The saltwater crocodile is the largest living reptile.[5] Males can grow up to a weight of 1,000–1,500kg (2,200–3,300lb) and a length of 6m (20ft), rarely exceeding 6.3m (21ft).[6][7] Females are much smaller and rarely surpass 3m (9.8ft).[8][9] It is also called the estuarine crocodile, Indo-Pacific crocodile, marine crocodile, sea crocodile, and, informally, the saltie.[10] A large and opportunistic hypercarnivorousapex predator, they ambush most of their prey and then drown or swallow it whole. They will prey on almost any animal that enters their territory, including other predators such as sharks, varieties of freshwater and saltwater fish including pelagic species, invertebrates such as crustaceans, various amphibians, other reptiles, birds, and mammals.[11][12]
Taxonomy and evolution
Sweetheart, a saltwater crocodile from Finnis River in northern Australia proposed as Crocodilus pethericki in 1985
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.[17] This purported species was later considered to be a misinterpretation of the physiological changes that very large male crocodiles undergo. However, Wells and Wellington's assertion that the Australian saltwater crocodiles may be distinctive enough from northern Asian saltwater crocodiles to warrant subspecies status, as could raninus from other Asian saltwater crocodiles, has been considered to possibly bear validity.[18]
The saltwater crocodile has a wide snout compared to most crocodiles. However, it has a longer snout than the mugger crocodile (C. palustris); its length is twice its width at the base.[27] A pair of ridges runs from the eyes along the centre of the snout. The scales are oval in shape and the scutes are either small compared to other species or commonly are entirely absent. In addition, an obvious gap is also present between the cervical and dorsal shields, and small, triangular scutes are present between the posterior edges of the large, transversely arranged scutes in the dorsal shield. The relative lack of scutes is considered an asset useful to distinguish saltwater crocodiles in captivity or in illicit leather trading, as well as in the few areas in the field where sub-adult or younger saltwater crocodiles may need to be distinguished from other crocodiles. It has fewer armour plates on its neck than other crocodilians.[28][29]
The adult saltwater crocodile's broad body contrasts with that of most other lean crocodiles, leading to early unverified assumptions the reptile was an alligator.[30]
Young saltwater crocodiles are pale yellow in colour with black stripes and spots on their bodies and tails. This colouration lasts for several years until the crocodiles mature into adults. The colour as an adult is much darker greenish-drab, with a few lighter tan or grey areas sometimes apparent. Several colour variations are known and some adults may retain fairly pale skin, whereas others may be so dark as to appear blackish. The ventral surface is white or yellow in colour in saltwater crocodiles of all ages. Stripes are present on the lower sides of their bodies, but do not extend onto their bellies. Their tails are grey with dark bands.[31][32]
Size
The weight of a crocodile increases approximately cubically as length increases (see square–cube law).[33] This explains why individuals at 6m (20ft) weigh more than twice as much as individuals at 5m (16ft).[30] In crocodiles, linear growth eventually decreases and they start getting bulkier at a certain point.[34]
Saltwater crocodiles are the largest extant riparian predators in the world. However, they start life fairly small. Newly hatched saltwater crocodiles measure about 28cm (11in) long and weigh an average of 71g (2.5oz).[35] 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.[36][37]
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 76cm (30in) long and 48cm (19in) wide near its base, with 98.3cm (38.7in) long mandibles; its length is not known, but based on skull-to-length ratios of large saltwater crocodiles its length was presumably in the 6.7–7m (22–23ft) 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.[8][38][9] If detached from the body, the head of a large male crocodile can weigh over 200kg (440lb), including the large muscles and tendons at the base of the skull that lend the crocodile its massive biting strength.[39] The largest tooth measured 9cm (3.5in) in length.[40][41] 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.[8]
Male size
An adult male saltwater crocodile, from young adults to older individuals, typically ranges 3.5to 5m (11ft 6in– 16ft 5in) in length and weighs 200 to 1,100kg (440 to 2,430lb).[42][43][44][45] On average, adult males range 4.0to 4.5m (13ft 1in– 14ft 9in) in length and weigh 408 to 770kg (899 to 1,698lb).[39][46] However average size largely depends on the location, habitat, and human interactions and thus varies from one study to another. In 1993, in a study conducted (published in 1998), eleven saltwater crocodiles were found to have measured 2.1to 5.5m (6ft 11in– 18ft 1in) and weighed between 32 and 1,010kg (71 and 2,227lb).[47] Very large, aged males can exceed 6m (19ft 8in) in length and presumably weigh up to 2,000kg (4,400lb).[30][8][38][46]
Cassius the largest living crocodile.
The largest confirmed saltwater crocodile on record drowned in a fishing net in Papua New Guinea, in 1979. Its dried skin plus head measured 6.2m (20ft 4in) in length and it was estimated to have been 6.3m (20ft 8in) when accounting for shrinkage and a missing tail tip.[9][8] Projected from their skull lengths, multiple specimens from Singapore were estimated to belong in life to male crocodiles measuring more than 6m (19ft 8in).[48] A large Vietnamese saltwater crocodile was reliably estimated, based on its skull after its death, at 6.3to 6.8m (20ft 8in– 22ft 4in).[49] 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 7m (23ft 0in).[9][30] A governmental study from Australia accepts that the very largest members of the species are likely to measure 6to 7m (19ft 8in– 23ft 0in) in length and weigh 900 to 1,500kg (2,000 to 3,300lb).[50] Furthermore, a research paper on the morphology and physiology of crocodilians by the same organisation estimates that saltwater crocodiles reaching sizes of 7m (23ft 0in) would weigh around 2,000kg (4,400lb).[51] Due to the extreme size and highly aggressive nature of the species, weight in larger specimens is frequently poorly documented. A 5.1-metre (16ft 9in) long individual named "Sweetheart" was found to have weighed 780kg (1,720lb).[52] Another large crocodile named "Gomek", measuring 5.42m (17ft 9in) in length weighed around 860kg (1,900lb). In 1992, a notorious man-eater, named "Bujang Senang" was killed in Sarawak, Malaysia. It measured 5.7m (18ft 8in) in length and weighed more than 900kg (2,000lb).[53] A saltwater–siamese hybrid named "Yai" (Thai: ใหญ่, meaning big; born 10 June 1972) at the Samutprakarn Crocodile Farm and Zoo, Thailand was claimed to be the largest crocodile ever held in captivity. It measured 6m (19ft 8in) in length and weighed approximately 1,118kg (2,465lb).[54] In 1962, a large male saltwater crocodile was shot in Adelaide River, Northern Territory. It was recorded to be 6.1m (20ft 0in) long and weighed 1,097kg (2,418lb).[55] A large male in the Philippines, named Lolong, was one of the largest saltwater crocodile ever caught and placed in captivity. He was 6.17m (20ft 3in) long and weighed 1,075kg (2,370lb).[9][56][57] Most recntly, the largest living crocodile in captivity was "Cassius", who was kept at Marineland Crocodile Park, a zoo located at Green Island, Queensland, Australia. He measured 5.48 m (18 ft 0 in) in length and weighs approximately 1,300 kg (2,870 lb) before his death on the 3rd of November 2024.[58][59][60]
Female size
