143-520: The saltwater crocodile ( Crocodylus porosus ) is a crocodilian native to saltwater habitats, brackish wetlands and freshwater rivers from India 's east coast across Southeast Asia and the Sundaic region to northern Australia and Micronesia . It has been listed as Least Concern on the IUCN Red List since 1996. It was hunted for its skin throughout its range up to the 1970s, and
286-484: A crown group (as opposed to a stem-based group ), Crocodylia is now restricted to only the last common ancestor of today's crocodilians and all of its descendants (living or extinct ). Crocodilia appears to be a Latinizing of the Greek κροκόδειλος ( crocodeilos ), which means both lizard and Nile crocodile . Crocodylia, as coined by Wermuth, in regards to the genus Crocodylus appears to be derived from
429-529: A fishing net in Papua New Guinea , in 1979. Its dried skin plus head measured 6.2 m (20 ft 4 in) in length and it was estimated to have been 6.3 m (20 ft 8 in) when accounting for shrinkage and a missing tail tip. Projected from their skull lengths, multiple specimens from Singapore were estimated to belong in life to male crocodiles measuring more than 6 m (19 ft 8 in). A large Vietnamese saltwater crocodile
572-485: 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
715-413: A "high walk" position, traveling with their legs erect rather than sprawling. Crocodilians have thick skin covered in non-overlapping scales. They have conical, peg-like teeth and a powerful bite. Like birds, crocodilians possess a four-chambered heart and lungs with unidirectional airflow. Like most other reptiles, they are ectotherms . Crocodilians are found mainly in the warmer and tropical areas of
858-563: A certain point. Saltwater crocodiles are the largest extant riparian predators in the world. However, they start life fairly small. Newly hatched saltwater crocodiles measure about 28 cm (11 in) long and weigh an average of 71 g (2.5 oz). These sizes and ages are almost identical to those at average sexual maturity in Nile crocodiles , despite the fact that average adult male saltwater crocodiles are considerably larger than average adult male Nile crocodiles. The largest skull of
1001-483: A change of strategy to concentrate on raising the saltwater crocodile, and demand for the eggs and juveniles of the New Guinea crocodile dried up. Since then, cropping of wild animals has been controlled in both Indonesia and Papua New Guinea. In the former it is limited to a belly width of 25 to 51 cm (10 to 20 in) for wet skins and in the latter to salted skins with a belly width of 18 to 51 cm (7 to 20 in). Some eggs and hatchlings are still removed from
1144-445: A crocodilian shut tight. All species have a palatal valve, a membranous flap of skin at the back of the oral cavity that protects the oesophagus and trachea when the animal is underwater. This enables them to open their mouths underwater without drowning. Crocodilians typically remain underwater for fifteen minutes or less at a time, but some can hold their breath for up to two hours under ideal conditions. The maximum diving depth
1287-399: A different way from those of other reptiles, a feature they share with some early archosaurs. One of the upper row of ankle bones, the ankle bone , moves with the tibia and fibula , while the heel bone moves with the foot and is where the ankle joint is located. The result is that the legs can be held almost vertically beneath the body when on land, and the foot swings during locomotion as
1430-629: A few became herbivores . The earliest stage of crocodilian evolution was the protosuchians in the late Triassic and early Jurassic. They were followed by the mesosuchians , which diversified widely during the Jurassic and the Tertiary. The eusuchians first appeared during the Early Cretaceous , and includes modern crocodilians. Protosuchians were small, mostly terrestrial animals with short snouts and long limbs. They had bony armor in
1573-509: A few days until the current changed direction. Sometimes, they also swam up and down river systems . Generally very lethargic , a trait that helps it survive months at a time without food, the saltwater crocodile will usually loiter in the water or bask in the sun during much of the day, preferring to hunt at night. A study of seasonal saltwater crocodile behaviour in Australia indicated that they are more active and more likely to spend time in
SECTION 10
#17327880641641716-469: A few key areas such as the Sundarbans . Off-setting this, goats , water buffalo and wild boar / pigs have been introduced to many of the areas occupied by saltwater crocodiles and returned to feral states to varying degrees, and thus can amply support large crocodiles. In Australia, the saltwater crocodile's taste for feral pigs and buffalo was a key factor in their recovery for hunting pressures over
1859-401: A higher surface-area-to-volume ratio . The kidneys and excretory system are much the same as in other reptiles, but crocodilians do not have a bladder . In fresh water, the osmolality (the concentration of solutes that contribute to a solution's osmotic pressure ) in the plasma is much higher than it is in the surrounding water. The animals are well-hydrated, and the urine in the cloaca
2002-539: A large male saltwater crocodile was shot in Adelaide River, Northern Territory . It was recorded to be 6.1 m (20 ft 0 in) long and weighed 1,097 kg (2,418 lb). A large male in the Philippines, named Lolong , was one of the largest saltwater crocodile ever caught and placed in captivity. He was 6.17 m (20 ft 3 in) long and weighed 1,075 kg (2,370 lb). Currently,
2145-454: A left and right aorta which are connected by a hole called the Foramen of Panizza . Like birds and mammals, crocodilians have separate vessels that direct blood flow to the lungs and the rest of the body respectively. They also have unique cog-teeth-like valves that, when interlocked, direct blood to the left aorta and away from the lungs, and then back around the body. This system may allow
2288-494: A length of up to 3.5 m (11 ft) for males and 2.7 m (8.9 ft) for females, and can weigh up to 200 kg (440 lb), although most specimens are smaller. In a study, two crocodiles measuring 2.91 to 3.15 m (9 ft 7 in – 10 ft 4 in) and weighing 123–186 kg (271–410 lb) had a bite force in the range of 4,782–5,938 N (1,075–1,335 lb f ). The body ranges from grey to brown in colour, with darker bandings on
2431-616: A member of the 'thoracosaurs', recovered as a sister taxon of Thoracosaurus within Gavialoidea, though it is uncertain whether 'thoracosaurs' were true gavialoids. Definitive alligatoroids first appeared during the Santonian - Campanian stages, while definitive longirostres first appeared during the Maastrichtian stage. The earliest known alligatoroids and gavialoids include highly derived forms, which indicates that
2574-417: A point where they might have become extinct. Around 1970, legislation was put in place and they received some protection. In the period 1977 to 1980, the harvest of wild skins was over 20,000 per year but in the 1980s this declined to 12,000 to 20,000. As well as this, some 2,500 to 10,000 eggs and hatchlings were collected annually to raise on ranches. However, in 1995, the largest ranch on the island initiated
2717-472: A range of vocalisations. An adult female can produce a repeated throaty "roar" when approached by another adult. The young start communicating with each other while still in the egg; this may help synchronise hatching. Newly hatched juveniles use various yelps and grunts. When startled, a warning sound emitted by one will send all the juveniles diving to the bottom of the water. Adults in the vicinity respond with growls, threats, and attacks. The distress noises of
