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{{Short description|Reptile of South Asia, Southeast Asia and Oceania}} | |||
{{taxobox | |||
{{pp-semi-indef}} | |||
| name = Saltwater Crocodile | |||
{{EngvarB|date=February 2014}} | |||
| status = LC | |||
{{Use dmy dates|date=May 2024}} | |||
{{Speciesbox | |||
| name = Saltwater crocodile | |||
| fossil_range = ]–], {{fossil_range|5.3|0|ref=<ref name="Rio2021">{{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=] |volume=9 |pages=e12094 |doi=10.7717/peerj.12094 |pmid=34567843 |pmc=8428266 |doi-access=free}}</ref>}} | |||
| image = SaltwaterCrocodile('Maximo').jpg | | image = SaltwaterCrocodile('Maximo').jpg | ||
| image_caption = {{small|Male}} | |||
| image_width = 250px | |||
| image2 = Female croc.jpg | |||
| image2_caption = {{small|Female}} | |||
| status = LC | | status = LC | ||
| status_system = |
| status_system =IUCN3.1 | ||
| status_ref = <ref name=iucn>{{cite iucn |title=''Crocodylus porosus'' |name-list-style=amp |author=Webb, G.J.W. |author2=Manolis, C. |author3=Brien, M.L. |author4=Balaguera-Reina, S.A. |author5=Isberg, S. |date=2021 |page=e.T5668A3047556 |doi=10.2305/IUCN.UK.2021-2.RLTS.T5668A3047556.en |access-date=20 November 2021}}</ref> | |||
| regnum = ]ia | |||
| status2 = CITES_A1 | |||
| phylum = ] | |||
| status2_system = CITES | |||
| classis = ] | |||
| status2_ref = <ref>{{cite web |title=Appendices {{!}} CITES|url=https://cites.org/eng/app/appendices.php|access-date=14 January 2022|website=cites.org}}</ref>{{NoteTag|Except populations of Australia, Indonesia, Malaysia and Papua New Guinea which are included in Appendix II.}} | |||
| ordo = ] | |||
| genus = Crocodylus | |||
| familia = ] | |||
| species = porosus | |||
| subfamilia = ] | |||
| authority = ], 1801 | |||
| genus = '']'' | |||
| species = '''''C. porosus''''' | |||
| binomial = ''Crocodylus porosus'' | |||
| binomial_authority = (], ]) | |||
| range_map = Crocodylus porosus range.PNG | | range_map = Crocodylus porosus range.PNG | ||
| range_map_caption = Range of the saltwater crocodile in black | | range_map_caption = Range of the saltwater crocodile in black | ||
}} | }} | ||
The '''saltwater crocodile''' ('''''Crocodylus porosus''''') is a ]n native to ] habitats, ] ]s and freshwater rivers from ]'s east coast across ] and the ] to northern ] and ]. It has been listed as ] on the ] since 1996.<ref name=iucn /> It was hunted for its skin throughout its range up to the 1970s, and is threatened by illegal killing and ]. It is regarded as dangerous to humans.<ref name=Webb_al2010>{{cite book |last1=Webb |first1=G. J. W. |last2=Manolis |first2=C. |last3=Brien |first3=M. L. |year=2010 |chapter=Saltwater Crocodile ''Crocodylus porosus'' |pages=99–113 |chapter-url=http://www.iucncsg.org/365_docs/attachments/protarea/18%20--8088e67a.pdf |editor1-last=Manolis |editor1-first=S. C. |editor2-last=Stevenson |editor2-first=C. |title=Crocodiles: Status Survey and Conservation Action Plan |edition=3rd |publisher=IUCN Crocodile Specialist Group |location=Darwin}}</ref> | |||
'''Saltwater''' or '''estuarine crocodile''' (''Crocodylus porosus'') is the largest of all living ] and ]s. It is found in suitable habitat throughout ], ], and the surrounding waters.Salt water crocodiles eat rocks to keep balance in water. Saltwater crocodiles are known in the ] of ] as "salties". The ] are misnamed after the resemblance of the "saltie" to ]s as compared to ]s, which also inhabit the Northern Territory. | |||
The saltwater crocodile is the largest living reptile.<ref>{{cite journal |title=Satellite tracking reveals long distance coastal travel and homing by translocated Estuarine Crocodiles, ''Crocodylus porosus'' |journal=PLOS ONE |year=2007 |volume=2 |pmid=17895990 |pmc=1978533 |doi=10.1371/journal.pone.0000949 |doi-access=free |last1=Read |first1=M. A. |last2=Grigg |first2=G. C. |last3=Irwin |first3=S. R. |last4=Shanahan |first4=D. |last5=Franklin |first5=C. E. |issue=9 |pages=e949 |bibcode=2007PLoSO...2..949R}}</ref> Males can grow up to a weight of {{cvt|1000|-|1500|kg}} and a length of {{cvt|6|m}}, rarely exceeding {{cvt|6.3|m}}.<ref name="Acid">{{cite journal |title=Estimation of total length from head length of Saltwater Crocodiles (''Crocodylus porosus'') in the Northern Territory, Australia |year=2013 |journal=Journal of Herpetology |volume=47 |issue=1 |pages=34–40 |doi=10.1670/11-094 |author1=Fukuda, Y. |name-list-style=amp |author2=Saalfeld, W. K. |author3=Lindner, G. |author4=Nichols, T. |s2cid=83912762 |url=https://www.researchgate.net/publication/274775364}}</ref><ref>{{cite book |author1=Rice, S. |title=Encyclopedia of Biodiversity |edition=Revised |date=2020 |publisher=Infobase Publishing |location=New York |isbn=9781438195926 |pages=230 |url=https://books.google.com/books?id=YtyPEAAAQBAJ&dq=saltwater+crocodile+1500+kg&pg=PA230}}</ref> Females are much smaller and rarely surpass {{cvt|3|m}}.<ref name=Whitaker_2008>{{cite journal |last1=Whitaker |first1=R. |last2=Whitaker |first2=N. |year=2008 |title=Who's got the biggest? |journal=Crocodile Specialist Group Newsletter |volume=27 |issue=4 |pages=26–30 |url=https://www.iucncsg.org/365_docs/attachments/protarea/907d4ded022a4ddefe525f89ee64b150.pdf}}</ref><ref name="Britton et al. 2012">{{cite journal |last1=Britton |first1=A. R. C. |last2=Whitaker |first2=R. |last3=Whitaker |first3=N. |title=Here be a Dragon: Exceptional size in Saltwater Crocodile (''Crocodylus porosus'') from the Philippines |journal=Herpetological Review |date=2012 |volume=43 |issue=4 |pages=541–546 |url=https://www.researchgate.net/publication/265511442}}</ref> It is also called the '''estuarine crocodile''', '''Indo-Pacific crocodile''', '''marine crocodile''', '''sea crocodile''', and, informally, the '''saltie'''.<ref>{{cite journal |author=Allen, G. R. |year=1974 |title=The marine crocodile, ''Crocodylus porosus'', from Ponape, Eastern Caroline Islands, with notes on food habits of crocodiles from the Palau Archipelago |journal=Copeia |volume=1974 |issue=2 |page=553 |doi=10.2307/1442558 |jstor=1442558}}</ref> A large and opportunistic ] ], they ] most of their prey and then drown or swallow it whole. They will prey on almost any animal that enters their territory, including other predators such as ]s, varieties of ] and ] including ] species, ]s such as ]s, various ]s, other ]s, ]s, and ]s.<ref name="Callaway, J. M. 1997">{{cite book |last1=Hua |first1=S. |last2=Buffetaut |first2=E. |year=1997 |chapter=Part V: Crocodylia |pages=357–374 |title=Ancient marine reptiles |location=Cambridge |publisher=Academic Press |isbn=978-0-12-155210-7 |doi=10.1016/B978-0-12-155210-7.X5000-5 |editor1-last=Callaway |editor1-first=J. M. |editor2-last=Nicholls |editor2-first=E. L. |chapter-url=https://reader.elsevier.com/reader/sd/pii/B9780121552107500193?token=49212F9BD94583575A4553B27CDA591A7B9C97B6698550E9A3E43766F27F48E72A8DF49B165E55D9E81AC46194045F04}}</ref><ref name="Blaber, S. J. 2008">{{cite book |last1=Blaber |first1=S. J. M. |year=2008 |title=Tropical estuarine fishes: ecology, exploration and conservation |location=Oxford |publisher=Blackwell Science |pages=185–201 |chapter=Mangroves and Estuarine Dependence |chapter-url=https://books.google.com/books?id=V53GoUTN_wYC&pg=PA196 |isbn=9780470694985}}</ref> | |||
==Anatomy and morphology== | |||
] | |||
The saltwater crocodile has a longer muzzle than the ], and is twice the length of its breadth at the base.<ref name="Guggisberg">{{cite book | author = Guggisberg, C.A.W. |url = | title = Crocodiles: Their Natural History, Folklore, and Conservation| year = 1972 | pages = 195 | isbn = 0715352725}}</ref> | |||
== Taxonomy and evolution == | |||
An adult male saltwater crocodile can usually grow {{convert|16|to(-)|18|ft|m}} and weigh about {{convert|1400|to(-)|2500|lb|kg}} <ref>http://www.flmnh.ufl.edu/cnhc/csp_cpor.htm</ref>. Females are much smaller than males, with typical female body lengths in the range of {{convert|2.1|to(-)|3|m|ft}}.<ref name = "ufl">, by Adam Britton from the Crocodilian Species List.</ref><ref></ref> The largest female on record measured about 4.2 m (14 feet).<ref name=autogenerated1>Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0851122359</ref> The saltwater crocodile has fewer armor plates on its neck than other crocodilians, and its broad body contrasts with that of most other lean crocodiles, leading to early unverified assumptions that the reptile was an alligator.<ref name = "ufl"/> | |||
], a saltwater crocodile from Finnis River in northern Australia proposed as ''Crocodilus pethericki'' in 1985]] | |||
''Crocodilus porosus'' was the ] proposed by ] who described a ] in 1801.<ref>{{cite book |last1=Schneider |first1=J. G. |year=1801 |title=Historiae Amphibiorum naturalis et literariae Fasciculus Secundus continens Crocodilos, Scincos, Chamaesauras, Boas, Pseudoboas, Elapes, Angues, Amphisbaenas et Caecilias |location=Jenae |publisher=Wesselhoeft |chapter=''Porosus'' |chapter-url=https://gdz.sub.uni-goettingen.de/id/PPN582122139?tify={%22pages%22:,%22view%22:%22info%22} |pages=159–160}}</ref> In the 19th and 20th centuries, several saltwater crocodile specimens were described with the following names: | |||
*''Crocodilus biporcatus'' proposed by ] in 1807 were 23 saltwater crocodile specimens from India, ] and ].<ref>{{cite journal |author=Cuvier, G. |year=1807 |title=Sur les différentes especes de crocodiles vivans et sur leurs caracteres distinctifs |journal=Annales du Muséum d'Histoire Naturelle Paris |volume=10 |pages=–86 |url=https://archive.org/details/annalesdumusum10mus}}</ref> | |||
*''Crocodilus biporcatus raninus'' proposed by ] and ] in 1844 was a crocodile from ].<ref>{{cite book |editor=Temminck, C. J. |title=Verhandelingen over de natuurlijke geschiedenis der Nederlandsche overzeesche Bezittingen, door de leden der Natuurkundige Commissie in Indie en andere Schrijvers |location=Leiden |publisher=S. en J. Luchtmans en C. C. van der Hoek |author=Müller, S. |author2=Schlegel, H. |year=1844 |chapter=Over de Krokodillen van den Indischen Archipel |pages=1–70 |chapter-url=https://archive.org/details/verhandelingeno1temm/page/n1059}}</ref> | |||
*''Crocodylus porosus australis'' proposed by ] in 1953 was a specimen from Australia.<ref>{{cite book |author=Deraniyagala, P. E. P. |year=1953 |title=A coloured atlas of some vertebrates from Ceylon |volume=Tetrapod Reptilia |publisher=Government Press |location=Colombo |chapter=''Crocodylus porosus australis'' ssp. nov. |pages=33–34}}</ref> | |||
*''Crocodylus pethericki'' proposed by Richard Wells and C. Ross Wellington in 1985 was a large-bodied, relatively large-headed and short-tailed crocodile specimen collected in 1979 in the Finnis River, ].<ref>{{cite journal |author1=Wells, R. W. |author2=Wellington, C. R. |name-list-style=amp |year=1985 |title=A classification of the Amphibia and Reptilia of Australia |journal=] |volume=1 |pages=1–61 |url=http://www.iucn-tftsg.org/wp-content/uploads/file/Articles/Wells_and_Wellington_1985.pdf}}</ref> This purported species was later considered to be a misinterpretation of the physiological changes that very large male crocodiles undergo. However, Wells and Wellington's assertion that the Australian saltwater crocodiles may be distinctive enough from northern Asian saltwater crocodiles to warrant ] status, as could ''raninus'' from other Asian saltwater crocodiles, has been considered to possibly bear validity.<ref>{{cite journal |author=Das, I. |author2=Charles, J. K. |title=A Record of ''Crocodylus raninus'' Müller & Schlegel, 1844 from Brunei, North-western Borneo |journal=Sabah Parks Nature Journal |volume=3 |year=2000 |pages=1–5}}</ref> | |||
Currently, the saltwater crocodile is considered a ].<ref name= Brazaitis>{{cite book |author=Brazaitis, P. |year=2001 |title=A Guide to the Identification of the Living Species of Crocodilians |publisher=Wildlife Conservation Society |location=New York}}</ref> | |||
The largest size saltwater crocodiles can reach is the subject of considerable controversy. The longest crocodile ever ''measured'' snout-to-tail and verified was the skin of a deceased crocodile, which was {{convert|6.2|m|ft}} long. Since skins tend to shrink slightly after removal from the carcass, this crocodile's living length was estimated at {{convert|6.3|m|ft}} and it probably weighed well over {{convert|1200|kg|lb}}.<ref name="uflfaq"></ref> Incomplete remains (the skull of a crocodile shot in ]<ref name=underwatertimes1></ref>) have been claimed to come from a {{convert|7.6|m|ft}} crocodile, but scholarly examination suggested a length no greater than {{convert|7|m|ft}}.<ref name = uflfaq/> There have been numerous claims of crocodiles in the {{convert|9|m|ft}} range: the individual shot in the ] in 1840, reported at {{convert|10|m|ft}}; another killed in 1823 at Jala Jala on ] reported at {{convert|8.2|m|ft}}; a reported {{convert|7.6|m|ft}} crocodile killed in the Hooghly River in the Alipore District of ]. However, examinations of these animals' skulls actually indicated animals ranging from {{convert|6|to(-)|6.6|m|ft}}.<ref name=autogenerated1>Wood, The Guinness Book of Animal Facts and Feats. Sterling Pub Co Inc (1983), ISBN 978-0851122359</ref> | |||
=== Evolution === | |||
With recent restoration in saltwater crocodile habitat and reduced poaching, it is possible that {{convert|7|m|ft}} or larger crocodiles are alive today.<ref name=maneater>, Daily Telegraph</ref> ] has accepted a claim of a {{convert|7|m|ft}} male saltwater crocodile, with an estimated weigh of {{convert|1360|kg|lb}}, living within Bhitarkanika Park in the state of Orissa, India,<ref name=underwatertimes1/><ref></ref> although, due the near impossible task of taping and weighing a very large, live crocodile, the accuracy of these dimension has not been verified. | |||
] remains of a saltwater crocodile ] in northern ] were dated to the ].<ref>{{cite journal |author=Molnar, R. E. |year=1979 |title=''Crocodylus porosus'' from the Pliocene Allingham formation of North Queensland. Results of the Ray E. Lemley expeditions, part 5 |journal=Memoirs of the Queensland Museum |volume=19 |pages=357–365}}</ref><ref>{{cite journal |author=Willis, P. M. A. |year=1997 |title=Review of fossil crocodilians from Australasia |journal=Australian Journal of Zoology |volume=30 |issue=3 |pages=287–298 |doi=10.7882/AZ.1997.004 |doi-access=free}}</ref> The saltwater crocodile's closest ] (living) relatives are the ] and the ].<ref name=Gatesy2008>{{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=] |volume=48 |issue=3 |pages=1232–1237 |doi=10.1016/j.ympev.2008.02.009 |pmid=18372192|bibcode=2008MolPE..48.1232G }}</ref><ref name=Srikulnath2015>{{cite journal |author1=Srikulnath, K. |author2=Thapana, W. |author3=Muangmai, N. |name-list-style=amp |year=2015 |title=Role of chromosome changes in ''Crocodylus'' evolution and diversity |journal=Genomics Inform |volume=13 |issue=4 |pages=102–111 |doi=10.5808/GI.2015.13.4.102 |pmc=4742319 |pmid=26865840}}</ref><ref name=LeeYates2018>{{cite journal |author=Lee, M. S. Y. |author2=Yates, A. M. |name-list-style=amp |date=2018 |title=Tip-dating and homoplasy: reconciling the shallow molecular divergences of modern gharials with their long fossil |journal=] |volume=285 |issue=1881 |doi=10.1098/rspb.2018.1071 |pmid=30051855 |pmc=6030529 |doi-access=free}}</ref><ref name=Hekkala2021>{{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 |doi-access=free}}</ref> | |||
The ] '']'' was thought to have evolved in Australia and Asia.<ref name=Oaks2011>{{cite journal |last1=Oaks |first1=J.R. |title=A time-calibrated species tree of Crocodylia reveals a recent radiation of the true crocodiles |journal=Evolution |volume=65 |issue=11 |year=2011 |pages=3285–3297 |doi=10.1111/j.1558-5646.2011.01373.x |pmid=22023592 |s2cid=7254442 |doi-access=free}}</ref> Results of a ] study supports its likely origin in Africa and later ] towards Southeast Asia and the Americas; it ] from its closest recent relative, the extinct '']'' of ], around {{mya|25}} near the boundary between the ] and ].<ref name=Hekkala2021/> | |||
A crocodile shot in Queensland in 1957 was reported to be {{convert|8.5|m|ft}} long, but no verified measurements were made and no remains of this crocodile exist. A "replica" of this crocodile has been made as a tourist attraction.<ref></ref><ref></ref><ref><http://animals.nationalgeographic.com/animals/reptiles/saltwater-crocodile.html></ref> Many other unconfirmed reports of 8+ metres (26+ ft) crocodiles have been made<ref name=harvard>, Alvin Powell, Harvard Gazette</ref><ref name=ng> at National Geographic</ref> but these are highly suspect.<ref name = uflfaq/> | |||
===Phylogeny=== | |||
Like all ], salties' jaws are extremely powerful. On ]'s ], Dr. Adam Britton mentioned that he had measured the ] of a 16ft saltie and got a reading of 3900lb. He also mentioned on the ] vs ] episode that the largest crocs on record could exert a bite pressure of over 4500lb. ]'s ] has measured the bite of a fully grown nile croc at 5000lb. | |||
Below is a ] based on a 2018 ] study by Lee & Yates simultaneously using ], molecular (]), and ] (] age) data,<ref name="LeeYates2018"/> as revised in 2021 after a ] study using DNA extracted from the extinct ''Voay''.<ref name=Hekkala2021/> | |||
{{clade| style=font-size:100%;line-height:85% | |||
|label1=] | |||
|1={{clade | |||
|1='']''{{extinct}} | |||
|label2='']'' | |||
|2={{clade | |||
|1={{clade | |||
|1={{clade | |||
|1='']''{{extinct}} | |||
|2='']''{{extinct}} }} | |||
|2={{clade | |||
|1='']''{{extinct}} | |||
|2=''Crocodylus'' Tirari Desert{{extinct}} }} }} | |||
|2={{clade | |||
|label1=Asia+Australia | |||
|1={{clade | |||
|1={{clade | |||
|1=''Crocodylus johnstoni'' ] ] | |||
|2={{clade | |||
|1=''Crocodylus novaeguineae'' ] | |||
|2=''Crocodylus mindorensis'' ] }} }} | |||
|2={{clade | |||
|1=''Crocodylus porosus'' '''Saltwater crocodile''' ] | |||
|2={{clade | |||
|1=''Crocodylus siamensis'' ] ] | |||
|2=''Crocodylus palustris'' ] ] }} }} }} | |||
|label2=Africa+New World | |||
|2={{clade | |||
|1={{clade | |||
|1='']''{{extinct}} | |||
|2='']''{{extinct}} }} | |||
|2={{clade | |||
|1=''Crocodylus suchus'' ] | |||
|2={{clade | |||
|1=''Crocodylus niloticus'' ] ] | |||
|label2=New World | |||
|2={{clade | |||
|1={{clade | |||
|1=''Crocodylus moreletii'' ] | |||
|2=''Crocodylus rhombifer'' ] ] }} | |||
|2={{clade | |||
|1=''Crocodylus intermedius'' ] | |||
|2=''Crocodylus acutus'' ] ] }} }} }} }} }} }} }} }} }} | |||
== |
==Description== | ||
], ]. Note the considerably more slender skull of a ] in the background.]] | |||
Saltwater crocodiles are severely depleted in numbers throughout much of their range, and are virtually extinct in ] (a few individuals may persist in isolated national parks) and ] (with the exception of occasional vagrants from ]). In ] they are known to exist in very small numbers within the countries rivers and mangroves. The status of this species is unknown within ] (although given the recent fatal and ironic attack on a convict, they are definitely present within the ]) <ref>http://www.msnbc.msn.com/id/24226179/</ref> and they are known to exist in ] solely within the ]. Although Saltwater Crocodiles were once very common in the ] (from which they disappeared in the 1980s) and other river systems, the future of this species in ] is now looking grim, given the near non-existent population sizes in some countries. However, it is also the least likely of crocodilians to become globally extinct due to its wide distribution and almost pre-colonial population sizes in ] and ]. In ] this crocodile is extremely rare in most areas but is very common in the north eastern part of the country (mainly ] and the ]). The population is sporadic in ] and ] with some areas harboring large populations (], for example) and others with very small, "at risk" populations (e.g., the ]). The saltwater crocodile is also present in very limited parts of the South Pacific, with an average population in the ], a very small and soon to be extinct population in ] (where the population officially stands at only three) and a decent but at-risk population (which may be rebounding) in ].<ref name = "ufl"/> In ] (which includes the top ends of the ], ] and ]) the Saltwater Crocodile is thriving, particularly in the multiple river systems near ] (such as the Adelaide, Mary and Daly Rivers, along with their adjacent ]s and ]) where exceptionally large (6 meter +) individuals are not uncommon. A rough estimate states that the Australian Saltwater Crocodile population stands somewhere between 100,000 and 200,000 adults. Their range extends from ] in ] through the entire ] coast all the way down to ] in ]. In ] they are also very common, existing within the coastal reaches of virtually every river system in the country, along with all estuaries and mangroves. | |||