Adult females typically measure from 2.7 to 3.1m (8ft 10in to 10ft 2in) in total length and weigh 76 to 103kg (168 to 227lb).[61][62][63] Large mature females reach 3.4m (11ft 2in) and weigh up to 120 to 200kg (260 to 440lb).[64] The largest female on record measured about 4.3m (14ft 1in) in total length.[39] Female are thus similar in size to other species of large crocodiles and average slightly smaller than females of some other species, like the Nile crocodile.[37] The saltwater crocodile has the greatest size sexual dimorphism, by far, of any extant crocodilian, as males average about 4 to 5 times as massive as adult females and can sometimes measure twice her total length. The reason for the male skewered dimorphism in this species is not definitively known but might be correlated with sex-specific territoriality and the need for adult male saltwater crocodiles to monopolise large stretches of habitat.[65][66] Due to the extreme sexual dimorphism of the species as contrasted with the more modest-sized dimorphism of other species, the average length of the species is only slightly more than some other extant crocodilians at 3.8–4m (12ft 6in– 13ft 1in).[19][27][67]
Reported sizes
Date
Location
Reported Length
Reported Weight
Reported Girth
Reported Skull Length
Scientifically Analyzed Length
Comments
1840
Bay of Bengal
1,005.84cm (396.00in)
2,721.55kg (6,000.0lb)
396.24cm (156.00in)
927mm (36.5in)
591.312cm (232.800in)
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.[68][38]
1823
Luzon, Philippines
822.96cm (324.00in)
Not listed
335.28cm (132.00in)
674mm (26.5in)
609.6cm (240.0in)
Skull preserved and measured by Thomas Barbour, who determined original length was taken along the curve of the belly.[69]
July 1957
Carpenteria, Australia
860cm (340in)
Not listed
Not listed
Not listed
Not listed
Killed by Krystyna Pawlowski while defending her three-year-old daughter[citation needed]
1926–1932
North Borneo
1,005.84cm (396.00in)
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.[70]
In China, it may have once inhabited coastal areas from Fujian province in the north to the border of Vietnam.[83] 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.[27]
Three historical records of saltwater crocodiles being found in Japanese coastal waters exist; an individual was found off the coast of Iwo Jima in 1744, another was found off Amami Ōshima in 1800, and finally, a third individual was caught by fishermen in Toyama Bay in 1932. All other occurrences of the species being present within Japanese territory are from World War II, and were found in areas that were formerly controlled by the Empire of Japan.[84]
In northern Australia, the saltwater crocodile is thriving, particularly in the multiple river systems near Darwin such as the Adelaide, Mary, and Daly Rivers, along with their adjacent billabongs and estuaries.[91][92] The saltwater crocodile population in Australia is estimated at 100,000 to 200,000 adults. Its range extends from Broome, Western Australia through the entire Northern Territory coast all the way south to Rockhampton, Queensland. The Alligator Rivers in the Arnhem Land region are misnamed due to the resemblance of the saltwater crocodile to alligators as compared to freshwater crocodiles, which also inhabit the Northern Territory.[93]
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.[94][95] 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.[96]
Behaviour and ecology
Saltwater crocodile sunning itselfAn adult saltwater crocodile swimming through a swamp
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.[97]
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 590km (370mi) 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 411km (255mi) 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.[94] Generally very lethargic, a trait that helps it survive months at a time without food, the saltwater crocodile will usually loiter in the water or bask in the sun during much of the day, preferring to hunt at night. A study of seasonal saltwater crocodile behaviour in Australia indicated that they are more active and more likely to spend time in the water during the Australian summer; conversely, they are less active and spend relatively more time basking in the sun during the winter.[98] 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.[99]
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.[100][101]
Hunting and diet
Feeding young adult in captivity, Western AustraliaSaltwater crocodile tears apart a pig carcass for consumption
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.[96] The diet of hatchling, juvenile, and subadult saltwater crocodiles has been subject to extensively greater scientific study than that of fully-grown crocodiles, in large part due to the aggression, territoriality, and size of adults that make them difficult for biologists to handle without significant risk to safety, for both humans and the crocodiles themselves. The main method used for capturing adult saltwater crocodiles is a huge pole with large hooks, meant for shark capture, that restrict the crocodile's jaws, but these can cause damage to their snouts; and even this is unproven to allow successful capture for crocodiles in excess of 4m (13ft 1in). While for example 20th century biological studies rigorously cataloged the stomach contents of "sacrificed" adult Nile crocodiles in Africa,[102] 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.[103][104][105] Hatchlings are restricted to feeding on smaller animals, such as small fish, frogs, insects and small aquatic invertebrates.[104] In addition to these prey, juveniles also take a variety of freshwater and saltwater fish, various amphibians, crustaceans, molluscs, such as large gastropods and cephalopods, birds, small to medium-sized mammals, and other reptiles, such as snakes and lizards. When crocodiles obtain a length of more than 1.2m (3ft 11in), the significance of small invertebrate prey fades in favour of small vertebrates, including fish and smaller mammals and birds.[106] 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.[107][108] Even swift-flying birds and bats may be snatched if close to the surface of water,[96] as well as wading birds while these are patrolling the shore looking for food, even down to the size of a common sandpiper.[35][109] 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).[110] Prey species recorded include primate species such as crab-eating macaques,[111]proboscis monkeys,[112] and gibbons. It preys on agile wallabies,[113]golden jackals, viverrids, turtles, flying foxes, hares, rodents, badgers, otters, chevrotains and pangolins.[114][115] A rare incidence of an adult 2.6m (8ft 6in) long saltwater crocodile preying on an Indian porcupine was reported in Sri Lanka.[116] 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.[108]
Studies have shown that, unlike freshwater crocodiles (which can easily die from eating poisonous toads), saltwater crocodiles are partially resistant to cane toad toxins and can consume them, but in only small quantities and not enough to provide effective natural control for this virulent introduced pest.[117] Large crocodiles, even the oldest males, do not ignore small species, especially those without developed escape abilities, when the opportunity arises. On the other hand, sub-adult saltwater crocodiles weighing only 8.7 to 15.8kg (19 to 35lb) (and measuring 1.36 to 1.79m (4ft 6in to 5ft 10in)) 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.[115][118][119] 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.[120]
