Page semi-protected
Crocodile
From Wikipedia, the free encyclopedia
For other uses, see Crocodile (disambiguation).
Crocodiles
Temporal range: Eocene – Holocene, 55–0 Ma
PreЄЄOSDCPTJKPgN
Nile crocodile head.jpg
Nile crocodile (Crocodylus niloticus)
Pangil Crocodile Park Davao City.jpg
Saltwater crocodile (Crocodylus porosus)
Scientific classification e
Kingdom:
Animalia
Phylum:
Chordata
Class: Reptilia
Order: Crocodilia
Family: Crocodylidae
Subfamily:
Crocodylinae
Cuvier, 1807
Type species
Crocodylus niloticus
Laurenti, 1768
Genera
Crocodylus
Osteolaemus
Mecistops (proposed)
† Voay
Crocodiles (subfamily Crocodylinae) or true crocodiles are large aquatic reptiles that live throughout
the tropics in Africa, Asia, the Americas and Australia. Crocodylinae, all of whose members are
considered true crocodiles, is classified as a biological subfamily. A broader sense of the term
crocodile, Crocodylidae that includes Tomistoma, is not used in this article. The term crocodile here
applies to only the species within the subfamily of Crocodylinae. The term is sometimes used even
more loosely to include all extant members of the order Crocodilia, which includes the alligators and
caimans (family Alligatoridae), the gharial and false gharial (family Gavialidae), and all other living
and fossil Crocodylomorpha.
Although they appear similar, crocodiles, alligators and the gharial belong to separate biological
families. The gharial, with its narrow snout, is easier to distinguish, while morphological differences
are more difficult to spot in crocodiles and alligators. The most obvious external differences are
visible in the head, with crocodiles having narrower and longer heads, with a more V-shaped than a
U-shaped snout compared to alligators and caimans. Another obvious trait is that the upper and
lower jaws of the crocodiles are the same width, and the teeth in the lower jaw fall along the edge
or outside the upper jaw when the mouth is closed; therefore, all teeth are visible, unlike an
alligator, which possesses in the upper jaw small depressions into which the lower teeth fit. Also,
when the crocodile's mouth is closed, the large fourth tooth in the lower jaw fits into a constriction
in the upper jaw. For hard-to-distinguish specimens, the protruding tooth is the most reliable feature
to define the species' family.[1] Crocodiles have more webbing on the toes of the hind feet and can
better tolerate saltwater due to specialized salt glands for filtering out salt, which are present, but
non-functioning, in alligators. Another trait that separates crocodiles from other crocodilians is their
much higher levels of aggression.[2]
Crocodile size, morphology, behaviour and ecology differ somewhat among species. However, they
have many similarities in these areas as well. All crocodiles are semiaquatic and tend to congregate
in freshwater habitats such as rivers, lakes, wetlands and sometimes in brackish water and saltwater.
They are carnivorous animals, feeding mostly on vertebrates such as fish, reptiles, birds and
mammals, and sometimes on invertebrates such as molluscs and crustaceans, depending on species
and age. All crocodiles are tropical species that, unlike alligators, are very sensitive to cold. They
separated from other crocodilians during the Eocene epoch, about 55 million years ago.[3] Many
species are at the risk of extinction, some being classified as critically endangered.
