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{{short description|Subfamily of large reptilian carnivores}}{{Other uses}}{{Pp|small=yes}}{{Use British English|date=June 2016}}{{Automatic taxobox| name = Crocodiles!Species name!! Image !! Distribution!! Description/Comments|Central African slender-snouted crocodile (Mecistops leptorhynchus)
Eocene – Holocene, {{Geological range>55|0}}| image = Nile crocodile head.jpg| image_caption = Nile crocodile (Crocodylus niloticus)| image2 = Pangil Crocodile Park Davao City.jpg| image2_caption = Saltwater crocodile (Crocodylus porosus)| taxon = CrocodylinaeGeorges Cuvier>Cuvier, 1807| type_species = Crocodylus niloticusJoseph Nicolai Laurenti>Laurenti, 1768| range_map = | range_map_caption = | subdivision_ranks = Genera| subdivision = }}Crocodiles (subfamily Crocodylinae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. Crocodylinae, all of whose members are considered true crocodiles, is classified as a biological subfamily. A broader sense of the term crocodile, Crocodylidae that includes Tomistoma, is not used in this article. The term crocodile here applies to only the species within the subfamily of Crocodylinae. The term is sometimes used even more loosely to include all extant members of the order Crocodilia, which includes the alligators and caimans (family Alligatoridae), the gharial and false gharial (family Gavialidae), and all other living and fossil Crocodylomorpha.Although they appear similar, crocodiles, alligators and the gharial belong to separate biological families. The gharial, with its narrow snout, is easier to distinguish, while morphological differences are more difficult to spot in crocodiles and alligators. The most obvious external differences are visible in the head, with crocodiles having narrower and longer heads, with a more V-shaped than a U-shaped snout compared to alligators and caimans. Another obvious trait is that the upper and lower jaws of the crocodiles are the same width, and the teeth in the lower jaw fall along the edge or outside the upper jaw when the mouth is closed; therefore, all teeth are visible, unlike an alligator, which possesses in the upper jaw small depressions into which the lower teeth fit. Also, when the crocodile's mouth is closed, the large fourth tooth in the lower jaw fits into a constriction in the upper jaw. For hard-to-distinguish specimens, the protruding tooth is the most reliable feature to define the species' family.WEB,weblink Crocodilian Biology Database - FAQ - What's the difference between a crocodile and an alligator, Flmnh.ufl.edu, 5 April 2009, Crocodiles have more webbing on the toes of the hind feet and can better tolerate saltwater due to specialized salt glands for filtering out salt, which are present, but non-functioning, in alligators. Another trait that separates crocodiles from other crocodilians is their much higher levels of aggression.BOOK, Guggisberg, C.A.W., Crocodiles: Their Natural History, Folklore, and Conservation, 1972, 195, 978-0-7153-5272-4, David & Charles, Newton Abbot, Crocodile size, morphology, behaviour and ecology differ somewhat among species. However, they have many similarities in these areas as well. All crocodiles are semiaquatic and tend to congregate in freshwater habitats such as rivers, lakes, wetlands and sometimes in brackish water and saltwater. They are carnivorous animals, feeding mostly on vertebrates such as fish, reptiles, birds and mammals, and sometimes on invertebrates such as molluscs and crustaceans, depending on species and age. All crocodiles are tropical species that, unlike alligators, are very sensitive to cold. They separated from other crocodilians during the Eocene epoch, about 55 million years ago.JOURNAL, Buchanan, L.A., 2009, Kambara taraina sp. nov (Crocodylia, Crocodyloidea), a new Eocene mekosuchine from Queensland, Australia, and a revision of the genus, Journal of Vertebrate Paleontology, 29, 2, 473–486, 10.1671/039.029.0220, Many species are at the risk of extinction, some being classified as critically endangered.

Etymology

The word "crocodile" comes from the Ancient Greek κροκόδιλος (crocodilos), "lizard", used in the phrase ho krokódilos tou potamoú, "the lizard of the (Nile) river". There are several variant Greek forms of the word attested, including the later form κροκόδειλος (crocodeilos)WEB,weblink Archived copy, 30 July 2008,weblink" title="web.archive.org/web/20160303205859weblink">weblink 3 March 2016, yes, dmy-all, found cited in many English reference works. In the Koine Greek of Roman times, crocodilos and crocodeilos would have been pronounced identically, and either or both may be the source of the Latinized form crocodīlus used by the ancient Romans. Crocodilos or crocodeilos is a compound of krokè ("pebbles"), and drilos/dreilos ("worm"), although drilos is only attested as a colloquial term for "penis".WEB,weblink Crocodile | Define Crocodile at Dictionary.com, Dictionary.reference.com, 26 April 2013, It is ascribed to Herodotus, and supposedly describes the basking habits of the Egyptian crocodile.WEB,weblink Online Etymology Dictionary, Etymonline.com, 16 March 2010, The form crocodrillus is attested in Medieval Latin. It is not clear whether this is a medieval corruption or derives from alternative Greco-Latin forms (late Greek corcodrillos and corcodrillion are attested). A (further) corrupted form cocodrille is found in Old French and was borrowed into Middle English as cocodril(le). The Modern English form crocodile was adapted directly from the Classical Latin crocodīlus in the 16th century, replacing the earlier form. The use of -y- in the scientific name Crocodylus (and forms derived from it) is a corruption introduced by Laurenti (1768).