Large animals taken by adult saltwater crocodiles include sambar deer, wild boar, Malayan tapirs, kangaroos, feral pigs,[121]humans, orangutans, dingos, tigers,[122] and large bovines, such as banteng,[50]water buffalo, and gaur.[74][123][124][125][126][127] 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.[96] Off-setting this, goats, water buffalo and wild boar/pigs have been introduced to many of the areas occupied by saltwater crocodiles and returned to feral states to varying degrees, and thus can amply support large crocodiles.[27] In Australia, the saltwater crocodile's taste for feral pigs and buffalo was a key factor in their recovery for hunting pressures over the last fifty years according to studies published in 2022 by Dr. Marianna Campbell et al.,. Isotopes taken from the bones of crocodiles collected over five decades ago when crocodiles populations were low and comparisons to specimens from modern populations suggest that initially, Australian saltwater crocodiles subsisted on a more estuarine diet, and both hunting pressures by humans and a reduction in aquatic prey in places like the Top End resulted in a dietary switch to more terrestrial prey that allowed them to grow and recover more rapidly from population declines.[128] Any type of livestock, such as chicken, sheep, pigs, horses and cattle, and domesticated animals/pets may be eaten if given the opportunity.[96] As a seagoing species, the saltwater crocodile also preys on a variety of saltwater bony fish and other marine animals, including sea snakes, sea turtles, sea birds, dugongs, rays (including large sawfish[129]), 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.[96][130][131][132][133][134] 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.[11][12]
The hunting methods utilised by saltwater crocodiles are indistinct from any other crocodilian, with the hunting crocodile submerging and quietly swimming over to the prey before pouncing upwards, striking suddenly. Unlike some other crocodilians, such as American alligators and even Nile crocodiles, they are not known to have hunted on dry land.[96][27] Young saltwater crocodiles are capable of breaching their entire body into the air in a single upward motion while hunting prey that may be perched on low hanging branches.[104] While hunting rhesus macaques, they have been seen to knock the monkeys off a bank by knocking them with their tail, forcing the macaque into water for easy consumption. However, whether tail use in hunting is intentional or just an accidental benefit is not definitely clear.[27] As with other crocodilians, their sharp, peg-like teeth are well-suited to seize and tightly grip prey, but not to shear flesh. Small prey are simply swallowed whole, while larger animals are dragged into deep water and drowned or crushed.[135] 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.[136] 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.[137]
Bite
Regression of mean body mass and bite force of C. porosusSaltwater crocodiles, even adults, can breach out of the water in upwards direction to capture food, although are most often seen to do so when coerced by bait, as seen here
Saltwater crocodiles have the strongest bite of any living animal. A 4.59m-long (15ft 1in)531kg (1,171lb) saltwater crocodile has been confirmed as having the highest bite force quotient ever recorded for an animal in a laboratory setting, with a value of 16,414N (3,690lbf) surpassing the previous record of 13,172N or 2,961lbf made by an American alligator (Alligator mississippiensis).[138][139] Based on the regression of mean body mass and mean bite force, the bite forces of multiple crocodile species, 1,308kg (2,884lb) individuals were estimated at 27,531 to 34,424N (6,189 to 7,739lbf).[139] The extraordinary bite of crocodilians is a result of their anatomy. The space for the jaw muscle in the skull is very large, which is easily visible from the outside as a bulge at each side. The nature of the muscle is extremely stiff, almost as hard as bone to the touch, such that it can appear to be a continuation of the skull. Another trait is that most of the muscle in a crocodile's jaw is arranged for clamping down. Despite the strong muscles to close the jaw, crocodiles have extremely small and weak muscles to open the jaw. The jaws of a crocodile can be securely shut with several layers of duct tape.[140]
Reproduction
Males reach sexual maturity around 3.3m (11ft) at around 16 years of age, while females reach sexual maturity at 2.1m (6ft 11in) and 12–14 years of age.[9] Saltwater crocodiles mate in the wet season, when water levels are at their highest. In Australia, the male and female engage in courtship in September and October, and the female lays eggs between November and March.[50] It is possible the rising temperatures of the wet season provoke reproductive behaviour in this species.[108] While crocodilians generally nest every year, there have been several recorded cases of female saltwater crocodiles nesting only every other year and also records of a female attempting to produce two broods in a single wet season.[108] The female selects the nesting site, and both parents will defend the nesting territory, which is typically a stretch of shore along tidal rivers or freshwater areas, especially swamps. Nests are often in a surprisingly exposed location, often in mud with little to no vegetation around, and thus limited protection from the sun and wind. The nest is a mound of mud and vegetation, usually measuring 175cm (69in) long and 53cm (21in) high, with an entrance averaging 160cm (63in) in diameter.[108] Some nests in unlikely habitats have occurred, such as rocky rubble or in a damp low-grass field.[141][142] 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).[27][143]
The female typically lays from 40 to 60 eggs, but some clutches have included up to 90. The eggs measure on average 8 by 5cm (3.1 by 2.0in) and weigh 113g (4.0oz) on average in Australia and 121g (4.3oz) in India.[50][144] These are relatively small, as the average female saltwater crocodile weighs around five times as much as a freshwater crocodile, but lays eggs that are only about 20% larger in measurement and 40% heavier than those of the smaller species.[35] The average weight of a new hatchling in Australia is reportedly 69.4g (2.45oz).[50] Although the female guards the nest for 80 to 98 days (in extreme high and low cases from 75 to 106 days), the loss of eggs is often high due to flooding and occasionally to predation.[50] As in all crocodilians, the sex of the hatchlings is determined by temperature. At 28–30 degrees all hatchlings will be female, at 30–32 degrees 86% of hatchlings are male, and at 33 or more degrees predominantly female (84%).[145] 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).[35] A majority of the loss of eggs of saltwater crocodiles occurs due to flooding of the nest hole.[108][146]
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.[147] By crocodilian standards, saltwater crocodile hatchlings are exceptionally aggressive to one another and will often fight almost immediately after being transported to water by their mother.[148] 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.[149] 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.[9][150]
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.[108][50][144][146] Pigs and cattle also occasionally inadvertently trample eggs and nests on occasion and degrade habitat quality where found in numbers.[151] 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.[152]
Saltwater crocodiles go through numerous physiological changes as they mature. Pictured here is a hatchling age or baby crocodile.
Seen here is a juvenile crocodile, which grows considerably in length over several years but is easily distinguished by slender build and size.
A saltwater crocodile in the subadult age range at Gembira Loka Zoo, similar but not as robust and relatively small-headed compared to adults.