Contents
1
Etymology
2
Species
3
Characteristics
3.1
Size
3.2
Teeth
4
Biology and behaviour
4.1
Senses
4.1.1
Vision
4.1.2
Olfaction
4.1.3
Hearing
4.1.4
Touch
4.2
Hunting and diet
4.2.1
Bite
4.3
Locomotion
4.4
Longevity
4.5
Social behaviour and vocalization
4.6
Reproduction
4.7
Cognition
5
Taxonomy and phylogeny
5.1
Phylogeny
6
Relationship with humans
6.1
Danger to humans
6.2
Crocodile products
6.3
In religion
6.4
Crocodile tears
6.5
The Surabaya Shark and Crocodile
6.6
Crocodile (walking)
7
See also
8
References
9
Further reading
10
External links
Etymology
The word "crocodile" comes from the Ancient Greek κροκόδιλος (crocodilos), "lizard", used in the
phrase ho krokódilos tou potamoú, "the lizard of the (Nile) river". There are several variant Greek
forms of the word attested, including the later form κροκόδειλος (crocodeilos)[4] found cited in
many English reference works.[5] In the Koine Greek of Roman times, crocodilos and crocodeilos
would have been pronounced identically, and either or both may be the source of the Latinized form
crocodīlus used by the ancient Romans. Crocodilos or crocodeilos is a compound of krokè
("pebbles"), and drilos/dreilos ("worm"), although drilos is only attested as a colloquial term for
"penis".[5] It is ascribed to Herodotus, and supposedly describes the basking habits of the Egyptian
crocodile.[6]
The form crocodrillus is attested in Medieval Latin.[5] It is not clear whether this is a medieval
corruption or derives from alternative Greco-Latin forms (late Greek corcodrillos and corcodrillion
are attested). A (further) corrupted form cocodrille is found in Old French and was borrowed into
Middle English as cocodril(le). The Modern English form crocodile was adapted directly from the
Classical Latin crocodīlus in the 16th century, replacing the earlier form. The use of -y- in the
scientific name Crocodylus (and forms derived from it) is a corruption introduced by Laurenti (1768).
Species
Distribution of crocodiles
A total of 14 extant species have been recognized. Further genetic study is needed for the
confirmation of proposed species under the genus Osteolaemus, which is currently monotypic.
Species name Image Distribution
Description/Comments
American crocodile (Crocodylus acutus) Crocodylus acutus mexico 02-edit1.jpg Throughout the
Caribbean Basin, including many of the Caribbean islands and South Florida.
A larger sized
species, with a greyish colour and a prominent V-shaped snout. Prefers brackish water, but also
inhabits lower stretches of rivers and true marine environments. This is one of the rare species that
exhibits regular sea-going behaviour, which explains the great distribution throughout the
Caribbean. It is also found in hypersaline lakes such as Lago Enriquillo, in the Dominican Republic,
which has one of the largest populations of this species.[7] Diet consists mostly of aquatic and
terrestrial vertebrates. Classified as Vulnerable, but certain local populations under greater threat.
Slender-snouted crocodile (Crocodylus cataphractus) Crocodylus cataphractus.jpg
Central and
Western Africa A medium sized species with a narrow and elongated snout. Lives in freshwater
habitats within tropical forests of the continent. Feeds mostly on fish but also other small to medium
sized vertebrates. Possibly belongs to its own monotypic genus, Mecistops.[8] Insufficient data on
conservation.
Orinoco crocodile (Crocodylus intermedius)
Croc inter.jpg Colombia and Venezuela
This
is a large species with a relatively elongated snout and a pale tan coloration with scattered dark
brown markings. Lives primarily in the Orinoco Basin. Despite having a rather narrow snout, preys on
a wide variety of vertebrates, including large mammals. It is a Critically Endangered species.
Freshwater crocodile (Crocodylus johnsoni)
Australia Cairns 18.jpg Northern Australia
A
smaller species with a narrow and elongated snout. It has light brown coloration with darker bands
on body and tail. Lives in rivers with considerable distance from the sea, to avoid confrontations with
saltwater crocodiles. Feeds mostly on fish and other small vertebrates.
Philippine crocodile (Crocodylus mindorensis) Crocodylus mindorensis basking on a rock in the
Disulap River, Barangay Disulap - ZooKeys-266-001-g102.jpg
Endemic to the Philippines
This
is a relatively small species with a rather broader snout. It has heavy dorsal armour and a goldenbrown colour that darkens as the animal matures. Prefers freshwater habitats and feeds on a variety
of small to medium sized vertebrates. This species is Critically Endangered and the most severely
threatened species of crocodile.[9]
Morelet's crocodile (Crocodylus moreletii)
Morelets.crocodile.arp.jpg
Atlantic regions of
Mexico, Belize and Guatemala A small to medium sized crocodile with a rather broad snout. It has a
dark greyish-brown colour and is found in mostly various freshwater habitats. Feeds on mammals,
birds and reptiles. It is listed as Least Concern.