] | |||
The saltwater crocodile has a wide snout compared to most crocodiles. However, it has a longer ] than the ] (''C. palustris''); its length is twice its width at the base.<ref name="Guggisberg">{{cite book |last=Guggisberg |first=C. A. W. |title=Crocodiles: Their Natural History, Folklore, and Conservation |year=1972 |page=195 |location=Newton Abbot |publisher=David & Charles |isbn=978-0-7153-5272-4}}</ref> A pair of ridges runs from the eyes along the centre of the snout. The scales are oval in shape and the ]s are either small compared to other species or commonly are entirely absent. In addition, an obvious gap is also present between the cervical and dorsal ], and small, triangular scutes are present between the posterior edges of the large, transversely arranged scutes in the dorsal shield. The relative lack of scutes is considered an asset useful to distinguish saltwater crocodiles in captivity or in illicit leather trading, as well as in the few areas in the field where sub-adult or younger saltwater crocodiles may need to be distinguished from other crocodiles. It has fewer armour plates on its neck than other crocodilians.<ref>{{cite book |last=Kondo |first=H. |year=1970 |title=Grolier's Amazing World of Reptiles |location=New York, NY |publisher=Grolier Interprises Inc.}}</ref><ref>{{cite book |last1=Ross |first1=F. D. |last2=Mayer |first2=G. C. |year=1983 |chapter=On the dorsal armor of the Crocodilia |pages= |title=Advances in Herpetology and Evolutionary Biology |chapter-url=https://archive.org/details/advancesinherpet00will |editor1-last=Rhodin |editor1-first=A. G. J. |editor2-last=Miyata |editor2-first=K. |publisher=Museum of Comparative Zoology |location=Cambridge |isbn=9780910999007}}</ref> | |||
The adult saltwater crocodile's broad body contrasts with that of most other lean crocodiles, leading to early unverified assumptions the reptile was an ].<ref name="ufl"/> | |||
Saltwater crocodiles once ranged as far west as the east coast of ] at the ]. These crocodiles were once believed to be a population of ]s, but they were later proven to be ''Crocodylus porosus''.<ref name = "ufl"/> | |||
Young saltwater crocodiles are pale yellow in colour with black stripes and spots on their bodies and tails. This colouration lasts for several years until the crocodiles mature into adults. The colour as an adult is much darker greenish-drab, with a few lighter tan or grey areas sometimes apparent. Several colour variations are known and some adults may retain fairly pale skin, whereas others may be so dark as to appear blackish. The ventral surface is white or yellow in colour in saltwater crocodiles of all ages. Stripes are present on the lower sides of their bodies, but do not extend onto their bellies. Their tails are grey with dark bands.<ref>{{cite book |last=Lanworn |first=R. |year=1972 |title=The Book of Reptiles |location=New York, NY |publisher=The Hamlyn Publishing Group Ltd. |isbn=978-0600312734}}</ref><ref>{{cite web |url=http://reptilianzone.com/saltwater-crocodile/ |title=Crocodylus porosus |date=17 February 2017 |publisher=ReptilianZone.com |access-date=2 March 2017 |archive-date=29 July 2017 |archive-url=https://web.archive.org/web/20170729173332/http://reptilianzone.com/saltwater-crocodile/ |url-status=dead}}</ref> | |||
==Habitat== | |||
===Size=== | |||
Saltwater crocodiles generally spend the tropical wet season in freshwater swamps and rivers, moving downstream to estuaries in the dry season, and sometimes traveling far out to sea. Crocodiles compete fiercely with each other for territory, with dominant males in particular occupying the most eligible stretches of freshwater creeks and streams. Junior crocodiles are thus forced into the more marginal river systems and sometimes into the ocean. This explains the large distribution of the animal (ranging from the east coast of India to northern Australia) as well as its being found in odd places on occasion (such as the Sea of Japan). Saltwater crocodiles can swim 15 to 18 miles per hour in short bursts, but when cruising go 2 to 3 mph. | |||
The weight of a crocodile increases approximately cubically as length increases (see ]).<ref>{{Cite journal |doi=10.1007/s00360-012-0732-1 |pmid=23233168 |title=Scaling of standard metabolic rate in estuarine crocodiles ''Crocodylus porosus'' |journal=Journal of Comparative Physiology B |volume=183 |issue=4 |pages=491–500 |year=2012 |last1=Seymour |first1=R. S. |last2=Gienger |first2=C. M. |last3=Brien |first3=M. L. |last4=Tracy |first4=C. R. |last5=Manolis |first5=C. S. |last6=Webb |first6=G. J. W. |last7=Christian |first7=K. A. |s2cid=3191541}}</ref> This explains why individuals at {{cvt|6|m|ft}} weigh more than twice as much as individuals at {{cvt|5|m|ft}}.<ref name="ufl">{{cite web |url=http://www.flmnh.ufl.edu/NATSCI/HERPETOLOGY/brittoncrocs/csp_cpor.htm |last=Britton |first=A. |title=''Crocodylus porosus'' (Schneider, 1801) |publisher=The Crocodilian Species List |url-status=dead |archive-date=8 January 2006 |archive-url=https://web.archive.org/web/20060108113747/http://www.flmnh.ufl.edu/NATSCI/HERPETOLOGY/brittoncrocs/csp_cpor.htm}}</ref> In crocodiles, linear growth eventually decreases and they start getting bulkier at a certain point.<ref>{{cite web |url=http://www.madrascrocbank.blogspot.com/2008/08/worlds-biggest-crocodiles.html |title=World's Biggest Crocodiles |publisher=Madras Crocodile Bank Trust|access-date=26 May 2016}}</ref> | |||
] | |||
Saltwater crocodiles are the largest extant ] predators in the world. However, they start life fairly small. Newly hatched saltwater crocodiles measure about {{cvt|28|cm}} long and weigh an average of {{cvt|71|g}}.<ref name="NewHolland">{{cite web |title=Insights into Crocodile lifestyles |url=http://www.newholland.com.au/products/docs/9781741108484.pdf |publisher=newholland.com.au |url-status=dead |archive-url=https://web.archive.org/web/20091004002656/http://www.newholland.com.au/products/docs/9781741108484.pdf |archive-date=4 October 2009}}</ref> These sizes and ages are almost identical to those at average sexual maturity in ]s, despite the fact that average adult male saltwater crocodiles are considerably larger than average adult male Nile crocodiles.<ref>{{cite journal |author1=Loveridge, J. P. |name-list-style=amp |author2=Blake, D. K. |year=1972 |title=Techniques in the immobilisation and handling of the Nile crocodile, ''Crocodylus niloticus'' |journal=National Museums and Monuments of Rhodesia |volume= |issue= |pages= |url=}}</ref><ref name=Bourquin>{{cite thesis |author=Bourquin, S. L. |year=2008 |title=The population ecology of the Nile Crocodile (''Crocodylus niloticus'') in the Panhandle Region of the Okavango Delta, Botswana |type=Doctoral dissertation |publisher=Stellenbosch University |url=http://scholar.sun.ac.za/handle/10019.1/1281}}</ref> | |||
==Diet & Behavior== | |||
]]] | |||
The largest skull of a saltwater crocodile that could be scientifically verified was of a specimen in the ], collected in ]. Its skull was {{cvt|76|cm}} long and {{cvt|48|cm}} wide near its base, with {{cvt|98.3|cm}} long mandibles; its length is not known, but based on skull-to-length ratios of large saltwater crocodiles its length was presumably in the {{cvt|6.7|-|7|m}} range, though it could have had an exceptionally large skull or may not have the same skull-to-total-length ratios as other large saltwater crocodiles.<ref name=Whitaker_2008/><ref name=Greer1974>{{cite journal |last1=Greer |first1=A. E. |title=On the maximum total length of the Salt-Water Crocodile (''Crocodylus porosus'') |jstor=1562913 |journal=Journal of Herpetology |volume=8 |issue=4 |year=1974 |pages=381–384 |doi=10.2307/1562913}}</ref><ref name="Britton et al. 2012"/> If detached from the body, the head of a large male crocodile can weigh over {{cvt|200|kg}}, including the large muscles and ]s at the base of the skull that lend the crocodile its massive biting strength.<ref name=Wood>{{cite book |last=Wood |first=G. |year=1983 |title=The Guinness Book of Animal Facts and Feats |isbn=978-0-85112-235-9 |url-access=registration |page=256 |url=https://archive.org/details/guinnessbookofan00wood/page/n261 |publisher=Guinness Superlatives}}</ref> The largest tooth measured {{cvt|9|cm}} in length.<ref>{{cite news |title=Australian crocodile Elvis sinks teeth into lawnmower |url=http://www.cnn.com/2011/12/28/world/asia/australia-crocodile-lawnmower/index.html |newspaper=CNN |date=2011}}</ref><ref>{{cite web |url=https://www.angelfire.com/mo2/animals1/crocodile/asc.html |title=Australian Saltwater Crocodile (Estuarine Crocodile) – ''Crocodylus porosus'' |website=Angelfire |access-date=25 July 2013}}</ref> | |||
The saltwater ] is an opportunistic ] capable of taking any animal that enters their territory, either in the water or on dry land. They have also been known to attack humans. Juveniles are restricted to smaller animals such as ]s, ]s, ]s, small ]s and ]. The larger the animal grows, the greater the variety of animals it includes in the diet, although relatively small ] make up an important part of the diet even in adults. Large adult saltwater crocodiles can potentially eat any animal within its range, including ]s, ], ], ]s, ]s, ]s, domestic livestock, pets, ], ]s, ], ],<ref name=underwatertimes2></ref><ref></ref> and ],<ref name=crocattack></ref><ref name=maneater/> among other large animals as well. ], ], water buffalo and gaur, all of which may weigh over a ton, are considered the largest prey taken by male crocodiles. The only threats to adult saltwater crocodiles are other crocodiles.<ref name=autogenerated1 /> Generally very ] – a trait which helps it survive months at a time without food – it typically loiters in the water or basks in the sun through much of the day, preferring to hunt at night. Capable of explosive bursts of speed when launching an attack from the water, many species of crocodile are also capable of fast land-movement. Many crocodiles are capable of explosive charges that can carry them nearly as fast as a running human. The 23 species of crocodilian can travel over land using the belly crawl, the walk, the high-walk, and the gallop. However, stories of crocodiles being faster than a race horse for short distances across the ground are little more than urban legend. | |||
Other crocodilians like the ] (''Gavialis gangeticus'') and the ] (''Tomistoma schlegelii'') have a proportionately longer skull, but both their skulls and their bodies are less massive than in the saltwater crocodile.<ref name=Whitaker_2008/> | |||
====Male size==== | |||
As an ], it usually waits for its prey to get close to the water's edge before striking, using its great strength to drag the animal back into the water. Most prey animals are killed by the great jaw pressure of the crocodile, although some animals may be incidentally drowned. It is an immensely powerful animal, having the strength to drag a fully grown water buffalo into a river, or crush a full-grown ]'s skull between its jaws. | |||
An adult male saltwater crocodile, from young adults to older individuals, typically ranges {{cvt|3.5|to(-)|5|m|ftin}} in length and weighs {{cvt|200|to|1100|kg}}.<ref>{{cite journal |author=Olsson, A. |author2=Phalen, D. |year=2012 |title=Preliminary studies of chemical immobilization of captive juvenile estuarine (''Crocodylus porosus'') and Australian freshwater (''C. johnstoni'') crocodiles with medetomidine and reversal with atipamezole |pmid=22642399 |journal=Veterinary Anaesthesia and Analgesia |volume=39 |issue=4 |pages=345–356 |doi=10.1111/j.1467-2995.2012.00721.x}}</ref><ref name= Webb>{{cite book |author=Webb, G. |author2=Manolis, S. C. |year=1989 |title=Crocodiles of Australia |publisher=Reed Books}}</ref><ref name= Webb2>{{cite journal |author=Webb, G. J. W. |author2=Messel, H. |author3=Crawford, J. |author4=Yerbury, M. J. |year=1978 |title=Growth rates of ''Crocodylus porosus'' (Reptilia: Crocodilia) from Arnhem Land, northern Australia |journal=Wildlife Research |volume=5 |issue=3 |pages=385–399 |doi=10.1071/WR9780385}}</ref><ref>{{cite book |title="Estuarine crocodiles." FAO species identification guide for fishery purposes. The Living Marine Resources of the Western Central Pacific |date=2001 |publisher=Rosenzweig, P. A. |pages=3972 |url=https://www.fao.org/3/y0870e/y0870e64.pdf}}</ref> On average, adult males range {{cvt|4.0|to(-)|4.5|m|ftin}} in length and weigh {{cvt|408|to|770|kg}}.<ref name="Wood"/><ref name="taylorfrancis.com">{{cite book |last1=Nayak |first1=Lakshman |last2=Sharma |first2=Satyabrata Das |last3=Pati |first3=Mitali Priyadarsini |title=Environmental Management of Marine Ecosystems |page=313 |chapter-url=https://www.taylorfrancis.com/chapters/edit/10.1201/9781315153933-12/conservation-management-saltwater-crocodile-crocodylus-porosus-bhitarkanika-wildlife-sanctuary-odisha-india-lakshman-nayak-satyabrata-das-sharma-mitali-priyadarsini-pati |chapter=Conservation and Management of Saltwater Crocodile (Crocodylus porosus) in Bhitarkanika Wildlife Sanctuary, Odisha, India |year=2018 |doi=10.1201/9781315153933 |isbn=9781315153933 }}{{Dead link|date=July 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> However average size largely depends on the location, habitat, and human interactions and thus varies from one study to another. In 1993, in a study conducted (published in 1998), eleven saltwater crocodiles were found to have measured {{Cvt|2.1|to(-)|5.5|m|ftin}} and weighed between {{Cvt|32|and|1010|kg|lb}}.<ref>{{cite journal |last1=Grigg |first1=Gordon C. |last2=Seebacherd |first2=Frank |last3=Beard |first3=Lyn A. |last4=Morris |first4=Don |title=Thermal relations of large crocodiles, Crocodylus porosus, free—ranging in a naturalistic situation |journal=Proceedings of the Royal Society of London. Series B: Biological Sciences |date=22 September 1998 |volume=265 |issue=1407 |pages=1793–1799 |doi=10.1098/rspb.1998.0504 |pmc=1689355 |language=en |issn=0962-8452}}</ref> Very large, aged males can exceed {{cvt|6|m|ftin}} in length and presumably weigh up to {{cvt|2000|kg}}.<ref name="ufl"/><ref name=Whitaker_2008/><ref name=Greer1974/><ref name="taylorfrancis.com"/> | |||
The largest confirmed saltwater crocodile on record drowned in a ] in ], in 1979. Its dried skin plus head measured {{cvt|6.2|m|ftin}} in length and it was estimated to have been {{cvt|6.3|m|ftin}} when accounting for shrinkage and a missing tail tip.<ref name="Britton et al. 2012" /><ref name="Whitaker_2008" /> Projected from their skull lengths, multiple specimens from ] were estimated to belong in life to male crocodiles measuring more than {{cvt|6|m|ftin}}.<ref>Fukuda, Y., How, C. B., Seah, B., Yang, S., Pocklington, K., & Peng, L. K. (2018). ''Historical, exceptionally large skulls of saltwater crocodiles discovered at the Lee Kong Chian Natural History Museum in Singapore''. The Raffles Bulletin of Zoology, 66, 810–813.</ref> A large Vietnamese saltwater crocodile was reliably estimated, based on its skull after its death, at {{cvt|6.3|to(-)|6.8|m|ftin}}.<ref>Ziegler, T., Tao, N. T., Minh, N. T., Manalo, R., Diesmos, A., & Manolis, C. (2019). ''A giant crocodile skull from Can Tho, named “Dau Sau”, represents the largest known saltwater crocodile (Crocodylus porosus) ever reported from Vietnam''. Tap chi Sinh hoc (Journal of Biology), 41(4), 25–30.</ref> However, according to evidence in the form of skulls coming from some of the largest crocodiles ever shot, the maximum possible size attained by the largest members of this species is considered to be {{cvt|7|m|ftin}}.<ref name="Britton et al. 2012" /><ref name="ufl" /> A governmental study from Australia accepts that the very largest members of the species are likely to measure {{cvt|6|to(-)|7|m|ftin}} in length and weigh {{cvt|900|to|1500|kg}}.<ref name="Leach" /> Furthermore, a research paper on the morphology and physiology of crocodilians by the same organisation estimates that saltwater crocodiles reaching sizes of {{cvt|7|m|ftin}} would weigh around {{cvt|2000|kg}}.<ref name="EnvironmentAU">{{cite web |url=http://www.environment.gov.au/system/files/pages/dc11235d-8b3b-43f7-b991-8429f477a1d4/files/40-fauna-2a-crocodylia-morphology.pdf |title=Morphology & Physiology of Crocodylia |author=Grigg, G. |author2=Gans, C. |publisher=Australian Government- Department of the Environment |access-date=17 May 2016}}</ref> Due to the extreme size and highly aggressive nature of the species, weight in larger specimens is frequently poorly documented. A {{convert|5.1|m|ftin|adj=on}} long individual named "]" was found to have weighed {{Cvt|780|kg|lb}}.<ref>{{cite web |title=Sweetheart |url=https://www.magnt.net.au/sweetheart-crocodile |website=MAGNT |language=en}}</ref> Another large crocodile named "]", measuring {{Cvt|5.42|m|ftin}} in length weighed around {{Cvt|860|kg|lb}}. In 1992, a notorious ], named "Bujang Senang" was killed in ], ]. It measured {{Cvt|5.7|m|ftin}} in length and weighed more than {{Cvt|900|kg|lb}}.<ref>{{cite book |author1=Ross, J. |title=Crocodiles: Status Survey and Conservation Action Plan |date=1998 |publisher=IUCN/SSC Crocodile Specialist Group |location=Gland, Switzerland |isbn=2-8317-0441-3 |pages=57 |edition=Second |url=https://www.iucncsg.org/365_docs/attachments/protarea/7305ae0fceffa62c765f6a4afdc82dad.pdf}}</ref> A saltwater–siamese hybrid named "Yai" ({{langx|th|ใหญ่}}, meaning big; born 10 June 1972) at the ], ] was claimed to be the largest crocodile ever held in captivity. It measured {{cvt|6|m|ftin}} in length and weighed approximately {{convert|1118|kg|abbr=on}}.<ref>{{cite book |title=The Guinness book of records, 1994 |date=1992 |publisher=Facts on File |location=New York |isbn=9780816026456 |pages=38}}</ref> In 1962, a large male saltwater crocodile was shot in ]. It was recorded to be {{Cvt|6.1|m|ftin}} long and weighed {{Cvt|1097|kg|lb|abbr=on}}.<ref>{{cite book |last1=Wood |first1=Gerald L. |title=The Guinness book of animal facts and feats |date=1982 |publisher=Guinness Superlatives |location=Enfield, Middlesex |isbn=978-0-85112-235-9 |pages=96 |edition=3rd}}</ref> A large male in the Philippines, named ], was one of the largest saltwater crocodile ever caught and placed in captivity. He was {{cvt|6.17|m|ftin}} long and weighed {{cvt|1075|kg}}.<ref name="Britton et al. 2012" /><ref name="Manalo">Manalo, R. I., & Alcala, A. C. (2013). ''Status of the crocodile (Crocodylus porosus, Schneider) industry in the Philippines''. Transactions of the National Academy of Science and Technology of the Philippines, 35(1), 219–222.</ref><ref>{{Cite news |author=Mullen, J. |title=Lolong, world's largest captive crocodile, dies in Philippines |date=2013 |website=CNN |url=http://www.cnn.com/2013/02/11/world/asia/philippines-crocodile-death/index.html|access-date=16 January 2021}}</ref> Following his death in 2013, the largest living crocodile in captivity was "]", who was kept at Marineland Crocodile Park, a zoo located at ], ], ]. He measured 5.48 m (18 ft 0 in) in length and weighs approximately 1,300 kg (2,870 lb) before his own death in November 2024.<ref>https://www.abc.net.au/news/2024-11-02/qld-cassius-worlds-largest-crocodile-in-captivity-dies/104553384</ref><ref>{{cite journal |author1=Webb, G. |title=Observation of large Nile crocodiles (Crocodylus niloticus) |journal=Crocodile Specialist Group Newsletter |date=2019 |volume=38 |issue=2 |pages=12–13 |url=https://www.iucncsg.org/365_docs/attachments/protarea/148b62b54651a87f36649bf1fe308d4c.pdf |publisher=IUCN - Species Survival Commission}}</ref><ref>{{cite web |title=Largest crocodile in captivity (living) |url=https://www.guinnessworldrecords.com/world-records/largest-crocodile-in-captivity |website=Guinness World Records |language=en-gb}}</ref> | |||
In its deadliest attack, called the "death roll," it grabs onto the animal and rolls powerfully. This is designed to initially throw any struggling large animal off balance making it easier to drag it into the water. The "death roll" is also used for tearing apart large animals once they are dead. | |||
== |
====Female size==== | ||