Juvenile salt water crocodiles at Karamjal Wildlife Breeding center, Bangladesh
Conservation status
Saltwater crocodileLarge saltwater crocodile in ABQ BioPark Zoo
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.[153] 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).[154] 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.[155][156] 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 3m (9ft 10in).[85][157]
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.[147][158]
Of all the crocodilians, the saltwater crocodile and Nile crocodile have the strongest tendencies to treat humans as prey.[159] The saltwater crocodile has a long history of attacking humans who unknowingly venture into its territory. As a result of its power, intimidating size and speed, survival of a direct predatory attack is unlikely if the crocodile is able to make direct contact. In contrast to alligators where a degree of coexistence may be the policy, the only recommended policy for dealing with saltwater crocodiles is to completely avoid their habitat whenever possible, as they are exceedingly aggressive when encroached upon.[27]
Exact data on attacks are limited outside Australia, where one or two fatal attacks are reported per year.[161] From 1971 to 2013, the total number of fatalities reported in Australia due to saltwater crocodile attack was 106.[162][161] The low level of attacks may be due to extensive efforts by wildlife officials in Australia to post crocodile warning signs at numerous at-risk billabongs, rivers, lakes and beaches.[163] Less-publicised attacks have been reported in Borneo,[164]Sumatra,[165]Eastern India (Andaman Islands),[166][167] and Burma.[168] In Sarawak, Borneo, the average number of fatal attacks is reportedly 2.8 annually for the years from 2000 to 2003.[169] In the Northern Territory in Australia, attempts have been made to relocate saltwater crocodiles who have displayed aggressive behaviour towards humans but these have proven ineffective as the problem crocodiles are apparently able to find their way back to their original territories.[170] In the Darwin area from 2007 to 2009, 67–78% of "problem crocodiles" were identified as males.[171]
Many attacks in areas outside Australia are believed to go unreported, with one study positing up to 20 to 30 attacks occur every year.[169] 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.[159] 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.[27][39][169] Despite their reputations, many wild saltwater crocodiles are normally quite wary of humans and will go out of their way to submerge and swim away from them, even large adult males, if previously subject to harassment or persecution.[172][173] 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 3m (9ft 10in) or less in length. Fatal attacks, more likely to be predatory in motivation, commonly involve larger crocodiles with an average estimated size of 4.3m (14ft 1in). 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.[169] In the Andaman Islands, the number of fatal attacks on humans has reportedly increased, possibly due to habitat destruction and reduction of natural prey.[174]
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.[175] 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.[39] Another notorious crocodile attack was in 1985, on ecofeminist Val Plumwood, who survived the attack and learned that the advice she had received that crocodiles do not attack canoes was inaccurate.[176][177]
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.[178]
Cultural references
1948 postage stamp depicting an Aboriginal artwork of the saltwater crocodile
The saltwater crocodile is considered holy on Timor. According to legend, the island was formed by a giant crocodile. The Papuan people have a similar and very involved myth and traditionally the crocodile was described as a relative (normally a father or grandfather).[27]
According to Wondjina, the mythology of Indigenous Australians, the saltwater crocodile was banished from the fresh water for becoming full of bad spirits and growing too large, unlike the freshwater crocodile, which was somewhat revered.[179] Aboriginal rock art depicting the saltwater crocodile is rare, although examples of up to 3,000 years old were found in caves in Kakadu and Arnhem land, roughly matching the distribution of the species. It is however depicted in contemporary aboriginal art.[180] The Larrakia people think of themselves as crocodile descendants, and regard it as their totem.[181] They respect crocodiles as protectors of harbours and do not eat crocodile meat.[182]
The species is featured on several postage stamps, including an 1894 State of North Borneo 12-cent stamp; a 1948 Australian 2 shilling stamp depicting an aboriginal rock artwork of the species; a 1966 Republic of Indonesia stamp; a 1994 Palau 20-cent stamp; a 1997 Australian 22-cent stamp; and a 2005 1 Malaysian ringgit postage stamp.
The saltwater crocodile has featured in contemporary Australian film and television including the Crocodile Dundee series of films, horror films Black Water and Rogue and The Crocodile Hunter television series. There are now several saltwater crocodile–themed parks in Australia.[citation needed]
Examples of large unconfirmed saltwater crocodiles
The largest size recorded for a saltwater crocodile has always been a subject of considerable controversy. The reason behind unverified sizes is either the case of insufficient/inconclusive data or exaggeration from a folkloric point of view. This section is dedicated to examples of the largest saltwater crocodiles recorded outside scientific norms measurement and estimation, with the aim of satisfying the public interest without creating data pollution, as well as serving an educational purpose of guiding the reader to separate fact from possible fiction. Below, in descending order starting from the largest, are some examples of large unconfirmed saltwater crocodiles, recorded throughout history.
A crocodile shot in the Bay of Bengal in 1840 was reported at 10.1m (33ft 2in). Furthermore, this specimen was claimed to have a belly girth of 4.17m (13ft 8in) and a body mass estimated 3,000kg (6,600lb). However, the skull of this specimen was examined by Guinness Records and found to be only 66.5cm (2ft 2+1⁄4in) in length, indicating the above size was considerably exaggerated and the animal would have probably measured no more than 5.89m (19ft 4in).[39]
James R. Montgomery, who ran a plantation near to the Lower Kinabatangan Segama Wetlands in Borneo from 1926 to 1932, claimed to have netted, killed, and examined numerous crocodiles well over 6.1m (20ft 0in) there, including a specimen he claims measured 10m (32ft 10in). However, no one scientifically confirmed any of Montgomery's specimens and no voucher specimens are known.[39]
A crocodile shot in Queensland in 1957, nicknamed Krys the croc (named after the woman that shot the crocodile in July 1957; Krystina Pawlowski), was reported to be 8.63m (28ft 4in) long, but no verified measurements were made and no remains of this crocodile exist.[183][184] A "replica" of this crocodile has been made as a tourist attraction.[185][186][187]
A crocodile killed in 1823 at Jalajala on the main island of Luzon in the Philippines was reported at 8.2m (26ft 11in). However the skull of the specimen is 66.5cm (26+1⁄4in) long indicating an animal of approximately 6.1m (20ft 0in).[39]
A crocodile shot in Odisha, India,[188] was claimed to measure 7.6m (24ft 11in) in life, but its skull, when given scholarly examination, was thought to have come from a crocodile of a length no greater than 7m (23ft 0in).[189]
A reported 7.6m (24ft 11in) 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 75cm (30in) long, actually indicating it could have measured 6.7m (22ft 0in).[39]
In 2006, Guinness accepted a 7.01m (23ft 0in), 2,000-kilogram (4,400lb) male saltwater crocodile living within Bhitarkanika Park in Odisha. Due to the difficulty of trapping and measuring a very large living crocodile, the accuracy of these dimensions is yet to be verified. These observations and estimations have been made by park officials over the course of ten years, from 2006 to 2016, however, regardless of the skill of the observers it cannot be compared to a verified tape measurement, especially considering the uncertainty inherent in visual size estimation in the wild.[190] In addition, this region may contain up to four other specimens measuring over 6.1m (20ft 0in).[188][191]
S. Baker (1874) claimed that in Sri Lanka in the 1800s, specimens measuring 6.7m (22ft 0in) or more were commonplace.[39] 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 6m (19ft 8in) in length.[39]
The record size for a crocodile from Papua New Guinea to be considered authentic by Guinness was a 6.32m (20ft 9in) specimen shot by Herb Schweighofer in May 1966 along the northeastern coast. This specimen had a belly girth of 2.74m (9ft 0in).[39]
↑ Except populations of Australia, Indonesia, Malaysia and Papua New Guinea which are included in Appendix II.
Related Research Articles
Crocodiles or true crocodiles are large, semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term “crocodile” is sometimes used more loosely to include all extant members of the order Crocodilia, which includes the alligators and caimans, the gharial and false gharial as well as other, extinct, taxa.