Species

(File:Crocodylidae Distribution.png|thumb|left|upright=3|Distribution of crocodiles){{Clear}}A total of 15 extant species have been recognized. Further genetic study is needed for the confirmation of proposed species under the genus Osteolaemus, which is currently monotypic.{| class="wikitable"
American crocodile ({{nowrap|Crocodylus acutus}})140 px) Throughout the Caribbean Basin, including many of the Caribbean islands and South Florida. A larger sized species, with a greyish colour and a prominent V-shaped snout. Prefers brackish water, but also inhabits lower stretches of rivers and true marine biology environments. This is one of the rare species that exhibits regular sea-going behaviour, which explains the great distribution throughout the Caribbean. It is also found in hypersaline lakes such as Lago Enriquillo, in the Dominican Republic, which has one of the largest populations of this species.HTTP://ANIMALS.NATIONALGEOGRAPHIC.COM/ANIMALS/REPTILES/AMERICAN-CROCODILE/ PUBLISHER=ANIMALS.NATIONALGEOGRAPHIC.COM ACCESS-DATE=25 APRIL 2013, Diet consists mostly of aquatic and terrestrial vertebrates. Classified as Vulnerable, but certain local populations under greater threat.
Orinoco crocodile ({{nowrap|Crocodylus intermedius}})140 px) Colombia and Venezuela This is a large species with a relatively elongated snout and a pale tan coloration with scattered dark brown markings. Lives primarily in the Orinoco Basin. Despite having a rather narrow snout, preys on a wide variety of vertebrates, including large mammals. It is a Critically Endangered species.
Freshwater crocodile ({{nowrap|Crocodylus johnstoni}})140 px) Northern Australia A smaller species with a narrow and elongated snout. It has light brown coloration with darker bands on body and tail. Lives in rivers with considerable distance from the sea, to avoid confrontations with saltwater crocodiles. Feeds mostly on fish and other small vertebrates.
Philippine crocodile ({{nowrap|Crocodylus mindorensis}})140 px) Endemic to the Philippines This is a relatively small species with a rather broader snout. It has heavy dorsal armour and a golden-brown colour that darkens as the animal matures. Prefers freshwater habitats and feeds on a variety of small to medium sized vertebrates. This species is Critically Endangered and the most severely threatened species of crocodile.(2011-09-06). "Pictures: Biggest Crocodile Ever Caught?". National Geographic Daily News.
Morelet's crocodile ({{nowrap|Crocodylus moreletii}})140 px) Atlantic regions of Mexico, Belize and Guatemala A small to medium sized crocodile with a rather broad snout. It has a dark greyish-brown colour and is found in mostly various freshwater habitats. Feeds on mammals, birds and reptiles. It is listed as Least Concern.
Nile crocodile ({{nowrap|Crocodylus niloticus}})140 px) Sub-saharan Africa A large and aggressive species with a broad snout, especially in older animals. It has a dark bronze coloration and darkens as the animal matures. Lives in a variety of freshwater habitats but is also found in brackish water. It is an apex predator that is capable of taking a wide array of African vertebrates, including large ungulates and other predators.HTTP://CROCODILIAN.COM/CNHC/CSP_CNIL.HTM >TITLE=IUCN-SSC CROCODILE SPECIALIST GROUP ACCESS-DATE=25 APRIL 2013, This species is listed as Least Concern.
New Guinea crocodile ({{nowrap|Crocodylus novaeguineae)}}140 px) The island of New Guinea A smaller species of crocodile with a grey-brown colour and dark brown to black markings on the tail. The young have a narrower V-shaped snout that becomes wider as the animal matures. Prefers freshwater habitats, even though is tolerant to salt water, in order to avoid competition and predation by the saltwater crocodile. This species feeds on small to mid-sized vertebrates.
Mugger crocodile ({{nowrap|Crocodylus palustris}})140 px) The Indian subcontinent and surrounding countries This is a modest sized crocodile with a very broad snout and an alligator-like appearance. It has dark-grey to brown coloration. Enlarged scutes around the neck make it a heavily armoured species. Prefers slow moving rivers, swamps and lakes. It can also be found in coastal swamps but avoids areas populated by saltwater crocodiles.weblink. Crocodile Species List. Retrieved on 2013-04-13. Feeds on a wide array of vertebrates.
Saltwater crocodile ({{nowrap|Crocodylus porosus}})140 px) Throughout {{nowrap|Southeast Asia}}, Northern Australia and surrounding waters The largest living reptile and most aggressive of all crocodiles. It is a big-headed species and has a relatively broad snout, especially when older. The coloration is pale yellow with black stripes when young but dark greenish-drab coloured as adults. Lives in brackish and marine biology environments as well as lower stretches of rivers. This species has the greatest distribution of all crocodiles. Tagged specimens showed long-distance marine travelling behaviour. It is the apex predator throughout its range and preys on virtually any animal within its reach. It is classified as Least Concern with several populations under greater risk.CROCODILE SPECIALIST GROUP CROCODYLUS POROSUS > JOURNAL = THE IUCN RED LIST OF THREATENED SPECIES PAGE = E.T5668A11503588 URL = HTTP://OLDREDLIST.IUCNREDLIST.ORG/DETAILS/5668/0 ACCESS-DATE = 23 DECEMBER 2017,
Cuban crocodile ({{nowrap|Crocodylus rhombifer}})140 px) Found only in the Zapata Swamp and Isle of Youth of Cuba It is a small but extremely aggressive species of crocodile that prefers freshwater swamps.HTTP://WWW.MARKOSHEA.INFO/REPTILEWORLD_ZONE2-4.PHP>TITLE=MARK O'SHEA - THE OFFICIAL WEBSITEdiet (nutrition)>diet in the past, preying on megafauna such as the giant sloth. This species sometimes displays pack-hunting behaviour, which might have been the key to hunting large species in the past, despite its small size.ALEXANDER > FIRST = MARC JOURNAL = AMERICAS (ENGLISH EDITION) PAGES = URL = HTTP://WWW.THEFREELIBRARY.COM/_/PRINT/PRINTARTICLE.ASPX?ID=141091822 ID = Critically Endangered, and the remaining wild population is under threat of hybridization.HTTP://NEWS.NATIONALGEOGRAPHIC.COM/NEWS/2011/06/110624-CUBAN-AMERICAN-CROCODILE-ANIMALS-HYBRIDS-SCIENCE/DATE=26 JUNE 2011,
Siamese crocodile ({{nowrap|Crocodylus siamensis}})140 px) Indonesia, Brunei, East Malaysia and southern Indochina A fairly small crocodile that prefers freshwater habitats. It has a relatively broad snout and olive-green to dark green coloration. It feeds on a variety of small to mid-sized vertebrates. Listed as Critically Endangered, but might be already extinct in the wild; status is unknown.SIMPSON >FIRST=BOYD TITLE=SIAMESE CROCODILE CROCODYLUS SIAMENSIS YEAR=2010 URL=HTTP://WWW.IUCNCSG.ORG/365_DOCS/ATTACHMENTS/PROTAREA/20_C-637B6A34.PDF, 13 January 2018,
West African crocodile ({{nowrap|Crocodylus suchus}})140 px) Western and Central Africa Recent studies revealed that this is distinct species from the larger Nile crocodile.Nile crocodile is two species, Nature.comSCHMITZ, A. >AUTHOR2=MAUSFELD, P. AUTHOR4=SHINE, T. AUTHOR6=AMATO, G. LAST-AUTHOR-AMP=YES TITLE=MOLECULAR EVIDENCE FOR SPECIES LEVEL DIVERGENCE IN AFRICAN NILE CROCODILES CROCODYLUS NILOTICUS (LAURENTI, 1786)VOLUME=2PAGES=703–12, 10.1016/j.crpv.2003.07.002, It has a slightly narrower snout and is much smaller compared to its larger cousin.
Dwarf crocodile ({{nowrap|Osteolaemus tetraspis}})140 px) Western Africa It is the smallest of all living crocodiles. It belongs to its own monotypic genus; however, new studies indicate there might be two or even three distinct species.EATON>FIRST=MITCHELL J.AUTHOR3=JOHN THORBJARNARSON TITLE=SPECIES-LEVEL DIVERSIFICATION OF AFRICAN DWARF CROCODILES (GENUS OSTEOLAEMUS): A GEOGRAPHIC AND PHYLOGENETIC PERSPECTIVEDATE=MARCH 2009ISSUE=3DOI=10.1016/J.YMPEV.2008.11.009 Vulnerable species>Vulnerable.
West African slender-snouted crocodile ({{nowrap>Mecistops cataphractus}})frameless|140x140px)|Western Africafreshwater habitats within tropical forests of the continent. Feeds mostly on fish but also other small to medium sized vertebrates. It is a Critically endangered>Critically Endangered species.
frameless|142x142px)|Central AfricaCritically endangered>Critically Endangered when lumped with M. cataphractus, although M. leptorhynchus is doing better in its home range.
{{For|information on Tomistoma or false gharial, that is recently not considered as a true crocodile|False gharial}}

Characteristics

{{hatnote|Crocodiles are similar to alligators and caimans; for their common characteristics and differences among them, see Crocodilia.}}File:Crocodilelyd5.png|thumb|Crocodiles, like dinosaurs, have the abdominal ribs modified into gastralia.]]A crocodile's physical traits allow it to be a successful predator. Its external morphology is a sign of its aquatic and predatory lifestyle. Its streamlined body enables it to swim swiftly; it also tucks its feet to the side while swimming, making it faster by decreasing water resistance. Crocodiles have webbed feet which, though not used to propel them through the water, allow them to make fast turns and sudden moves in the water or initiate swimming. Webbed feet are an advantage in shallow water, where the animals sometimes move around by walking. Crocodiles have a palatal flap, a rigid tissue at the back of the mouth that blocks the entry of water. The palate has a special path from the nostril to the glottis that bypasses the mouth. The nostrils are closed during submergence.Like other archosaurs, crocodilians are diapsid, although their post-temporal fenestrae are reduced. The walls of the braincase are bony but lack supratemporal and postfrontal bones.Grigg, Gordon and Gans, Carl (1993) Morphology And Physiology Of The Crocodylia {{webarchive|url=https://web.archive.org/web/20050720011236weblink |date=20 July 2005 }}, in Fauna of Australia Vol 2A Amphibia and Reptilia, chapter 40, pp. 326–336. Australian Government Publishing Service, Canberra. Their tongues are not free, but held in place by a membrane that limits movement; as a result, crocodiles are unable to stick out their tongues.BOOK, Huchzermeyer, Fritz, 2003, Crocodiles: Biology, Husbandry and Diseases, CABI Publishing, 978-0-85199-656-1,weblink 13, Crocodiles have smooth skin on their bellies and sides, while their dorsal surfaces are armoured with large osteoderms. The armoured skin has scales and is thick and rugged, providing some protection. They are still able to absorb heat through this armour, as a network of small capillaries allows blood through the scales to absorb heat. Crocodilian scales have pores believed to be sensory in function, analogous to the lateral line in fishes. They are particularly seen on their upper and lower jaws. Another possibility is that they are secretory, as they produce an oily substance which appears to flush mud off.