2860-471: A revision of many reptilian and amphibian names—argued strongly for "Crocodylia". However, it was not until the advent of cladistics and phylogenetic nomenclature that a more solid justification for one spelling over the other was proposed. Prior to 1988, Crocodilia was a group that encompassed the modern-day animals, as well as their more distant relatives now in the larger groups called Crocodylomorpha and Pseudosuchia . Under its current definition as
3003-699: A role in the crushing of food. Digestion takes place more quickly at higher temperatures. When digesting a meal, CO2-rich blood towards the lungs is redirected to the stomach, supplying more acid for the oxyntic glands . Compared to crocodiles, alligators digest more carbohydrates relative to protein. Crocodilians have a very low metabolic rate and consequently, low energy requirements. They can withstand extended fasting, living on stored fat . Even recently hatched crocodiles are able to survive 58 days without food, losing 23% of their bodyweight during this time. Crocodilians are ectotherms , relying mostly on their environment to control their body temperature. The sun's heat
SECTION 20
#17327880641643146-516: A saltwater crocodile that could be scientifically verified was of a specimen in the Muséum national d'Histoire naturelle , collected in Cambodia . Its skull was 76 cm (30 in) long and 48 cm (19 in) wide near its base, with 98.3 cm (38.7 in) long mandibles; its length is not known, but based on skull-to-length ratios of large saltwater crocodiles its length was presumably in
3289-525: A single olfactory chamber and the vomeronasal organ disappears when they reach adulthood. Behavioural and olfactometer experiments indicate that crocodiles detect both air-borne and water-soluble chemicals and use their olfactory system for hunting. When above water, crocodiles enhance their ability to detect volatile odorants by gular pumping, a rhythmic movement of the floor of the pharynx . They appear to have lost their pineal organ , but still show signs of melatonin rhythms. The skin of crocodilians
3432-434: A suitable concentration of salt in body fluids. Osmoregulation is related to the quantity of salts and water exchanged with the environment. Intake of water and salts takes place across the lining of the mouth, when water is drunk, incidentally while feeding, and when present in foods. Water is lost during breathing, and both salts and water are lost in the urine and faeces, through the skin, and via salt-excreting glands on
3575-480: A variety of freshwater and saltwater fish, various amphibians , crustaceans , molluscs , such as large gastropods and cephalopods , birds, small to medium-sized mammals , and other reptiles, such as snakes and lizards . When crocodiles obtain a length of more than 1.2 m (3 ft 11 in), the significance of small invertebrate prey fades in favour of small vertebrates, including fish and smaller mammals and birds. Among crustacean prey, large mud crabs of
3718-404: A wide snout compared to most crocodiles. However, it has a longer snout than the mugger crocodile ( C. palustris ); its length is twice its width at the base. A pair of ridges runs from the eyes along the centre of the snout. The scales are oval in shape and the scutes are either small compared to other species or commonly are entirely absent. In addition, an obvious gap is also present between
3861-434: A youngster when handled at a ranching facility was observed to cause all the larger animals to become involved in frenzied activity, with some rushing towards the juvenile and others thrashing about in the water and slapping their heads down on the surface. The IUCN listed this crocodile as being " Vulnerable " in its Red List of Threatened Species in 1986 and 1988, but changed the assessment to " Least Concern " in 1996. At
4004-1373: Is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological , molecular ( DNA sequencing ), and stratigraphic ( fossil age) data, as revised by the 2021 Hekkala et al. paleogenomics study using DNA extracted from the extinct Voay . Note: Crocodylus halli is missing in this diagram, as it was declared a separate species a year after Lee & Yates published their findings. Voay † Crocodylus anthropophagus † Crocodylus thorbjarnarsoni † Crocodylus palaeindicus † Crocodylus Tirari Desert † Crocodylus johnstoni Freshwater crocodile [REDACTED] Crocodylus novaeguineae New Guinea crocodile Crocodylus mindorensis Philippine crocodile Crocodylus porosus Saltwater crocodile [REDACTED] Crocodylus siamensis Siamese crocodile [REDACTED] Crocodylus palustris Mugger crocodile [REDACTED] Crocodylus checchiai † Crocodylus falconensis † Crocodylus suchus West African crocodile Crocodylus niloticus Nile crocodile [REDACTED] Crocodylus moreletii Morelet's crocodile Crocodylus rhombifer Cuban crocodile [REDACTED] Crocodylus intermedius Orinoco crocodile Crocodylus acutus American crocodile [REDACTED] The New Guinea crocodile grows to
4147-462: 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 ( C. halli ). In the past it included the Philippine crocodile , C. n. mindorensis , as
4290-553: Is abundant and dilute, nitrogen being excreted as ammonium bicarbonate . Sodium loss is low and mainly takes place through the skin in freshwater conditions. In seawater, the opposite is true. The osmolality in the plasma is lower than the surrounding water, which is dehydrating for the animal. The cloacal urine is much more concentrated, white, and opaque, with the nitrogenous waste being mostly excreted as insoluble uric acid . New Guinea crocodile C. n. novaeguineae The New Guinea crocodile ( Crocodylus novaeguineae )
4433-417: Is clad in non-overlapping scales known as scutes which are covered with in beta-keratin . Many of the scutes are strengthened by bony plates known as osteoderms . They are most numerous on the back and neck of the animal. The belly and underside of the tail possess rows of broad, flat and square-shaped scales. In between crocodilian scales are hinge areas which consist mainly of alpha-keratin . Underneath
Saltwater crocodile - Misplaced Pages Continue
4576-456: Is diversity in snout and tooth shape, all crocodilian species have essentially the same body morphology. They have solidly built lizard-like bodies with wide, cylindrical torsos, flat heads, long snouts, short necks and tails compressed from side-to-side. Their limbs are reduced in size; the front feet have five mostly non-webbed digits, and the hind feet have four webbed digits and an extra fifth. The pelvis and ribs of crocodilians are modified;
4719-490: Is hunting) weaker members of the buffalo herd. Studies have shown that, unlike freshwater crocodiles (which can easily die from eating poisonous toads), saltwater crocodiles are partially resistant to cane toad toxins and can consume them, but in only small quantities and not enough to provide effective natural control for this virulent introduced pest. Large crocodiles, even the oldest males, do not ignore small species, especially those without developed escape abilities, when
4862-418: Is not fully understood, but it has been suggested that they may be mechanosensory organs. There are prominent paired integumentary glands in skin folds on the throat, and others in the side walls of the cloaca. Various functions for these have been suggested. They may play a part in communication, as indirect evidence suggest that they secrete pheromones used in courtship or nesting. The skin of crocodilians
5005-560: Is permanently erect and relies on cloacal muscles to protrude it out and elastic ligaments and a tendon to pull it back in. The gonads are located near the kidneys . Crocodilians range in size from the Paleosuchus and Osteolaemus species, which reach 1–1.5 m (3 ft 3 in – 4 ft 11 in), to the saltwater crocodile and Nile crocodile, which reach 6 m (20 ft) and weigh up to 1,000 kg (2,200 lb), though some prehistoric species such as
5148-689: Is the closest relative of the New Guinea Crocodile. It is also endemic to the island of New Guinea , where it inhabits the lower part of the island, located south of the New Guinea highlands . Crocodylus halli was declared a separate species in 2019, and was named after Philip M. Hall, a researcher at the University of Florida who performed the initial studies to clarify the species' distinctiveness. Both species look very much alike, however they differ both genetically and regarding