Adult females typically measure from {{cvt|2.7|to|3.1|m|ftin}} in total length and weigh {{cvt|76|to|103|kg}}.<ref>{{cite journal |author=Kay, W. R. |year=2005 |title=Movements and home ranges of radio-tracked ''Crocodylus porosus'' in the Cambridge Gulf region of Western Australia |journal=Wildlife Research |volume=31 |issue=5 |pages=495–508 |doi=10.1071/WR04037 |url=https://espace.library.uq.edu.au/view/UQ:10080/WR04037.pdf}}</ref><ref name= Campbell>{{cite journal |author=Campbell, H. A. |author2=Dwyer, R. G. |author3=Irwin, T. R. |author4=Franklin, C. E. |year=2013 |title=Home range utilisation and long-range movement of estuarine crocodiles during the breeding and nesting season |journal=PLOS ONE |volume=8 |issue=5 |pages=e62127 |pmc=3641080 |pmid=23650510 |doi=10.1371/journal.pone.0062127 |bibcode=2013PLoSO...862127C|doi-access=free}}</ref><ref>{{cite journal |author=Mercado, V. P. |year=2008 |title=Current status of the crocodile industry in the Republic of the Philippines |url=http://philippinecrocodile.com.ph/current_status_of_crocodile_industry_in_the_republ.html?ckattempt=1 |journal=National Museum Papers |volume=14 |pages=26–34}}</ref> Large mature females reach {{cvt|3.4|m|ftin}} and weigh up to {{cvt|120|to|200|kg}}.<ref>McDonald, K. R., Dennis, A. J., Kyne, P. J., Debus, S. J., & Curtis, L. (2012). ''Queensland's Threatened Animals''. CSIRO Publishing, pg. 185–186.</ref> The largest female on record measured about {{cvt|4.3|m|ftin}} in total length.<ref name="Wood" /> Female are thus similar in size to other species of large crocodiles and average slightly smaller than females of some other species, like the Nile crocodile.<ref name= Bourquin/> The saltwater crocodile has the greatest size sexual dimorphism, by far, of any extant crocodilian, as males average about 4 to 5 times as massive as adult females and can sometimes measure twice her total length. The reason for the male skewered dimorphism in this species is not definitively known but might be correlated with sex-specific territoriality and the need for adult male saltwater crocodiles to monopolise large stretches of habitat.<ref>{{cite journal |author1=Halliday, T. R. |author2=Verrell, P. A. |year=1988 |title=Body size and age in amphibians and reptiles |journal=Journal of Herpetology |volume=22 |issue=3 |pages=253–265 |doi=10.2307/1564148 |jstor=1564148}}</ref><ref>Cox, R. M., Butler, M. A., & John-Alder, H. B. (2007). ''The evolution of sexual size dimorphism in reptiles''. Sex, size and gender roles: evolutionary studies of sexual size dimorphism, 38–49.</ref> Due to the extreme sexual dimorphism of the species as contrasted with the more modest-sized dimorphism of other species, the average length of the species is only slightly more than some other extant crocodilians at {{cvt|3.8|-|4|m|ftin}}.<ref name="Brazaitis" /><ref name="Guggisberg" /><ref>{{cite book |first=P. |last=Brazaitis|author-link=Peter Brazaitis |date=1987 |title=Identification of Crocodilian Skins |publisher=Pty Lim |location=Chipping Norton, Australia}}</ref> | |||
].]] | |||
Saltwater crocodiles are very dangerous animals, but data on attacks is limited outside of Australia, and estimates of human fatalities vary wildly between dozens to thousands annually. It is likely that, given this species low population within most of its non-Australian/New Guinean range, the number of attacks is probably within the lower range of estimates. Most attacks by adult "salties" are fatal, given the animals' size and strength. In Australia, attacks are rare and usually make headlines when they do occur. There are, on average, no more than one or two fatal attacks reported per year in the country.<ref></ref> The low level of attacks is most likely due to the extensive effort by local wildlife officials to post crocodile "warning" signs at nearly every ], river, lake and even at some beaches and also due to the relatively well-informed nature of the local citizens. In the Aboriginal community of ], which occupies roughly half of the top end of the Northern Territory, attacks may go unreported and may be more common. The majority of "unreported" attacks most likely occur in ], where the species population is very high and precautions are few. There have also been recent, less public attacks in ], ], ] and in ]{{Fact|date=January 2009}}. | |||
=== |
====Reported sizes==== | ||
{|class="wikitable sortable collapsible collapsed" | |||
] | |||
|- | |||
Dr. Adam Britton, a researcher with , has been studying crocodilian intelligence. In so doing, he has compiled a of Australian saltwater crocodile calls, and associated them with behaviors. His position is that while crocodilian brains are much smaller than those of mammals (as low as 0.05% of body weight in the saltwater crocodile), they are capable of learning difficult tasks with very little conditioning. He also infers that the crocodile calls hint at a deeper language ability than currently accepted. He suggests that saltwater crocodiles are clever animals that can possibly learn faster than lab rats. They have also learned to track the migratory route of their prey as the climate changes. | |||
! Date !! Location !! Reported Length !! Reported Weight !! Reported Girth !! Reported Skull Length !! Scientifically Analyzed Length !! Comments | |||
|- | |||
|1840 | |||
|Bay of Bengal | |||
|{{cvt|1005.84|cm}} | |||
|{{cvt|2721.55|kg}} | |||
|{{cvt|396.24|cm}} | |||
|{{cvt|927|mm}} | |||
|{{cvt|591.312|cm}} | |||
|Skull saved, but was later shown to be measured incorrectly by calculating from snout to posterior edge of lower jaw, per GA Greer. Actual skull length was 655mm.<ref name="Catalogue of the chelonians, rhynchocephalians, and crocodiles in the British Museum (Natural History)">{{cite book |author=] |title=Catalogue of the chelonians, rhynchocephalians, and crocodiles in the British Museum (Natural History) |publisher=British Museum (Natural History). Department of Zoology |year=1889}}</ref><ref name=Greer1974/> | |||
|- | |||
|- | |||
|1823 | |||
|Luzon, Philippines | |||
|{{cvt|822.96|cm}} | |||
|Not listed | |||
|{{cvt|335.28|cm}} | |||
|{{cvt|674|mm}} | |||
|{{cvt|609.6|cm}} | |||
|Skull preserved and measured by Thomas Barbour, who determined original length was taken along the curve of the belly.<ref name="Twenty Years in the Philippines ">{{cite book |author=La Gironière, P. |title=Twenty Years in the Philippines |publisher=Harper & Brothers |year=1854}}</ref> | |||
|- | |||
|- | |||
|July 1957 | |||
|Carpenteria, Australia | |||
|{{cvt|860|cm}} | |||
|Not listed | |||
|Not listed | |||
|Not listed | |||
|Not listed | |||
|Killed by Krystyna Pawlowski while defending her three-year-old daughter{{citation needed|date=August 2021}} | |||
|- | |||
|- | |||
|1926–1932 | |||
|North Borneo | |||
|{{cvt|1005.84|cm}} | |||
|Not listed | |||
|Not listed | |||
|Not listed | |||
|Not listed | |||
|Sighted by James R Montgomery sleeping on a river bank and was considered a legend by the ] people said to be over 200 years old.<ref name="Guinness Book of World Records Animal Facts and Feats">{{cite book |author=Wood, G.L. |title=Guinness Book of World Records Animal Facts and Feats |publisher=Sterling Pub Co., Inc |year=1982 |isbn=978-0851122359}}</ref> | |||
|} | |||
==Distribution and habitat== | |||
==Bibliography== | |||
], ], northern ]]] | |||
* {{IUCN2006|assessors=Crocodile Specialist Group|year=1996|id=5668|title=Crocodylus porosus|downloaded=9 May 2006}} | |||
]]] | |||
]]] | |||
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The saltwater crocodile inhabits coastal brackish ] swamps, river deltas and freshwater rivers from India's east coast, Sri Lanka and Bangladesh to Myanmar, Malaysia, Brunei, Indonesia, ], ], ], ], ], ], ] and Australia's north coast.<ref name=iucn/><ref name=Webb_al2010/> The southernmost population in India lives in Odisha's ]; in northern Odisha, it has not been recorded since the 1930s.<ref>{{cite journal |author1=Singh, L. A. K. |author2=Kar, S. K. |name-list-style=amp |year=2006 |title=Status of the Saltwater Crocodile in Orissa: an overview |journal=Journal of the Bombay Natural History Society |volume=103 |issue=2/3 |pages=274–285}}</ref> It occurs along the ] coasts and in the ].<ref>{{cite journal |author1=Andrews, H. V. |author2=Whitaker, R. |name-list-style=amp |year=1994 |title=Status of the saltwater crocodile (''Crocodylus porosus'' Schneider, 1801) in North Andaman Island |journal=Hamadryad |volume=19 |pages=79–92}}</ref><ref>{{cite book |author1=Whitaker, N. |year=2008 |title=Survey of Human/Crocodile Conflict in the Union Territory of the Andaman Islands, Hut Bay, Little Andaman, January 2008 |publisher=Madras Crocodile Trust |location=Madras |url=https://www.iucncsg.org/365_docs/attachments/protarea/Whit-f1a1ce2f.pdf}}</ref><ref name= Kumar>{{cite book |author1=Kumar, A. |author2=Kumar, S. |author3=Zaidi, Y. F. |author4=Kanaujia, A. |name-list-style=amp |year=2012 |title=A review on status and conservation of salt water crocodile (''Crocodylus porosus'') in India |pages=141–148 |url=http://www.upsbdb.org/pdf/Souvenir2012/ch-16.pdf}}</ref><ref>{{cite journal |author1=Das, C. S. |author2=Jana, R. |name-list-style=amp |year=2018 |title=Human–crocodile conflict in the Indian Sundarban: an analysis of spatio-temporal incidences in relation to people's livelihood |journal=Oryx |volume=52 |issue=4 |pages=661–668 |doi=10.1017/S0030605316001502|doi-access=free}}</ref><ref>{{cite journal |author1=Aziz, M. A. |author2=Islam, M. A. |name-list-style=amp |year=2018 |title=Population status and spatial distribution of saltwater crocodile, ''Crocodylus porosus'' in the Sundarbans of Bangladesh |journal=Bangladesh Journal of Zoology |volume=46 |issue=1 |pages=33–44 |url=https://www.banglajol.info/index.php/BJZ/article/download/37624/25519 |doi=10.3329/bjz.v46i1.37624 |doi-access=free}}</ref> In ], it occurs foremost in western and southern parts of the country.<ref>{{cite journal |author1=Amarasinghe, A. T. |author2=Madawala, M. B. |author3=Karunarathna, D. S. |author4=Manolis, S. C. |author5=de Silva, A. |author6=Sommerlad, R. |name-list-style=amp |year=2015 |title=Human-crocodile conflict and conservation implications of saltwater crocodiles ''Crocodylus porosus'' (Reptilia: Crocodylia: Crocodylidae) in Sri Lanka |journal=Journal of Threatened Taxa |volume=7 |issue=5 |pages=7111–7130 |doi=10.11609/JoTT.o4159.7111-30 |doi-access=free}}</ref> | |||
==References==<!-- BiodiversConserv17:2037. --> | |||
{{reflist}} | |||
In Myanmar, it inhabits the ].<ref>{{cite journal |author=Thorbjarnarson, J. |author2=Platt, S. G. |author3=Khaing, U. |name-list-style=amp |year=2000 |title=A population survey of the estuarine crocodile in the Ayeyarwady Delta, Myanmar |journal=Oryx |volume=34 |issue=4 |pages=317–324 |doi=10.1046/j.1365-3008.2000.00135.x|doi-access=free}}</ref> | |||
Marshall, Ben "The Crocodile" New York Publishers Inc. 1999 | |||
In southern Thailand, it was recorded in ].<ref>{{cite journal |author=Pauwels, O. S. |author2=Laohawat, O. A. |author3=Naaktae, W. |author4=Puangjit, C. |author5=Wisusutharom, T. |author6=Chimsunchart, C. |author7=David, P. |name-list-style=amp |year=2002 |title=Reptile and amphibian diversity in Phang-nga Province, southern Thailand |journal=Tropical Natural History |volume=2 |issue=1 |pages=25–30 |url=https://www.tci-thaijo.org/index.php/tnh/article/download/102862/82406}}</ref> | |||
In Singapore, it inhabits the ] and marshes near Kranji and Mandai.<ref>{{Cite web |last1=Chen |first1=H. |last2=Woon |first2=W. |date=2021 |title=I Went Searching for Giant 'Extinct' Crocs in Singapore. They're Very Much Alive |url=https://www.vice.com/en/article/88nq7k/crocodile-sighting-singapore-photos |access-date=16 July 2023 |website=Vice}}</ref> It is ] in Cambodia, China, Seychelles, Thailand and Vietnam.<ref name=Webb_al2010/><ref>{{cite journal |author=Stuart, B. L. |author2=Hayes, B. |author3=Manh, B. H. |author4=Platt, S. G. |name-list-style=amp |year=2002 |title=Status of crocodiles in the U Minh Thuong Nature Reserve, southern Vietnam |journal=Pacific Conservation Biology |volume=8 |issue=1 |page=62 |doi=10.1071/PC020062 |s2cid=54020729}}</ref><ref>{{cite journal |author=Platt, S. G. |author2=Holloway, R. H. P. |author3=Evans, P. T. |author4=Paudyal, K. |author5=Piron, H. |author6=Rainwater, T. R. |name-list-style=amp |year=2006 |title=Evidence for the historic occurrence of ''Crocodylus porosus'' Schneider, 1801 in Tonle Sap, Cambodia |journal=Hamadryad |volume=30 |issue=1/2 |page=206}}</ref> | |||
In China, it may have once inhabited coastal areas from ] province in the north to the border of Vietnam.<ref>{{cite journal |author=Webb, G. J. |year=2000 |title=Risk of extinction and categories of endangerment: perspectives from long-lived reptiles |journal=Population Ecology |volume=42 |issue=1 |pages=11–17 |doi=10.1007/s101440050004 |bibcode=2000PopEc..42...11W |s2cid=42753122 |url=https://www.researchgate.net/publication/225457944}}</ref> References to crocodile attacks on humans and livestock during the ] and ] dynasties indicate that until the 18th century, it may have occurred in lower ] and ], ], ], portions of coastal ] province and ].<ref name=Guggisberg/> | |||
Three historical records of saltwater crocodiles being found in ]ese coastal waters exist; an individual was found off the coast of ] in 1744, another was found off ] in 1800, and finally, a third individual was caught by fishermen in ] in 1932. All other occurrences of the species being present within Japanese territory are from World War II, and were found in areas that were formerly controlled by the Empire of Japan.<ref>{{Cite journal |last=Takashima |first=Haruo |date=1955 |title=Records of crocodile captured in the neighbouring sea of Japan |url=https://www.jstage.jst.go.jp/article/jyio1952/1/7/1_7_300/_article/-char/en |journal=Journal of the Yamashina Institute for Ornithology |volume=1 |issue=7 |pages=300–302 |doi=10.3312/jyio1952.1.300}}</ref> | |||
In Malaysia, it was recorded in Klias, Segama and ]s in ].<ref name="Stuebing, R. B. 1994">{{cite journal |author=Stuebing, R. B. |author2=Ismail, G. |author3=Ching, L. H. |name-list-style=amp |year=1994 |title=The distribution and abundance of the Indo-Pacific crocodile ''Crocodylus porosus'' Schneider in the Klias River, Sabah, east Malaysia |journal=Biological Conservation |volume=69 |issue=1 |pages=1–7 |doi=10.1016/0006-3207(94)90322-0 |bibcode=1994BCons..69....1S}}</ref><ref>{{cite journal |author=Kaur, T. |year=2006 |title=Segama River survey |journal=Crocodile Specialist Group Newsletter |volume=25 |issue=1 |page=15}}</ref><ref>{{cite journal |author1=Evans, L. |author2=Jones, T. |author3=Pang, K. |author4=Saimin, S. |author5=Goossens, B. |name-list-style=amp |year=2016 |title=Spatial ecology of estuarine crocodile (''Crocodylus porosus'') nesting in a fragmented landscape |journal=Sensors |volume=16 |issue=9 |page=1527 |doi=10.3390/s16091527 |pmid=27657065 |pmc=5038800 |bibcode=2016Senso..16.1527E |doi-access=free}}</ref> In ], it was recorded by a ] in ].<ref>{{cite journal |author1=Mohd-Azlan, J. |author2=Zulaiha, J. |author3=Lading, E. |author4=Nuriza, A. |author5=Das, I. |name-list-style=amp |year=2016 |title=Employing Camera Traps for Studying Habitat Use by Crocodiles in a Mangrove Forest in Sarawak, Borneo |journal=Herpetological Review |volume=47 |issue=4 |pages=579–583 |url=https://www.researchgate.net/publication/311614241}}</ref> In the ], it is present along the coasts of ], ], ], ], ], and ]. Its status along ] is unknown, where one individual was captured in the 2010s.<ref>{{cite book |author=Sideleau, B. |year=2016 |chapter=Notes on the current status of the saltwater crocodile, ''Crocodylus porosus'', within East Nusa Tenggara Province, Indonesia |title=Crocodiles. Proceedings of the 24th Working Meeting of the Crocodile Specialist Group Skukuza, South Africa, 23–26 May 2016 |editor=Crocodile Specialist Group |publisher=IUCN |location=Gland |pages=149–152 |chapter-url=https://www.iucncsg.org/365_docs/attachments/protarea/cbb669b854f5d9b31438d0eca189915e.pdf#page=150}}</ref> In the ], it is present around the ], the ], and many other islands in the region, including the ]. In ], it is common within the coastal reaches of every river system, such as the ] and in the ].<ref>{{cite journal |author=Jelden, D. C. |year=1980 |title=Preliminary Studies on the Breeding Biology of ''Crocodylus porosus'' and ''Crocodylus n. novaguineae'' on the Middle Sepik (Papua New Guinea) |journal=Amphibia-Reptilia |volume=1 |issue=3 |pages=353–358 |doi=10.1163/156853881X00456}}</ref> | |||
In the ], it occurs in a few coastal sites like eastern ], ], the ], and ] on ].<ref name=Webb_al2010/> | |||
], Australia]] | |||
In northern Australia, the saltwater crocodile is thriving, particularly in the multiple river systems near ] such as the ], ], and ] Rivers, along with their adjacent ]s and ].<ref>{{cite journal |author=Messel, H. |author2=Vorlicek, G. C. |name-list-style=amp |year=1986 |title=Population-Dynamics and Status of ''Crocodylus porosus'' in the Tidal Waterways of Northern Australia |doi=10.1071/WR9860071 |journal=Wildlife Research |volume=13 |issue=1 |pages=71–111}}</ref><ref>{{cite journal |author1=Read, M. A. |author2=Miller, J. D. |author3=Bell, I. P. |author4=Felton, A. |name-list-style=amp |year=2004 |title=The distribution and abundance of the estuarine crocodile, ''Crocodylus porosus'', in Queensland |journal=Wildlife Research |volume=31 |issue=5 |pages=527–534 |doi=10.1071/WR02025 |url=https://www.researchgate.net/publication/230555947}}</ref> The saltwater crocodile population in Australia is estimated at 100,000 to 200,000 adults. Its range extends from ] through the entire Northern Territory coast all the way south to ]. The ] in the ] region are misnamed due to the resemblance of the saltwater crocodile to alligators as compared to ]s, which also inhabit the Northern Territory.<ref>{{cite web |title=West Alligator River |url=http://www.ntlis.nt.gov.au/placenames/view.jsp?id=19576 |website=Northern Territory Land Information System |publisher=Northern Territory Government|access-date=25 September 2012}}</ref> | |||
Because of its ability to swim long distances at sea, individual saltwater crocodiles appeared occasionally in areas far away from their general range, up to ].<ref name=Campbell_al2010>{{cite journal |name-list-style=amp |author1=Campbell, H.A. |author2=Watts, M. E. |author3=Sullivan, S. |author4=Read, M. A. |author5=Choukroun, S. |author6=Irwin, S. R. |author7=Franklin, C. E. |year=2010 |title=Estuarine crocodiles ride surface currents to facilitate long-distance travel |journal=Journal of Animal Ecology |volume=79 |issue=5 |pages=955–964 |doi=10.1111/j.1365-2656.2010.01709.x |pmid=20546063 |bibcode=2010JAnEc..79..955C |doi-access=free}}</ref><ref>{{cite journal |author=Spennemann, D.H.R. |year=2021 |journal=Pacific Science |volume=74 |issue=3 |pages=211–227 |doi=10.2984/74.3.1 |title=Cruising the currents: observations of extra-limital Saltwater Crocodiles (''Crocodylus porosus'' Schneider, 1801) in the Pacific Region. Supplemental |s2cid=231875504 |url=https://www.researchgate.net/publication/349379909}}</ref> | |||
Saltwater crocodiles generally spend the tropical wet season in freshwater swamps and rivers, moving downstream to estuaries in the dry season. Crocodiles compete fiercely with each other for territory, with dominant males in particular occupying the most eligible stretches of freshwater creeks and streams. Junior crocodiles are thus forced into marginal river systems and sometimes into the ocean. This explains the large distribution of the species, as well as its being found in the odd places on occasion such as the ]. Like all crocodiles, they can survive for prolonged periods in only warm temperatures, and crocodiles seasonally vacate parts of Australia if cold spells hit.<ref name=Ross>{{cite book |title=Crocodiles and Alligators |editor1-last=Ross |editor1-first=C. A. |editor2-last=Garnett |editor2-first=S. |publisher=Checkmark Books |year=1989 |isbn=978-0816021741}}</ref> | |||
==Behaviour and ecology== | |||
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The primary behaviour to distinguish the saltwater crocodile from other ]s is its tendency to occupy salt water. Though other crocodiles also have ]s that enable them to survive in saltwater, a trait that alligators do not possess, most other species do not venture out to sea except during extreme conditions.<ref>{{cite book |author=Schmidt-Nielsen, K. |year=1997 |title=Animal physiology: adaptation and environment |location=Cambridge |publisher=Cambridge University Press |chapter=Marine air-breathing vertebrates |pages=343–354 |chapter-url=https://books.google.com/books?id=Af7IwQWJoCMC&pg=PA351 |isbn=9780521570985}}</ref> | |||
Saltwater crocodiles use ]s to travel long distances. In Australia, 20 crocodiles were tagged with ]s; 8 of them ventured out into ], and one of them traveled {{cvt|590|km}} along the coast in 25 days from the North Kennedy River on the eastern coast of ], around ], to the west coast in the ]. Another individual swam {{cvt|411|km}} in 20 days. Without having to move around much, sometimes simply by floating, the current-riding behaviour allows for the conservation of energy. They interrupted their movements and resided in sheltered bays for a few days until the current changed direction. Sometimes, they also swam up and down ]s.<ref name=Campbell_al2010/> | |||