Nile crocodile (Crocodylus niloticus)
Nile croc couple 690V1510 - Flickr - Lip Kee.jpg Subsaharan Africa A large and aggressive species with a broad snout, especially in older animals. It has
a dark bronze coloration and darkens as the animal matures. Lives in a variety of freshwater habitats
but is also found in brackish water. It is an apex predator that is capable of taking a wide array of
African vertebrates, including large ungulates and other predators.[10] This species is listed as Least
Concern.
New Guinea crocodile (Crocodylus novaeguineae)
Neuguinea-krokodil-0272.jpg The island
of New Guinea A smaller species of crocodile with a grey-brown colour and dark brown to black
markings on the tail. The young have a narrower V-shaped snout that becomes wider as the animal
matures. Prefers freshwater habitats, even though is tolerant to salt water, in order to avoid
competition and predation by the saltwater crocodile. This species feeds on small to mid-sized
vertebrates.
Mugger crocodile (Crocodylus palustris) Mugger crocodile Crocodylus palustris (2155269175).jpgThe
Indian subcontinent and surrounding countries This is a modest sized crocodile with a very broad
snout and an alligator-like appearance. It has dark-grey to brown coloration with enlarged scutes
around the neck, making it a considerably heavy armoured species. Prefers slow moving rivers,
swamps and lakes. It can also be found in coastal swamps but avoids areas populated by saltwater
crocodiles.[11] Feeds on a wide array of vertebrates.
Saltwater crocodile (Crocodylus porosus)
Crocodylus porosus 4.jpg
Throughout
Southeast Asia, Northern Australia and surrounding waters
The largest living reptile and most
aggressive of all crocodiles. It is a big-headed species and has a relatively broad snout, especially
when older. The coloration is pale yellow with black stripes when young but dark greenish-drab
coloured as adults. Lives in brackish and marine environments as well as lower stretches of rivers.
This species has the greatest distribution of all crocodiles. Tagged specimens showed long-distance
marine travelling behaviour. It is the apex predator throughout its range and preys on virtually any
animal within its reach. It is classified as Least Concern with several populations under greater
risk.[12]
Cuban crocodile (Crocodylus rhombifer) Cuban Crocodile.JPG Found only in the Zapata Swamp
and Isle of Youth of Cuba
It is a small but extremely aggressive species of crocodile that
prefers freshwater swamps.[13] The coloration is vibrant even as adults and the scales have a
"pebbled" appearance. It is a relatively terrestrial species with agile locomotion on land, sometimes
displays terrestrial hunting. The snout is broad with a thick upper-jaw and large teeth. The unique
characteristics and fossil record indicates a rather specialized diet in the past, preying on megafauna
such as the giant sloth. This species sometimes displays pack-hunting behaviour, which might have
been the key to hunting large species in the past, despite its small size.[14] Today most prey are
small to medium sized vertebrates. It is Critically Endangered, and the remaining wild population is
under threat of hybridization.[15]
Siamese crocodile (Crocodylus siamensis)
3.06b.jpg
Indonesia, Brunei, East Malaysia and
southern Indochina
A fairly small crocodile that prefers freshwater habitats. It has a relatively
broad snout and olive-green to dark green coloration. It feeds on a variety of small to mid-sized
vertebrates. Listed as Critically Endangered, but might be already extinct in the wild; status is
unknown.[16]
West African crocodile (Crocodylus suchus)
Crocodile - Copenhagen Zoo.jpg Western and
Central Africa Recent studies revealed that this is distinct species from the larger Nile
crocodile.[17][18] It has a slightly narrower snout and is much smaller compared to its larger cousin.