5291-416: Is the main means of warming for any crocodilian, while immersion in water may either raise its temperature via conduction , or cool the animal in hot weather. The main method for regulating its temperature is behavioural. Temperate-living alligators may start the day by basking in the sun on land, and move into the water for the afternoon, with parts of the back breaking the surface so it can still be warmed by
5434-500: 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. Crocodilia Crocodylia ( / k r ɒ k ə ˈ d ɪ l i ə / ) is an order of semiaquatic , predatory reptiles known as crocodilians . They first appeared during
5577-497: Is threatened by illegal killing and habitat loss . It is regarded as dangerous to humans. The saltwater crocodile is the largest living reptile. Males can grow up to a weight of 1,000–1,500 kg (2,200–3,300 lb) and a length of 6 m (20 ft), rarely exceeding 6.3 m (21 ft). Females are much smaller and rarely surpass 3 m (9.8 ft). It is also called the estuarine crocodile , Indo-Pacific crocodile , marine crocodile , sea crocodile , and, informally,
5720-443: Is tough and can withstand damage from conspecifics , and the immune system is effective enough to heal wounds within a few days. In the genus Crocodylus the skin contains chromatophores , allowing them to change color from dark to light and vice versa. The crocodilian has perhaps the most complex vertebrate circulatory system . It has a four-chambered heart and two ventricles , an unusual trait among extant reptiles, and both
5863-501: Is unknown, but crocodiles can dive to at least 20 m (66 ft). Vocalizing is produced by vibrating vocal folds in the larynx . The folds of the American alligator have a complex morphology consisting of epithelium , lamina propria and muscle, and according to Riede et al. (2015), "it is reasonable to expect species-specific morphologies in vocal folds/analogues as far back as basal reptiles". Crocodilian vocal folds lack
Saltwater crocodile - Misplaced Pages Continue
6006-468: Is usually maintained between 25 and 35 °C (77 and 95 °F), and mainly stays in the range 30 to 33 °C (86 to 91 °F). Both the American and Chinese alligator can be found in areas that sometimes experience periods of frost in winter. In cold weather, they remain submerged with their tails in deeper, less cold water and their nostrils just projecting through the surface. If ice forms on
6149-514: 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. The weight of a crocodile increases approximately cubically as length increases (see square–cube law ). This explains why individuals at 6 m (20 ft) weigh more than twice as much as individuals at 5 m (16 ft). In crocodiles, linear growth eventually decreases and they start getting bulkier at
6292-477: The Americas , Africa , Asia and Oceania . They usually inhabit freshwater habitats , but some can live in saltier environments and even swim out to sea. They have a largely carnivorous diet. Some species like the gharial are specialized feeders, while others like the saltwater crocodile have generalized diets. Crocodilians are generally solitary and territorial , though they sometimes hunt in groups. During
6435-608: 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
6578-551: The Indonesian provinces of South Papua . It is separated from the New Guinea crocodile by the New Guinea Highlands , a mountain range that runs along the centre of the island. DNA analysis has revealed these to be genetically distinct species, and there are some differences in their morphology and behavior. There are estimated to be between 50,000 and 100,000 New Guinea and Hall's New Guinea crocodiles in
6721-805: The Isle of Wight in the United Kingdom. It was followed by crocodilians such as the Planocraniidae , the so-called 'hoofed crocodiles', in the Palaeogene . Spanning the Cretaceous and Palaeogene periods is the genus Borealosuchus of North America, with six species, though its phylogenetic position is not settled. The three primary branches of Crocodilia had diverged by the Late Cretaceous . The possible earliest-known members of
6864-521: 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 (family Crocodylidae), the alligators and caimans (family Alligatoridae ), and the gharial and false gharial (family Gavialidae ). Although
7007-625: 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,
7150-774: The Top End resulted in a dietary switch to more terrestrial prey that allowed them to grow and recover more rapidly from population declines. Any type of livestock , such as chicken , sheep , pigs, horses and cattle , and domesticated animals/pets may be eaten if given the opportunity. As a seagoing species, the saltwater crocodile also preys on a variety of saltwater bony fish and other marine animals , including sea snakes , sea turtles , sea birds , dugongs , rays (including large sawfish ), and small sharks . Most witnessed acts of predation on marine animals have occurred in coastal waters or within sight of land, with female sea turtles and their babies caught during mating season when
7293-409: The cartilaginous processes of the ribs allow the thorax to collapse when submerging and the structure of the pelvis can accommodate large amounts of food, or more air in the lungs. Both sexes have a cloaca , a single chamber and outlet near the tail into which the intestinal , urinary and genital tracts open. It houses the penis in males and the clitoris in females. The crocodilian penis
SECTION 50
#17327880641647436-442: The eardrums are protected by flaps that can be opened or closed by muscles. Crocodilians have a wide hearing range , with sensitivity comparable to most birds and many mammals. Hearing in crocodilians does not degrade as the animal gets older as they can regrow and replace hair cells . The well-developed trigeminal nerve allows them to detect vibrations in the water (such as those made by potential prey). Crocodilians have just
7579-651: 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 3.5 to 5 m (11 ft 6 in – 16 ft 5 in) in length and weighs 200 to 1,100 kg (440 to 2,430 lb). On average, adult males range 4.0 to 4.5 m (13 ft 1 in – 14 ft 9 in) in length and weigh 408 to 770 kg (899 to 1,698 lb). However average size largely depends on
7722-529: The pancreas , spleen , small intestine , and liver also function more efficiently. When submerged, a crocodilian's heart may beat at only one or two beats a minute, with little blood flow to the muscle. When it rises and takes a breath, its heart rate almost immediately speeds up, and the muscles receive newly oxygenated blood. Unlike many marine mammals , crocodilians have little myoglobin to store oxygen in their muscles. During diving, an increasing concentration of bicarbonate ions causes haemoglobin in
7865-406: The pterygoid bones . This allowed the animal to breathe through its nostrils while its mouth was open underwater. The eusuchians continued this process with the interior nostrils now opening through an aperture in the pterygoid bones. The vertebrae of eusuchians had one convex and one concave articulating surface. The oldest known eusuchian is Hylaeochampsa vectiana from the Early Cretaceous of
8008-454: The saltie . A large and opportunistic hypercarnivorous apex predator , they ambush most of their prey and then drown or swallow it whole. They will prey on almost any animal that enters their territory, including other predators such as sharks , varieties of freshwater and saltwater fish including pelagic species, invertebrates such as crustaceans , various amphibians , other reptiles , birds , and mammals . Crocodilus porosus
