodile tears}}

The term "crocodile tears" (and equivalents in other languages) refers to a false, insincere display of emotion, such as a hypocrite crying fake tears of grief. It is derived from an ancient anecdote that crocodiles weep in order to lure their prey, or that they cry for the victims they are eating, first told in the Bibliotheca by Photios I of Constantinople.{{cite book |title=Bibliothèque. Tome VIII : Codices 257–280. |last=PHOTIUS |others=Texte établi et traduit par R. Henry. |year=1977 |publisher=Les Belles Lettres |location=Paris |language=fr, grc |isbn=978-2-251-32227-8 |page=93 }} The story is repeated in bestiaries such as De bestiis et aliis rebus. This tale was first spread widely in English in the stories of the Travels of Sir John Mandeville in the 14th century, and appears in several of Shakespeare's plays.{{cite book |url=https://books.google.com/books?id=8-KxOZWvNdgC&pg=PT185 |title=Curious creatures in zoology |author=John Ashton |isbn=978-1-4092-3184-4 |year=2009}} In fact, crocodiles can and do generate tears, but they do not actually cry.[http://www.flmnh.ufl.edu/cnhc/cbd-faq-q6.htm Britton, Adam (n.d.). Do crocodiles cry 'crocodile tears'?] Crocodilian Biology Database. Retrieved 13 March 2006 from the Crocodile Specialist Group, Crocodile Species List, FAQ.

In the UK, a row of schoolchildren walking in pairs, or two by two is known as "crocodile".Martin H. Manser, Turton and Nigel D. Turton {{Google books|DXHJ1ylVHnYC|Advanced Learner's Dictionary|page=164}}Angela Brazil {{Google books|mmtGAgAAQBAJ|The Nicest Girl in the School|page=50}}

The French clothing company Lacoste features a crocodile in its logo. The American shoe company Crocs also uses this imagery in its logo.{{Cite web |last=Sandu |first=Bogdan |date=2023-09-25 |title=The Crocs Logo History, Colors, Font, and Meaning |url=https://www.designyourway.net/blog/crocs-logo/ |access-date=2024-10-29 |website=Design Your Way |language=en-US}}

{{Portal|Reptiles}}

{{div col|colwidth=30em}}

• Alligator meat
• The Crocodile Hunter
• Crocodilian armor
• Game (hunting)
• Sewer alligator
• Sobek – an ancient Egyptian deity associated with the Nile crocodile

{{div col end}}

{{clear}}

{{Reflist|30em}}

{{notelist}}

• Iskandar, DT (2000). Turtles and Crocodiles of Insular Southeast Asia and New Guinea. ITB, Bandung.
• Crocodilian Biology Database, FAQ. [http://www.flmnh.ufl.edu/cnhc/cbd-faq-q3.htm FLMNH.ufl.edu], "How long do crocodiles live for?" {{sic}} Adam Britton.
• Crocodilian Biology Database, FAQ. [http://www.flmnh.ufl.edu/cnhc/cbd-faq-q4.htm FLMNH.ufl.edu], "How fast can a crocodile run?" Adam Britton.

{{wiktionary}}

{{Wikispecies|Crocodylidae}}

{{Wikiversity}}

• {{Commons-inline|Crocodile}}
• [http://www.crocodilian.com/ Crocodilian Online] {{Webarchive|url=https://web.archive.org/web/20110708204615/http://www.crocodilian.com/ |date=8 July 2011 }}
• [http://www.flmnh.ufl.edu/cnhc/cbd.html Crocodilian Biology Database]
• [https://web.archive.org/web/20060623064651/http://www.nit.com.au/travel/story.aspx?id=3696 Crocodile Attacks in Australia]
• [http://news.bbc.co.uk/2/hi/science/nature/680840.stm BBC news finds powerful agent in crocodile blood]
• [http://www.scmp.com/lifestyle/fashion-luxury/article/2096381/worlds-most-expensive-handbag-sells-hong-kong-over-us377000 World's most expensive handbag sells in Hong Kong for over US$377,000 – a Hermès white crocodile] (31 May 2017), South China Morning Post
• [https://www.bbc.co.uk/news/world-asia-44844367 292 New Guinea crocodiles massacred] in West Papua, Indonesia

{{Crocodilia|C.}}

{{Extinct Crocodilia|C.}}

{{Crocs}}

{{Meat}}

{{Taxonbar|from=Q43169|from2=Q2535664}}

{{Authority control}}

{{DEFAULTSORT:Crocodile}}

Category:Extant Ypresian first appearances

Category:Taxa named by Georges Cuvier

Category:Crocodilian families