Generally very ], a trait that helps it survive months at a time without food, the saltwater crocodile will usually loiter in the water or bask in the sun during much of the day, preferring to hunt at night. A study of seasonal saltwater crocodile behaviour in Australia indicated that they are more active and more likely to spend time in the water during the Australian summer; conversely, they are less active and spend relatively more time basking in the sun during the winter.<ref>{{cite journal |doi=10.1098/rspb.1998.0504 |pmc=1689355 |title=Thermal relations of large crocodiles, Crocodylus porosus, free-ranging in a naturalistic situation |year=1998 |last1=Grigg |first1=G. C. |last2=Seebacherd |first2=F. |last3=Beard |first3=L. A. |last4=Morris |first4=D. |journal=Proceedings of the Royal Society B: Biological Sciences |volume=265 |issue=1407 |pages=1793–1799}}</ref> Saltwater crocodiles, however, are among the most active of all crocodilians, spending more time cruising and active, especially in water. They are much less ] than most species of crocodiles, spending less time on land except for ]. At times, they tend to spend weeks at sea in search of land and in some cases, ]s have been observed growing on crocodile scales, indicative of the long periods they spend at sea.<ref>{{cite web |url=http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Arthropoda/Crustacea/Maxillopoda/Cirripedia/Lepas_anatifera.html |title=''Lepas anatifera'' Linnaeus, 1758 |publisher=WallaWalla |access-date=2 December 2011 |url-status=dead |archive-url=https://web.archive.org/web/20071018081738/http://www.wallawalla.edu/academics/departments/biology/rosario/inverts/Arthropoda/Crustacea/Maxillopoda/Cirripedia/Lepas_anatifera.html |archive-date=18 October 2007}}</ref> | |||
While crocodilian brains are much smaller than those of mammals (as low as 0.05% of body weight in the saltwater crocodile), saltwater crocodiles are capable of learning difficult tasks with very little conditioning, learning to track the migratory route of their prey as the seasons change, and may possess a deeper communication ability than currently accepted.<ref>{{cite web |url=http://crocodilian.com/big-gecko |title=Big Gecko – Crocodile Management, Research and Filming |publisher=Crocodilian.com |access-date=25 July 2013 |archive-date=10 August 2011 |archive-url=https://web.archive.org/web/20110810023555/http://crocodilian.com/big-gecko/ |url-status=dead}}</ref><ref>{{cite web |url=http://crocodilian.com/cnhc/croccomm.html |title=Crocodile Communication: Crocodiles, Caimans, Alligators, Gharials |publisher=Flmnh.ufl.edu |date=5 March 1996 |access-date=25 July 2013}}</ref> | |||
===Hunting and diet=== | |||
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Like most species in the crocodilian family, saltwater crocodiles are not fastidious in their choice of food, and readily vary their ] selection according to availability. Nor are they voracious, as they are able to survive on relatively little food for a prolonged period. Because of their size and distribution, saltwater crocodiles hunt the broadest range of prey species of any modern crocodilian.<ref name=Ross/> The diet of hatchling, juvenile, and subadult saltwater crocodiles has been subject to extensively greater scientific study than that of fully-grown crocodiles, in large part due to the aggression, territoriality, and size of adults that make them difficult for biologists to handle without significant risk to safety, for both humans and the crocodiles themselves. The main method used for capturing adult saltwater crocodiles is a huge pole with large hooks, meant for shark capture, that restrict the crocodile's jaws, but these can cause damage to their snouts; and even this is unproven to allow successful capture for crocodiles in excess of {{cvt|4|m|ftin}}. While for example 20th century biological studies rigorously cataloged the stomach contents of "sacrificed" adult ]s in ],<ref name=Cott>{{cite journal |author=Cott, H. B. |year=1961 |title=Scientific results of an inquiry into the ecology and economic status of the Nile crocodile (''Crocodilus niloticus'') in Uganda and Northern Rhodesia |journal=Transactions of the Zoological Society of London |volume=29 |issue=4 |pages=211–356 |doi=10.1111/j.1096-3642.1961.tb00220.x}}</ref> few such studies were done on behalf of saltwater crocodiles despite the plethora that were slaughtered due to the leather trade during that time period. Therefore, the diet of adults is more likely to be based on reliable eye-witness accounts.<ref name="Webb, G. J. 1991">{{cite journal |author=Webb, G. J. |author2=Hollis, G. J. |author3=Manolis, S. C. |year=1991 |title=Feeding, growth, and food conversion rates of wild juvenile saltwater crocodiles (''Crocodylus porosus'') |journal=Journal of Herpetology |pages=462–473 |jstor=1564770 |volume=25 |issue=4 |doi=10.2307/1564770}}</ref><ref name= Davenport>{{cite journal |author=Davenport, J. |author2=Grove, D. J. |author3=Cannon, J. |author4=Ellis, T. R. |author5=Stables, R. |year=1990 |title=Food capture, appetite, digestion rate and efficiency in hatchling and juvenile ''Crocodylus porosus'' |journal=Journal of Zoology |volume=220 |issue=4 |pages=569–592 |doi=10.1111/j.1469-7998.1990.tb04736.x}}</ref><ref>{{cite journal |author=Webb, G. J. |author2=Messel, H. |year=1977 |title=Crocodile capture techniques |journal=The Journal of Wildlife Management |pages=572–575 |doi=10.2307/3800531 |volume=41 |issue=3 |jstor=3800531}}</ref> Hatchlings are restricted to feeding on smaller animals, such as small fish, frogs, insects and small aquatic ]s.<ref name=Davenport/> In addition to these prey, juveniles also take a variety of freshwater and saltwater fish, various ]s, ]s, ]s, such as large ]s and ]s, birds, small to medium-sized ]s, and other reptiles, such as snakes and ]s. When crocodiles obtain a length of more than {{cvt|1.2|m|ftin}}, the significance of small invertebrate prey fades in favour of small vertebrates, including fish and smaller mammals and birds.<ref>{{cite journal |author=Taylor, J. A. |year=1979 |title=The foods and feeding habits of subadult ''Crocodylus porosus'' Schneider in northern Australia |journal=Wildlife Research |volume=6 |issue=3 |pages=347–359 |doi=10.1071/WR9790347}}</ref> | |||
Among crustacean prey, large ]s of the genus '']'' are frequently consumed, especially in mangrove habitats. Ground-living birds, such as the ] and different kinds of ]s, especially the ], are the most commonly preyed upon birds, due to the increased chance of encounter.<ref>{{cite web |url=http://a-z-animals.com/animals/emu/ |title=Emu (Dromaius Novaehollandiae) – Animals – A–Z Animals – Animal Facts, Information, Pictures, Videos, Resources and Links |publisher=A–Z Animals |access-date=25 July 2013}}</ref><ref name=Messel>{{cite book |author=Messel, H. |author2=Vorlicek, G. C. |year=1989 |chapter=Ecology of ''Crocodylus porosus'' in northern Australia |pages=164–183 |title=Crocodiles: Their Ecology, Management and Conservation |publisher=IUCN |isbn=2880329876}}</ref> Even swift-flying birds and ]s may be snatched if close to the surface of water,<ref name="Ross"/> as well as ]s while these are patrolling the shore looking for food, even down to the size of a ].<ref name=NewHolland/><ref>{{cite journal |author=Yalden, D. |author2=Dougall, T. |year=2004 |title=Production, Survival, and Catchability of Chicks of Common Sandpipers ''Actitis hypoleucos'' |journal=Wader Study Group Bulletin |volume=104 |pages=82–84 |url=https://sora.unm.edu/node/121771}}</ref> Mammalian prey of juveniles and subadults are usually as large as the smaller species of ]s, such as the ] (''Tragulus napu'') and ] (''Hyelaphus porcinus'').<ref>{{cite journal |author1=Cramb, R. A. |author2=Sujang, P. S. |year=2013 |title=The mouse deer and the crocodile: oil palm smallholders and livelihood strategies in Sarawak, Malaysia |journal=The Journal of Peasant Studies |volume=40 |issue=1 |pages=129–154 |s2cid=126939848 |doi=10.1080/03066150.2012.750241}}</ref> Prey species recorded include ] species such as ]s,<ref>{{cite journal |author=Galdikas, B. M. |author2=Yeager, C. P. |year=1984 |title=Brief report: Crocodile predation on a crab-eating macaque in Borneo |journal=American Journal of Primatology |volume=6 |issue=1 |pages=49–51 |doi=10.1002/ajp.1350060106 |pmid=31986847 |s2cid=84208150}}</ref> ]s,<ref>{{cite journal |author1=Otani, Y. |author2=Tuuga, A. |author3=Bernard, H. |author4=Matsuda, I. |year=2012 |title=Opportunistic predation and predation-related events on long-tailed macaque and proboscis monkey in Kinabatangan, Sabah, Malaysia |journal=Journal of Tropical Biology and Conservation |volume=9 |pages=214–218}}</ref> and ]s. It preys on ],<ref>{{cite journal |author=Blumstein, D. T. |author2=Daniel, J. C. |author3=Sims, R. A. |year=2003 |title=Group size but not distance to cover influences agile wallaby (''Macropus agilis'') time allocation |journal=Journal of Mammalogy |volume=84 |issue=1 |pages=197–204 |doi-access=free |doi=10.1644/1545-1542(2003)084<0197:GSBNDT>2.0.CO;2}}</ref> ]s, ]s, turtles, ]es, ]s, ]s, ]s, ]s, ]s and ]s.<ref>{{cite book |author=Kruuk, H. |year=1995 |title=Wild Otters |place=New York |publisher=Oxford University Press}}</ref><ref name=Corlett>{{cite journal |author=Corlett, R. T. |year=2011 |title=Vertebrate carnivores and predation in the Oriental (Indomalayan) region |journal=Raffles Bulletin of Zoology |volume=59 |pages=325–360 |url=https://www.researchgate.net/publication/235998137}}</ref> A rare incidence of an adult {{cvt|2.6|m}} long saltwater crocodile preying on an ] was reported in Sri Lanka.<ref>{{Cite journal |last1=Samarasinghe |first1=D. J. S. |last2=Alwis |first2=D. |date=2017 |title=''Crocodylus porosus'' (Saltwater Crocodile) diet |url=https://www.researchgate.net/publication/320014937 |journal=Herpetological Review |volume=48 |issue=3 |pages=630–631}}</ref> Unlike fish, crabs and aquatic creatures, mammals and birds are usually found only sporadically in or next to water; so crocodiles seem to search for places where such prey may be concentrated, e.g. the water under a tree holding a ] colony, or spots where herds of water buffaloes feed, in order to capture small animals disturbed by the buffalo or (if a large adult crocodile is hunting) weaker members of the buffalo herd.<ref name=Messel/> | |||
Studies have shown that, unlike ]s (which can easily die from eating poisonous toads), saltwater crocodiles are partially resistant to ] toxins and can consume them, but in only small quantities and not enough to provide effective natural control for this virulent introduced pest.<ref>{{cite journal |author=Letnic, M. |author2=Webb, J. K. |author3=Shine, R. |year=2008 |title=Invasive cane toads (''Bufo marinus'') cause mass mortality of freshwater crocodiles (''Crocodylus johnstoni'') in tropical Australia |journal=Biological Conservation |volume=141 |issue=7 |pages=1773–1782 |doi=10.1016/j.biocon.2008.04.031 |bibcode=2008BCons.141.1773L}}</ref> Large crocodiles, even the oldest males, do not ignore small species, especially those without developed escape abilities, when the opportunity arises. On the other hand, sub-adult saltwater crocodiles weighing only {{cvt|8.7|to|15.8|kg}} (and measuring {{cvt|1.36|to|1.79|m}}) have been recorded killing and eating ]s weighing 50 to 92% of their own body mass in ], and so are capable of attacking large prey from an early age.<ref name= Corlett/><ref>{{cite journal |author=Kar, S. K. |author2=Bustard, H. R. |year=1983 |title=Saltwater crocodile attacks on man |journal=Biological Conservation |volume=25 |issue=4 |pages=377–382 |doi=10.1016/0006-3207(83)90071-X |bibcode=1983BCons..25..377K}}</ref><ref>{{cite journal |author=Kar, S. K. |author2=Bustard, H. R. |year=1983 |title=Attacks on domestic livestock by juvenile saltwater crocodile, ''Crocodylus porosus'', in Bhitarkanika Wildlife Sanctuary, Orissa India |journal=Amphibia-Reptilia |volume=4 |issue=1 |pages=81–83 |doi=10.1163/156853883X00283}}</ref> It was found that the diet of specimens in juvenile to subadult range, since they feed on any animals up to their own size practically no matter how small, was more diverse than that of adults, which often ignored all prey below a certain size limit.<ref>{{cite journal |author=Hanson, J. O. |author2=Salisbury, S. W. |author3=Campbell, H. A. |author4=Dwyer, R. G. |author5=Jardine T. D. |author6=Franklin, C. E. |year=2015 |title=Feeding across the food web: The interaction between diet, movement and body size in estuarine crocodiles (''Crocodylus porosus'') |journal=Austral Ecology |volume=40 |issue=3 |pages=275–286 |doi=10.1111/aec.12212 |bibcode=2015AusEc..40..275H |s2cid=85858989}}</ref> | |||
Large animals taken by adult saltwater crocodiles include ], ], ]s, ]s, ]s,<ref>{{cite web |date=26 April 2022 |title=Swine dining: crocodiles are thriving in the NT and it could be because of feral pigs |url=https://www.theguardian.com/environment/2022/apr/27/swine-dining-crocodiles-are-thriving-in-the-nt-and-it-could-be-because-of-feral-pigs |access-date=27 April 2022 |website=the Guardian}}</ref> ]s, ]s, ]s, ]s,<ref name="FAO2012">{{Cite journal |author=Pandit, P. K. |journal=Tigerpaper |volume=XXXIX |issue=1 |url=http://www.fao.org/3/a-am998e.pdf |date=2012 |title=Sundarban Tiger − a new prey species of estuarine crocodile at Sundarban Tiger Reserve, India |pages=1–5}}</ref> and large bovines, such as ],<ref name=Leach/> ], and ].<ref name=Kumar/><ref name=Collins>{{cite journal |author=Collins, B. |year=2005 |title=Crocodiles Inside Out: A Guide to the Crocodilians and Their Functional Morphology |journal=Austral Ecology |volume=30 |issue=4 |pages=487–508 |doi=10.1111/j.1442-9993.2005.01448.x |bibcode=2005AusEc..30..487C}}</ref><ref>{{cite journal |author=Russon, A. E. |author2=Kuncoro, P. |author3=Ferisa, A. |author4=Handayani, D. P. |year=2010 |title=How orangutans (''Pongo pygmaeus'') innovate for water |journal=Journal of Comparative Psychology |volume=124 |issue=1 |pages=14–28 |pmid=20175593 |doi=10.1037/a0017929}}</ref><ref>{{cite journal |author1=NG, M. |author2=Mendyk, R. W. |name-list-style=amp |year=2012 |title=Predation of an Adult Malaysian Water monitor ''Varanus salvator macromaculatus'' by an Estuarine Crocodile ''Crocodylus porosus'' |journal=Biawak |volume=6 |issue=1 |pages=34–38 |url=https://www.academia.edu/3514270}}</ref><ref>{{cite book |publisher=Oxford University Press |author=Butler, J. R. |author2=Linnell, J. D. |author3=Morrant, D. |author4=Athreya, V. |author5=Lescureux, N. |author6=McKeown, A. |name-list-style=amp |year=2013 |chapter=Dog eat dog, cat eat dog: social-ecological dimensions of dog predation by wild carnivores |title=Free-Ranging Dogs and Wildlife Conservation |page=117 |chapter-url=https://www.researchgate.net/publication/258336275}}</ref><ref>{{cite journal |author=De Silva, M. |author2=Dissanayake, S. |author3=Santiapillai, C. |year=1994 |title=Aspects of the population dynamics of the wild Asiatic water buffalo (''Bubalus bubalis'') in Ruhuna National Park, Sri Lanka |journal=Journal of South Asian Natural History |volume=1 |issue=1 |pages=65–76 |url=http://static1.1.sqspcdn.com/static/f/1199264/18690328/1339420173567/April+1994.+Vol.+1+No.+1+pp.+65-76.pdf}}</ref> However, larger animals are taken only sporadically because only large males typically attack very large prey, and large ungulates and other sizeable wild mammals are only sparsely distributed in this species' range, outside of a few key areas such as the ]s.<ref name=Ross/> Off-setting this, ]s, ] and ]/]s have been introduced to many of the areas occupied by saltwater crocodiles and returned to feral states to varying degrees, and thus can amply support large crocodiles.<ref name=Guggisberg/> In Australia, the saltwater crocodile's taste for feral pigs and buffalo was a key factor in their recovery for hunting pressures over the last fifty years according to studies published in 2022 by Dr. Marianna Campbell ''et al.,''. Isotopes taken from the bones of crocodiles collected over five decades ago when crocodiles populations were low and comparisons to specimens from modern populations suggest that initially, Australian saltwater crocodiles subsisted on a more estuarine diet, and both hunting pressures by humans and a reduction in aquatic prey in places like the ] resulted in a dietary switch to more terrestrial prey that allowed them to grow and recover more rapidly from population declines.<ref>{{cite journal |last=Darwin |first=Charles |url=https://phys.org/news/2022-04-diet-contribute-rapid-recovery-apex.html |title=Change in diet may contribute to rapid recovery of apex predator, new research reveals |journal=Biology Letters |year=2022 |volume=18 |issue=4 |doi=10.1098/rsbl.2021.0676 |publisher=Phys.org |pmid=35472283 |pmc=9042529 |s2cid=248396446 |access-date=25 May 2022}}</ref> Any type of ], such as ], ], pigs, ]s and ], and domesticated animals/pets may be eaten if given the opportunity.<ref name=Ross/> As a seagoing species, the saltwater crocodile also preys on a variety of saltwater ] and other ]s, including ]s, ]s, ]s, ]s, ]s (including large ]<ref>{{cite web |title=Green Sawfish |url=http://www.flmnh.ufl.edu/fish/Gallery/Descript/Greensawfish/Greensawfish.htm |website=FLMNH Ichthyology Department|access-date=22 October 2015}}</ref>), and small ]s. Most witnessed acts of predation on marine animals have occurred in coastal waters or within sight of land, with female sea turtles and their babies caught during mating season when the turtles are closer to shore, and ]s being the only largish shark with a strong propensity to patrol brackish and fresh waters.<ref name=Ross/><ref>{{Cite book |title=The Saltwater Wetland |first1=P. |last1=Walker |first2=E. |last2=Wood |url=https://books.google.com/books?id=SW0Bdq6QOxAC |publisher=Infobase Publishing |date=2009 |isbn=9781438122359}}</ref><ref>{{cite book |title=Significant Trade in Wildlife: a review of selected species in CITES Appendix II |volume=((2: reptiles and invertebrates]])) |editor1=Luxmoore, R. |editor2=Groombridge, B. |editor3=Broad, S. |publisher=IUCN Conservation Monitoring Centre |url=https://archive.org/details/significanttrade02luxm |year=1988 |isbn=9782880329549}}</ref><ref>{{Cite book |title=Shark!: Killer Tales from the Dangerous Depths: Killer Tales from the Dangerous Depths (Large Print 16pt) |url=https://books.google.com/books?id=JfZtiHLVhmMC |date=2011 |isbn=9781459613287 |first=R. |last=Reid |publisher=ReadHowYouWant.com}}</ref><ref>{{cite web |url=http://www.underwatertimes.com/news.php?article_id=84173256109 |title=No Bull: Saltwater Crocodile Eats Shark |publisher=UnderwaterTimes.com |date=2007 |access-date=30 April 2011}}</ref><ref>{{cite journal |author=Whiting, S. D. |author2=Whiting, A. U. |name-list-style=amp |year=2011 |title=Predation by the Saltwater Crocodile (''Crocodylus porosus'') on sea turtle adults, eggs, and hatchlings |journal=Chelonian Conservation and Biology |volume=10 |issue=2 |pages=198–205 |doi=10.2744/CCB-0881.1 |s2cid=85816270}}</ref> However, there is evidence that saltwater crocodiles do hunt while out in the open seas, based upon the remains of pelagic fishes that dwell only miles away from land being found in their stomachs.<ref name="Callaway, J. M. 1997"/><ref name="Blaber, S. J. 2008"/> | |||
The hunting methods utilised by saltwater crocodiles are indistinct from any other crocodilian, with the hunting crocodile submerging and quietly swimming over to the prey before pouncing upwards, striking suddenly. Unlike some other crocodilians, such as ]s and even ]s, they are not known to have hunted on dry land.<ref name="Ross"/><ref name=Guggisberg/> Young saltwater crocodiles are capable of breaching their entire body into the air in a single upward motion while hunting prey that may be perched on low hanging branches.<ref name=Davenport/> While hunting ]s, they have been seen to knock the monkeys off a bank by knocking them with their tail, forcing the macaque into water for easy consumption. However, whether tail use in hunting is intentional or just an accidental benefit is not definitely clear.<ref name=Guggisberg/> As with other crocodilians, their sharp, peg-like teeth are well-suited to seize and tightly grip prey, but not to ] flesh. Small prey are simply swallowed whole, while larger animals are dragged into deep water and ] or crushed.<ref name="news.nationalgeographic.com">{{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=12 June 2013}}</ref> Large prey is then torn into manageable pieces by "death rolling", the spinning of the crocodile to twist off hunks of meat or by sudden jerks of the head.<ref>{{cite web |url=http://marinebio.org/species.asp?id=187 |title=Saltwater Crocodiles, ''Crocodylus porosus'' ~ |publisher=Marinebio.org |date=2013 |access-date=25 July 2013}}</ref> Occasionally, food items will be stored for later consumption once a crocodile eats its fill, although this can lead to scavenging by interlopers such as monitor lizards.<ref>{{cite journal |author=Doody, J. S. |year=2009 |title=Eyes bigger than stomach: prey caching and retrieval in the saltwater crocodile, ''Crocodylus porosus'' |journal=Herpetological Review |volume=40 |issue=1 |page=26}}</ref> | |||