8151-866: The 1930s. It occurs along the Andaman and Nicobar Islands coasts and in the Sundarbans . In Sri Lanka , it occurs foremost in western and southern parts of the country. In Myanmar, it inhabits the Ayeyarwady Delta . In southern Thailand, it was recorded in Phang Nga Province . In Singapore, it inhabits the Sungei Buloh Wetland Reserve and marshes near Kranji and Mandai. It is locally extinct in Cambodia, China, Seychelles, Thailand and Vietnam. In China, it may have once inhabited coastal areas from Fujian province in
8294-494: The 6.7–7 m (22–23 ft) range, though it could have had an exceptionally large skull or may not have the same skull-to-total-length ratios as other large saltwater crocodiles. If detached from the body, the head of a large male crocodile can weigh over 200 kg (440 lb), including the large muscles and tendons at the base of the skull that lend the crocodile its massive biting strength. The largest tooth measured 9 cm (3.5 in) in length. Other crocodilians like
8437-525: The Nile crocodile. The saltwater crocodile has the greatest size sexual dimorphism, by far, of any extant crocodilian, as males average about 4 to 5 times as massive as adult females and can sometimes measure twice her total length. The reason for the male skewered dimorphism in this species is not definitively known but might be correlated with sex-specific territoriality and the need for adult male saltwater crocodiles to monopolise large stretches of habitat. Due to
8580-512: The Philippine crocodile is, in part, paraphyletic with regard to the New Guinea crocodile, and that the latter may constitutes a population within the Philippine crocodile. Among their two samples for the New Guinea crocodile, one was part of the Philippine crocodile clade and the other was separate, estimated to have diverged 2.6–6.8 million years ago. Both samples were taken from captives (could potentially be misidentified or hybrids ) and
8723-569: The aggression, territoriality, and size of adults that make them difficult for biologists to handle without significant risk to safety, for both humans and the crocodiles themselves. The main method used for capturing adult saltwater crocodiles is a huge pole with large hooks, meant for shark capture, that restrict the crocodile's jaws, but these can cause damage to their snouts; and even this is unproven to allow successful capture for crocodiles in excess of 4 m (13 ft 1 in). While for example 20th century biological studies rigorously cataloged
SECTION 60
#17327880641648866-486: The ancient Greek κρόκη ( kroke )—meaning shingle or pebble—and δρîλος or δρεîλος ( dr(e)ilos ) for "worm". The name may refer to the animal's habit of resting on the pebbled shores of the Nile . Crocodilians, and birds, are members of the Archosaur clade. Archosaurs are distinguished from other reptiles particularly by two sets of extra openings in the skull: the antorbital fenestra located in front of
9009-443: The animal matures. The New Guinea crocodile bears a physical similarity to the nearby Philippine crocodile ( C. mindorensis ) and Siamese crocodile ( C. siamensis ). The colouring is similar to that of the freshwater crocodile ( Crocodylus johnsoni ) of northern Australia, but the snout is somewhat shorter and broader. This crocodile is to be found in the freshwater swamps, marshes and lakes of northern New Guinea, particularly in
9152-428: The animal needs to stop or steer in a different direction, the limbs are splayed out. Swimming is normally achieved with gentle sinuous movements of the tail, but they can move faster when pursuing or being pursued. Crocodilians are less well-adapted for moving on land, and are unusual among vertebrates in having two different means of terrestrial locomotion: the "high walk" and the "low walk". Their ankle joints flex in
9295-642: The animal's eye socket and the mandibular fenestra on the jaw. Archosaurs comprise two main groups: the Pseudosuchia (crocodilians and their relatives), and the Avemetatarsalia ( dinosaurs , pterosaurs , and their relatives). The split between these two is assumed to have happened close to the Permian–Triassic extinction event (informally known as the Great Dying). Crocodylomorpha ,
9438-462: The animals to remain submerged for a longer period, but this explanation has been questioned. Other possible reasons for the peculiar circulatory system include assistance with thermoregulatory needs, prevention of pulmonary oedema , or faster recovery from metabolic acidosis . Retaining carbon dioxide within the body permits an increase in the rate of gastric acid secretion and thus the efficiency of digestion, and other gastrointestinal organs such as
9581-403: The ankle rotates. The limbs move much the same as in other quadrupeds , with the left forelimb moving first, followed by the right hindlimb, then right forelimb, and finally left hindlimb, and repeat. The high walk of crocodilians, with the belly and most of the tail held off the ground and the limbs held directly under the bodies, resembles that of mammals and birds. The low walk is similar to
9724-443: The belly outward, and the diaphragmaticus pulls the liver back. When exhaling, the internal intercostal muscles push the ribs inward, while the rectus abdominis pulls the hips and liver forwards and the belly inward. Crocodilians can also use these muscles to adjust the position of their lungs, controlling their buoyancy in the water. An animal sinks when the lungs are pulled towards the tail and floats when they move back towards
9867-404: The blood from the calcium and magnesium in these dermal bones act as a buffer during prolonged submersion when increasing levels of carbon dioxide would otherwise cause acidosis . Some scutes contain a single pore known as an integumentary sense organ. Crocodiles and gharials have these on large parts of their bodies, while alligators and caimans only have them on the head. Their exact function
10010-604: The blood to release oxygen for the muscles. Crocodilians were traditionally thought to breathe like mammals, with airflow moving in and out tidally, but studies published in 2010 and 2013 conclude that crocodilians breathe more like birds , with airflow moving in a unidirectional loop within the lungs. When a crocodilian inhales, air flows through the trachea and into two primary bronchi , or airways, which split off into narrower secondary passageways. The air continues to move through these, then into even narrower tertiary airways, and then into other secondary airways which were bypassed
10153-483: The bone structure of their skulls . The genus Crocodylus likely originated in Africa and radiated outwards towards Southeast Asia and the Americas, although an Australia/Asia origin has also been considered. Phylogenetic evidence supports Crocodylus diverging from its closest recent relative, the extinct Voay of Madagascar , around 25 million years ago, near the Oligocene / Miocene boundary. Below
10296-587: The breeding season, dominant males try to monopolize available females. Females lay their eggs in holes or mounds, and similar to many birds, care for their hatched young. Some species of crocodilians (particularly the Nile crocodile ) are known to have attacked humans . Humans are the greatest threat to crocodilian populations through activities that include hunting, poaching, and habitat destruction , but farming of crocodilians has greatly reduced unlawful trading in wild skins. Artistic and literary representations of crocodilians have appeared in human cultures around
10439-647: The cervical and dorsal shields , and small, triangular scutes are present between the posterior edges of the large, transversely arranged scutes in the dorsal shield. The relative lack of scutes is considered an asset useful to distinguish saltwater crocodiles in captivity or in illicit leather trading, as well as in the few areas in the field where sub-adult or younger saltwater crocodiles may need to be distinguished from other crocodiles. It has fewer armour plates on its neck than other crocodilians. The adult saltwater crocodile's broad body contrasts with that of most other lean crocodiles, leading to early unverified assumptions