Crocodylia is an order of semiaquatic, predatory reptiles known as crocodilians. They first appeared during the Late Cretaceous and are the closest living relatives of birds. Crocodilians are a type of crocodylomorph pseudosuchian, a subset of archosaurs that appeared about 235 million years ago and were the only survivors of the Triassic–Jurassic extinction event. The order includes the true crocodiles, the alligators and caimans, and the gharial and false gharial. Although the term "crocodiles" is sometimes used to refer to all of these, it is less ambiguous to use "crocodilians".
The American alligator, sometimes referred to as a gator, or common alligator is a large crocodilian reptile native to the Southeastern United States and a small section of northeastern Mexico. It is one of the two extant species in the genus Alligator, and is larger than the only other living alligator species, the Chinese alligator.
The mugger crocodile is a medium-sized broad-snouted crocodile, also known as mugger and marsh crocodile. It is native to freshwater habitats from southern Iran to the Indian subcontinent, where it inhabits marshes, lakes, rivers and artificial ponds. It rarely reaches a body length of 5 m and is a powerful swimmer, but also walks on land in search of suitable waterbodies during the hot season. Both young and adult mugger crocodiles dig burrows to which they retreat when the ambient temperature drops below 5 °C (41 °F) or exceeds 38 °C (100 °F). Females dig holes in the sand as nesting sites and lay up to 46 eggs during the dry season. The sex of hatchlings depends on temperature during incubation. Both parents protect the young for up to one year. They feed on insects, and adults prey on fish, reptiles, birds and mammals.
The black caiman is a crocodilian reptile endemic to South America. With a maximum length of around 5 to 6 m and a mass of over 450 kg (1,000 lb), it is the largest living species of the family Alligatoridae, and the third-largest crocodilian in the Neotropical realm. True to its common and scientific names, the black caiman has a dark greenish-black coloration as an adult. In some individuals, the pigmentation can appear almost jet-black. It has grey to brown banding on the lower jaw; juveniles have a more vibrant coloration compared to adults, with prominent white-pale yellow banding on the flanks that remains present well into adulthood. The banding on young animals helps with camouflage by breaking up their body outline, on land or in water, in an effort to avoid predation. The morphology is quite different from other caimans but the bony ridge that occurs in other caimans is present. The head is large and heavy, an advantage in catching larger prey. Like all crocodilians, caimans are long, squat creatures, with big jaws, long tails and short legs. They have thick, scaled skin, and their eyes and noses are located on the tops of their heads. This enables them to see and breathe while the rest of their bodies are underwater.
Sarcosuchus is an extinct genus of crocodyliform and distant relative of living crocodilians that lived during the Early Cretaceous, from the late Hauterivian to the early Albian, 133 to 112 million years ago of what is now Africa and South America. The genus name comes from the Greek σάρξ (sarx) meaning flesh and σοῦχος (souchus) meaning crocodile. It was one of the largest pseudosuchians, with the largest specimen of S. imperator reaching approximately 9–9.5 metres (29.5–31.2 ft) long and weighing up to 3.45–4.3 metric tons. It is known from two species; S. imperator from the early Albian Elrhaz Formation of Niger, and S. hartti from the Late Hauterivian of northeastern Brazil. Other material is known from Morocco and Tunisia and possibly Libya and Mali.
The Nile crocodile is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed in sub-Saharan Africa, occurring mostly in the eastern, southern, and central regions of the continent, and lives in different types of aquatic environments such as lakes, rivers, swamps and marshlands. It occasionally inhabits deltas, brackish lakes and rarely also saltwater. Its range once stretched from the Nile Delta throughout the Nile River. Lake Turkana in Kenya has one of the largest undisturbed Nile crocodile populations.
The American crocodile is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas, with populations present from South Florida, the Caribbean islands of Cuba, Jamaica, Hispaniola, and the coasts of Mexico to as far south as Peru, Ecuador, Colombia, and Venezuela.
Deinosuchus is an extinct genus of alligatoroid crocodilian, related to modern alligators and caimans, that lived 82 to 73 million years ago (Ma), during the late Cretaceous period. The name translates as "terrible crocodile" and is derived from the Greek deinos (δεινός), "terrible", and soukhos (σοῦχος), "crocodile". The first remains were discovered in North Carolina in the 1850s; the genus was named and described in 1909. Additional fragments were discovered in the 1940s and were later incorporated into an influential, though inaccurate, skull reconstruction at the American Museum of Natural History. Knowledge of Deinosuchus remains incomplete, but better cranial material found in recent years has expanded scientific understanding of this massive predator.
The freshwater crocodile, also known commonly as the Australian freshwater crocodile, Johnstone's crocodile, and the freshie, is a species of crocodile native to the northern regions of Australia. Unlike its much larger Australian relative, the saltwater crocodile, the freshwater crocodile is not known as a man-eater, although it bites in self-defence, and brief, nonfatal attacks have occurred, apparently the result of mistaken identity.
The Orinoco crocodile is a critically endangered crocodile. Its population is very small, and they can only be found in the Orinoco river basin in Venezuela and Colombia. Extensively hunted for their skins in the 19th and 20th centuries, it is one of the most endangered species of crocodiles. It is a very large species of crocodilian; males have been reported up to 6.8 m in the past, weighing over 900 kg (2,000 lb), but such sizes do not exist today, 5.2 m being a more widely accepted maximum size. A large male today may attain 4.2 m in length and can weigh up to 450 kg (1,000 lb), while females are substantially smaller with the largest likely to weigh around 225 kg (496 lb). Sexual dimorphism is not as profound as in other crocodilian species. The coloration is light even in adults.
Bhitarkanika National Park is a 145 km2 (56 sq mi) large national park in northeast Kendrapara district in Odisha in eastern India. It was designated on 16 September 1998 and obtained the status of a Ramsar site on 19 August 2002. The area is also been designated as the second Ramsar site of the State after the Chilika Lake. It is surrounded by Bhitarkanika Wildlife Sanctuary, which spread over 672 km2 (259 sq mi). Gahirmatha Beach and Marine Sanctuary are to the east, separating the swamp region and mangroves from the Bay of Bengal. The national park and wildlife sanctuary is inundated by the rivers Brahmani, Baitarani, Dhamra, and Pathsala. It hosts many mangrove species, and is the second largest mangrove ecosystem in India.
The Philippine crocodile, also known as the Mindoro crocodile, the Philippine freshwater crocodile, the bukarot in Ilocano, and more generally as a buwaya in most Filipino lowland cultures, is one of two species of crocodiles found in the Philippines; the other is the larger saltwater crocodile (Crocodylus porosus). The Philippine crocodile, the species endemic only to the country, went from data deficient to critically endangered in 2008 from exploitation and unsustainable fishing methods, such as dynamite fishing. Conservation methods are being taken by the Dutch/Filipino Mabuwaya foundation, the Crocodile Conservation Society and the Zoological Institute of HerpaWorld in Mindoro island. It is strictly prohibited to kill a crocodile in the country, and it is punishable by law.