Size

File:Large Crocodylus porosus.jpg|thumb|230px|A saltwater crocodilesaltwater crocodileSize greatly varies among species, from the dwarf crocodile to the saltwater crocodile. Species of Osteolaemus grow to an adult size of just {{convert|1.5|to|1.9|m|ft|abbr=on}},weblink. Crocodilian Species List. Retrieved on 2012-04-14 whereas the saltwater crocodile can grow to sizes over {{convert|7|m|ft|abbr=on}} and weigh {{convert|1000|kg|lb|abbr=on}}.Guinness Book of World Records. Retrieved on 2013-04-08. Several other large species can reach over {{convert|5.2|m|ft|abbr=on}} long and weigh over {{convert|900|kg|lb|abbr=on}}. Crocodilians show pronounced sexual dimorphism, with males growing much larger and more rapidly than females. Despite their large adult sizes, crocodiles start their lives at around {{convert|20|cm|in|abbr=on}} long. The largest species of crocodile is the saltwater crocodile, found in eastern India, northern Australia, throughout South-east Asia, and in the surrounding waters.The brain volume of two adult crocodiles was 5.6 cm3 for a spectacled caiman and 8.5 cm3 for a larger Nile crocodile.JOURNAL, 10.1371/journal.pone.0178491, 28614349, 5470673, 2017PLoSO..1278491J, Volume of the crocodilian brain and endocast during ontogeny, PLOS ONE, 12, 6, e0178491, Jirak, Daniel, Janacek, Jiri, 2017, The largest crocodile ever held in captivity is an estuarine–Siamese hybrid named Yai (, meaning big; born 10 June 1972) at the Samutprakarn Crocodile Farm and Zoo, Thailand. This animal measures {{convert|6|m|abbr=on}} in length and weighs {{convert|1114|kg|abbr=on}}.The Guinness Book of Records. Largest Captive Crocodile, Worldcrocodile.comThe longest crocodile captured alive is Lolong, which was measured at {{convert|6.17|m|ft|abbr=on}} and weighed at {{convert|1075|kg|abbr=on}} by a National Geographic team in Agusan del Sur Province, Philippines.WEB, Britton, Adam, Lolong officially the world's largest crocodile in captivity,weblink Crocodilian.com, 12 July 2012, 2012-06-23, WEB, Displaced Species,weblink PhilStar, 12 July 2012, WEB, GMA News with Ben Serrano, Paterno Esmaquel, yes, NatGeo team confirms Lolong the croc is world's longest,weblink GMA News Online Top Stories, GMA Network Inc., 15 November 2011,

Teeth

Crocodiles are polyphyodonts; they are able to replace each of their 80 teeth up to 50 times in their 35- to 75-year lifespan.WEB,weblink Solving an Alligator Mystery May Help Humans Regrow Lost Teeth, Rachel, Nuwer, JOURNAL,weblink Specialized stem cell niche enables repetitive renewal of alligator teeth, Ping, Wu, Xiaoshan, Wu, Ting-Xin, Jiang, Ruth M., Elsey, Bradley L., Temple, Stephen J., Divers, Travis C., Glenn, Kuo, Yuan, Min-Huey, Chen, Randall B., Widelitz, Cheng-Ming, Chuong, 28 May 2013, PNAS, 110, 22, E2009–E2018, www.pnas.org, 10.1073/pnas.1213202110, 23671090, 3670376, 2013PNAS..110E2009W, Next to each full-grown tooth, there is a small replacement tooth and an odontogenic stem cell in the dental lamina in standby that can be activated if required.Specialized stem cell niche enables repetitive renewal of alligator teeth {{webarchive |url=https://web.archive.org/web/20131104212952weblink |date=4 November 2013 }}

Biology and behaviour

Crocodilians are more closely related to birds and dinosaurs than to most animals classified as reptiles, the three families being included in the group Archosauria ('ruling reptiles'). Despite their prehistoric look, crocodiles are among the more biologically complex reptiles. Unlike other reptiles, a crocodile has a cerebral cortex and a four-chambered heart. Crocodilians also have the functional equivalent of a diaphragm by incorporating muscles used for aquatic locomotion into respiration.JOURNAL, Uriona TJ, Farmer CG, 2008, Recruitment of the diaphragmaticus, ischiopubis and other respiratory muscles to control pitch and roll in the American alligator (Alligator mississippiensis), Journal of Experimental Biology, 211, 1141–1147, 18344489, 10.1242/jeb.015339, Pt 7, Salt glands are present in the tongues of crocodiles and they have a pore opening on the surface of the tongue, a trait that separates them from alligators. Salt glands are dysfunctional in Alligatoridae. Their function appears to be similar to that of salt glands in marine turtles. Crocodiles do not have sweat glands and release heat through their mouths. They often sleep with their mouths open and may pant like a dog.WEB, Anitai, Stefan, 14 Amazing Facts About Crocodiles – Living dinosaurs,weblink Softpedia, 1 April 2008, Four species of freshwater crocodile climb trees to bask in areas lacking a shoreline.JOURNAL,weblink Climbing behaviour in extant crocodilians, Dinets, Vladimir, Britton, Adam, Shirley, Matthew, Herpetology Notes, 2013, 7, 3–7,

Senses

(File:A crocodiles eye (7825799462).jpg|thumb|Crocodile eye)Crocodiles have acute senses, an evolutionary advantage that makes them successful predators. The eyes, ears and nostrils are located on top of the head, allowing the crocodile to lie low in the water, almost totally submerged and hidden from prey.