10582-559: The coast in 25 days from the North Kennedy River on the eastern coast of Far North Queensland , around Cape York Peninsula , to the west coast in the Gulf of Carpentaria . Another individual swam 411 km (255 mi) in 20 days. Without having to move around much, sometimes simply by floating, the current-riding behaviour allows for the conservation of energy. They interrupted their movements and resided in sheltered bays for
10725-567: The crocodilian family, saltwater crocodiles are not fastidious in their choice of food, and readily vary their prey selection according to availability. Nor are they voracious, as they are able to survive on relatively little food for a prolonged period. Because of their size and distribution, saltwater crocodiles hunt the broadest range of prey species of any modern crocodilian. The diet of hatchling, juvenile, and subadult saltwater crocodiles has been subject to extensively greater scientific study than that of fully-grown crocodiles, in large part due to
10868-453: The day, dispersing at night to feed. Females become sexually mature when about 1.6 to 2 metres (5 ft 3 in to 6 ft 7 in) long and males at about 2.5 metres (8 ft 2 in). Eggs are laid about 14 days after mating. In the northern population, breeding takes place during the dry season between August and October. A floating nest composed of vegetation is made in a shallow water location such as in an overgrown channel, at
11011-656: 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
11154-404: The edge of a lake, on a scroll swale or beside a stream. A clutch of between 22 and 45 eggs is laid and covered with further vegetation. In the southern population, the wet season is chosen for reproduction. The nest is sometimes built in similar locations to the northern nests, but is more often on land, and a smaller number of rather larger eggs is laid. In both populations, the mother stays near
11297-485: The elasticity of mammalian ones; but the larynx is still capable of complex motor control similar to birds and mammals and can adequately control its fundamental frequency . Crocodilian teeth can only hold onto prey, and food is swallowed unchewed. The stomach consists of a grinding gizzard and a digestive chamber. Indigestible items are regurgitated as pellets. The stomach is more acidic than that of any other vertebrate and contains ridges for gastroliths , which play
11440-1340: The extinct Voay of Madagascar , around 25 million years ago near the boundary between the Oligocene and Miocene . Below is a cladogram based on a 2018 tip dating study by Lee & Yates simultaneously using morphological , molecular ( DNA sequencing ), and stratigraphic ( fossil age) data, as revised in 2021 after a paleogenomics study using DNA extracted from the extinct Voay . Voay † Crocodylus anthropophagus † Crocodylus thorbjarnarsoni † Crocodylus palaeindicus † Crocodylus Tirari Desert † Crocodylus johnstoni Freshwater crocodile [REDACTED] Crocodylus novaeguineae New Guinea crocodile Crocodylus mindorensis Philippine crocodile Crocodylus porosus Saltwater crocodile [REDACTED] Crocodylus siamensis Siamese crocodile [REDACTED] Crocodylus palustris Mugger crocodile [REDACTED] Crocodylus checchiai † Crocodylus falconensis † Crocodylus suchus West African crocodile Crocodylus niloticus Nile crocodile [REDACTED] Crocodylus moreletii Morelet's crocodile Crocodylus rhombifer Cuban crocodile [REDACTED] Crocodylus intermedius Orinoco crocodile Crocodylus acutus American crocodile [REDACTED] The saltwater crocodile has
11583-847: The extreme sexual dimorphism of the species as contrasted with the more modest-sized dimorphism of other species, the average length of the species is only slightly more than some other extant crocodilians at 3.8–4 m (12 ft 6 in – 13 ft 1 in). The saltwater crocodile inhabits coastal brackish mangrove swamps, river deltas and freshwater rivers from India's east coast, Sri Lanka and Bangladesh to Myanmar, Malaysia, Brunei, Indonesia, Philippines , Timor Leste , Palau , Solomon Islands , Singapore , Papua New Guinea , Vanuatu and Australia's north coast. The southernmost population in India lives in Odisha's Bhitarkanika Wildlife Sanctuary ; in northern Odisha, it has not been recorded since
11726-444: The extreme size and highly aggressive nature of the species, weight in larger specimens is frequently poorly documented. A 5.1-metre (16 ft 9 in) long individual named " Sweetheart " was found to have weighed 780 kg (1,720 lb). Another large crocodile named " Gomek ", measuring 5.42 m (17 ft 9 in) in length weighed around 860 kg (1,900 lb). In 1992, a notorious man-eater , named "Bujang Senang"
11869-596: The eye clean. When a crocodilian leaves the water and dries off, this substance is visible as "tears". While eyesight is fairly good in air, it is significantly weakened underwater. Crocodilians appear to have gone through a "nocturnal bottleneck" early in their history with their eyes losing traits like sclerotic rings , an annular pad of the lens and colored cone oil droplets , giving them dichromatic vision (red-green colorblindness). Since then, some crocodilians appear to have re-evolved full colour vision . The ears are adapted for hearing both in air and underwater, and
12012-413: The first time. The air then flows back into the primary airways and is exhaled. The lungs of crocodilians are attached to the liver and the pelvis by the diaphragmaticus muscle ( analogous of the diaphragm in mammals). During inhalation, the external intercostal muscles expand the ribs, allowing the animal to take in more air, while the ischiopubis muscle causes the hips to swing downwards and push
12155-417: The food; instead, the crocodile's head is tossed to move the prey to the back of the mouth before the prey is swallowed whole. This crocodile is surprisingly agile and can lunge its body upward into the air to catch bats , flying birds, and leaping fish. It can also probe into the mud at the bottom of a river or swamp with its snout to search for crabs and mollusks. Adult and young New Guinea crocodiles have
12298-419: The form of two rows of plates extending from head to tail; this armor would still be found in later species. Their vertebrae were convex on the two main articulating surfaces, and the secondary palate was little developed as it consisted only of a maxilla . The mesosuchians saw a fusion of the palatine bones to the secondary palate and a great extension of the nasal passages behind the palatine and in front of
12441-407: The genus Scylla are frequently consumed, especially in mangrove habitats. Ground-living birds, such as the emu and different kinds of water birds , especially the magpie goose , are the most commonly preyed upon birds, due to the increased chance of encounter. Even swift-flying birds and bats may be snatched if close to the surface of water, as well as wading birds while these are patrolling
12584-486: The group may be Portugalosuchus and Zholsuchus from the Cenomanian - Turonian stages. The classification of Portugalosuchus has been disputed by some researchers who claimed that it may be outside the crown group crocodilians. The morphology-based phylogenetic analyses based on the new neuroanatomical data obtained from its skull using micro-CT scans suggested that this taxon is a crown group crocodilian and
12727-616: The group that later give rise to modern crocodilians, emerged in the Late Triassic . While the most basal crocodylomorphs were large, the ones that gave rise to crocodilians were small, slender, and leggy. This evolutionary grade, the so-called " sphenosuchians " first appeared around Carnian of the Late Triassic . They ate small, fast prey and survived into the Late Jurassic . As the Triassic ended, crocodylomorphs became
12870-409: The head. This allows them to move through the water without creating disturbances that could alert potential prey. They can also spin and twist by moving their lungs laterally. Swimming and diving crocodilians appear to rely on lung volume more for buoyancy than oxygen storage. Just before diving, the animal exhales to reduce its lung volume and reach negative buoyancy. When diving, the nostrils of