The New Guinea crocodile is a small species of crocodile found on the island of New Guinea north of the mountain ridge that runs along the centre of the island. The population found south of the mountain ridge, formerly considered a genetically distinct population, is now considered a distinct species, Hall's New Guinea crocodile. In the past it included the Philippine crocodile, C. n. mindorensis, as a subspecies, but today they are regarded as separate species. The habitat of the New Guinea crocodile is mostly freshwater swamps and lakes. It is most active at night when it feeds on fish and a range of other small animals. A female crocodile lays a clutch of eggs in a nest composed of vegetation and she lies up nearby to guard the nest. There is some degree of parental care for newly hatched juveniles. This crocodile was over-hunted for its valuable skin in the mid 20th century, but conservation measures have since been put in place, it is reared in ranches and the International Union for Conservation of Nature (IUCN) lists it as being of "Least Concern".
Morelet's crocodile, also known as the Mexican crocodile or Belize crocodile, is a modest-sized crocodilian found only in the Atlantic regions of Mexico, Belize and Guatemala. It usually grows to about 3 metres (10 ft) in length. It is a species at least concern for extinction according to the International Union for Conservation of Nature. The species has a fossil record in Guatemala.
Paludirex is an extinct genus of mekosuchine crocodylian from the Pliocene and Pleistocene of Australia. A large and robust semi-aquatic ambush hunter capable of attaining lengths of up to 5 m (16 ft), it was likely the top predator of Australia's waterways prior to the appearance of modern saltwater crocodiles. Two species are known, the smaller Paludirex gracilis and the larger Paludirex vincenti. A third as of yet unnamed species may have also existed.
Euthecodon is an extinct genus of long-snouted crocodile. It was common throughout much of Africa during the Neogene, with fossils being especially common in Kenya, Ethiopia, and Libya. Although superficially resembling that of gharials, the long snout was a trait developed independently from that of other crocodilians and suggests a diet of primarily fish. Euthecodon coexisted with a wide range of other crocodiles in the areas it inhabited before eventually going extinct during the Pleistocene.
The Cuban crocodile is a small-medium species of crocodile endemic to Cuba. Typical length is 2.1–2.3 m (6.9–7.5 ft) and typical weight 70–80 kg (150–180 lb). Large males can reach as much as 3.5 m (11 ft) in length and weigh more than 215 kg (474 lb). Despite its smaller size, it is a highly aggressive animal, and potentially dangerous to humans.
Crocodylus thorbjarnarsoni is an extinct species of crocodile from the Pliocene and Pleistocene of the Turkana Basin in Kenya. It is closely related to the species Crocodylus anthropophagus, which lived during the same time in Tanzania. C. thorbjarnarsoni could be the largest known true crocodile, with the largest skull found indicating a possible total length up to 7.6 m (25 ft). It may have been a predator of early hominins. Crocodylus thorbjarnarsoni was named by Christopher Brochu and Glenn Storrs in 2012 in honor of John Thorbjarnarson, a conservationist who worked to protect endangered crocodilians.
Astorgosuchus is an extinct monospecific genus of crocodilian, closely related to true crocodiles, that lived in Pakistan during the late Oligocene period. This crocodile may have reached lengths of up to 7–8 m (23–26 ft) and is known to have preyed on many of the large mammals found in its environment. Bite marks of a large crocodile have been found on the bones of juvenile Paraceratherium, however if these were left by Astorgosuchus cannot be said with certainty. The genus contains a single species, Astorgosuchus bugtiensis, which was originally named as a species of Crocodylus in 1908 and was moved to its own genus in 2019.
1 2 3 4 Webb, G. J. W.; Manolis, C.; Brien, M. L. (2010). "Saltwater Crocodile Crocodylus porosus"(PDF). In Manolis, S. C.; Stevenson, C. (eds.). Crocodiles: Status Survey and Conservation Action Plan (3rded.). Darwin: IUCN Crocodile Specialist Group. pp.99–113.
↑ Allen, G. R. (1974). "The marine crocodile, Crocodylus porosus, from Ponape, Eastern Caroline Islands, with notes on food habits of crocodiles from the Palau Archipelago". Copeia. 1974 (2): 553. doi:10.2307/1442558. JSTOR1442558.
↑ Schneider, J. G. (1801). "Porosus". Historiae Amphibiorum naturalis et literariae Fasciculus Secundus continens Crocodilos, Scincos, Chamaesauras, Boas, Pseudoboas, Elapes, Angues, Amphisbaenas et Caecilias. Jenae: Wesselhoeft. pp.159–160.
↑ Müller, S.; Schlegel, H. (1844). "Over de Krokodillen van den Indischen Archipel". In Temminck, C. J. (ed.). Verhandelingen over de natuurlijke geschiedenis der Nederlandsche overzeesche Bezittingen, door de leden der Natuurkundige Commissie in Indie en andere Schrijvers. Leiden: S. en J. Luchtmans en C. C. van der Hoek. pp.1–70.
↑ Deraniyagala, P. E. P. (1953). "Crocodylus porosus australis ssp. nov.". A coloured atlas of some vertebrates from Ceylon. Vol.Tetrapod Reptilia. Colombo: Government Press. pp.33–34.
↑ Das, I.; Charles, J. K. (2000). "A Record of Crocodylus raninus Müller & Schlegel, 1844 from Brunei, North-western Borneo". Sabah Parks Nature Journal. 3: 1–5.
1 2 Brazaitis, P. (2001). A Guide to the Identification of the Living Species of Crocodilians. New York: Wildlife Conservation Society.
↑ Molnar, R. E. (1979). "Crocodylus porosus from the Pliocene Allingham formation of North Queensland. Results of the Ray E. Lemley expeditions, part 5". Memoirs of the Queensland Museum. 19: 357–365.
1 2 3 4 5 6 7 8 9 10 Guggisberg, C. A. W. (1972). Crocodiles: Their Natural History, Folklore, and Conservation. Newton Abbot: David & Charles. p.195. ISBN978-0-7153-5272-4.
↑ Kondo, H. (1970). Grolier's Amazing World of Reptiles. New York, NY: Grolier Interprises Inc.
↑ Seymour, R. S.; Gienger, C. M.; Brien, M. L.; Tracy, C. R.; Manolis, C. S.; Webb, G. J. W.; Christian, K. A. (2012). "Scaling of standard metabolic rate in estuarine crocodiles Crocodylus porosus". Journal of Comparative Physiology B. 183 (4): 491–500. doi:10.1007/s00360-012-0732-1. PMID23233168. S2CID3191541.
↑ Loveridge, J. P. & Blake, D. K. (1972). "Techniques in the immobilisation and handling of the Nile crocodile, Crocodylus niloticus". National Museums and Monuments of Rhodesia.
1 2 3 Greer, A. E. (1974). "On the maximum total length of the Salt-Water Crocodile (Crocodylus porosus)". Journal of Herpetology. 8 (4): 381–384. doi:10.2307/1562913. JSTOR1562913.
↑ Olsson, A.; Phalen, D. (2012). "Preliminary studies of chemical immobilization of captive juvenile estuarine (Crocodylus porosus) and Australian freshwater (C. johnstoni) crocodiles with medetomidine and reversal with atipamezole". Veterinary Anaesthesia and Analgesia. 39 (4): 345–356. doi:10.1111/j.1467-2995.2012.00721.x. PMID22642399.