Vision

Crocodiles have very good night vision, and are mostly nocturnal hunters. They use the disadvantage of most prey animals' poor nocturnal vision to their advantage. The light receptors in crocodilians' eyes include cones and numerous rods, so it is assumed all crocodilians can see colours.WEB,weblink Reptiles, evergreen, 29 April 2013,weblink" title="web.archive.org/web/20130615152003weblink">weblink 15 June 2013, yes, dmy-all, Crocodiles have vertical-slit shaped pupils, similar to those of domestic cats. One explanation for the evolution of slit pupils is that they exclude light more effectively than a circular pupil, helping to protect the eyes during daylight.JOURNAL, Land, M.F., 2006, Visual optics: the shapes of pupils, Current Biology, 16, 5, R167–R168, 10.1016/j.cub.2006.02.046, 16527734, On the rear wall of the eye is a tapetum lucidum, which reflects incoming light back onto the retina, thus utilizing the small amount of light available at night to best advantage. In addition to the protection of the upper and lower eyelids, crocodiles have a nictitating membrane (sometimes called a "third eye-lid") that can be drawn over the eye from the inner corner while the lids are open. The eyeball surface is thus protected under the water while a certain degree of vision is still possible.WEB,weblink Crocodile, Encyclopædia Britannica, 29 April 2013,

Olfaction

Crocodilian sense of smell is also very well developed, aiding them to detect prey or animal carcasses that are either on land or in water, from far away. It is possible that crocodiles use olfaction in the egg prior to hatching.Chemoreception in crocodiles is especially interesting because they hunt in both terrestrial and aquatic surroundings. Crocodiles have only one olfactory chamber and the vomeronasal organ is absent in the adultsJOURNAL, Hansen, A, 2007, Olfactory and solitary chemosensory cells: two different chemosensory systems in the nasal cavity of the American alligator, Alligator mississippiensis, BMC Neuroscience, 8, 64, 10.1186/1471-2202-8-64, 17683564, 1950884, indicating all olfactory perception is limited to the olfactory system. Behavioural and olfactometer experiments indicate that crocodiles detect both air-borne and water-soluble chemicals and use their olfactory system for hunting. When above water, crocodiles enhance their ability to detect volatile odorants by gular pumping, a rhythmic movement of the floor of the pharynx.JOURNAL, Gans, C., Clark, B., 1976, Studies on ventilation of Caiman crocodilus (Crocodilia: Reptilia), Respir. Physiol, 26, 3, 285–301, 10.1016/0034-5687(76)90001-3, 951534, JOURNAL, Putterill, J.F., Soley, J.T., 2006, Morphology of the gular valve of the Nile crocodile, Crocodylus niloticus (Laurenti, 1768), J. Morphol., 267, 8, 924–939, 10.1002/jmor.10448, 16634086, Crocodiles close their nostrils when submerged, so olfaction underwater is unlikely. Underwater food detection is presumably gustatory and tactile.Schwenk, K. (2008). Comparative anatomy and physiology of chemical senses in nonavian aquatic reptiles. In, Sensory Evolution on the Threshold: Adaptations in Secondarily Aquatic Vertebrates. J.G.M Thewissen and S. Nummels (Eds). University of California Press, Berkeley. pp. 65–81

Hearing

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

Touch

Caudal: The upper and lower jaws are covered with sensory pits, visible as small, black speckles on the skin, the crocodilian version of the lateral line organs seen in fish and many amphibians, though arising from a completely different origin. These pigmented nodules encase bundles of nerve fibers innervated beneath by branches of the trigeminal nerve. They respond to the slightest disturbance in surface water, detecting vibrations and small pressure changes as small as a single drop.NEWS,weblink Alligators detect silent ripples when hunting, CBCnews, 2002, 29 April 2013, CBC News, This makes it possible for crocodiles to detect prey, danger and intruders, even in total darkness. These sense organs are known as domed pressure receptors (DPRs).JOURNAL, Jackson, K., Brooks, D.R., 2007, Do crocodiles co-opt their sense of "touch" to "taste"? A possible new type of vertebrate sensory organ,weblink PDF, Amphibia-Reptilia, 28, 2, 277–285, 10.1163/156853807780202486, Post-Caudal: While alligators and caimans have DPRs only on their jaws, crocodiles have similar organs on almost every scale on their bodies. The function of the DPRs on the jaws is clear; to catch prey, but it is still not clear what the function is of the organs on the rest of the body. The receptors flatten when exposed to increased osmotic pressure, such as that experienced when swimming in sea water hyperosmotic to the body fluids. When contact between the integument and the surrounding sea water solution is blocked, crocodiles are found to lose their ability to discriminate salinities. It has been proposed that the flattening of the sensory organ in hyperosmotic sea water is sensed by the animal as "touch", but interpreted as chemical information about its surroundings. This might be why in alligators they are absent on the rest of the body.WEB,weblink Crocodilian Biology Database - Integumentary Sense Organs, Crocodilian.com, 26 April 2013,

Hunting and diet

(File:Crocodile attack during Mara River crossing - frame 1 - Flickr - Lip Kee.jpg|thumb|Nile crocodile attacking wildebeest)(File:Crocodile at Ranganathittu, Mysore, Karnataka.JPG|thumb|Even a cruising crocodile is difficult to locate)Crocodiles are ambush predators, waiting for fish or land animals to come close, then rushing out to attack. Crocodiles mostly eat fish, amphibians, crustaceans, molluscs, birds, reptiles, and mammals, and they occasionally cannibalize smaller crocodiles. What a crocodile eats varies greatly with species, size and age. From the mostly fish-eating species, like the slender-snouted and freshwater crocodiles, to the larger species like the Nile crocodile and the saltwater crocodile that prey on large mammals, such as buffalo, deer and wild boar, diet shows great diversity. Diet is also greatly affected by the size and age of the individual within the same species. All young crocodiles hunt mostly invertebrates and small fish, gradually moving on to larger prey. Being ectothermic (cold-blooded) predators, they have a very slow metabolism, so they can survive long periods without food. Despite their appearance of being slow, crocodiles have a very fast strike and are top predators in their environment, and various species have been observed attacking and killing other predators such as sharks and big cats.WEB,weblink Saltwater Crocodile, Saltwater Crocodile Profile, Facts, Information, Photos, Pictures, Sounds, Habitats, Reports, News – National Geographic, Animals.nationalgeographic.com, 16 March 2010, WEB,weblink Crocodilian Species - Nile Crocodile (Crocodylus niloticus), Crocodilian.com, 26 April 2013, As opportunistic predators, crocodiles would also prey upon young and dying elephants and hippos when given the chance.WEB,weblink When two tribes go to war: Incredible moment legion of hippos turn and flee after stand-off with more than 100 crocodiles in epic Zambian river battle, Daily Mail, Damien Gayle, 2014-04-16, April 16, 2014WEB,weblink Crocodiles attack elephants, Scientific American, Darren Naish, February 4, 2013WEB,weblink Tragic hippo tot is tossed around by crocodile after young animal is snatched while its mother had her back turned, Daily Mail, Simon Tomlinson, 2014-08-05, August 5, 2014 Crocodiles are also known to be aggressive scavengers who feed upon carrion and steal from other predators.WEB,weblink Saltwater Crocodile Profile, Australian Animal, Evidence suggests that crocodiles also feed upon fruits, based on the discovery of seeds in stools and stomachs from many subjects as well as accounts of them feeding.WEB,weblink ARE CROCODILES SECRET FRUIT-LOVERS?, Popular Science, Jon Tennant, November 13, 2013WEB,weblink Crikey! Crocodiles and Alligators Snack on Fruit, Live Science, Charles Q. Choi, August 27, 2013Crocodiles have the most acidic stomach of any vertebrate. They can easily digest bones, hooves and horns. The BBC TVBBC channel 1 program Inside The Perfect Predator, Thursday 25 March 2010 reported that a Nile crocodile that has lurked a long time underwater to catch prey builds up a large oxygen debt. When it has caught and eaten that prey, it closes its right aortic arch and uses its left aortic arch to flush blood loaded with carbon dioxide from its muscles directly to its stomach; the resulting excess acidity in its blood supply makes it much easier for the stomach lining to secrete more stomach acid to quickly dissolve bulks of swallowed prey flesh and bone. Many large crocodilians swallow stones (called gastroliths or stomach stones), which may act as ballast to balance their bodies or assist in crushing food, similar to grit ingested by birds. Herodotus claimed that Nile crocodiles had a symbiotic relationship with certain birds, such as the Egyptian plover, which enter the crocodile's mouth and pick leeches feeding on the crocodile's blood; with no evidence of this interaction actually occurring in any crocodile species, it is most likely mythical or allegorical fiction.WEB, Adam Britton,weblink Croc Blog: Crocodile myths #1 – the curious trochilus, Crocodilian.blogspot.com, 6 September 2009, 26 April 2013,