13013-488: The high walk, but without the body being raised, and is quite different from the sprawling walk of salamanders and lizards. The animal can change from one walk to the other instantaneously, but the high walk is the usual means of locomotion on land. The animal may push its body up and use this form immediately, or may take one or two strides of low walk before raising the body higher. Unlike most other land vertebrates, when crocodilians increase their pace of travel they increase
13156-459: The hind limbs launching the body forward and the fore limbs subsequently taking the weight. Next, the hind limbs swing forward as the spine flexes dorso-ventrally , and this sequence of movements is repeated. During terrestrial locomotion, a crocodilian can keep its back and tail straight, since the scales are attached to the vertebrae by muscles. Whether on land or in water, crocodilians can jump or leap by pressing their tails and hind limbs against
13299-486: The hunting crocodile submerging and quietly swimming over to the prey before pouncing upwards, striking suddenly. Unlike some other crocodilians, such as American alligators and even Nile crocodiles , they are not known to have hunted on dry land. Young saltwater crocodiles are capable of breaching their entire body into the air in a single upward motion while hunting prey that may be perched on low hanging branches. While hunting rhesus macaques , they have been seen to knock
13442-501: The interior. It has been known to enter brackish waters but is very rare in coastal areas, and never found in the presence of the competing saltwater crocodile ( C. porosus ). The animal was first described from the area of the Sepik River in the north of Papua New Guinea. The closely related Hall's New Guinea crocodile is found in the southern half of the island, with a range that extends from southeastern Papua New Guinea to
13585-554: The jaws are closed as their teeth fit into grooves along the outside lining of the upper jaw. By contrast the lower teeth of alligators and caimans normally fit into holes along the inside lining of the upper jaw. Thus they are hidden when the jaws are closed. Crocodilians are homodonts , meaning each of their teeth are all of the same type (they do not possess different tooth types, such as canines and molars) and polyphyodonts are able to replace each of their approximately 80 teeth up to 50 times in their 35- to 75-year lifespan. They are
13728-436: The jaws are larger and more powerful than the ones that open them, and a crocodilian's jaws can be held shut by a person fairly easily. Conversely, the jaws are extremely difficult to pry open. The powerful closing muscles attach at the middle of the lower jaw and the jaw hinge attaches behind the atlanto-occipital joint , giving the animal a wide gape. A folded membrane holds the tongue stationary. Crocodilians have some of
13871-795: The largest living crocodile in captivity, named " Cassius ", is kept at Marineland Crocodile Park, a zoo located at Green Island , Queensland , Australia . It measures 5.48 m (18 ft 0 in) in length and weighs approximately 1,300 kg (2,870 lb). Adult females typically measure from 2.7 to 3.1 m (8 ft 10 in to 10 ft 2 in) in total length and weigh 76 to 103 kg (168 to 227 lb). Large mature females reach 3.4 m (11 ft 2 in) and weigh up to 120 to 200 kg (260 to 440 lb). The largest female on record measured about 4.3 m (14 ft 1 in) in total length. Female are thus similar in size to other species of large crocodiles and average slightly smaller than females of some other species, like
14014-437: 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
14157-425: The late Cretaceous Deinosuchus were even larger at up to about 11 m (36 ft) and 3,450 kg (7,610 lb). They tend to be sexually dimorphic , with males much larger than females. Crocodilians are excellent swimmers. During aquatic locomotion , the muscular tail undulates from side to side to drive the animal through the water while the limbs are held close to the body to reduce drag . When
14300-533: The location, habitat, and human interactions and thus varies from one study to another. In 1993, in a study conducted (published in 1998), eleven saltwater crocodiles were found to have measured 2.1 to 5.5 m (6 ft 11 in – 18 ft 1 in) and weighed between 32 and 1,010 kg (71 and 2,227 lb). Very large, aged males can exceed 6 m (19 ft 8 in) in length and presumably weigh up to 2,000 kg (4,400 lb). The largest confirmed saltwater crocodile on record drowned in
14443-424: The long periods they spend at sea. While crocodilian brains are much smaller than those of mammals (as low as 0.05% of body weight in the saltwater crocodile), saltwater crocodiles are capable of learning difficult tasks with very little conditioning, learning to track the migratory route of their prey as the seasons change, and may possess a deeper communication ability than currently accepted. Like most species in
14586-699: The long-snouted gavialids more closely related to crocodiles than to alligators, with the new grouping of gavialids and crocodiles named Longirostres . Below is a cladogram from 2021 showing the relationships of the major extant crocodilian groups. This analysis was based off mitochondrial DNA , including that of the recently extinct Voay robustus : Caiman [REDACTED] Melanosuchus [REDACTED] Paleosuchus [REDACTED] Alligator [REDACTED] Crocodylus [REDACTED] † Voay Mecistops [REDACTED] Osteolaemus [REDACTED] Gavialis [REDACTED] Tomistoma [REDACTED] Though there
14729-471: The monkeys off a bank by knocking them with their tail, forcing the macaque into water for easy consumption. However, whether tail use in hunting is intentional or just an accidental benefit is not definitely clear. As with other crocodilians, their sharp, peg-like teeth are well-suited to seize and tightly grip prey, but not to shear flesh. Small prey are simply swallowed whole, while larger animals are dragged into deep water and drowned or crushed. Large prey
14872-462: The multiple river systems near Darwin such as the Adelaide , Mary , and Daly Rivers, along with their adjacent billabongs and estuaries . The saltwater crocodile population in Australia is estimated at 100,000 to 200,000 adults. Its range extends from Broome, Western Australia through the entire Northern Territory coast all the way south to Rockhampton, Queensland . The Alligator Rivers in
15015-459: The nest during the incubation period, which lasts about 80 days. When the eggs start to hatch, the emerging young are quite vocal, and both male and female crocodiles have been observed transporting hatching and newly hatched young to open water, carrying them delicately in their mouths. Newly hatched New Guinea crocodiles feed on aquatic insects , spiders , tadpoles , freshwater snails , frogs , fish and small mammals . As they grow, so does
15158-578: The north to the border of Vietnam. References to crocodile attacks on humans and livestock during the Han and Song dynasties indicate that until the 18th century, it may have occurred in lower Pearl River and Macau , Han River , Min River , portions of coastal Guangxi province and Hainan Island . Three historical records of saltwater crocodiles being found in Japanese coastal waters exist; an individual
15301-456: The only non-mammalian vertebrates with tooth sockets . Next to each full-grown tooth there is a small replacement tooth and an odontogenic stem cell in the dental lamina , which can be activated when required. Tooth replacement slows and eventually stops as the animal ages. The eyes, ears and nostrils of crocodilians are at the top of the head. This allows them to stalk their prey with most of their bodies underwater. When in bright light,