Dwarf crocodile (Osteolaemus tetraspis)Dwarf crocodile 01.JPG Western Africa It is the smallest of
all living crocodiles. It belongs to its own monotypic genus; however, new studies indicate there
might be two or even three distinct species.[19] It is a heavily armoured species with uniform black
coloration in adults, while juveniles have a lighter brown banding. Lives in the tropical forests of
Western Africa. Feeds on small vertebrates and large aquatic invertebrates. It is a fairly terrestrial
species and exhibits terrestrial hunting, especially at night. This species is classified as Vulnerable.
For information on Tomistoma or false gharial, that is recently not considered as a true crocodile,
see False gharial.
Characteristics
Crocodiles are similar to alligators and caimans; for their common characteristics and differences
among them, see Crocodilia.
Crocodiles, like dinosaurs, have the abdominal ribs modified into gastralia.
A crocodile’s physical traits allow it to be a successful predator. Its external morphology is a sign of
its aquatic and predatory lifestyle. Its streamlined body enables it to swim swiftly; it also tucks its
feet to the side while swimming, making it faster by decreasing water resistance. Crocodiles have
webbed feet which, though not used to propel them through the water, allow them to make fast
turns and sudden moves in the water or initiate swimming. Webbed feet are an advantage in
shallower water where the animals sometimes move around by walking. Crocodiles have a palatal
flap, a rigid tissue at the back of the mouth that blocks the entry of water. The palate has a special
path from the nostril to the glottis that bypasses the mouth. The nostrils are closed during
submergence.
Like other archosaurs, crocodilians are diapsid, although their post-temporal fenestrae are reduced.
The walls of the braincase are bony but lack supratemporal and postfrontal bones.[20] Their tongues
are not free, but held in place by a membrane that limits movement; as a result, crocodiles are
unable to stick out their tongues.[21] Crocodiles have smooth skin on their bellies and sides, while
their dorsal surfaces are armoured with large osteoderms. The armoured skin has scales and is thick
and rugged, providing some protection. They are still able to absorb heat through this armour, as a
network of small capillaries allows blood through the scales to absorb heat. Crocodilian scales have
pores believed to be sensory in function, analogous to the lateral line in fishes. They are particularly
seen on their upper and lower jaws. Another possibility is that they are secretory, as they produce
an oily substance which appears to flush mud off.[20]
Size
A saltwater crocodile in captivity
Size greatly varies among species, from the dwarf crocodile to the saltwater crocodile. Species of
Osteolaemus grow to an adult size of just 1.5 to 1.9 m (4.9 to 6.2 ft),[22] whereas the saltwater
crocodile can grow to sizes over 7 m (23 ft) and weigh 1,000 kg (2,200 lb).[23] Several other large
species can reach over 5.2 m (17 ft) long and weigh over 900 kg (2,000 lb). Crocodilians show
pronounced sexual dimorphism, with males growing much larger and more rapidly than females.[20]
Despite their large adult sizes, crocodiles start their lives at around 20 cm (7.9 in) long. The largest
species of crocodile is the saltwater crocodile, found in eastern India, northern Australia, throughout
South-east Asia, and in the surrounding waters.
The largest crocodile ever held in captivity is an estuarine–Siamese hybrid named Yai (Thai: ใหญ่,
meaning big) (born 10 June 1972) at the Samutprakarn Crocodile Farm and Zoo, Thailand. This
animal measures 6 m (20 ft) in length and weighs 1,114 kg (2,456 lb).[24]
The longest crocodile captured alive is Lolong, which was measured at 6.17 m (20.2 ft) and weighed
at 1,075 kg (2,370 lb) by a National Geographic team in Agusan del Sur Province,
Philippines.[25][26][27]
Teeth
Crocodiles are polyphyodonts; they are able to replace each of their 80 teeth up to 50 times in their
35- to 75-year lifespan.[28][29] Next to each full-grown tooth, there is a small replacement tooth
and an odontogenic stem cell in the dental lamina in standby that can be activated if required.[30]
Biology and behaviour
Crocodiles are similar to alligators and caimans; for their common biology and differences between
them, see Crocodilia.
