Saltwater Crocodile

, a saltwater crocodile from Finnis River in northern Australia proposed as Crocodilus pethericki in 1985]] 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 Asian saltwater crocodiles to warrant subspecies status has been considered to possibly bear validity. Currently, the saltwater crocodile is considered a monotypic species.

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 near the boundary between the Oligocene and Miocene.

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The weight of a crocodile increases approximately cubically as length increases (see square–cube law). This explains why individuals at weigh more than twice as much as individuals at . 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 long and weigh an average of . 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 long and wide near its base, with long mandibles; its length is not known, but based on skull-to-length ratios of large saltwater crocodiles its length was presumably in the 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. The largest tooth measured 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.

An adult male saltwater crocodile, from young adults to older individuals, typically ranges in length and weighs . On average, adult males range in length and weigh . 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 and weighed between . Very large, aged males can exceed in length and presumably weigh up to . A large Vietnamese saltwater crocodile was reliably estimated, based on its skull after its death, at . 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 . Due to the extreme size and highly aggressive nature of the species, weight in larger specimens is frequently poorly documented. A long individual named "Sweetheart" was found to have weighed . Another large crocodile named "Gomek", measuring in length weighed around . In 1992, a notorious man-eater, named "Bujang Senang" was killed in Sarawak, Malaysia. It measured in length and weighed more than . A saltwater–siamese hybrid named "Yai" (, 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 in length and weighed approximately . In 1962, a large male saltwater crocodile was shot in Adelaide River, Northern Territory. It was recorded to be long and weighed . A large male in the Philippines, named Lolong, was one of the largest saltwater crocodile ever caught and placed in captivity. He was long and weighed . 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 weighed approximately 1,300 kg (2,870 lb) before his death in November 2024.

Adult females typically measure from in total length and weigh . Large mature females reach and weigh up to . The largest female on record measured about in total length. 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 .

{|class="wikitable sortable collapsible collapsed" |- ! Date !! Location !! Reported Length !! Reported Weight !! Reported Girth !! Reported Skull Length !! Scientifically Analyzed Length !! Comments |- |1840 |Bay of Bengal | | | | | |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. |- |- |July 1957 |Carpenteria, Australia | |Not listed |Not listed |Not listed |Not listed |Killed by Krystyna Pawlowski while defending her three-year-old daughter |- |- |1926–1932 |North Borneo | |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. |}

, Isabela, northern Philippines]] ]] ]] ]] 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. 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. 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. 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 Gladstone, 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.

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 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 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. 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. Saltwater crocodiles are able to stay fully submerged underwater for long periods of time. To extend an aerobic dive, they can reduce their heart rate and oxygen consumption. Voluntary dives for up to two hours have been reported and even much longer dives considered to be possible for large individuals when their metabolic rate is reduced. Diving depth of C. porosus is poorly studied, but they have been recorded at depths of and can probably go much deeper. 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. While Saltwater crocodiles are the least social and most aggressive crocodilians, it still showed varies interspecific variations of gregariousness. Their social systems are dynamic, influenced by the time of year, as well as the sex and maturity of the individuals. Individuals have been known to maintain specific associations for up to five years.

) with food (Chital) in Sundarbans National Park, West Bengal, India.]] 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. 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. 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, 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 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. 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 (and measuring ) 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, 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. Any type of livestock, such as chicken, sheep, pigs, horses and cattle, and domesticated animals/pets may be eaten if given the opportunity.), 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. 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.

Saltwater crocodiles have the strongest bite of any living animal. A 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 surpassing the previous record of 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, individuals were estimated at .

Males reach sexual maturity around at around 16 years of age, while females reach sexual maturity at and 12–14 years of age. 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 and weigh on average in Australia and in India. 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). 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. 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. 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. 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, Bangladesh

]] 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 . 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.

===Attacks on humans=== ]] Of all the crocodilians, the saltwater crocodile and Nile crocodile have the strongest tendency to becoming man-eating animals. 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. 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 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. 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 or less in length. Fatal attacks, more likely to be predatory in motivation, commonly involve larger crocodiles with an average estimated size of . 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. 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. 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.

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 . Furthermore, this specimen was claimed to have a belly girth of and a body mass estimated . However, the skull of this specimen was examined by Guinness Records and found to be only in length, indicating the above size was considerably exaggerated and the animal would have probably measured no more than . 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 . However the skull of the specimen is long indicating an animal of approximately . was claimed to measure in life, but its skull, when given scholarly examination, was thought to have come from a crocodile of a length no greater than . * A reported 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 long, actually indicating it could have measured . In addition, this region may contain up to four other specimens measuring over . * S. Baker (1874) claimed that in Sri Lanka in the 1800s, specimens measuring 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 in length. * The record size for a crocodile from Papua New Guinea to be considered authentic by Guinness was a specimen shot by Herb Schweighofer in May 1966 along the northeastern coast. This specimen had a belly girth of .