====Bite==== | |||
] | |||
] | |||
Saltwater crocodiles have the strongest ] of any living animal. A {{cvt|4.59|m|ftin|adj=mid|-long}} {{cvt|531|kg|lb|adj=mid}} saltwater crocodile has been confirmed as having the highest ] ever recorded for an animal in a laboratory setting, with a value of {{cvt|16414|N|lbf}} surpassing the previous record of {{cvt|13172|N|lbf|disp=or}} made by an ] (''Alligator mississippiensis'').<ref>{{cite journal |title=Comparison of bite-force performance between long-term captive and wild American alligators (Alligator mississippiensis) |journal=] |volume=262 |issue=1 |pages=21–28 |doi=10.1017/S0952836903004400 |year=2004 |url=http://www.alligatorfarm.us/images/Research/Erickson%20et%20al.%202004.pdf |last1=Erickson |first1=G. M. |last2=Lappin |first2=A. K. |last3=Parker |first3=T. |last4=Vliet |first4=K. A. |name-list-style=amp}}</ref><ref name="erickson">{{cite journal |last=Erickson |first=G.M. |author2=Gignac, P.M. |author3=Steppan, S.J. |author4=Lappin, A.K. |author5=Vliet, K.A. |name-list-style=amp |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 |pmid=22431965 |pmc=3303775 |bibcode=2012PLoSO...731781E |doi-access=free}}</ref> Based on the regression of mean body mass and mean bite force, the bite forces of multiple crocodile species, {{cvt|1308|kg}} individuals were estimated at {{cvt|27531|to|34424|N|lbf}}.<ref name="erickson"/> The extraordinary bite of crocodilians is a result of their ]. The space for the jaw muscle in the ] is very large, which is easily visible from the outside as a bulge at each side. The nature of the ] is extremely stiff, almost as hard as bone to the touch, such that it can appear to be a continuation 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. The jaws of a crocodile can be securely shut with several layers of ].<ref>{{cite book |author=Cogger, H.G. |year=1996 |title=Reptiles and Amphibians of Australia |place=Chatswood, NSW |publisher=Reed Books}}</ref> | |||
===Reproduction=== | |||
Males reach sexual maturity around {{cvt|3.3|m}} at around 16 years of age, while females reach sexual maturity at {{cvt|2.1|m}} and 12–14 years of age.<ref name="Britton et al. 2012"/> | |||
Saltwater crocodiles mate in the wet season, when water levels are at their highest. In Australia, the male and female engage in courtship in September and October, and the female lays eggs between November and March.<ref name=Leach/> It is possible the rising temperatures of the wet season provoke reproductive behaviour in this species.<ref name=Messel/> While crocodilians generally nest every year, there have been several recorded cases of female saltwater crocodiles nesting only every other year and also records of a female attempting to produce two broods in a single wet season.<ref name=Messel/> The female selects the nesting site, and both parents will defend the nesting territory, which is typically a stretch of shore along tidal rivers or freshwater areas, especially swamps. Nests are often in a surprisingly exposed location, often in mud with little to no vegetation around, and thus limited protection from the sun and wind. The nest is a mound of mud and vegetation, usually measuring {{cvt|175|cm}} long and {{cvt|53|cm}} high, with an entrance averaging {{cvt|160|cm}} in diameter.<ref name=Messel/> Some nests in unlikely habitats have occurred, such as rocky rubble or in a damp low-grass field.<ref>{{cite journal |author=Somaweera, R. |author2=Shine, R. |name-list-style=amp |year=2013 |title=Nest-site selection by crocodiles at a rocky site in the Australian tropics: Making the best of a bad lot |journal=Austral Ecology |volume=38 |issue=3 |pages=313–325 |doi=10.1111/j.1442-9993.2012.02406.x |bibcode=2013AusEc..38..313S}}</ref><ref>{{cite journal |author=Magnusson, W. E. |year=1980 |title=Habitat required for nesting by ''Crocodylus porosus'' (Reptilia: Crocodilidae) in northern Australia |journal=Australian Wildlife Research |volume=7 |issue=1 |pages=149–156 |doi=10.1071/WR9800149 |url=https://www.researchgate.net/publication/248882409}}</ref> The female crocodile usually scratches a layer of leaves and other debris around the nest entrance and this covering is reported to produce an "astonishing" amount of warmth for the eggs (coincidentally these nesting habits are similar to those of the birds known as ]s that nest in upland areas of the same ]n regions where saltwater crocodiles are found).<ref name=Guggisberg/><ref>{{cite journal |author=Seymour, R. S. |author2=Ackerman, R. A. |year=1980 |title=Adaptations to underground nesting in birds and reptiles |journal=American Zoologist |volume=20 |issue=2 |pages=437–447 |doi=10.1093/icb/20.2.437|doi-access=free}}</ref> | |||
The female typically lays from 40 to 60 eggs, but some clutches have included up to 90. The eggs measure on average {{cvt|8|by|5|cm}} and weigh {{cvt|113|g}} on average in Australia and {{cvt|121|g}} in ].<ref name=Leach/><ref name=Gopi/> These are relatively small, as the average female saltwater crocodile weighs around five times as much as a freshwater crocodile, but lays eggs that are only about 20% larger in measurement and 40% heavier than those of the smaller species.<ref name=NewHolland/> The average weight of a new hatchling in Australia is reportedly {{cvt|69.4|g}}.<ref name=Leach/> Although the female guards the nest for 80 to 98 days (in extreme high and low cases from 75 to 106 days), the loss of eggs is often high due to flooding and occasionally to predation.<ref name=Leach/> As in all crocodilians, the sex of the hatchlings is determined by temperature. At 28–30 degrees all hatchlings will be female, at 30–32 degrees 86% of hatchlings are male, and at 33 or more degrees predominantly female (84%).<ref>{{cite journal |author=Lang, J. W. |author2=Andrews, H. V. |name-list-style=amp |year=1994 |title=Temperature-dependent sex determination in crocodilians |journal=Journal of Experimental Zoology |volume=270 |issue=1 |pages=28–44 |doi=10.1002/jez.1402700105}}</ref> In Australia, ]s (''Varanus giganteus'') commonly eat freshwater crocodile eggs (feeding on up to 95% of the clutch if discovered), but are relatively unlikely to eat saltwater crocodile eggs due to the vigilance of the imposing mother, with about 25% of the eggs being lost to goannas (less than half as many Nile crocodile eggs are estimated to be eaten by monitors in Africa).<ref name=NewHolland/> A majority of the loss of eggs of saltwater crocodiles occurs due to flooding of the nest hole.<ref name=Messel/><ref name=Magnusson>{{cite journal |author=Magnusson, W. E. |year=1982 |title=Mortality of eggs of the crocodile ''Crocodylus porosus'' in northern Australia |journal=Journal of Herpetology |pages=121–130 |jstor=1563804 |volume=16 |issue=2 |doi=10.2307/1563804}}</ref> | |||
As in most crocodilian species, the female saltwater crocodile exhibits a remarkable level of maternal care for a reptile. She excavates the nest in response to "yelping" calls from the hatchlings, and even gently rolls eggs in her mouth to assist hatching. The female will then carry the hatchlings to water in her mouth (as ] and ] females have been observed doing when their eggs hatch) and remains with the young for several months. Despite her diligence, losses of baby crocodiles are heavy due to various predators and unrelated crocodiles of their own species. Only approximately 1% of the hatchlings will survive to adulthood.<ref name="autogenerated1"/> By crocodilian standards, saltwater crocodile hatchlings are exceptionally aggressive to one another and will often fight almost immediately after being transported to water by their mother.<ref>{{cite journal |author=Brien, M. L. |author2=Webb, G. J. |author3=Lang, J. W. |author4=McGuinness, K. A. |author5=Christian, K. A. |name-list-style=amp |year=2013 |title=Born to be bad: agonistic behaviour in hatchling saltwater crocodiles (''Crocodylus porosus'') |journal=Behaviour |volume=150 |issue=7 |pages=737–762 |url=https://www.researchgate.net/publication/255965327 |doi=10.1163/1568539x-00003078}}</ref> The young naturally start to disperse after around 8 months, and start to exhibit territorial behaviour at around 2.5 years old. They are the most territorial of extant crocodilians and, due to their aggressiveness to conspecifics, from the dispersed immature stage on, they are never seen in concentrations or loose groups as are most other crocodilians.<ref>{{cite book |author=Lang, J. W. |year=1987 |chapter=Crocodilian behaviour: implications for management |pages=273–294 |title=Wildlife management: crocodiles and alligators |editor1=Webb, G. J. W. |editor2=Manolis, S. C. |editor3=Whitehead, P. J. |publisher=Surrey Beatty & Sons |url=https://www.researchgate.net/publication/255965122}}</ref> However, even females will not reach proper sexual maturity for another 10 years. Saltwater crocodiles that survive to adulthood can attain a very long ], with an estimated life expectancy upwards of 70 years, and some individuals possibly exceed 100 years, although no such extreme ages have been verified for any crocodilian.<ref name="Britton et al. 2012"/><ref>{{cite web |title=Estuarine Crocodile |publisher=UNEP-WCMC |url=http://www.unep-wcmc.org/species/data/species_sheets/crocodil.htm |archive-url=https://web.archive.org/web/20010814155251/http://www.unep-wcmc.org/species/data/species_sheets/crocodil.htm |url-status=dead |archive-date=14 August 2001 |access-date=25 July 2013}}</ref> | |||
While adults have no natural predators, baby saltwater crocodiles may fall prey to ]s (occasionally, but not commonly, the numerous ] in Australia, and the ] (''Varanus salvator'') further north), predatory fish (especially the ] (''Lates calcarifer'')), ]s, ]s, various aquatic and raptorial birds (e.g. ]s (''Ephippiorhynchus asiaticus'') and ]s (''Haliaeetus leucogaster'')), ], larger crocodiles, and many other predators.<ref name=Messel/><ref name=Leach>{{cite report |author1=Leach, G. |author2=Delaney, R. |author3=Fukuda, Y. |name-list-style=amp |year=2009 |title=Management program for the saltwater crocodile in the Northern Territory of Australia, 2009–2014 |publisher=Department of Natural Resources, Environment, the Arts and Sport}}</ref><ref name=Gopi>{{cite journal |author=Gopi, G.V. |author2=Angom, S. |year=2007 |url=https://www.researchgate.net/publication/261207960 |title=Aspects of nesting biology of ''Crocodylus porosus'' at Bhitarkanika, Orissa, Eastern India |journal=Journal of the Bombay Natural History Society |volume=104 |issue=3 |pages=328–333}}</ref><ref name=Magnusson/> Pigs and cattle also occasionally inadvertently trample eggs and nests on occasion and degrade habitat quality where found in numbers.<ref>{{cite journal |author=Webb, G. J. W. |author2=Manolis, S. C. |author3=Buckworth, R. |author4=Sack, G. C. |name-list-style=amp |year=1983 |title=An examination of ''Crocodylus porosus'' nests in two northern Australian freshwater swamps, with an analysis of embryo mortality |journal=Wildlife Research |volume=10 |issue=3 |pages=571–605 |doi=10.1071/WR9830571}}</ref> Juveniles may also fall prey to tigers and ]s (''Panthera pardus'') in certain parts of their range, although encounters between these predators are rare, and cats are likely to avoid areas with saltwater crocodiles.<ref>{{cite journal |author=Somaweera, R. |author2=Brien, M. |author3=Shine, R. |name-list-style=amp |year=2013 |title=The role of predation in shaping crocodilian natural history |journal=Herpetological Monographs |volume=27 |issue=1 |pages=23–51 |doi=10.1655/HERPMONOGRAPHS-D-11-00001 |s2cid=86167446}}</ref> | |||
<gallery widths="200px" heights="150px"> | |||
File:Hatchling saltwater crocodile.jpg|Saltwater crocodiles go through numerous physiological changes as they mature. Pictured here is a hatchling age or baby crocodile. | |||
File:Saltwater Crocodile (Crocodylus porosus) juvenile (8067785958).jpg|Seen here is a juvenile crocodile, which grows considerably in length over several years but is easily distinguished by slender build and size. | |||
File:Saltwater crocodile (Crocodylus porosus), Gembira Loka Zoo, 2015-03-15 01.jpg|A saltwater crocodile in the subadult age range at Gembira Loka Zoo, similar but not as robust and relatively small-headed compared to adults. | |||
File:Captivated Saltwater Crocodiles of Sundarbans 01.jpg| Juvenile salt water crocodiles at Karamjal Wildlife Breeding center, ] | |||
</gallery> | |||
==Conservation status== | |||
] | |||
]]] | |||
The species is considered of minimal concern for extinction but is protected from the effects of international trade under the ] as follows: | |||
* Appendix I (prohibiting all commercial trade in the species or its parts/derivatives): All wild populations except for those of Australia, Indonesia and Papua New Guinea; | |||
* Appendix II (commercial trade allowed with export permit; import permits may or may not be required depending on the laws of the importing country): Australia, Indonesia and Papua New Guinea wild populations, plus all worldwide populations bred in captivity for commercial purposes. | |||
The saltwater crocodile was often hunted for its meat and eggs, and its skin is the most commercially valuable of any crocodilian. Unregulated hunting during the 20th century caused a dramatic decline in the species throughout its range, with the population in northern Australia reduced by 95% by 1971. The years from 1940 to 1970 were the peak of unregulated hunting and may have regionally caused irreparable damage to saltwater crocodile populations.<ref name= Whitaker2>{{cite book |author=Whitaker, R. |year=1982 |chapter=Status of Asian crocodilians |page=237 |title=Crocodiles. Proceedings of the 5th Working Meeting of the Crocodile Specialist Group of the Species Survival Commission of the International Union for Conservation of Nature and Natural Resources Convened at the Florida State Museum, Gainesville, Florida, USA, 12 to 16 August 1980 |editor=Crocodile Specialist Group |publisher=IUCN |location=Gland}}</ref> The species currently has full legal protection in all Australian states and territories where it is found – Western Australia (since 1970), Northern Territory (since 1971) and Queensland (since 1974).<ref>{{cite web |url=http://www.environment.gov.au/cgi-bin/sprat/public/publicspecies.pl?taxon_id=1774 |title=Crocodylus porosus – Salt-water Crocodile, Estuarine Crocodile |publisher=Environment.gov.au |access-date=8 August 2013}}</ref> Illegal hunting still persists in some areas, with protection in some countries being grossly ineffective, and trade is often difficult to monitor and control over such a vast range. However, many areas have not recovered; some population surveys have shown that although young crocodiles are present, fewer than 10% of specimens spotted are in adult size range and do not include any particularly large males, such as ] or ]. This is indicative of both potential continued persecution and exploitation and a non-recovered breeding population.<ref>Gramantez, D. (2008) ''A case study of the Saltwater Crocodile Crocodylus porosus in Muthurajawela Marsh, Sri Lanka – Considerations for conservation''. IUCN- Crocodile Specialist Group.</ref><ref>{{cite journal |author=Brazaitis, P. |author2=Eberdong, J. |author3=Brazaitis, P. J. |author4=Watkins-Colwell, G. J. |year=2009 |title=Notes on the saltwater crocodile, ''Crocodylus porosus'', in the Republic of Palau |journal=Bulletin of the Peabody Museum of Natural History |volume=50 |issue=1 |pages=27–48 |doi=10.3374/014.050.0103 |s2cid=84984946}}</ref> In a more balanced population, such as those from ] or Sabah on Borneo, 28% and 24.2% of specimens observed were in the adult size range of more than {{convert|3|m|ftin|0|abbr=on}}.<ref name="Stuebing, R. B. 1994"/><ref>{{cite book |author=Kar, S. K. |year=1992 |chapter=Conservation, research, and management of estuarine crocodiles ''Crocodylus porosus'' Schneider in Bhitarkania Wildlife Sanctuary, Orissa, India during the last 17 years |pages=222–242 |title=Crocodiles. Proceedings of the 11th Working Meeting of the Crocodile Specialist Group of the IUCN Species Survival Commission convened at Victoria Falls, Zimbabwe, 2 to 7 August 1992 |volume=1 |editor=Crocodile Specialist Group |publisher=IUCN |location=Gland |chapter-url=http://www.iucncsg.org/365_docs/attachments/protarea/11th-40a1b3c3.pdf}}</ref> | |||
Habitat loss continues to be a major problem for the species. In northern Australia, much of the nesting habitat of the saltwater crocodile is susceptible to trampling by feral water buffalo, although buffalo eradication programs have now reduced this problem considerably. Even where large areas of suitable habitat remain, subtle habitat alterations can be a problem, such as in the ], where freshwater areas, used for nesting, are being increasingly converted to human agriculture. After the commercial value of crocodile skins waned, perhaps the greatest immediate challenge to implementing conservation efforts has been the occasional danger the species can pose to humans, and the resulting negative view of the crocodile.<ref name="autogenerated1">{{cite web |url=http://www.flmnh.ufl.edu/cnhc/csp_cpor.htm |title=Crocodilian Species – Australian Saltwater Crocodile (''Crocodylus porosus'') |publisher=Flmnh.ufl.edu |access-date=26 December 2010}}</ref><ref>{{cite journal |author=Tisdell, C. |author2=Nantha, H. S. |author3=Wilson, C. |year=2007 |title=Endangerment and likeability of wildlife species: How important are they for payments proposed for conservation? |journal=Ecological Economics |volume=60 |issue=3 |pages=627–633 |doi=10.1016/j.ecolecon.2006.01.007 |bibcode=2007EcoEc..60..627T}}</ref> | |||
==Relationship with humans== | |||
===Attacks on humans=== | |||
{{See also|Crocodile attack}} | |||
Of all the crocodilians, the saltwater crocodile and ] have the strongest tendencies to treat humans as prey.<ref name=SideleauBritton2012/> The saltwater crocodile has a long history of attacking humans who unknowingly venture into its territory. As a result of its power, intimidating size and speed, survival of a direct predatory attack is unlikely if the crocodile is able to make direct contact. In contrast to ] where a degree of coexistence may be the policy, the only recommended policy for dealing with saltwater crocodiles is to completely avoid their habitat whenever possible, as they are exceedingly aggressive when encroached upon.<ref name="Guggisberg"/> | |||
].<ref>{{cite web |url=https://nt.gov.au/__data/assets/pdf_file/0006/202578/crocodile-management.pdf |title=Crocodile Management |publisher=Northern Territory Government|access-date=6 May 2016}}</ref>]] | |||