15444-473: The only surviving pseudosuchians. During the early Jurassic period, the dinosaurs became dominant on land, and the crocodylomorphs underwent major adaptive diversifications to fill ecological niches vacated by recently extinguished groups. Mesozoic crocodylomorphs had a much greater diversity of forms than modern crocodilians. Some became small fast-moving insectivores , others specialist fish-eaters , still others marine and terrestrial carnivores , and
15587-586: The opportunity arises. On the other hand, sub-adult saltwater crocodiles weighing only 8.7 to 15.8 kg (19 to 35 lb) (and measuring 1.36 to 1.79 m (4 ft 6 in to 5 ft 10 in)) have been recorded killing and eating goats weighing 50 to 92% of their own body mass in Orissa, India , and so are capable of attacking large prey from an early age. It was found that the diet of specimens in juvenile to subadult range, since they feed on any animals up to their own size practically no matter how small,
15730-401: The pupils of a crocodilian contract into narrow slits, whereas in darkness they become large circles. This is typical for animals that hunt at night. Crocodilians also possess a tapetum lucidum which enhances vision in low light. When the animal completely submerges, the nictitating membranes cover its eyes. In addition, glands on the nictitating membrane secrete a salty lubricant that keeps
15873-738: The region, including the Torres Strait Islands . In Papua New Guinea , it is common within the coastal reaches of every river system, such as the Fly River and in the Bismarck Archipelago . In the Philippines , it occurs in a few coastal sites like eastern Luzon , Palawan , the Liguasan Marsh , and Agusan River on Mindanao . In northern Australia, the saltwater crocodile is thriving, particularly in
16016-488: The reptile was an alligator . Young saltwater crocodiles are pale yellow in colour with black stripes and spots on their bodies and tails. This colouration lasts for several years until the crocodiles mature into adults. The colour as an adult is much darker greenish-drab, with a few lighter tan or grey areas sometimes apparent. Several colour variations are known and some adults may retain fairly pale skin, whereas others may be so dark as to appear blackish. The ventral surface
16159-590: The result should therefore be treated with caution. The genus name Crocodylus comes from the Greek kroko which means a pebble and deilos , a worm or man, referring to the knobbly appearance of the dorsal surface of the reptile. The specific epithet novaeguineae is from the Latin and means "of New Guinea". Other common names for this crocodile include New Guinea freshwater crocodile, Singapore large grain, Puk Puk, Buaya air tawar and Wahne huala. Crocodylus halli , also known as Hall's New Guinea crocodile,
16302-534: The saltwater crocodile from other crocodiles is its tendency to occupy salt water. Though other crocodiles also have salt glands that enable them to survive in saltwater, a trait that alligators do not possess, most other species do not venture out to sea except during extreme conditions. Saltwater crocodiles use ocean currents to travel long distances. In Australia, 20 crocodiles were tagged with satellite transmitters ; 8 of them ventured out into open ocean , and one of them traveled 590 km (370 mi) along
16445-660: The shore looking for food, even down to the size of a common sandpiper . Mammalian prey of juveniles and subadults are usually as large as the smaller species of ungulates , such as the greater mouse-deer ( Tragulus napu ) and hog deer ( Hyelaphus porcinus ). Prey species recorded include primate species such as crab-eating macaques , proboscis monkeys , and gibbons . It preys on agile wallabies , golden jackals , viverrids , turtles, flying foxes , hares , rodents , badgers , otters , chevrotains and pangolins . A rare incidence of an adult 2.6 m (8 ft 6 in) long saltwater crocodile preying on an Indian porcupine
16588-486: The size of their prey and their consumption of fish rises, but they still will eat anything of a worthwhile size that they can find. An adult's diet is largely fish, caught by sweeping the snout sideways and snapping at the prey, but also includes shrimps , crabs , frogs, snakes , birds and medium-sized mammals. A crocodile catches its prey by stealth with a flick of its head, impaling it with its sharp teeth and gripping and crushing it. The jaws cannot move sideways to chew
16731-424: The speed at which the lower half of each limb (rather than the whole leg) swings forward, so stride length increases while stride duration decreases. Though typically slow on land, crocodilians can produce brief bursts of speed, and some can run at 12 to 14 km/h (7.5 to 8.7 mph) for short distances. In some small species such as the freshwater crocodile , a running can progress to galloping. This involves
16874-544: The stomach contents of "sacrificed" adult Nile crocodiles in Africa , few such studies were done on behalf of saltwater crocodiles despite the plethora that were slaughtered due to the leather trade during that time period. Therefore, the diet of adults is more likely to be based on reliable eye-witness accounts. Hatchlings are restricted to feeding on smaller animals, such as small fish, frogs, insects and small aquatic invertebrates . In addition to these prey, juveniles also take
17017-868: The strongest bite forces in the animal kingdom. In a study published in 2003, an American alligator's bite force was measured at up to 2,125 lbf (9.45 kN). In a 2012 study, a saltwater crocodile's bite force was measured even higher, at 3,700 lbf (16 kN). This study also found no correlation between bite force and snout shape. Nevertheless, the gharial's extremely slender jaws are relatively weak and built more for quick jaw closure. The bite force of Deinosuchus may have measured 23,000 lbf (100 kN), even greater than that of theropod dinosaurs like Tyrannosaurus . Crocodilian teeth vary from dull and rounded to sharp and pointy. Broad-snouted species have teeth that vary in size, while those of slender-snouted species are more consistent. In general both rows of teeth are visible on crocodiles and gharials when
17160-585: The subject of debate and conflicting results. Many studies and their resulting cladograms , or "family trees" of crocodilians, have found the "short-snouted" families of Crocodylidae and Alligatoridae to be close relatives, with the long-snouted Gavialidae as a divergent branch of the tree. The resulting group of short-snouted species, named Brevirostres , was supported mainly by morphological studies which analyzed skeletal features alone. However, recent molecular studies using DNA sequencing of living crocodilians have rejected this distinct group Brevirostres, with
17303-450: The substrate and launching themselves into the air. A fast entry into water from a muddy bank can be effected by plunging to the ground, twisting the body from side to side and splaying out the limbs. The snout shape of crocodilians varies between species. Alligators and caimans generally have wider, U-shaped snouts while those of crocodiles are typically narrower and V-shaped. The gharial's are extremely elongated. The muscles that close
17446-406: The sun. At night it remains submerged, and its temperature slowly falls. The basking period is longer in winter. Tropical crocodiles bask briefly in the morning but then move into the water for rest of the day. They may also move to land at nightfall, as it is cooler. Gaping with the mouth can provide cooling by evaporation from the mouth lining. By these means, the temperature range of crocodilians
17589-463: The surface, the dermis is thick with collagen . Both the head and jaws lack actual scales and are instead covered in tight keratinised skin that is fused directly to the bones of the skull and which over time develop a pattern of cracks as the skull develops. The skin on the neck and sides is loose. The scutes contain blood vessels and may act to absorb or release heat during thermoregulation . Research also suggests that alkaline ions released into