Bite

File:Nile Crocodile (Crocodylus niloticus) trying to swallow a big Tilapia (Oreochromis sp.)... (16818888756).jpg|thumb|left|Nile crocodile trying to swallow a big Tilapia in Kruger National ParkKruger National ParkSince they feed by grabbing and holding onto their prey, they have evolved sharp teeth for piercing and holding onto flesh, and powerful muscles to close the jaws and hold them shut. The teeth are not well-suited to tearing flesh off of large prey items as are the dentition and claws of many mammalian carnivores, the hooked bills and talons of raptorial birds, or the serrated teeth of sharks. However, this is an advantage rather than a disadvantage to the crocodile since the properties of the teeth allow it to hold onto prey with the least possibility of the prey animal escaping. Cutting teeth, combined with the exceptionally high bite force, would pass through flesh easily enough to leave an escape opportunity for prey. The jaws can bite down with immense force, by far the strongest bite of any animal. The force of a large crocodile's bite is more than {{convert|5000|lbf|N|abbr=on}}, which was measured in a {{convert|5.5|m|ft|abbr=on}} Nile crocodile, in the field;National Geographic documentary; "Bite Force", Brady Barr. comparing to {{convert|335|lbf|N|abbr=on}} for a Rottweiler, {{convert|800|lbf|N|abbr=on}} for a hyena, {{convert|2200|lbf|N|abbr=on}} for an American alligator,WEB,weblink National Geographic's Dr. Brady Barr's Bite Pressure Tests | Dog Facts, Dogfacts.wordpress.com, 26 April 2013, 2008-02-03, {{failed verification|date=October 2014}} and {{convert|4095|lbf|N|abbr=on}} for the largest confirmed great white shark.JOURNAL, Wroe, S., Huber, D. R., Lowry, M., McHenry, C., Moreno, K., Clausen, P., Ferrara, T. L., Cunningham, E., Dean, M. N., Summers, A. P., Three-dimensional computer analysis of white shark jaw mechanics: how hard can a great white bite?,weblink Journal of Zoology, 276, 4, 336–342, 2008, 10.1111/j.1469-7998.2008.00494.x, A {{convert|5.2|m|ft|abbr=on}} long saltwater crocodile has been confirmed as having the strongest bite force ever recorded for an animal in a laboratory setting. It was able to apply a bite force value of {{convert|3700|lbf|N|abbr=on}}, and thus surpassed the previous record of {{convert|2125|lbf|N|abbr=on}} made by a {{convert|3.9|m|ft|abbr=on}} long American alligator.JOURNAL, The ontogeny of bite-force performance in American alligator (Alligator mississippiensis), Journal of Zoology, 260, 3, 317–327,weblink PDF, 10.1017/S0952836903003819, 2003, Erickson, Gregory M., Lappin, A. Kristopher, Vliet, Kent A., JOURNAL,weblink Australian saltwater crocodiles are world's most powerful biters, PLOS ONE, 7, 3, e31781, 10.1371/journal.pone.0031781, 22431965, 16 March 2012, 26 April 2013, 2012PLoSO...731781E, Erickson, Gregory M., Gignac, Paul M., Steppan, Scott J., Lappin, A. Kristopher, Vliet, Kent A., Brueggen, John D., Inouye, Brian D., Kledzik, David, Webb, Grahame J. W., Taking the measurements of several {{convert|5.2|m|ft|abbr=on}} crocodiles as reference, the bite forces of 6-m individuals were estimated at {{convert|7700|lbf|N|abbr=on}}.WEB,weblink Crocodiles Have Strongest Bite Ever Measured, Hands-on Tests Show, News.nationalgeographic.com, 15 March 2012, 26 April 2013, The study, led by Dr. Gregory M. Erickson, also shed light on the larger, extinct species of crocodilians. Since crocodile anatomy has changed only slightly over the last 80 million years, current data on modern crocodilians can be used to estimate the bite force of extinct species. An {{convert|11|to(-)|12|m|ft|adj=on}} Deinosuchus would apply a force of {{convert|23100|lbf|N|abbr=on}}, nearly twice that of the latest, higher bite force estimations of Tyrannosaurus ({{convert|12814|lbf|N|abbr=on}}).WEB,weblink The Tyrannosaurus Rex's Dangerous and Deadly Bite, Smithsonian Institution, October 2012, Brian, Switek, JOURNAL,weblink Bates, K. T., Falkingham, P.L., 2012-02-29, Estimating maximum bite performance in Tyrannosaurus rex using multi-body dynamics, Biological Letters, 8, 4, 660–664, 10.1098/rsbl.2012.0056, 22378742, 3391458, Crispian Scully, (2002) Oxford Handbook of Applied Dental Sciences, Oxford University Press –{{ISBN|978-0-19-851096-3}} P156 The extraordinary bite of crocodilians is a result of their anatomy. The space for the jaw muscle in the skull is very large, which is easily visible from the outside as a bulge at each side. The muscle is so stiff, it is almost as hard as bone to touch, as if it were the continuum of the skull. Another trait is that most of the muscle in a crocodile's jaw is arranged for clamping down. Despite the strong muscles to close the jaw, crocodiles have extremely small and weak muscles to open the jaw. Crocodiles can thus be subdued for study or transport by taping their jaws or holding their jaws shut with large rubber bands cut from automobile inner tubes.

Locomotion

(File:Crocodile farm in Mexico.JPG|thumb|A crocodile, in a farm, gaping to thermoregulate)Crocodiles can move quickly over short distances, even out of water. The land speed record for a crocodile is {{convert|17|km/h|0|abbr=on}} measured in a galloping Australian freshwater crocodile.WEB, Britton, Adam, Crocodilian Biology Database FAQ, "How fast can a crocodile run?",weblink 2 February 2008, Maximum speed varies between species. Some species can gallop, including Cuban crocodiles, Johnston's crocodiles, New Guinea crocodiles, African dwarf crocodiles, and even small Nile crocodiles. The fastest means by which most species can move is a "belly run", in which the body moves in a snake-like (sinusoidal) fashion, limbs splayed out to either side paddling away frantically while the tail whips to and fro. Crocodiles can reach speeds of {{convert|10|-|11|km/h|0|abbr=on}} when they "belly run", and often faster if slipping down muddy riverbanks. When a crocodile walks quickly, it holds its legs in a straighter and more upright position under its body, which is called the "high walk". This walk allows a speed of up to 5 km/h.BOOK, Walters, Martin, Johnson, Jinny, Encyclopedia of Animals, Marks and Spencer p.l.c, 978-1-84273-964-8, 145, Crocodiles may possess a homing instinct. In northern Australia, three rogue saltwater crocodiles were relocated {{convert|400|km|0|abbr=on}} by helicopter, but returned to their original locations within three weeks, based on data obtained from tracking devices attached to them.JOURNAL, Read M. A., Grigg G. C., Irwin S. R., Shanahan D., Franklin C. E., 2007, Satellite Tracking Reveals Long Distance Coastal Travel and Homing by Translocated Estuarine Crocodiles, Crocodylus porosus, PLoS ONE, 2, 9, e949, 10.1371/journal.pone.0000949, Lusseau, David, 17895990, 1978533, 2007PLoSO...2..949R,