Exact data on attacks are limited outside Australia, where one or two fatal attacks are reported per year.<ref name="Caldicott et al. 2005">{{cite journal |last=Caldicott |first=David G.E. |author2=Croser, D. |author3=Manolis, C. |author4=Webb, G. |author5=Britton, A. |title=Crocodile attack in Australia: an analysis of its incidence and review of the pathology and management of crocodilian attacks in general |journal=Wilderness & Environmental Medicine |date=September 2005 |volume=16 |issue=3 |pages=143–159 |doi=10.1580/1080-6032(2005)162.0.CO;2 |pmid=16209470 |doi-access=free}}</ref> From 1971 to 2013, the total number of fatalities reported in Australia due to saltwater crocodile attack was 106.<ref>Manolis, S. C., & Webb, G. J. (September 2013). "Assessment of saltwater crocodile (''Crocodylus porosus'') attacks in Australia (1971–2013): implications for management", pp. 97–104 in ''Crocodiles Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group''. Gland, Switzerland: IUCN.</ref><ref name="Caldicott et al. 2005"/> The low level of attacks may be due to extensive efforts by wildlife officials in Australia to post crocodile warning signs at numerous at-risk billabongs, rivers, lakes and beaches.<ref>{{cite book |author=Nichols, T. |author2=Letnic, M. |year=2008 |chapter=Problem crocodiles: reducing the risk of attacks by ''Crocodylus porosus'' in Darwin Harbour, Northern Territory, Australia |title=Urban herpetology |volume=3 |pages=503–511|chapter-url=https://www.researchgate.net/publication/259471883}}</ref> Less-publicised attacks have been reported in ],<ref>{{cite web |url=http://www.iht.com/articles/ap/2007/04/25/asia/AS-GEN-Malaysia-Crocodile-Attacks.php |archive-url=https://web.archive.org/web/20070811033904/http://www.iht.com/articles/ap/2007/04/25/asia/AS-GEN-Malaysia-Crocodile-Attacks.php |archive-date=11 August 2007 |title=Rise in Borneo crocodile attacks may be linked to Malaysia's logging, palm oil, expert says |publisher=Associated Press via International Herald Tribune |date=25 April 2007 |access-date=18 August 2010}}</ref> ],<ref>{{cite web |url=https://www.telegraph.co.uk/news/worldnews/1581715/Woman-saves-daughter-from-crocodile.html |archive-url=https://ghostarchive.org/archive/20220111/https://www.telegraph.co.uk/news/worldnews/1581715/Woman-saves-daughter-from-crocodile.html |archive-date=11 January 2022 |url-access=subscription |url-status=live |title=Woman saves daughter from crocodile |publisher=Telegraph |date=14 March 2008 |access-date=25 July 2013}}{{cbignore}}</ref> ] (]),<ref>{{cite web |url=http://www.kalingatimes.com/orissa_news/news2/20080505_Two_injured_in_crocodile_attack.htm |archive-url=https://web.archive.org/web/20080607221308/http://www.kalingatimes.com/orissa_news/news2/20080505_Two_injured_in_crocodile_attack.htm |archive-date=7 June 2008 |title=KalingaTimes.com: Two injured in crocodile attack in Orissa |date=7 June 2008 |access-date=25 July 2013}}</ref><ref>{{cite web |url=http://today.msnbc.msn.com/id/37003327/ |archive-url=https://web.archive.org/web/20100513062250/http://today.msnbc.msn.com/id/37003327 |url-status=dead |archive-date=13 May 2010 |title=Croc kills woman 4 years after her sister's death – TODAY.com |publisher=] |date=5 October 2010 |access-date=25 July 2013}}</ref> and ].<ref>{{cite web |url=http://www.iht.com/articles/ap/2008/04/20/asia/AS-GEN-Myanmar-Crocodile.php|archive-url=https://web.archive.org/web/20080517023623/http://www.iht.com/articles/ap/2008/04/20/asia/AS-GEN-Myanmar-Crocodile.php|archive-date=17 May 2008 |title=Crocodile kills man accused of illegal logging in Myanmar wildlife sanctuary |publisher=Associated Press via International Herald Tribune |date=20 April 2008 |access-date=18 August 2010}}</ref> In ], ], the average number of fatal attacks is reportedly 2.8 annually for the years from 2000 to 2003.<ref name= AttackResearch/> In the ] in Australia, attempts have been made to relocate saltwater crocodiles who have displayed aggressive behaviour towards humans but these have proven ineffective as the problem crocodiles are apparently able to find their way back to their original territories.<ref>{{cite journal |author=Walsh, B. |author2=Whitehead, P. J. |year=1993 |title=Problem crocodiles, ''Crocodylus porosus'', at Nhulunbuy, Northern Territory: an assessment of relocation as a management strategy |journal=Wildlife Research |volume=20 |issue=1 |pages=127–135 |doi=10.1071/WR9930127}}</ref> In the ] from 2007 to 2009, 67–78% of "problem crocodiles" were identified as males.<ref>Delaney, R., Fukuda, Y., & Saalfeld, K. (2009). ''SALTWATER CROCODILE (''Crocodylus porosus'') MANAGEMENT PROGRAM''. Northern Territory Government, Department of Natural Resources, Environment, the Arts and Sport.</ref> | |||
Many attacks in areas outside Australia are believed to go unreported, with one study positing up to 20 to 30 attacks occur every year.<ref name= AttackResearch>{{cite web |url=http://iucncsg.org/ph1/modules/Crocodilians/attacks.html|archive-url=https://web.archive.org/web/20090503090108/http://iucncsg.org/ph1/modules/Crocodilians/attacks.html |archive-date=3 May 2009 |title=Crocodile Specialist Group – Crocodilian Attacks |access-date=25 July 2013}}</ref> This number may be conservative in light of several areas where humans and saltwater crocodiles co-exist in relatively undeveloped, low-economy and rural regions, where attacks are likely to go unreported.<ref name=SideleauBritton2012>Sideleau, B., & Britton, A. R. C. (2012). "A preliminary analysis of worldwide crocodilian attacks", pp. 111–114 in ''Crocodiles'' Proceedings of the 21st Working Meeting of the IUCN-SSC Crocodile Specialist Group. Gland, Switzerland: IUCN.</ref> However, claims in the past that saltwater crocodiles are responsible for thousands of human fatalities annually are likely to have been exaggerations and were probably falsified to benefit leather companies, hunting organisations and other sources that may have benefited from maximising the negative perception of crocodiles for financial gain.<ref name= Guggisberg/><ref name="Wood"/><ref name= AttackResearch/> Despite their reputations, many wild saltwater crocodiles are normally quite wary of humans and will go out of their way to submerge and swim away from them, even large adult males, if previously subject to harassment or persecution.<ref>{{cite journal |author=Webb, G. J. W. |author2=Messel, H. |year=1979 |title=Wariness in ''Crocodylus porosus'' (Reptilia: Crocodilidae) |journal=Wildlife Research |volume=6 |issue=2 |pages=227–234 |doi=10.1071/WR9790227}}</ref><ref>Somaweera, R. & A. de Silva (2013). ''Using traditional knowledge to minimize human-crocodile conflict in Sri Lanka'', pp. 257. In: Crocodiles. Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group. IUCN, Gland, Switzerland.</ref> Some attacks on humans appear to be territorial rather than predatory in nature, with crocodiles over two years in age often attacking anything that comes into their area (including boats). Humans can usually escape alive from such encounters, which comprise about half of all attacks. Non-fatal attacks usually involve crocodiles of {{convert|3|m|ftin|0|abbr=on}} or less in length. Fatal attacks, more likely to be predatory in motivation, commonly involve larger crocodiles with an average estimated size of {{convert|4.3|m|ftin|0|abbr=on}}. Under normal circumstances, ]s are believed to be responsible for a considerably greater number of fatal attacks on humans than saltwater crocodiles, but this may have more to do with the fact that many people in Africa tend to rely on riparian areas for their livelihood, which is less prevalent in most of Asia and certainly less so in Australia.<ref name= AttackResearch/> In the ], the number of fatal attacks on humans has reportedly increased, possibly due to habitat destruction and reduction of natural prey.<ref>Sivaperuman, C. (2014). ''Saltwater Crocodiles in Andaman and Nicobar Islands, with Special Reference to Human–Crocodile Conflict''. Marine Faunal Diversity in India: Taxonomy, Ecology and Conservation, 453.</ref> | |||
During the Japanese retreat in the ] on 19 February 1945, saltwater crocodiles may have been responsible for the deaths of over 400 Japanese soldiers. British soldiers encircled the swampland through which the Japanese were retreating, condemning the Japanese to a night in the mangroves, which were home to thousands of saltwater crocodiles. Many Japanese soldiers did not survive this night, but the attribution of the majority of their deaths to crocodile attacks has been doubted.<ref>{{cite journal |author=Platt, S. G. |author2=W. K. Ko |author3=M. Kalyar Myo |author4=L. L. Khaing |author5=T. Rainwater |title=Man eating by estuarine crocodiles: the Ramree Island massacre revisited |journal=Herpetological Bulletin |year=2001 |volume=75 |pages=15–18}}</ref> Another reported mass attack involved a cruise in eastern ] where a boat accident forced 28 people into the water where they were reportedly consumed by saltwater crocodiles.<ref name="Wood"/> Another notorious crocodile attack was in 1985, on ecofeminist ], who survived the attack and learned that the advice she had received that crocodiles do not attack canoes was inaccurate.<ref>{{cite web |url=http://www.nma.gov.au/collections/highlights/val_plumwood_canoe |title=National Museum of Australia – Val Plumwood canoe |publisher=Nma.gov.au |access-date=25 July 2013 |archive-date=12 October 2018 |archive-url=https://web.archive.org/web/20181012174231/http://www.nma.gov.au/collections/highlights/val_plumwood_canoe |url-status=dead}}</ref><ref>{{cite web |url=http://www.aislingmagazine.com/aislingmagazine/articles/TAM30/ValPlumwood.html |title=Val Plumwood Prey to a Crocodile |publisher=Aislingmagazine.com |access-date=25 July 2013}}</ref> | |||
In July 2018, a 600-strong mob slaughtered 292 saltwater and ]s in Papua province in Indonesia in a revenge attack after a man who encroached upon the sanctuary was devoured.<ref>{{cite news |url=https://www.washingtonpost.com/news/animalia/wp/2018/07/16/a-crocodile-killed-an-indonesian-man-so-his-village-slaughtered-nearly-300-crocodiles/ |title=A crocodile killed an Indonesian man — so his village slaughtered nearly 300 crocodiles |first=Cleve R. Jr. |last=Wootson |date=16 July 2018 |newspaper=Washington Post}}</ref> | |||
===Cultural references=== | |||
] | |||
The saltwater crocodile is considered holy on ]. According to legend, the island was formed by a giant crocodile. The ] have a similar and very involved myth and traditionally the crocodile was described as a relative (normally a father or grandfather).<ref name="Guggisberg"/> | |||
According to ], the mythology of ]s, the saltwater crocodile was banished from the fresh water for becoming full of bad spirits and growing too large, unlike the freshwater crocodile, which was somewhat revered.<ref>{{cite web |url=http://www.australianstamp.com/coin-web/feature/history/abdream.htm |title=Historical Feature – Aboriginal Dreamtime Legends |publisher=Australianstamp.com |date=2007 |access-date=8 August 2013 |archive-date=16 October 2013 |url-status=dead |archive-url=https://web.archive.org/web/20131016192334/http://www.australianstamp.com/coin-web/feature/history/abdream.htm}}</ref> Aboriginal rock art depicting the saltwater crocodile is rare, although examples of up to 3,000 years old were found in caves in Kakadu and Arnhem land, roughly matching the distribution of the species. It is however depicted in contemporary aboriginal art.<ref>{{cite journal |author=Fijn, N. |year=2013 |title=Living with crocodiles: engagement with a powerful reptilian being |journal=Animal Studies Journal |volume=2 |issue=2 |pages=1–27 |url=http://ro.uow.edu.au/asj/vol2/iss2/2/ }}{{Dead link|date=December 2024 |bot=InternetArchiveBot |fix-attempted=yes }}</ref> | |||
The ] think of themselves as crocodile descendants, and regard it as their totem.<ref>{{cite web |last= |first= |date= |title=Two decades of fierce determination |url=https://www.oric.gov.au/publications/spotlight/two-decades-fierce-determination|access-date=16 January 2021 |website=Office of the Registrar of Indigenous Corporations}}</ref> They respect crocodiles as protectors of harbours and do not eat crocodile meat.<ref>{{cite news |author=Rawlinson, C. |date=2012 |url=https://www.abc.net.au/local/audio/2012/07/02/3536791.htm |title=Learning Larrakia: totem animal 'Dungalaba' |newspaper=ABC Radio Darwin}}</ref> | |||
The species is featured on several postage stamps, including an 1894 State of North Borneo 12-cent stamp; a 1948 Australian 2 shilling stamp depicting an aboriginal rock artwork of the species; a 1966 Republic of Indonesia stamp; a 1994 Palau 20-cent stamp; a 1997 Australian 22-cent stamp; and a 2005 1 Malaysian ringgit postage stamp. | |||
The saltwater crocodile has featured in contemporary Australian film and television including the '']'' series of films, horror films '']'' and '']'' and '']'' television series. There are now several saltwater crocodile–themed parks in Australia.{{citation needed|date=December 2019}} | |||
===Examples of large unconfirmed saltwater crocodiles=== | |||
The largest size recorded for a saltwater crocodile has always been a subject of considerable controversy. The reason behind unverified sizes is either the case of insufficient/inconclusive data or exaggeration from a folkloric point of view. This section is dedicated to examples of the largest saltwater crocodiles recorded outside scientific norms measurement and estimation, with the aim of satisfying the public interest without creating data pollution, as well as serving an educational purpose of guiding the reader to separate fact from possible fiction. Below, in descending order starting from the largest, are some examples of large unconfirmed saltwater crocodiles, recorded throughout history. | |||
* A crocodile shot in the ] in 1840 was reported at {{convert|10.1|m|ftin|0|abbr=on}}. Furthermore, this specimen was claimed to have a belly girth of {{convert|4.17|m|ftin|0|abbr=on}} and a body mass estimated {{convert|3000|kg|lb|abbr=on}}. However, the skull of this specimen was examined by Guinness Records and found to be only {{convert|66.5|cm|ftin|frac=4|abbr=on}} in length, indicating the above size was considerably exaggerated and the animal would have probably measured no more than {{convert|5.89|m|ftin|frac=2|abbr=on}}.<ref name="Wood"/> | |||
* James R. Montgomery, who ran a plantation near to the ] in ] from 1926 to 1932, claimed to have netted, killed, and examined numerous crocodiles well over {{convert|6.1|m|ftin|0|abbr=on}} there, including a specimen he claims measured {{convert|10|m|ftin|0|abbr=on}}. However, no one scientifically confirmed any of Montgomery's specimens and no voucher specimens are known.<ref name="Wood"/> | |||
* A crocodile shot in Queensland in 1957, nicknamed Krys the croc (named after the woman that shot the crocodile in July 1957; Krystina Pawlowski), was reported to be {{convert|8.63|m|ftin|frac=2|abbr=on}} long, but no verified measurements were made and no remains of this crocodile exist.<ref>{{cite news |title=Monster croc? Welcome to my nightmare |url=http://www.news.com.au/welcome-to-my-nightmare/story-e6frer76-1225961861480 |newspaper=The Sunday Mail |date=28 November 2010 |publisher=news.com.au |url-status=dead |archive-url=https://web.archive.org/web/20120607045222/http://www.news.com.au/welcome-to-my-nightmare/story-e6frer76-1225961861480 |archive-date=7 June 2012}}</ref><ref>{{cite news |last=Reid |first=Robert |title=Death of a monster |url=http://www.theaustralian.com.au/news/health-science/death-of-a-monster/story-e6frg8gf-1111118162303|access-date=2 April 2011 |newspaper=The Australian |date=28 November 2008}}</ref> A "replica" of this crocodile has been made as a tourist attraction.<ref>{{cite web |url=http://www.giveanaussieago.com.au/towns/Normanton.html |title=QLD – NORMANTON – Home of largest Crocodile ever shot! |publisher=Give An Aussie A Go |access-date=25 July 2013}}</ref><ref>{{cite web |url=http://www.abc.net.au/backyard/stories/s1020946.htm |title=Krys the crocodile, Normanton, Queensland :: Backyard |publisher=abc.net.au |date=6 January 2004 |url-status=dead |archive-url=https://web.archive.org/web/20090213125204/http://www.abc.net.au/backyard/stories/s1020946.htm |archive-date=13 February 2009}}</ref><ref>{{cite web |url=http://animals.nationalgeographic.com/animals/reptiles/saltwater-crocodile.html |archive-url=https://web.archive.org/web/20070625102719/http://animals.nationalgeographic.com/animals/reptiles/saltwater-crocodile.html |url-status=dead |archive-date=25 June 2007 |title=Saltwater Crocodiles, Saltwater Crocodile Pictures, Saltwater Crocodile Facts – National Geographic |publisher=Animals.nationalgeographic.com |access-date=25 July 2013}}</ref> | |||
* A crocodile killed in 1823 at ] on the main island of ] in the ] was reported at {{convert|8.2|m|ftin|0|abbr=on}}. However the skull of the specimen is {{convert|66.5|cm|in|frac=4|abbr=on}} long indicating an animal of approximately {{convert|6.1|m|ftin|0|abbr=on}}.<ref name="Wood"/> | |||
* A crocodile shot in ], India,<ref name="underwatertimes1">{{cite web |title=Guinness: India Park Home to World's Largest Crocodile |url=http://www.underwatertimes.com/news.php?article_id=51790108324 |publisher=UnderwaterTimes.com |access-date=30 April 2011}}</ref> was claimed to measure {{convert|7.6|m|ftin|0|abbr=on}} in life, but its skull, when given scholarly examination, was thought to have come from a crocodile of a length no greater than {{convert|7|m|ftin|0|abbr=on}}.<ref>{{cite web |url=http://crocodilian.com/cnhc/cbd-faq-q2.htm |title=Crocodilian Biology Database. FAQ |publisher=Crocodilian.com |access-date=24 May 2012}}</ref> | |||
* A reported {{convert|7.6|m|ftin|0|abbr=on}} crocodile was killed in the ] in the Alipore District of ]. However, examinations of the animal's skull, one of the largest skulls known to exist for the species at {{convert|75|cm|in|0|abbr=on}} long, actually indicating it could have measured {{convert|6.7|m|ftin|0|abbr=on}}.<ref name="Wood"/> | |||
* In 2006, ] accepted a {{convert|7.01|m|ftin|0|abbr=on}}, {{convert|2000|kg|adj=on}} male saltwater crocodile living within ] in Odisha. Due to the difficulty of trapping and measuring a very large living crocodile, the accuracy of these dimensions is yet to be verified. These observations and estimations have been made by park officials over the course of ten years, from 2006 to 2016, however, regardless of the skill of the observers it cannot be compared to a verified tape measurement, especially considering the uncertainty inherent in visual size estimation in the wild.<ref name=Bayliss>Bayliss, P. (1987). ''Survey methods and monitoring within crocodile management programmes''. Surrey Beatty & Sons, Chipping Norton, pages 157–175</ref> In addition, this region may contain up to four other specimens measuring over {{convert|6.1|m|ftin|0|abbr=on}}.<ref name="underwatertimes1"/><ref name="ohmynews1">{{cite web |url=http://english.ohmynews.com/articleview/article_view.asp?no=298369&rel_no=1 |title=World's Largest Reptile Found in India |publisher=ohmynews.com |last=Mishra |first=Braja Kishore |date=14 June 2006 |access-date=13 December 2007 |archive-date=8 January 2008 |archive-url=https://web.archive.org/web/20080108203350/http://english.ohmynews.com/articleview/article_view.asp?no=298369&rel_no=1 |url-status=dead}}</ref> | |||
* S. Baker (1874) claimed that in ] in the 1800s, specimens measuring {{convert|6.7|m|ftin|0|abbr=on}} or more were commonplace.<ref name="Wood"/> However, the largest specimen killed on the island that was considered authentic by Guinness Records was a suspected man-eater killed in the ] and measuring exactly {{convert|6|m|ftin|0|abbr=on}} in length.<ref name="Wood"/> | |||
*The record size for a crocodile from ] to be considered authentic by Guinness was a {{convert|6.32|m|ftin|0|abbr=on}} specimen shot by Herb Schweighofer in May 1966 along the northeastern coast. This specimen had a belly girth of {{convert|2.74|m|ftin|0|abbr=on}}.<ref name="Wood"/> | |||
==See also== | ==See also== | ||
*] | * ] | ||
* ] | |||
* Crocodile farming in Iran | |||
== Explanatory notes == | |||
{{NoteFoot}} | |||
==References== | |||
{{Reflist|30em}} | |||
==External links== | ==External links== | ||
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{{Wikispecies|Crocodylus porosus}} | ||
{{Commons category|Crocodylus porosus}} | |||
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* | |||
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* from Dr. Britton's site | |||
* | |||
*Brief from Dr. Britton and others discussing ] intelligence | |||
* from Dr. Britton's ({{Webarchive|url=https://web.archive.org/web/20110708204615/http://www.crocodilian.com/ |date=8 July 2011 }}) | |||
* Brief ({{Webarchive|url=https://web.archive.org/web/20111120102606/http://dml.cmnh.org/2001May/msg00788.html |date=20 November 2011 }}) from Dr. Britton and others discussing ] intelligence | |||
* {{cite web |url=http://blogs.scientificamerican.com/tetrapod-zoology/saltwater-crocodile-crocodiles-part-iii/ |title=The Saltwater Crocodile, and all that it implies (crocodiles part III) |author=Naish, D. |work=Scientific American |series=Tetrapod Zoology |year=2012 |access-date=12 June 2015}} | |||
{{Crocodilia|C.}} | {{Crocodilia|C.}} | ||
{{Crocs}} | {{Crocs}} | ||
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Latest revision as of 19:26, 25 December 2024
Reptile of South Asia, Southeast Asia and Oceania
Saltwater crocodile Temporal range: Pliocene–Present, 5.3–0 Ma PreꞒ Ꞓ O S D C P T J K Pg N | |
---|---|
Male | |
Female | |
Conservation status | |
Least Concern (IUCN 3.1) | |
CITES Appendix I (CITES) | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Reptilia |
Clade: | Archosauromorpha |
Clade: | Archosauriformes |
Order: | Crocodilia |
Family: | Crocodylidae |
Genus: | Crocodylus |
Species: | C. porosus |
Binomial name | |
Crocodylus porosus Schneider, 1801 | |
Range of the saltwater crocodile in black |
The saltwater crocodile (Crocodylus porosus) is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia. It has been listed as Least Concern on the IUCN Red List since 1996. It was hunted for its skin throughout its range up to the 1970s, and is threatened by illegal killing and habitat loss. It is regarded as dangerous to humans.