17732-456: The tail and body which become less noticeable as the animal grows. Longitudinal ridges in front of the eyes and some granular scales on the back of the neck between four large scales are distinctive features of this species. There are some differences between the northerly and southerly populations in the morphology of the skull and the arrangement of the scales. The snout is pointed and relatively narrow during juvenile stages and becomes wider as
17875-577: The term "crocodiles" is sometimes used to refer to all of these, it is less ambiguous to use "crocodilians". Extant crocodilians have long flat heads with long snouts and tails compressed on the sides, with their eyes, ears, and nostrils at the top of the head. Alligators and caimans tend to have broader U-shaped jaws, that when closed, only show the upper teeth, while crocodiles usually have narrower V-shaped jaws with both rows of teeth visible when closed. Gharials have extremely slender and elongated jaws. All crocodilians are good swimmers and can move on land in
18018-607: The time it was stated that the animal has a large area of suitable habitat and seemed to be plentiful. Its status has not been reassessed since then. It is included in Appendix II of the Convention on International Trade in Endangered Species of Wild Fauna and Flora ( CITES ). The skin of the New Guinea crocodile is valuable and in the 1950s and 1960s the animals in the northern population were heavily hunted to
18161-678: The time of the actual divergence between the three lineages must have been a pre-Campanian event. Additionally, scientists conclude that environmental factors played a major role in the evolution of crocodilians and their ancestors, with warmer climate being associated with high evolutionary rates and large body sizes. Crocodylia is cladistically defined as the last common ancestor of Gavialis gangeticus (the gharial ), Alligator mississippiensis ( American alligator ), and Crocodylus rhombifer (the Cuban crocodile ) and all of its descendants. The phylogenetic relationships of crocodilians has been
18304-415: The tongue, though these are only present in crocodiles and gharials. The skin is a largely effective barrier to both water and ions, and gaping causes water loss by evaporation. Large animals are better able to maintain homeostasis at times of osmotic stress than smaller ones. Newly hatched crocodilians are much less tolerant of exposure to salt water than are older juveniles, presumably because they have
18447-442: The turtles are closer to shore, and bull sharks being the only largish shark with a strong propensity to patrol brackish and fresh waters. However, there is evidence that saltwater crocodiles do hunt while out in the open seas, based upon the remains of pelagic fishes that dwell only miles away from land being found in their stomachs. The hunting methods utilised by saltwater crocodiles are indistinct from any other crocodilian, with
18590-445: The very largest members of the species are likely to measure 6 to 7 m (19 ft 8 in – 23 ft 0 in) in length and weigh 900 to 1,500 kg (2,000 to 3,300 lb). Furthermore, a research paper on the morphology and physiology of crocodilians by the same organisation estimates that saltwater crocodiles reaching sizes of 7 m (23 ft 0 in) would weigh around 2,000 kg (4,400 lb). Due to
18733-607: The water during the Australian summer; conversely, they are less active and spend relatively more time basking in the sun during the winter. Saltwater crocodiles, however, are among the most active of all crocodilians, spending more time cruising and active, especially in water. They are much less terrestrial than most species of crocodiles, spending less time on land except for basking . At times, they tend to spend weeks at sea in search of land and in some cases, barnacles have been observed growing on crocodile scales, indicative of
18876-419: The water, they maintain ice-free breathing holes, and there have been occasions when their snouts have become frozen into the ice. Temperature sensing probes implanted in wild American alligators have found that their core body temperatures can descend to around 5 °C (41 °F), but as long as they remain able to breathe they show no ill effects when the weather warms up. All crocodilians need to maintain
19019-403: The wild. New Guinea crocodiles have a mostly aquatic lifestyle and are largely nocturnal. They spend much of the day underwater, often with their nostrils and eyes above the surface. Powerful side-to-side movements of their tails propel them through the water and they use both tail and legs to steer. When on land, they favour shady, dense areas of undergrowth. They tend to bask in a group during
19162-418: The world since Ancient Egypt . "Crocodilia" and "Crocodylia" have been used interchangeably for decades starting with Schmidt's redescription of the group from the formerly defunct term Loricata . Schmidt used the older term "Crocodilia", based on Owen 's original name for the group. Wermuth opted for "Crocodylia" as the proper name, basing it on the type genus Crocodylus ( Laurenti , 1768). Dundee—in
19305-724: Was found off the coast of Iwo Jima in 1744, another was found off Amami Ōshima in 1800, and finally, a third individual was caught by fishermen in Toyama Bay in 1932. All other occurrences of the species being present within Japanese territory are from World War II, and were found in areas that were formerly controlled by the Empire of Japan. In Malaysia, it was recorded in Klias, Segama and Kinabatangan Rivers in Sabah . In Sarawak , it
19448-606: Was killed in Sarawak , Malaysia . It measured 5.7 m (18 ft 8 in) in length and weighed more than 900 kg (2,000 lb). A saltwater–siamese hybrid named "Yai" ( Thai : ใหญ่ , meaning big; born 10 June 1972) at the Samutprakarn Crocodile Farm and Zoo , Thailand was claimed to be the largest crocodile ever held in captivity. It measured 6 m (19 ft 8 in) in length and weighed approximately 1,118 kg (2,465 lb). In 1962,
19591-566: Was more diverse than that of adults, which often ignored all prey below a certain size limit. Large animals taken by adult saltwater crocodiles include sambar deer , wild boar , Malayan tapirs , kangaroos , feral pigs , humans , orangutans , dingos , tigers , and large bovines, such as banteng , water buffalo , and gaur . However, larger animals are taken only sporadically because only large males typically attack very large prey, and large ungulates and other sizeable wild mammals are only sparsely distributed in this species' range, outside of
19734-476: 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 ". The New Guinea crocodile was first described by the American herpetologist Karl Patterson Schmidt in 1928 as Crocodylus novaeguineae . At one time it
19877-745: 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
20020-420: Was reliably estimated, based on its skull after its death, at 6.3 to 6.8 m (20 ft 8 in – 22 ft 4 in). However, according to evidence in the form of skulls coming from some of the largest crocodiles ever shot, the maximum possible size attained by the largest members of this species is considered to be 7 m (23 ft 0 in). A governmental study from Australia accepts that
20163-472: 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
20306-400: 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: Currently, the saltwater crocodile is considered a monotypic species . Fossil remains of a saltwater crocodile excavated in northern Queensland were dated to
20449-458: Was thought that there were two subspecies , C. n. novaeguineae , the New Guinea crocodile native to Papua New Guinea and Western New Guinea , and C. n. mindorensis , the Philippine crocodile , native to several islands including Busuanga , Luzon , Masbate , Mindoro , Negros , Samar and Mindanao . Most authorities now consider that the Philippine crocodile is an entirely separate species. DNA sequencing data reported in 2011 showed that
#163836