Longevity

Measuring crocodile age is unreliable, although several techniques are used to derive a reasonable guess. The most common method is to measure lamellar growth rings in bones and teeth—each ring corresponds to a change in growth rate which typically occurs once a year between dry and wet seasons.WEB,weblink Crocodilian Biology Database, FAQ. "How long do crocodiles live for?", Flmnh.ufl.edu, 26 April 2013, Bearing these inaccuracies in mind, it can be safely said that all crocodile species have an average lifespan of at least 30–40 years, and in the case of larger species an average of 60–70 years. The oldest crocodiles appear to be the largest species. C. porosus is estimated to live around 70 years on average, with limited evidence of some individuals exceeding 100 years.WEB,weblink Crocodilian Biology Database - FAQ - How long do crocodiles live for?, Crocodilian.com, 26 April 2013, In captivity, some individuals are claimed to have lived for over a century. A male crocodile lived to an estimated age of 110–115 years in a Russian zoo in Yekaterinburg. Named Kolya, he joined the zoo around 1913 to 1915, fully grown, after touring in an animal show, and lived until 1995.NEWS, Associated Press, Crocodile at Russian zoo dies; on display since czars, 16 February 1995, The News–Journal, Daytona Beach, Florida, 70, 47, News–Journal Corporation,weblink A male freshwater crocodile lived to an estimated age of 120–140 years at the Australia Zoo.NEWS, Freshie the croc dies at age 140, Kieran, Campbell, 24 March 2010,weblink Sunshine Coast Daily, Known affectionately as "Mr. Freshie", he was rescued around 1970 by Bob Irwin and Steve Irwin, after being shot twice by hunters and losing an eye as a result, and lived until 2010. Crocworld Conservation Centre, in Scottburgh, South Africa, claims to have a male Nile crocodile that was born in 1900. Named Henry, the crocodile is said to have lived in Botswana along the Okavango River, according to centre director Martin Rodrigues.WEB,weblink Johannesburg: World's oldest crocodile turns 114, IBN Live, December 16, 2014, December 19, 2014, WEB,weblink Celebran cumpleaños del cocodrilo más longevo del mundo, El Nuevo Día, December 16, 2014, December 19, 2014,

Social behaviour and vocalization

(File:Crocodiles resting together.jpeg|thumbnail|right|Captive crocodiles resting together with open jaws.)Crocodiles are the most social of reptiles. Even though they do not form social groups, many species congregate in certain sections of rivers, tolerating each other at times of feeding and basking. Most species are not highly territorial, with the exception of the saltwater crocodile, which is a highly territorial and aggressive species. A mature male will not tolerate any other males at any time of the year. Most other species are more flexible. There is a certain form of hierarchy in crocodiles: the largest and heaviest males are at the top, having access to the best basking site, while females are priority during a group feeding of a big kill or carcass. A good example of the hierarchy in crocodiles would be the case of the Nile crocodile. This species clearly displays all of these behaviours. Studies in this area are not thorough, however, and many species are yet to be studied in greater detail.WEB,weblink Crocodilian Species List, Crocodilian.com, 26 April 2013, Mugger crocodiles are also known to show toleration in group feedings and tend to congregate in certain areas. However, males of all species are aggressive towards each other during mating season, to gain access to females.Crocodiles are also the most vocal of all reptiles, producing a wide variety of sounds during various situations and conditions, depending on species, age, size and sex. Depending on the context, some species can communicate over 20 different messages through vocalizations alone.WEB,weblink Crocodilian Communication, Crocodilian.com, 29 April 2013, Some of these vocalizations are made during social communication, especially during territorial displays towards the same sex and courtship with the opposite sex; the common concern being reproduction. Therefore most conspecific vocalization is made during the breeding season, with the exception being year-round territorial behaviour in some species and quarrels during feeding. Crocodiles also produce different distress calls and in aggressive displays to their own kind and other animals; notably other predators during interspecific predatory confrontations over carcasses and terrestrial kills.Specific vocalisations include â€”
  • Chirp: When about to hatch, the young make a "peeping" noise, which encourages the female to excavate the nest. The female then gathers the hatchlings in her mouth and transports them to the water, where they remain in a group for several months, protected by the femaleWEB,weblinkweblink" title="web.archive.org/web/20090123041108weblink">weblink yes, 23 January 2009, Arkive, Nile crocodile (Crocodylus niloticus), 29 April 2013,
  • Distress call: A high-pitched call used mostly by younger animals to alert other crocodiles to imminent danger or an animal being attacked.
  • Threat call: A hissing sound that has also been described as a coughing noise.
  • Hatching call: Emitted by a female when breeding to alert other crocodiles that she has laid eggs in her nest.
  • Bellowing: Male crocodiles are especially vociferous. Bellowing choruses occur most often in the spring when breeding groups congregate, but can occur at any time of year. To bellow, males noticeably inflate as they raise the tail and head out of water, slowly waving the tail back and forth. They then puff out the throat and with a closed mouth, begin to vibrate air. Just before bellowing, males project an infrasonic signal at about 10 Hz through the water, which vibrates the ground and nearby objects. These low-frequency vibrations travel great distances through both air and water to advertise the male's presence and are so powerful they result in the water's appearing to "dance".WEB,weblinkweblink" title="archive.today/20130629045148weblink">weblink yes, 29 June 2013, Hays, J., Crocodiles: Their history, characteristics and behavior, 2008, 31 May 2013,

Reproduction

(File:Nile crocodile eggs.jpg|thumb|Crocodile eggs)Crocodiles lay eggs, which are laid in either holes or mound nests, depending on species. A hole nest is usually excavated in sand and a mound nest is usually constructed out of vegetation. Nesting periods range from a few weeks up to six months. Courtship takes place in a series of behavioural interactions that include a variety of snout rubbing and submissive display that can take a long time. Mating always takes place in water, where the pair can be observed mating several times. Females can build or dig several trial nests which appear incomplete and abandoned later. Egg-laying usually takes place at night and about 30–40 minutes.BOOK, K. Richardson, G. Webb, C. Manolis, Crocodiles: Inside and Out, 2000, Females are highly protective of their nests and young. The egg are hard shelled, but translucent at the time of egg-laying. Depending on the species of crocodile, 7 to 95 eggs are laid. Crocodile embryos do not have sex chromosomes, and unlike humans, sex is not determined genetically. Sex is determined by temperature, where at {{convert|30|°C|0|abbr=on}} or less most hatchlings are females and at {{convert|31|°C|0|abbr=on}}, offspring are of both sexes. A temperature of {{convert|32|to|33|°C|0|abbr=on}} gives mostly males whereas above {{convert|33|°C|0|abbr=on}} in some species continues to give males, but in other species resulting in females, which are sometimes called high-temperature females.BOOK, G. Webb, C. Manolis, Crocodiles of Australia, 1989, Temperature also affects growth and survival rate of the young, which may explain the sexual dimorphism in crocodiles. The average incubation period is around 80 days, and also is dependent on temperature and species that usually ranges from 65 to 95 days. The eggshell structure is very conservative through evolution but there are enough changes to tell different species apart by their eggshell microstructure.JOURNAL, Marzola, M., Russo, J., Mateus, O., 2015, Identification and comparison of modern and fossil crocodilian eggs and eggshell structures, Historical Biology, 27, 1, 115–133, 10.1080/08912963.2013.871009, At the time of hatching, the young start calling within the eggs. They have an egg-tooth at the tip of their snouts, which is developed from the skin, and that helps them pierce out of the shell. Hearing the calls, the female usually excavates the nest and sometimes takes the unhatched eggs in her mouth, slowly rolling the eggs to help the process. The young is usually carried to the water in the mouth. She would then introduce her hatchlings to the water and even feed them.WEB,weblink Do crocodilians (sometimes) feed their young?, Science Blogs, Darren Naish, November 8, 2008 The mother would then take care of her young for over a year before the next mating season. In the absence of the mother crocodile, the father would act in her place to take care of the young.WEB,weblink 10 Delightful Baby Animals that Grow up to Be Fatal Predators, Odd Stuff, February 3, 2012 However, even with a sophisticated parental nurturing, young crocodiles have a very high mortality rate due to their vulnerability to predation.WEB,weblink THE LIFE CYCLE OF ALLIGATORS AND CROCODILES, Demand Media, Jasey Kelly, A group of hatchlings is called a pod or crèche and may be protected for months.