The saltwater crocodile is the largest living reptile. Males can grow up to a weight of 1,000–1,500 kg (2,200–3,300 lb) and a length of 6 m (20 ft), rarely exceeding 6.3 m (21 ft). Females are much smaller and rarely surpass 3 m (9.8 ft). It is also called the estuarine crocodile, Indo-Pacific crocodile, marine crocodile, sea crocodile, and, informally, the saltie. A large and opportunistic hypercarnivorous apex predator, they ambush most of their prey and then drown or swallow it whole. They will prey on almost any animal that enters their territory, including other predators such as sharks, varieties of freshwater and saltwater fish including pelagic species, invertebrates such as crustaceans, various amphibians, other reptiles, birds, and mammals.
Taxonomy and evolution
Crocodilus porosus was the scientific name proposed by Johann Gottlob Theaenus Schneider who described a zoological specimen in 1801. In the 19th and 20th centuries, several saltwater crocodile specimens were described with the following names:
- Crocodilus biporcatus proposed by Georges Cuvier in 1807 were 23 saltwater crocodile specimens from India, Java and Timor.
- Crocodilus biporcatus raninus proposed by Salomon Müller and Hermann Schlegel in 1844 was a crocodile from Borneo.
- Crocodylus porosus australis proposed by Paulus Edward Pieris Deraniyagala in 1953 was a specimen from Australia.
- Crocodylus pethericki proposed by Richard Wells and C. Ross Wellington in 1985 was a large-bodied, relatively large-headed and short-tailed crocodile specimen collected in 1979 in the Finnis River, Northern Territory. This purported species was later considered to be a misinterpretation of the physiological changes that very large male crocodiles undergo. However, Wells and Wellington's assertion that the Australian saltwater crocodiles may be distinctive enough from northern Asian saltwater crocodiles to warrant subspecies status, as could raninus from other Asian saltwater crocodiles, has been considered to possibly bear validity.
Currently, the saltwater crocodile is considered a monotypic species.
Evolution
Fossil remains of a saltwater crocodile excavated in northern Queensland were dated to the Pliocene. The saltwater crocodile's closest extant (living) relatives are the Siamese crocodile and the mugger crocodile.
The genus Crocodylus was thought to have evolved in Australia and Asia. Results of a phylogenetic study supports its likely origin in Africa and later radiation towards Southeast Asia and the Americas; it genetically diverged from its closest recent relative, the extinct Voay of Madagascar, around 25 million years ago near the boundary between the Oligocene and Miocene.
Phylogeny
Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological, molecular (DNA sequencing), and stratigraphic (fossil age) data, as revised in 2021 after a paleogenomics study using DNA extracted from the extinct Voay.
Crocodylinae |
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Description
The saltwater crocodile has a wide snout compared to most crocodiles. However, it has a longer snout than the mugger crocodile (C. palustris); its length is twice its width at the base. A pair of ridges runs from the eyes along the centre of the snout. The scales are oval in shape and the scutes are either small compared to other species or commonly are entirely absent. In addition, an obvious gap is also present between the cervical and dorsal shields, and small, triangular scutes are present between the posterior edges of the large, transversely arranged scutes in the dorsal shield. The relative lack of scutes is considered an asset useful to distinguish saltwater crocodiles in captivity or in illicit leather trading, as well as in the few areas in the field where sub-adult or younger saltwater crocodiles may need to be distinguished from other crocodiles. It has fewer armour plates on its neck than other crocodilians.
The adult saltwater crocodile's broad body contrasts with that of most other lean crocodiles, leading to early unverified assumptions the reptile was an alligator.
Young saltwater crocodiles are pale yellow in colour with black stripes and spots on their bodies and tails. This colouration lasts for several years until the crocodiles mature into adults. The colour as an adult is much darker greenish-drab, with a few lighter tan or grey areas sometimes apparent. Several colour variations are known and some adults may retain fairly pale skin, whereas others may be so dark as to appear blackish. The ventral surface is white or yellow in colour in saltwater crocodiles of all ages. Stripes are present on the lower sides of their bodies, but do not extend onto their bellies. Their tails are grey with dark bands.
Size
The weight of a crocodile increases approximately cubically as length increases (see square–cube law). This explains why individuals at 6 m (20 ft) weigh more than twice as much as individuals at 5 m (16 ft). In crocodiles, linear growth eventually decreases and they start getting bulkier at a certain point.
Saltwater crocodiles are the largest extant riparian predators in the world. However, they start life fairly small. Newly hatched saltwater crocodiles measure about 28 cm (11 in) long and weigh an average of 71 g (2.5 oz). These sizes and ages are almost identical to those at average sexual maturity in Nile crocodiles, despite the fact that average adult male saltwater crocodiles are considerably larger than average adult male Nile crocodiles.
The largest skull of a saltwater crocodile that could be scientifically verified was of a specimen in the Muséum national d'Histoire naturelle, collected in Cambodia. Its skull was 76 cm (30 in) long and 48 cm (19 in) wide near its base, with 98.3 cm (38.7 in) long mandibles; its length is not known, but based on skull-to-length ratios of large saltwater crocodiles its length was presumably in the 6.7–7 m (22–23 ft) range, though it could have had an exceptionally large skull or may not have the same skull-to-total-length ratios as other large saltwater crocodiles. If detached from the body, the head of a large male crocodile can weigh over 200 kg (440 lb), including the large muscles and tendons at the base of the skull that lend the crocodile its massive biting strength. The largest tooth measured 9 cm (3.5 in) in length. Other crocodilians like the gharial (Gavialis gangeticus) and the false gharial (Tomistoma schlegelii) have a proportionately longer skull, but both their skulls and their bodies are less massive than in the saltwater crocodile.
Male size
An adult male saltwater crocodile, from young adults to older individuals, typically ranges 3.5 to 5 m (11 ft 6 in – 16 ft 5 in) in length and weighs 200 to 1,100 kg (440 to 2,430 lb). On average, adult males range 4.0 to 4.5 m (13 ft 1 in – 14 ft 9 in) in length and weigh 408 to 770 kg (899 to 1,698 lb). However average size largely depends on the location, habitat, and human interactions and thus varies from one study to another. In 1993, in a study conducted (published in 1998), eleven saltwater crocodiles were found to have measured 2.1 to 5.5 m (6 ft 11 in – 18 ft 1 in) and weighed between 32 and 1,010 kg (71 and 2,227 lb). Very large, aged males can exceed 6 m (19 ft 8 in) in length and presumably weigh up to 2,000 kg (4,400 lb).
The largest confirmed saltwater crocodile on record drowned in a fishing net in Papua New Guinea, in 1979. Its dried skin plus head measured 6.2 m (20 ft 4 in) in length and it was estimated to have been 6.3 m (20 ft 8 in) when accounting for shrinkage and a missing tail tip. Projected from their skull lengths, multiple specimens from Singapore were estimated to belong in life to male crocodiles measuring more than 6 m (19 ft 8 in). A large Vietnamese saltwater crocodile was reliably estimated, based on its skull after its death, at 6.3 to 6.8 m (20 ft 8 in – 22 ft 4 in). However, according to evidence in the form of skulls coming from some of the largest crocodiles ever shot, the maximum possible size attained by the largest members of this species is considered to be 7 m (23 ft 0 in). A governmental study from Australia accepts that the very largest members of the species are likely to measure 6 to 7 m (19 ft 8 in – 23 ft 0 in) in length and weigh 900 to 1,500 kg (2,000 to 3,300 lb). Furthermore, a research paper on the morphology and physiology of crocodilians by the same organisation estimates that saltwater crocodiles reaching sizes of 7 m (23 ft 0 in) would weigh around 2,000 kg (4,400 lb). Due to the extreme size and highly aggressive nature of the species, weight in larger specimens is frequently poorly documented. A 5.1-metre (16 ft 9 in) long individual named "Sweetheart" was found to have weighed 780 kg (1,720 lb). Another large crocodile named "Gomek", measuring 5.42 m (17 ft 9 in) in length weighed around 860 kg (1,900 lb). In 1992, a notorious man-eater, named "Bujang Senang" was killed in Sarawak, Malaysia. It measured 5.7 m (18 ft 8 in) in length and weighed more than 900 kg (2,000 lb). A saltwater–siamese hybrid named "Yai" (Thai: ใหญ่, meaning big; born 10 June 1972) at the Samutprakarn Crocodile Farm and Zoo, Thailand was claimed to be the largest crocodile ever held in captivity. It measured 6 m (19 ft 8 in) in length and weighed approximately 1,118 kg (2,465 lb). In 1962, a large male saltwater crocodile was shot in Adelaide River, Northern Territory. It was recorded to be 6.1 m (20 ft 0 in) long and weighed 1,097 kg (2,418 lb). A large male in the Philippines, named Lolong, was one of the largest saltwater crocodile ever caught and placed in captivity. He was 6.17 m (20 ft 3 in) long and weighed 1,075 kg (2,370 lb). Following his death in 2013, the largest living crocodile in captivity was "Cassius", who was kept at Marineland Crocodile Park, a zoo located at Green Island, Queensland, Australia. He measured 5.48 m (18 ft 0 in) in length and weighs approximately 1,300 kg (2,870 lb) before his own death in November 2024.
Female size
Adult females typically measure from 2.7 to 3.1 m (8 ft 10 in to 10 ft 2 in) in total length and weigh 76 to 103 kg (168 to 227 lb). Large mature females reach 3.4 m (11 ft 2 in) and weigh up to 120 to 200 kg (260 to 440 lb). The largest female on record measured about 4.3 m (14 ft 1 in) in total length. Female are thus similar in size to other species of large crocodiles and average slightly smaller than females of some other species, like the Nile crocodile. The saltwater crocodile has the greatest size sexual dimorphism, by far, of any extant crocodilian, as males average about 4 to 5 times as massive as adult females and can sometimes measure twice her total length. The reason for the male skewered dimorphism in this species is not definitively known but might be correlated with sex-specific territoriality and the need for adult male saltwater crocodiles to monopolise large stretches of habitat. Due to the extreme sexual dimorphism of the species as contrasted with the more modest-sized dimorphism of other species, the average length of the species is only slightly more than some other extant crocodilians at 3.8–4 m (12 ft 6 in – 13 ft 1 in).
Reported sizes
Date | Location | Reported Length | Reported Weight | Reported Girth | Reported Skull Length | Scientifically Analyzed Length | Comments |
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1840 | Bay of Bengal | 1,005.84 cm (396.00 in) | 2,721.55 kg (6,000.0 lb) | 396.24 cm (156.00 in) | 927 mm (36.5 in) | 591.312 cm (232.800 in) | Skull saved, but was later shown to be measured incorrectly by calculating from snout to posterior edge of lower jaw, per GA Greer. Actual skull length was 655mm. |
1823 | Luzon, Philippines | 822.96 cm (324.00 in) | Not listed | 335.28 cm (132.00 in) | 674 mm (26.5 in) | 609.6 cm (240.0 in) | Skull preserved and measured by Thomas Barbour, who determined original length was taken along the curve of the belly. |
July 1957 | Carpenteria, Australia | 860 cm (340 in) | Not listed | Not listed | Not listed | Not listed | Killed by Krystyna Pawlowski while defending her three-year-old daughter |
1926–1932 | North Borneo | 1,005.84 cm (396.00 in) | Not listed | Not listed | Not listed | Not listed | Sighted by James R Montgomery sleeping on a river bank and was considered a legend by the Seluke people said to be over 200 years old. |
Distribution and habitat
The saltwater crocodile inhabits coastal brackish mangrove swamps, river deltas and freshwater rivers from India's east coast, Sri Lanka and Bangladesh to Myanmar, Malaysia, Brunei, Indonesia, Philippines, Timor Leste, Palau, Solomon Islands, Singapore, Papua New Guinea, Vanuatu and Australia's north coast. The southernmost population in India lives in Odisha's Bhitarkanika Wildlife Sanctuary; in northern Odisha, it has not been recorded since the 1930s. It occurs along the Andaman and Nicobar Islands coasts and in the Sundarbans. In Sri Lanka, it occurs foremost in western and southern parts of the country.
In Myanmar, it inhabits the Ayeyarwady Delta. In southern Thailand, it was recorded in Phang Nga Province. In Singapore, it inhabits the Sungei Buloh Wetland Reserve and marshes near Kranji and Mandai. It is locally extinct in Cambodia, China, Seychelles, Thailand and Vietnam.
In China, it may have once inhabited coastal areas from Fujian province in the north to the border of Vietnam. References to crocodile attacks on humans and livestock during the Han and Song dynasties indicate that until the 18th century, it may have occurred in lower Pearl River and Macau, Han River, Min River, portions of coastal Guangxi province and Hainan Island.
Three historical records of saltwater crocodiles being found in Japanese coastal waters exist; an individual was found off the coast of Iwo Jima in 1744, another was found off Amami Ōshima in 1800, and finally, a third individual was caught by fishermen in Toyama Bay in 1932. All other occurrences of the species being present within Japanese territory are from World War II, and were found in areas that were formerly controlled by the Empire of Japan.
In Malaysia, it was recorded in Klias, Segama and Kinabatangan Rivers in Sabah. In Sarawak, it was recorded by a camera trap in Kuching Wetlands National Park. In the Lesser Sunda Islands, it is present along the coasts of Sumba, Lembata Island, Flores, Menipo, Rote Island, and Timor. Its status along Alor Island is unknown, where one individual was captured in the 2010s. In the Maluku Islands, it is present around the Kai Islands, the Aru Islands, and many other islands in the region, including the Torres Strait Islands. In Papua New Guinea, it is common within the coastal reaches of every river system, such as the Fly River and in the Bismarck Archipelago. In the Philippines, it occurs in a few coastal sites like eastern Luzon, Palawan, the Liguasan Marsh, and Agusan River on Mindanao.
In northern Australia, the saltwater crocodile is thriving, particularly in the multiple river systems near Darwin such as the Adelaide, Mary, and Daly Rivers, along with their adjacent billabongs and estuaries. The saltwater crocodile population in Australia is estimated at 100,000 to 200,000 adults. Its range extends from Broome, Western Australia through the entire Northern Territory coast all the way south to Rockhampton, Queensland. The Alligator Rivers in the Arnhem Land region are misnamed due to the resemblance of the saltwater crocodile to alligators as compared to freshwater crocodiles, which also inhabit the Northern Territory.
Because of its ability to swim long distances at sea, individual saltwater crocodiles appeared occasionally in areas far away from their general range, up to Fiji. Saltwater crocodiles generally spend the tropical wet season in freshwater swamps and rivers, moving downstream to estuaries in the dry season. Crocodiles compete fiercely with each other for territory, with dominant males in particular occupying the most eligible stretches of freshwater creeks and streams. Junior crocodiles are thus forced into marginal river systems and sometimes into the ocean. This explains the large distribution of the species, as well as its being found in the odd places on occasion such as the Sea of Japan. Like all crocodiles, they can survive for prolonged periods in only warm temperatures, and crocodiles seasonally vacate parts of Australia if cold spells hit.
Behaviour and ecology
The primary behaviour to distinguish the saltwater crocodile from other crocodiles is its tendency to occupy salt water. Though other crocodiles also have salt glands that enable them to survive in saltwater, a trait that alligators do not possess, most other species do not venture out to sea except during extreme conditions.
Saltwater crocodiles use ocean currents to travel long distances. In Australia, 20 crocodiles were tagged with satellite transmitters; 8 of them ventured out into open ocean, and one of them traveled 590 km (370 mi) along the coast in 25 days from the North Kennedy River on the eastern coast of Far North Queensland, around Cape York Peninsula, to the west coast in the Gulf of Carpentaria. Another individual swam 411 km (255 mi) in 20 days. Without having to move around much, sometimes simply by floating, the current-riding behaviour allows for the conservation of energy. They interrupted their movements and resided in sheltered bays for a few days until the current changed direction. Sometimes, they also swam up and down river systems. Generally very lethargic, a trait that helps it survive months at a time without food, the saltwater crocodile will usually loiter in the water or bask in the sun during much of the day, preferring to hunt at night. A study of seasonal saltwater crocodile behaviour in Australia indicated that they are more active and more likely to spend time in the water during the Australian summer; conversely, they are less active and spend relatively more time basking in the sun during the winter. Saltwater crocodiles, however, are among the most active of all crocodilians, spending more time cruising and active, especially in water. They are much less terrestrial than most species of crocodiles, spending less time on land except for basking. At times, they tend to spend weeks at sea in search of land and in some cases, barnacles have been observed growing on crocodile scales, indicative of the long periods they spend at sea.
While crocodilian brains are much smaller than those of mammals (as low as 0.05% of body weight in the saltwater crocodile), saltwater crocodiles are capable of learning difficult tasks with very little conditioning, learning to track the migratory route of their prey as the seasons change, and may possess a deeper communication ability than currently accepted.
Hunting and diet
Like most species in the crocodilian family, saltwater crocodiles are not fastidious in their choice of food, and readily vary their prey selection according to availability. Nor are they voracious, as they are able to survive on relatively little food for a prolonged period. Because of their size and distribution, saltwater crocodiles hunt the broadest range of prey species of any modern crocodilian. The diet of hatchling, juvenile, and subadult saltwater crocodiles has been subject to extensively greater scientific study than that of fully-grown crocodiles, in large part due to the aggression, territoriality, and size of adults that make them difficult for biologists to handle without significant risk to safety, for both humans and the crocodiles themselves. The main method used for capturing adult saltwater crocodiles is a huge pole with large hooks, meant for shark capture, that restrict the crocodile's jaws, but these can cause damage to their snouts; and even this is unproven to allow successful capture for crocodiles in excess of 4 m (13 ft 1 in). While for example 20th century biological studies rigorously cataloged the stomach contents of "sacrificed" adult Nile crocodiles in Africa, few such studies were done on behalf of saltwater crocodiles despite the plethora that were slaughtered due to the leather trade during that time period. Therefore, the diet of adults is more likely to be based on reliable eye-witness accounts. Hatchlings are restricted to feeding on smaller animals, such as small fish, frogs, insects and small aquatic invertebrates. In addition to these prey, juveniles also take a variety of freshwater and saltwater fish, various amphibians, crustaceans, molluscs, such as large gastropods and cephalopods, birds, small to medium-sized mammals, and other reptiles, such as snakes and lizards. When crocodiles obtain a length of more than 1.2 m (3 ft 11 in), the significance of small invertebrate prey fades in favour of small vertebrates, including fish and smaller mammals and birds. Among crustacean prey, large mud crabs of the genus Scylla are frequently consumed, especially in mangrove habitats. Ground-living birds, such as the emu and different kinds of water birds, especially the magpie goose, are the most commonly preyed upon birds, due to the increased chance of encounter. Even swift-flying birds and bats may be snatched if close to the surface of water, as well as wading birds while these are patrolling the shore looking for food, even down to the size of a common sandpiper. Mammalian prey of juveniles and subadults are usually as large as the smaller species of ungulates, such as the greater mouse-deer (Tragulus napu) and hog deer (Hyelaphus porcinus). Prey species recorded include primate species such as crab-eating macaques, proboscis monkeys, and gibbons. It preys on agile wallabies, golden jackals, viverrids, turtles, flying foxes, hares, rodents, badgers, otters, chevrotains and pangolins. A rare incidence of an adult 2.6 m (8 ft 6 in) long saltwater crocodile preying on an Indian porcupine was reported in Sri Lanka. Unlike fish, crabs and aquatic creatures, mammals and birds are usually found only sporadically in or next to water; so crocodiles seem to search for places where such prey may be concentrated, e.g. the water under a tree holding a flying fox colony, or spots where herds of water buffaloes feed, in order to capture small animals disturbed by the buffalo or (if a large adult crocodile is hunting) weaker members of the buffalo herd.