↑ Webb, G.; Manolis, S. C. (1989). Crocodiles of Australia. Reed Books.
↑ Webb, G. J. W.; Messel, H.; Crawford, J.; Yerbury, M. J. (1978). "Growth rates of Crocodylus porosus (Reptilia: Crocodilia) from Arnhem Land, northern Australia". Wildlife Research. 5 (3): 385–399. doi:10.1071/WR9780385.
↑ Fukuda, Y., How, C. B., Seah, B., Yang, S., Pocklington, K., & Peng, L. K. (2018). Historical, exceptionally large skulls of saltwater crocodiles discovered at the Lee Kong Chian Natural History Museum in Singapore. The Raffles Bulletin of Zoology, 66, 810–813.
↑ Ziegler, T., Tao, N. T., Minh, N. T., Manalo, R., Diesmos, A., & Manolis, C. (2019). A giant crocodile skull from Can Tho, named “Dau Sau”, represents the largest known saltwater crocodile (Crocodylus porosus) ever reported from Vietnam. Tap chi Sinh hoc (Journal of Biology), 41(4), 25–30.
1 2 3 4 5 6 7 Leach, G.; Delaney, R. & Fukuda, Y. (2009). Management program for the saltwater crocodile in the Northern Territory of Australia, 2009–2014 (Report). Department of Natural Resources, Environment, the Arts and Sport.
↑ The Guinness book of records, 1994. New York: Facts on File. 1992. p.38. ISBN9780816026456.
↑ Wood, Gerald L. (1982). The Guinness book of animal facts and feats (3rded.). Enfield, Middlesex: Guinness Superlatives. p.96. ISBN978-0-85112-235-9.
↑ Manalo, R. I., & Alcala, A. C. (2013). Status of the crocodile (Crocodylus porosus, Schneider) industry in the Philippines. Transactions of the National Academy of Science and Technology of the Philippines, 35(1), 219–222.
↑ McDonald, K. R., Dennis, A. J., Kyne, P. J., Debus, S. J., & Curtis, L. (2012). Queensland's Threatened Animals. CSIRO Publishing, pg. 185–186.
↑ Halliday, T. R.; Verrell, P. A. (1988). "Body size and age in amphibians and reptiles". Journal of Herpetology. 22 (3): 253–265. doi:10.2307/1564148. JSTOR1564148.
↑ Cox, R. M., Butler, M. A., & John-Alder, H. B. (2007). The evolution of sexual size dimorphism in reptiles. Sex, size and gender roles: evolutionary studies of sexual size dimorphism, 38–49.
↑ Brazaitis, P. (1987). Identification of Crocodilian Skins. Chipping Norton, Australia: Pty Lim.
↑ George Albert Boulenger (1889). Catalogue of the chelonians, rhynchocephalians, and crocodiles in the British Museum (Natural History). British Museum (Natural History). Department of Zoology.
↑ La Gironière, P. (1854). Twenty Years in the Philippines [1819–1839]. Harper & Brothers.
↑ Wood, G.L. (1982). Guinness Book of World Records Animal Facts and Feats. Sterling Pub Co., Inc. ISBN978-0851122359.
↑ Singh, L. A. K. & Kar, S. K. (2006). "Status of the Saltwater Crocodile in Orissa: an overview". Journal of the Bombay Natural History Society. 103 (2/3): 274–285.
↑ Andrews, H. V. & Whitaker, R. (1994). "Status of the saltwater crocodile (Crocodylus porosus Schneider, 1801) in North Andaman Island". Hamadryad. 19: 79–92.
↑ Stuart, B. L.; Hayes, B.; Manh, B. H. & Platt, S. G. (2002). "Status of crocodiles in the U Minh Thuong Nature Reserve, southern Vietnam". Pacific Conservation Biology. 8 (1): 62. doi:10.1071/PC020062. S2CID54020729.
↑ Platt, S. G.; Holloway, R. H. P.; Evans, P. T.; Paudyal, K.; Piron, H. & Rainwater, T. R. (2006). "Evidence for the historic occurrence of Crocodylus porosus Schneider, 1801 in Tonle Sap, Cambodia". Hamadryad. 30 (1/2): 206.
1 2 Stuebing, R. B.; Ismail, G. & Ching, L. H. (1994). "The distribution and abundance of the Indo-Pacific crocodile Crocodylus porosus Schneider in the Klias River, Sabah, east Malaysia". Biological Conservation. 69 (1): 1–7. Bibcode:1994BCons..69....1S. doi:10.1016/0006-3207(94)90322-0.
↑ Kaur, T. (2006). "Segama River survey". Crocodile Specialist Group Newsletter. 25 (1): 15.
↑ Jelden, D. C. (1980). "Preliminary Studies on the Breeding Biology of Crocodylus porosus and Crocodylus n. novaguineae on the Middle Sepik (Papua New Guinea)". Amphibia-Reptilia. 1 (3): 353–358. doi:10.1163/156853881X00456.
↑ Messel, H. & Vorlicek, G. C. (1986). "Population-Dynamics and Status of Crocodylus porosus in the Tidal Waterways of Northern Australia". Wildlife Research. 13 (1): 71–111. doi:10.1071/WR9860071.
↑ Cott, H. B. (1961). "Scientific results of an inquiry into the ecology and economic status of the Nile crocodile (Crocodilus niloticus) in Uganda and Northern Rhodesia". Transactions of the Zoological Society of London. 29 (4): 211–356. doi:10.1111/j.1096-3642.1961.tb00220.x.
↑ Webb, G. J.; Hollis, G. J.; Manolis, S. C. (1991). "Feeding, growth, and food conversion rates of wild juvenile saltwater crocodiles (Crocodylus porosus)". Journal of Herpetology. 25 (4): 462–473. doi:10.2307/1564770. JSTOR1564770.
1 2 3 Davenport, J.; Grove, D. J.; Cannon, J.; Ellis, T. R.; Stables, R. (1990). "Food capture, appetite, digestion rate and efficiency in hatchling and juvenile Crocodylus porosus". Journal of Zoology. 220 (4): 569–592. doi:10.1111/j.1469-7998.1990.tb04736.x.
↑ Webb, G. J.; Messel, H. (1977). "Crocodile capture techniques". The Journal of Wildlife Management. 41 (3): 572–575. doi:10.2307/3800531. JSTOR3800531.
↑ Taylor, J. A. (1979). "The foods and feeding habits of subadult Crocodylus porosus Schneider in northern Australia". Wildlife Research. 6 (3): 347–359. doi:10.1071/WR9790347.
1 2 3 4 5 6 7 Messel, H.; Vorlicek, G. C. (1989). "Ecology of Crocodylus porosus in northern Australia". Crocodiles: Their Ecology, Management and Conservation. IUCN. pp.164–183. ISBN2880329876.
↑ Cramb, R. A.; Sujang, P. S. (2013). "The mouse deer and the crocodile: oil palm smallholders and livelihood strategies in Sarawak, Malaysia". The Journal of Peasant Studies. 40 (1): 129–154. doi:10.1080/03066150.2012.750241. S2CID126939848.