Cognition

Crocodiles possess some advanced cognitive abilities.NEWS,weblink Scary smart! Clever crocodiles, alligators use sticks to lure prey, Los Angeles Times, Amina Khan, Los Angeles Times, 2013-12-06, December 06, 2013WEB,weblink Crocodiles and their ilk may be smarter than they look, Washington Post, Jason G. Goldman, December 9, 2013WEB,weblink Scary smart! Clever crocodiles, alligators use sticks to lure prey, Phys Org, October 13, 2014 They can observe and use patterns of prey behaviour, such as when prey come to the river to drink at the same time each day. Vladimir Dinets of the University of Tennessee, observed that crocodiles use twigs as bait for birds looking for nesting material.WEB,weblink Crocodiles are cleverer than previously thought: Some crocodiles use lures to hunt their prey, ScienceDaily, December 4, 2013, December 8, 2013, They place sticks on their snouts and partly submerge themselves. When the birds swooped in to get the sticks, the crocodiles then catch the birds. Crocodiles only do this in spring nesting seasons of the birds, when there is high demand for sticks to be used for building nests. Vladimir also discovered other similar observations from various scientists, some dating back to the 19th century. Aside from using sticks, crocodiles are also capable of cooperative hunting.WEB,weblinkweblink" title="web.archive.org/web/20000930224445weblink">weblink yes, 2000-09-30, The Crocodile Files, One World Magazine, Large numbers of crocodiles swim in circles to trap fish and take turns snatching them. In hunting larger prey, crocodiles swarm in, with one holding the prey down as the others rip it apart.

Taxonomy and phylogeny

Most species are grouped into the genus Crocodylus. The other extant genus, Osteolaemus, is monotypic (as is Mecistops, if recognized).File:Crocfarm.jpg|thumb|Crocodile farmCrocodile farmFile:Crocadiles.jpg|right|thumb|Crocodiles in Costa RicaCosta RicaFile:Crocodylus acutus mexico 01.jpg|thumb|right|American crocodile at La Manzanilla, Jalisco, MexicoLa Manzanilla, Jalisco, MexicoFile:Voay robustus.JPG|thumb|A skull of the extinct Voay robustusVoay robustus

Phylogeny

The cladogram below follows the topology from a 2012 analysis of morphological traits by Christopher A. Brochu and Glenn W. Storrs.JOURNAL, Brochu, C. A., Storrs, G. W., 10.1080/02724634.2012.652324, A giant crocodile from the Plio-Pleistocene of Kenya, the phylogenetic relationships of Neogene African crocodylines, and the antiquity of Crocodylus in Africa, Journal of Vertebrate Paleontology, 32, 3, 587–602, 2012, Many extinct species of Crocodylus might represent different genera. "Crocodylus" pigotti, for example, was placed in the newly erected genus Brochuchus in 2013.JOURNAL, Conrad, J. L., Jenkins, K., Lehmann, T., Manthi, F. K., Peppe, D. J., Nightingale, S., Cossette, A., Dunsworth, H. M., Harcourt-Smith, W. E. H., 10.1080/02724634.2013.743404, McNulty, K. P., New specimens of "Crocodylus" pigotti (Crocodylidae) from Rusinga Island, Kenya, and generic reallocation of the species, Journal of Vertebrate Paleontology, 33, 3, 629–646, 2013, C. suchus was not included because its morphological codings were identical to those of C. niloticus. However, the authors suggested that the lack of differences was due to limited specimen sampling, and considered the two species to be distinct. This analysis found weak support for the clade Osteolaeminae. Brochu named Osteolaeminae in 2003 as a subfamily of Crocodylidae separate from Crocodylinae, but the group has since been classified within Crocodylinae. It includes the living genus Osteolaemus as well as the extinct species Voay robustus and Rimasuchus lloydi.{hide}clade| style=font-size:85%;line-height:85%|label1= Crocodylinae 
|1={{clade
|1={{clade
|1=†"Crocodylus" pigotti
|2=†"Crocodylus" gariepensis
|3={{clade
|1=†Euthecodon arambourgii
|2=†Euthecodon brumpti{edih} }}
|label2=Osteolaeminae
|2={{clade
|1=†Rimasuchus lloydi
|2={{clade
|1=†Voay robustus
|2={{clade
|1=Osteolaemus osborni
|2=Osteolaemus tetraspis}} }} }}
|3={{clade
|1=Mecistops cataphractus
|label2= Crocodylus 
|2={{clade
|1=†C. checchiai
|2=†C. palaeindicus
|3={{clade
|1=†C. anthropophagus
|2=†C. thorbjarnarsoni}}
|4=C. niloticus
|5={{clade
|1=C. siamensis
|2={{clade
|1=C. palustris
|2={{clade
|1=C. porosus
|2=C. johnsoni
|3=C. mindorensis
|4={{clade
|1=C. novaeguineae
|2=C. raninus}} }} }} }}
|6={{clade
|1=C. acutus
|2=C. intermedius
|3=C. rhombifer
|4=C. moreletii}} }} }} }} }}
A 2013 analysis by Jack L. Conrad, Kirsten Jenkins, Thomas Lehmann, and others did not support Osteolaeminae as a true clade but rather a paraphyletic group consisting of two smaller clades. They informally called these clades "osteolaemins" and "mecistopins". "Osteolaemins" include Osteolaemus, Voay, Rimasuchus, and Brochuchus and "mecistopins" include Mecistops and Euthecodon.

Relationship with humans

Danger to humans

File:Marine Stingers Sign Cairns.JPG|thumb|Crocodile warning sign, Trinity Beach, QueenslandTrinity Beach, QueenslandThe larger species of crocodiles are very dangerous to humans, mainly because of their ability to strike before the person can react.WEB, Crocodilian Attacks,weblink IUCN Crocodile Specialist Group (iucncsg.org), 3 February 2013, The saltwater crocodile and Nile crocodile are the most dangerous, killing hundreds of people each year in parts of Southeast Asia and Africa. The mugger crocodile and American crocodile are also dangerous to humans.

Crocodile products

{{Further|Crocodile farm}}File:Crocodile wallets.jpg|thumb|left|Crocodile leather wallets from a BangkokBangkokCrocodiles are protected in many parts of the world, but are also farmed commercially. Their hides are tanned and used to make leather goods such as shoes and handbags; crocodile meat is also considered a delicacy.NEWS,weblink Anahuac Journal; Alligator Farmer Feeds Demand for All the Parts, The New York Times, 30 November 1998, Lyman, Rick, 13 November 2013, The most commonly farmed species are the saltwater and Nile crocodiles, while a hybrid of the saltwater and the rare Siamese crocodile is also bred in Asian farms. Farming has resulted in an increase in the saltwater crocodile population in Australia, as eggs are usually harvested from the wild, so landowners have an incentive to conserve their habitat. Crocodile leather can be made into goods such as wallets, briefcases, purses, handbags, belts, hats, and shoes. Crocodile oil has been used for various purposes.BOOK, Elisabeth Janos, Country Folk Medicine: Tales of Skunk Oil, Sassafras Tea and Other Old-Time Remedies,weblink 2004, Globe Pequot Press, 978-1-59228-178-7, 56, Crocodiles were eaten by Vietnamese while they were taboo and off limits for Chinese. Vietnamese women who married Chinese men adopted the Chinese taboo.BOOK, Erica J. Peters, Appetites and Aspirations in Vietnam: Food and Drink in the Long Nineteenth Century,weblink 2012, Rowman Altamira, 978-0-7591-2075-4, 142–, Crocodile meat is occasionally eaten as an "exotic" delicacy in the western world.WEB, Armstrong, Hilary, Best exotic restaurants in London,weblink London Evening Standard, 4 September 2016, 8 April 2009, Due to high demand for crocodile products, TRAFFIC states that 1,418,487 Nile Crocodile skins were exported from Africa between 2006 and 2015.WEB,weblink Reptiles and amphibians - Species we work with at TRAFFIC, www.traffic.org, en, 2019-01-10,