Studies have shown that, unlike freshwater crocodiles (which can easily die from eating poisonous toads), saltwater crocodiles are partially resistant to cane toad toxins and can consume them, but in only small quantities and not enough to provide effective natural control for this virulent introduced pest. Large crocodiles, even the oldest males, do not ignore small species, especially those without developed escape abilities, when the opportunity arises. On the other hand, sub-adult saltwater crocodiles weighing only 8.7 to 15.8 kg (19 to 35 lb) (and measuring 1.36 to 1.79 m (4 ft 6 in to 5 ft 10 in)) have been recorded killing and eating goats weighing 50 to 92% of their own body mass in Orissa, India, and so are capable of attacking large prey from an early age. It was found that the diet of specimens in juvenile to subadult range, since they feed on any animals up to their own size practically no matter how small, was more diverse than that of adults, which often ignored all prey below a certain size limit.
Large animals taken by adult saltwater crocodiles include sambar deer, wild boar, Malayan tapirs, kangaroos, feral pigs, humans, orangutans, dingos, tigers, and large bovines, such as banteng, water buffalo, and gaur. However, larger animals are taken only sporadically because only large males typically attack very large prey, and large ungulates and other sizeable wild mammals are only sparsely distributed in this species' range, outside of a few key areas such as the Sundarbans. Off-setting this, goats, water buffalo and wild boar/pigs have been introduced to many of the areas occupied by saltwater crocodiles and returned to feral states to varying degrees, and thus can amply support large crocodiles. In Australia, the saltwater crocodile's taste for feral pigs and buffalo was a key factor in their recovery for hunting pressures over the last fifty years according to studies published in 2022 by Dr. Marianna Campbell et al.,. Isotopes taken from the bones of crocodiles collected over five decades ago when crocodiles populations were low and comparisons to specimens from modern populations suggest that initially, Australian saltwater crocodiles subsisted on a more estuarine diet, and both hunting pressures by humans and a reduction in aquatic prey in places like the Top End resulted in a dietary switch to more terrestrial prey that allowed them to grow and recover more rapidly from population declines. Any type of livestock, such as chicken, sheep, pigs, horses and cattle, and domesticated animals/pets may be eaten if given the opportunity. As a seagoing species, the saltwater crocodile also preys on a variety of saltwater bony fish and other marine animals, including sea snakes, sea turtles, sea birds, dugongs, rays (including large sawfish), and small sharks. Most witnessed acts of predation on marine animals have occurred in coastal waters or within sight of land, with female sea turtles and their babies caught during mating season when the turtles are closer to shore, and bull sharks being the only largish shark with a strong propensity to patrol brackish and fresh waters. However, there is evidence that saltwater crocodiles do hunt while out in the open seas, based upon the remains of pelagic fishes that dwell only miles away from land being found in their stomachs.
The hunting methods utilised by saltwater crocodiles are indistinct from any other crocodilian, with the hunting crocodile submerging and quietly swimming over to the prey before pouncing upwards, striking suddenly. Unlike some other crocodilians, such as American alligators and even Nile crocodiles, they are not known to have hunted on dry land. Young saltwater crocodiles are capable of breaching their entire body into the air in a single upward motion while hunting prey that may be perched on low hanging branches. While hunting rhesus macaques, they have been seen to knock the monkeys off a bank by knocking them with their tail, forcing the macaque into water for easy consumption. However, whether tail use in hunting is intentional or just an accidental benefit is not definitely clear. As with other crocodilians, their sharp, peg-like teeth are well-suited to seize and tightly grip prey, but not to shear flesh. Small prey are simply swallowed whole, while larger animals are dragged into deep water and drowned or crushed. Large prey is then torn into manageable pieces by "death rolling", the spinning of the crocodile to twist off hunks of meat or by sudden jerks of the head. Occasionally, food items will be stored for later consumption once a crocodile eats its fill, although this can lead to scavenging by interlopers such as monitor lizards.
Bite
Saltwater crocodiles have the strongest bite of any living animal. A 4.59 m-long (15 ft 1 in) 531 kg (1,171 lb) saltwater crocodile has been confirmed as having the highest bite force quotient ever recorded for an animal in a laboratory setting, with a value of 16,414 N (3,690 lbf) surpassing the previous record of 13,172 N or 2,961 lbf made by an American alligator (Alligator mississippiensis). Based on the regression of mean body mass and mean bite force, the bite forces of multiple crocodile species, 1,308 kg (2,884 lb) individuals were estimated at 27,531 to 34,424 N (6,189 to 7,739 lbf). 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 nature of the muscle is extremely stiff, almost as hard as bone to the touch, such that it can appear to be a continuation 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. The jaws of a crocodile can be securely shut with several layers of duct tape.
Reproduction
Males reach sexual maturity around 3.3 m (11 ft) at around 16 years of age, while females reach sexual maturity at 2.1 m (6 ft 11 in) and 12–14 years of age. Saltwater crocodiles mate in the wet season, when water levels are at their highest. In Australia, the male and female engage in courtship in September and October, and the female lays eggs between November and March. It is possible the rising temperatures of the wet season provoke reproductive behaviour in this species. While crocodilians generally nest every year, there have been several recorded cases of female saltwater crocodiles nesting only every other year and also records of a female attempting to produce two broods in a single wet season. The female selects the nesting site, and both parents will defend the nesting territory, which is typically a stretch of shore along tidal rivers or freshwater areas, especially swamps. Nests are often in a surprisingly exposed location, often in mud with little to no vegetation around, and thus limited protection from the sun and wind. The nest is a mound of mud and vegetation, usually measuring 175 cm (69 in) long and 53 cm (21 in) high, with an entrance averaging 160 cm (63 in) in diameter. Some nests in unlikely habitats have occurred, such as rocky rubble or in a damp low-grass field. The female crocodile usually scratches a layer of leaves and other debris around the nest entrance and this covering is reported to produce an "astonishing" amount of warmth for the eggs (coincidentally these nesting habits are similar to those of the birds known as megapodes that nest in upland areas of the same Australasian regions where saltwater crocodiles are found).
The female typically lays from 40 to 60 eggs, but some clutches have included up to 90. The eggs measure on average 8 by 5 cm (3.1 by 2.0 in) and weigh 113 g (4.0 oz) on average in Australia and 121 g (4.3 oz) in India. These are relatively small, as the average female saltwater crocodile weighs around five times as much as a freshwater crocodile, but lays eggs that are only about 20% larger in measurement and 40% heavier than those of the smaller species. The average weight of a new hatchling in Australia is reportedly 69.4 g (2.45 oz). Although the female guards the nest for 80 to 98 days (in extreme high and low cases from 75 to 106 days), the loss of eggs is often high due to flooding and occasionally to predation. As in all crocodilians, the sex of the hatchlings is determined by temperature. At 28–30 degrees all hatchlings will be female, at 30–32 degrees 86% of hatchlings are male, and at 33 or more degrees predominantly female (84%). In Australia, goannas (Varanus giganteus) commonly eat freshwater crocodile eggs (feeding on up to 95% of the clutch if discovered), but are relatively unlikely to eat saltwater crocodile eggs due to the vigilance of the imposing mother, with about 25% of the eggs being lost to goannas (less than half as many Nile crocodile eggs are estimated to be eaten by monitors in Africa). A majority of the loss of eggs of saltwater crocodiles occurs due to flooding of the nest hole.
As in most crocodilian species, the female saltwater crocodile exhibits a remarkable level of maternal care for a reptile. She excavates the nest in response to "yelping" calls from the hatchlings, and even gently rolls eggs in her mouth to assist hatching. The female will then carry the hatchlings to water in her mouth (as Nile crocodile and American alligator females have been observed doing when their eggs hatch) and remains with the young for several months. Despite her diligence, losses of baby crocodiles are heavy due to various predators and unrelated crocodiles of their own species. Only approximately 1% of the hatchlings will survive to adulthood. By crocodilian standards, saltwater crocodile hatchlings are exceptionally aggressive to one another and will often fight almost immediately after being transported to water by their mother. The young naturally start to disperse after around 8 months, and start to exhibit territorial behaviour at around 2.5 years old. They are the most territorial of extant crocodilians and, due to their aggressiveness to conspecifics, from the dispersed immature stage on, they are never seen in concentrations or loose groups as are most other crocodilians. However, even females will not reach proper sexual maturity for another 10 years. Saltwater crocodiles that survive to adulthood can attain a very long maximum life span, with an estimated life expectancy upwards of 70 years, and some individuals possibly exceed 100 years, although no such extreme ages have been verified for any crocodilian.
While adults have no natural predators, baby saltwater crocodiles may fall prey to monitor lizards (occasionally, but not commonly, the numerous goanna in Australia, and the Asian water monitor (Varanus salvator) further north), predatory fish (especially the barramundi (Lates calcarifer)), wild boars, rats, various aquatic and raptorial birds (e.g. black-necked storks (Ephippiorhynchus asiaticus) and white-bellied sea eagles (Haliaeetus leucogaster)), pythons, larger crocodiles, and many other predators. Pigs and cattle also occasionally inadvertently trample eggs and nests on occasion and degrade habitat quality where found in numbers. Juveniles may also fall prey to tigers and leopards (Panthera pardus) in certain parts of their range, although encounters between these predators are rare, and cats are likely to avoid areas with saltwater crocodiles.
- Saltwater crocodiles go through numerous physiological changes as they mature. Pictured here is a hatchling age or baby crocodile.
- Seen here is a juvenile crocodile, which grows considerably in length over several years but is easily distinguished by slender build and size.
- A saltwater crocodile in the subadult age range at Gembira Loka Zoo, similar but not as robust and relatively small-headed compared to adults.
- Juvenile salt water crocodiles at Karamjal Wildlife Breeding center, Bangladesh
Conservation status
The species is considered of minimal concern for extinction but is protected from the effects of international trade under the Convention on International Trade in Endangered Species (CITES) as follows:
- Appendix I (prohibiting all commercial trade in the species or its parts/derivatives): All wild populations except for those of Australia, Indonesia and Papua New Guinea;
- Appendix II (commercial trade allowed with export permit; import permits may or may not be required depending on the laws of the importing country): Australia, Indonesia and Papua New Guinea wild populations, plus all worldwide populations bred in captivity for commercial purposes.
The saltwater crocodile was often hunted for its meat and eggs, and its skin is the most commercially valuable of any crocodilian. Unregulated hunting during the 20th century caused a dramatic decline in the species throughout its range, with the population in northern Australia reduced by 95% by 1971. The years from 1940 to 1970 were the peak of unregulated hunting and may have regionally caused irreparable damage to saltwater crocodile populations. The species currently has full legal protection in all Australian states and territories where it is found – Western Australia (since 1970), Northern Territory (since 1971) and Queensland (since 1974). Illegal hunting still persists in some areas, with protection in some countries being grossly ineffective, and trade is often difficult to monitor and control over such a vast range. However, many areas have not recovered; some population surveys have shown that although young crocodiles are present, fewer than 10% of specimens spotted are in adult size range and do not include any particularly large males, such as Sri Lanka or Palau. This is indicative of both potential continued persecution and exploitation and a non-recovered breeding population. In a more balanced population, such as those from Bhitarkanika National Park or Sabah on Borneo, 28% and 24.2% of specimens observed were in the adult size range of more than 3 m (9 ft 10 in).
Habitat loss continues to be a major problem for the species. In northern Australia, much of the nesting habitat of the saltwater crocodile is susceptible to trampling by feral water buffalo, although buffalo eradication programs have now reduced this problem considerably. Even where large areas of suitable habitat remain, subtle habitat alterations can be a problem, such as in the Andaman Islands, where freshwater areas, used for nesting, are being increasingly converted to human agriculture. After the commercial value of crocodile skins waned, perhaps the greatest immediate challenge to implementing conservation efforts has been the occasional danger the species can pose to humans, and the resulting negative view of the crocodile.
Relationship with humans
Attacks on humans
See also: Crocodile attackOf all the crocodilians, the saltwater crocodile and Nile crocodile have the strongest tendencies to treat humans as prey. The saltwater crocodile has a long history of attacking humans who unknowingly venture into its territory. As a result of its power, intimidating size and speed, survival of a direct predatory attack is unlikely if the crocodile is able to make direct contact. In contrast to alligators where a degree of coexistence may be the policy, the only recommended policy for dealing with saltwater crocodiles is to completely avoid their habitat whenever possible, as they are exceedingly aggressive when encroached upon.
Exact data on attacks are limited outside Australia, where one or two fatal attacks are reported per year. From 1971 to 2013, the total number of fatalities reported in Australia due to saltwater crocodile attack was 106. The low level of attacks may be due to extensive efforts by wildlife officials in Australia to post crocodile warning signs at numerous at-risk billabongs, rivers, lakes and beaches. Less-publicised attacks have been reported in Borneo, Sumatra, Eastern India (Andaman Islands), and Burma. In Sarawak, Borneo, the average number of fatal attacks is reportedly 2.8 annually for the years from 2000 to 2003. In the Northern Territory in Australia, attempts have been made to relocate saltwater crocodiles who have displayed aggressive behaviour towards humans but these have proven ineffective as the problem crocodiles are apparently able to find their way back to their original territories. In the Darwin area from 2007 to 2009, 67–78% of "problem crocodiles" were identified as males.
Many attacks in areas outside Australia are believed to go unreported, with one study positing up to 20 to 30 attacks occur every year. This number may be conservative in light of several areas where humans and saltwater crocodiles co-exist in relatively undeveloped, low-economy and rural regions, where attacks are likely to go unreported. However, claims in the past that saltwater crocodiles are responsible for thousands of human fatalities annually are likely to have been exaggerations and were probably falsified to benefit leather companies, hunting organisations and other sources that may have benefited from maximising the negative perception of crocodiles for financial gain. Despite their reputations, many wild saltwater crocodiles are normally quite wary of humans and will go out of their way to submerge and swim away from them, even large adult males, if previously subject to harassment or persecution. Some attacks on humans appear to be territorial rather than predatory in nature, with crocodiles over two years in age often attacking anything that comes into their area (including boats). Humans can usually escape alive from such encounters, which comprise about half of all attacks. Non-fatal attacks usually involve crocodiles of 3 m (9 ft 10 in) or less in length. Fatal attacks, more likely to be predatory in motivation, commonly involve larger crocodiles with an average estimated size of 4.3 m (14 ft 1 in). Under normal circumstances, Nile crocodiles are believed to be responsible for a considerably greater number of fatal attacks on humans than saltwater crocodiles, but this may have more to do with the fact that many people in Africa tend to rely on riparian areas for their livelihood, which is less prevalent in most of Asia and certainly less so in Australia. In the Andaman Islands, the number of fatal attacks on humans has reportedly increased, possibly due to habitat destruction and reduction of natural prey.
During the Japanese retreat in the Battle of Ramree Island on 19 February 1945, saltwater crocodiles may have been responsible for the deaths of over 400 Japanese soldiers. British soldiers encircled the swampland through which the Japanese were retreating, condemning the Japanese to a night in the mangroves, which were home to thousands of saltwater crocodiles. Many Japanese soldiers did not survive this night, but the attribution of the majority of their deaths to crocodile attacks has been doubted. Another reported mass attack involved a cruise in eastern India where a boat accident forced 28 people into the water where they were reportedly consumed by saltwater crocodiles. Another notorious crocodile attack was in 1985, on ecofeminist Val Plumwood, who survived the attack and learned that the advice she had received that crocodiles do not attack canoes was inaccurate.
In July 2018, a 600-strong mob slaughtered 292 saltwater and New Guinea crocodiles in Papua province in Indonesia in a revenge attack after a man who encroached upon the sanctuary was devoured.
Cultural references
The saltwater crocodile is considered holy on Timor. According to legend, the island was formed by a giant crocodile. The Papuan people have a similar and very involved myth and traditionally the crocodile was described as a relative (normally a father or grandfather).
According to Wondjina, the mythology of Indigenous Australians, the saltwater crocodile was banished from the fresh water for becoming full of bad spirits and growing too large, unlike the freshwater crocodile, which was somewhat revered. Aboriginal rock art depicting the saltwater crocodile is rare, although examples of up to 3,000 years old were found in caves in Kakadu and Arnhem land, roughly matching the distribution of the species. It is however depicted in contemporary aboriginal art. The Larrakia people think of themselves as crocodile descendants, and regard it as their totem. They respect crocodiles as protectors of harbours and do not eat crocodile meat.
The species is featured on several postage stamps, including an 1894 State of North Borneo 12-cent stamp; a 1948 Australian 2 shilling stamp depicting an aboriginal rock artwork of the species; a 1966 Republic of Indonesia stamp; a 1994 Palau 20-cent stamp; a 1997 Australian 22-cent stamp; and a 2005 1 Malaysian ringgit postage stamp.
The saltwater crocodile has featured in contemporary Australian film and television including the Crocodile Dundee series of films, horror films Black Water and Rogue and The Crocodile Hunter television series. There are now several saltwater crocodile–themed parks in Australia.
Examples of large unconfirmed saltwater crocodiles
The largest size recorded for a saltwater crocodile has always been a subject of considerable controversy. The reason behind unverified sizes is either the case of insufficient/inconclusive data or exaggeration from a folkloric point of view. This section is dedicated to examples of the largest saltwater crocodiles recorded outside scientific norms measurement and estimation, with the aim of satisfying the public interest without creating data pollution, as well as serving an educational purpose of guiding the reader to separate fact from possible fiction. Below, in descending order starting from the largest, are some examples of large unconfirmed saltwater crocodiles, recorded throughout history.
- A crocodile shot in the Bay of Bengal in 1840 was reported at 10.1 m (33 ft 2 in). Furthermore, this specimen was claimed to have a belly girth of 4.17 m (13 ft 8 in) and a body mass estimated 3,000 kg (6,600 lb). However, the skull of this specimen was examined by Guinness Records and found to be only 66.5 cm (2 ft 2+1⁄4 in) in length, indicating the above size was considerably exaggerated and the animal would have probably measured no more than 5.89 m (19 ft 4 in).
- James R. Montgomery, who ran a plantation near to the Lower Kinabatangan Segama Wetlands in Borneo from 1926 to 1932, claimed to have netted, killed, and examined numerous crocodiles well over 6.1 m (20 ft 0 in) there, including a specimen he claims measured 10 m (32 ft 10 in). However, no one scientifically confirmed any of Montgomery's specimens and no voucher specimens are known.
- A crocodile shot in Queensland in 1957, nicknamed Krys the croc (named after the woman that shot the crocodile in July 1957; Krystina Pawlowski), was reported to be 8.63 m (28 ft 4 in) long, but no verified measurements were made and no remains of this crocodile exist. A "replica" of this crocodile has been made as a tourist attraction.
- A crocodile killed in 1823 at Jalajala on the main island of Luzon in the Philippines was reported at 8.2 m (26 ft 11 in). However the skull of the specimen is 66.5 cm (26+1⁄4 in) long indicating an animal of approximately 6.1 m (20 ft 0 in).
- A crocodile shot in Odisha, India, was claimed to measure 7.6 m (24 ft 11 in) in life, but its skull, when given scholarly examination, was thought to have come from a crocodile of a length no greater than 7 m (23 ft 0 in).
- A reported 7.6 m (24 ft 11 in) crocodile was killed in the Hooghly River in the Alipore District of Calcutta. However, examinations of the animal's skull, one of the largest skulls known to exist for the species at 75 cm (30 in) long, actually indicating it could have measured 6.7 m (22 ft 0 in).
- In 2006, Guinness accepted a 7.01 m (23 ft 0 in), 2,000-kilogram (4,400 lb) male saltwater crocodile living within Bhitarkanika Park in Odisha. Due to the difficulty of trapping and measuring a very large living crocodile, the accuracy of these dimensions is yet to be verified. These observations and estimations have been made by park officials over the course of ten years, from 2006 to 2016, however, regardless of the skill of the observers it cannot be compared to a verified tape measurement, especially considering the uncertainty inherent in visual size estimation in the wild. In addition, this region may contain up to four other specimens measuring over 6.1 m (20 ft 0 in).
- S. Baker (1874) claimed that in Sri Lanka in the 1800s, specimens measuring 6.7 m (22 ft 0 in) or more were commonplace. However, the largest specimen killed on the island that was considered authentic by Guinness Records was a suspected man-eater killed in the Eastern Province and measuring exactly 6 m (19 ft 8 in) in length.
- The record size for a crocodile from Papua New Guinea to be considered authentic by Guinness was a 6.32 m (20 ft 9 in) specimen shot by Herb Schweighofer in May 1966 along the northeastern coast. This specimen had a belly girth of 2.74 m (9 ft 0 in).
See also
Explanatory notes
- Except populations of Australia, Indonesia, Malaysia and Papua New Guinea which are included in Appendix II.
References
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External links
- Fisheries Western Australia – Estuarine Crocodile Fact Sheet
- Saltwater crocodiles in freedom: Authentic pictures and descriptions
- Comprehensive Saltwater Crocodile web site unique information, plentiful images and video presentations
- Saltwater crocodile calls from Dr. Britton's crocodilian.com (Archived 8 July 2011 at the Wayback Machine)
- Brief discussion (Archived 20 November 2011 at the Wayback Machine) from Dr. Britton and others discussing dromaeosaurid intelligence
- Naish, D. (2012). "The Saltwater Crocodile, and all that it implies (crocodiles part III)". Scientific American. Tetrapod Zoology. Retrieved 12 June 2015.
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