↑ Galdikas, B. M.; Yeager, C. P. (1984). "Brief report: Crocodile predation on a crab-eating macaque in Borneo". American Journal of Primatology. 6 (1): 49–51. doi:10.1002/ajp.1350060106. PMID31986847. S2CID84208150.
↑ Otani, Y.; Tuuga, A.; Bernard, H.; Matsuda, I. (2012). "Opportunistic predation and predation-related events on long-tailed macaque and proboscis monkey in Kinabatangan, Sabah, Malaysia". Journal of Tropical Biology and Conservation. 9: 214–218.
↑ Letnic, M.; Webb, J. K.; Shine, R. (2008). "Invasive cane toads (Bufo marinus) cause mass mortality of freshwater crocodiles (Crocodylus johnstoni) in tropical Australia". Biological Conservation. 141 (7): 1773–1782. Bibcode:2008BCons.141.1773L. doi:10.1016/j.biocon.2008.04.031.
↑ Kar, S. K.; Bustard, H. R. (1983). "Attacks on domestic livestock by juvenile saltwater crocodile, Crocodylus porosus, in Bhitarkanika Wildlife Sanctuary, Orissa India". Amphibia-Reptilia. 4 (1): 81–83. doi:10.1163/156853883X00283.
↑ Hanson, J. O.; Salisbury, S. W.; Campbell, H. A.; Dwyer, R. G.; Jardine T. D.; Franklin, C. E. (2015). "Feeding across the food web: The interaction between diet, movement and body size in estuarine crocodiles (Crocodylus porosus)". Austral Ecology. 40 (3): 275–286. Bibcode:2015AusEc..40..275H. doi:10.1111/aec.12212. S2CID85858989.
↑ Whiting, S. D. & Whiting, A. U. (2011). "Predation by the Saltwater Crocodile (Crocodylus porosus) on sea turtle adults, eggs, and hatchlings". Chelonian Conservation and Biology. 10 (2): 198–205. doi:10.2744/CCB-0881.1. S2CID85816270.
↑ Doody, J. S. (2009). "Eyes bigger than stomach: prey caching and retrieval in the saltwater crocodile, Crocodylus porosus". Herpetological Review. 40 (1): 26.
↑ Lang, J. W. & Andrews, H. V. (1994). "Temperature-dependent sex determination in crocodilians". Journal of Experimental Zoology. 270 (1): 28–44. doi:10.1002/jez.1402700105.
1 2 Magnusson, W. E. (1982). "Mortality of eggs of the crocodile Crocodylus porosus in northern Australia". Journal of Herpetology. 16 (2): 121–130. doi:10.2307/1563804. JSTOR1563804.
↑ Lang, J. W. (1987). "Crocodilian behaviour: implications for management". In Webb, G. J. W.; Manolis, S. C.; Whitehead, P. J. (eds.). Wildlife management: crocodiles and alligators. Surrey Beatty & Sons. pp.273–294.
↑ Webb, G. J. W.; Manolis, S. C.; Buckworth, R. & Sack, G. C. (1983). "An examination of Crocodylus porosus nests in two northern Australian freshwater swamps, with an analysis of embryo mortality". Wildlife Research. 10 (3): 571–605. doi:10.1071/WR9830571.
↑ Somaweera, R.; Brien, M. & Shine, R. (2013). "The role of predation in shaping crocodilian natural history". Herpetological Monographs. 27 (1): 23–51. doi:10.1655/HERPMONOGRAPHS-D-11-00001. S2CID86167446.
↑ Whitaker, R. (1982). "Status of Asian crocodilians". In Crocodile Specialist Group (ed.). Crocodiles. Proceedings of the 5th Working Meeting of the Crocodile Specialist Group of the Species Survival Commission of the International Union for Conservation of Nature and Natural Resources Convened at the Florida State Museum, Gainesville, Florida, USA, 12 to 16 August 1980. Gland: IUCN. p.237.
↑ Gramantez, D. (2008) A case study of the Saltwater Crocodile Crocodylus porosus in Muthurajawela Marsh, Sri Lanka – Considerations for conservation. IUCN- Crocodile Specialist Group.
↑ Brazaitis, P.; Eberdong, J.; Brazaitis, P. J.; Watkins-Colwell, G. J. (2009). "Notes on the saltwater crocodile, Crocodylus porosus, in the Republic of Palau". Bulletin of the Peabody Museum of Natural History. 50 (1): 27–48. doi:10.3374/014.050.0103. S2CID84984946.
↑ Tisdell, C.; Nantha, H. S.; Wilson, C. (2007). "Endangerment and likeability of wildlife species: How important are they for payments proposed for conservation?". Ecological Economics. 60 (3): 627–633. Bibcode:2007EcoEc..60..627T. doi:10.1016/j.ecolecon.2006.01.007.
1 2 Sideleau, B., & Britton, A. R. C. (2012). "A preliminary analysis of worldwide crocodilian attacks", pp. 111–114 in Crocodiles Proceedings of the 21st Working Meeting of the IUCN-SSC Crocodile Specialist Group. Gland, Switzerland: IUCN.
↑ Manolis, S. C., & Webb, G. J. (September 2013). "Assessment of saltwater crocodile (Crocodylus porosus) attacks in Australia (1971–2013): implications for management", pp. 97–104 in Crocodiles Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group. Gland, Switzerland: IUCN.
↑ Walsh, B.; Whitehead, P. J. (1993). "Problem crocodiles, Crocodylus porosus, at Nhulunbuy, Northern Territory: an assessment of relocation as a management strategy". Wildlife Research. 20 (1): 127–135. doi:10.1071/WR9930127.
↑ Delaney, R., Fukuda, Y., & Saalfeld, K. (2009). SALTWATER CROCODILE (Crocodylus porosus) MANAGEMENT PROGRAM. Northern Territory Government, Department of Natural Resources, Environment, the Arts and Sport.
↑ Webb, G. J. W.; Messel, H. (1979). "Wariness in Crocodylus porosus (Reptilia: Crocodilidae)". Wildlife Research. 6 (2): 227–234. doi:10.1071/WR9790227.
↑ Somaweera, R. & A. de Silva (2013). Using traditional knowledge to minimize human-crocodile conflict in Sri Lanka, pp. 257. In: Crocodiles. Proceedings of the 22nd Working Meeting of the IUCN-SSC Crocodile Specialist Group. IUCN, Gland, Switzerland.
↑ Sivaperuman, C. (2014). Saltwater Crocodiles in Andaman and Nicobar Islands, with Special Reference to Human–Crocodile Conflict. Marine Faunal Diversity in India: Taxonomy, Ecology and Conservation, 453.
↑ Platt, S. G.; W. K. Ko; M. Kalyar Myo; L. L. Khaing; T. Rainwater (2001). "Man eating by estuarine crocodiles: the Ramree Island massacre revisited". Herpetological Bulletin. 75: 15–18.
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