In religion

File:Sobek Oxford.jpg|thumb|right|Statue of Sobek from the mortuary temple of Amenemhat III. circa 1810 BC. Ashmolean MuseumAshmolean Museum(File:Plaque with Crocodile Deity, ca. 700-900.,33.448.12.jpg|thumb|Brooklyn Museum – Plaque with Crocodile Deity, ca. 700–900.,33.448.12)Crocodiles have appeared in various forms in religions across the world. Ancient Egypt had Sobek, the crocodile-headed god, with his cult-city Crocodilopolis, as well as Taweret, the goddess of childbirth and fertility, with the back and tail of a crocodile.WEB,weblink Egypt: The Crocodile God, Sobek, Tour Egypt, Catherine C. Harris, The Jukun shrine in the Wukari Federation, Nigeria is dedicated to crocodiles in thanks for their aid during migration.WEB,weblink Nigeria: How Giant Crocodiles Guided Jukun to Kwararafa, All Africa, Fidelis Mac-Leva, June 24, 2009 In Madagascar various peoples such as the Sakalava and Antandroy see crocodiles as ancestor spirits and under local fady often offer them food;Campbell, Gwyn (2012). David Griffiths and the Missionary "History of Madagascar". Leiden, The Netherlands: Brill. {{ISBN|978-90-04-19518-9}}.Marty Crump, Livros no Google PlayEye of Newt and Toe of Frog, Adder's Fork and Lizard's Leg: The Lore and Mythology of Amphibians and Reptiles, University of Chicago Press, 16/11/2015 in the case of the latter at least a crocodile features prominently as an ancestor deity.Campbell, Gwyn (2012). David Griffiths and the Missionary "History of Madagascar". Leiden, The Netherlands: Brill. {{ISBN|978-90-04-19518-9}}. A Athenæum article makes a claim of a specific crocodile deity named textually as "Jacaret", but less biased sources do not mention this theonym in any capacity.Crocodiles appear in different forms in Hinduism. Varuna, a Vedic and Hindu god, rides a part-crocodile makara; his consort Varuni rides a crocodile. Similarly the goddess personifications of the Ganga and Yamuna rivers are often depicted as riding crocodiles.WEB, Holy Rivers, Lakes, and Oceans, Heart of Hinduism, ISKCON Educational Services, 2004,weblink Most rivers are considered female and are personified as goddesses. Ganga, who features in the Mahabharata, is usually shown riding on a crocodile (see right)., 16 September 2014,weblink" title="web.archive.org/web/20141014184216weblink">weblink 14 October 2014, yes, dmy-all, JOURNAL, Ganga The River Goddess - Tales in Art and Mythology, August 2003, Nitin, Kumar,weblink The second distinguishing aspect of Ganga's iconography is her animal mount, which is often shown serving as a pedestal for her. This is the makara, a hybrid creature having the body of a crocodile and the tail of a fish. The makara in Hindu thought corresponds to the star sign of Capricorn in western astrology. The crocodile is a unique animal in that it can live on both land and sea. It thus denotes the wisdom of both the earth and waters., WEB, Hindu gods and their holy mounts, Sri.Venkateswara Zoological Park,weblink The river goddesses, Ganga and Yamuna, were appropriately mounted on a tortoise and a crocodile respectively., yes,weblink" title="web.archive.org/web/20140623165912weblink">weblink 23 June 2014, dmy-all, Also in India, in Goa, crocodile worship is practised, including the annual Mannge Thapnee ceremony.JOURNAL, The Crocodile is God in Goa, Crocodile Specialist Group Newsletter, January–March 1995, 14, 1, 8,weblink PDF, In Latin America, Cipactli was the giant earth crocodile of the Aztec and other Nahua peoples.WEB,weblink Cipactli and Aztec Creation, Ancient Origins, John Black, May 19, 2013

Crocodile tears

The term "crocodile tears" (and equivalents in other languages) refers to a false, insincere display of emotion, such as a hypocrite crying fake tears of grief. It is derived from an ancient anecdote that crocodiles weep in order to lure their prey, or that they cry for the victims they are eating, first told in the Bibliotheca by Photios I of Constantinople.BOOK, Bibliothèque. Tome VIII : Codices 257–280., PHOTIUS, Texte établi et traduit par R. Henry., 1977, Les Belles Lettres, Paris, French, Ancient Greek, 978-2-251-32227-8, 93, The story is repeated in bestiaries such as De bestiis et aliis rebus. This tale was first spread widely in English in the stories of the Travels of Sir John Mandeville in the 14th century, and appears in several of Shakespeare's plays.BOOK,weblink Curious creatures in zoology, John Ashton, 978-1-4092-3184-4, 2009, In fact, crocodiles can and do generate tears, but they do not actually cry.Britton, Adam (n.d.). Do crocodiles cry 'crocodile tears'? Crocodilian Biology Database. Retrieved March 13, 2006 from the Crocodile Specialist Group, Crocodile Species List, FAQ.

The Surabaya Shark and Crocodile

(File:Soerabaja.jpg|thumb|left|upright|Fighting shark and crocodile, the emblem of Surabaya city applied since colonial times, derived from local folk etymology)The name of Surabaya, Indonesia, is locally believed to be derived from the words "suro" (shark) and "boyo" (crocodile), two creatures which, in a local myth, fought each other in order to gain the title of "the strongest and most powerful animal" in the area. It was said that the two powerful animals agreed for a truce and set boundaries; that the shark's domain would be in the sea while the crocodile's domain would be on the land. However one day the shark swam into the river estuary to hunt, this angered the crocodile, who declared it his territory. The Shark argued that the river was a water-realm which meant that it was shark territory, while the crocodile argued that the river flowed deep inland, so it was therefore crocodile territory. A ferocious fight resumed as the two animals bit each other. Finally the shark was badly bitten and fled to the open sea, and the crocodile finally ruled the estuarine area that today is the city.BOOK, Irwan Rouf, Shenia Ananda, Rangkuman 100 Cerita Rakyat Indonesia: Dari Sabang Sampai Merauke,weblink 2013, AnakKita, 978-602-9003-82-6, 60, Another source alludes to a Jayabaya prophecy—a 12th-century psychic king of Kediri Kingdom—as he foresaw a fight between a giant white shark and a giant white crocodile taking place in the area, which is sometimes interpreted as a foretelling of the Mongol invasion of Java, a major conflict between the forces of the Kublai Khan, Mongol ruler of China, and those of Raden Wijaya's Majapahit in 1293.WEB, Welcome to Surabaya City, East Java, Surabaya Tourism, EastJava.com,weblink 17 November 2014, The two animals are now used as the city's symbol, with the two facing and circling each other, as depicted in a statue appropriately located near the entrance to the city zoo (see photo on the Surabaya page).

Crocodile (walking)

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

See also

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References

{{Reflist|30em}}

Further reading

  • Iskandar, DT (2000). Turtles and Crocodiles of Insular Southeast Asia and New Guinea. ITB, Bandung.
  • Crocodilian Biology Database, FAQ. FLMNH.ufl.edu, "How long do crocodiles live for?" {{sic}} Adam Britton.
  • Crocodilian Biology Database, FAQ. FLMNH.ufl.edu, "How fast can a crocodile run?" Adam Britton.

External links

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