Crocodilians are more closely related to birds and dinosaurs than to most animals classified as
reptiles, the three families being included in the group Archosauria ('ruling reptiles'). Despite their
prehistoric look, crocodiles are among the more biologically complex reptiles. Unlike other reptiles, a
crocodile has a cerebral cortex and a four-chambered heart. Crocodilians also have the functional
equivalent of a diaphragm by incorporating muscles used for aquatic locomotion into
respiration.[31] Salt glands are present in the tongues of crocodiles and they have a pore opening on
the surface of the tongue, a trait that separates them from alligators. Salt glands are dysfunctional in
Alligatoridae.[20] Their function appears to be similar to that of salt glands in marine turtles.
Crocodiles do not have sweat glands and release heat through their mouths. They often sleep with
their mouths open and may pant like a dog.[32] Four species of freshwater crocodile climb trees to
bask in areas lacking a shoreline.[33]
Senses
Crocodile eye
Crocodiles have acute senses, an evolutionary advantage that makes them successful predators. The
eyes, ears and nostrils are located on top of the head, allowing the crocodile to lie low in the water,
almost totally submerged and hidden from prey.
Vision
Crocodiles have very good night vision, and are mostly nocturnal hunters. They use the disadvantage
of most prey animals' poor nocturnal vision to their advantage. The light receptors in crocodilians’
eyes include cones and numerous rods, so it is assumed all crocodilians can see colours.[34]
Crocodiles have vertical-slit shaped pupils, similar to those of domestic cats. One explanation for the
evolution of slit pupils is that they exclude light more effectively than a circular pupil, helping to
protect the eyes during daylight.[35] On the rear wall of the eye is a tapetum lucidum, which reflects
incoming light back onto the retina, thus utilizing the small amount of light available at night to best
advantage. In addition to the protection of the upper and lower eyelids, crocodiles have a nictitating
membrane (sometimes called a "third eye-lid") that can be drawn over the eye from the inner corner
while the lids are open. The eyeball surface is thus protected under the water while a certain degree
of vision is still possible.[36]
Olfaction
Crocodilian sense of smell is also very well developed, aiding them to detect prey or animal carcasses
that are either on land or in water, from far away. It is possible that crocodiles use olfaction in the
egg prior to hatching.[36]
Chemoreception in crocodiles is especially interesting because they hunt in both terrestrial and
aquatic surroundings. Crocodiles have only one olfactory chamber and the vomeronasal organ is
absent in the adults[37] indicating all olfactory perception is limited to the olfactory system.
Behavioural and olfactometer experiments indicate that crocodiles detect both air-borne and watersoluble 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.[38][39] Crocodiles close their nostrils when submerged, so olfaction underwater is unlikely.
Underwater food detection is presumably gustatory and tactile.[40]
Hearing
Crocodiles can hear well; their tympanic membranes are concealed by flat flaps that may be raised
or lowered by muscles.[20]
Touch
Caudal: The upper and lower jaws are covered with sensory pits, visible as small, black speckles on
the skin, the crocodilian version of the lateral line organs seen in fish and many amphibians, though
arising from a completely different origin. These pigmented nodules encase bundles of nerve fibers
innervated beneath by branches of the trigeminal nerve. They respond to the slightest disturbance
in surface water, detecting vibrations and small pressure changes as small as a single drop.[41] This
makes it possible for crocodiles to detect prey, danger and intruders, even in total darkness. These
sense organs are known as domed pressure receptors (DPRs).[42]
Post-Caudal: While alligators and caimans have DPRs only on their jaws, crocodiles have similar
organs on almost every scale on their bodies. The function of the DPRs on the jaws is clear; to catch
prey, but it is still not clear what the function is of the organs on the rest of the body. The receptors
flatten when exposed to increased osmotic pressure, such as that experienced when swimming in
sea water hyperosmotic to the body fluids. When contact between the integument and the
surrounding sea water solution is blocked, crocodiles are found to lose their ability to discriminate
salinities. It has been proposed that the flattening of the sensory organ in hyperosmotic sea water is
sensed by the animal as “touch”, but interpreted as chemical information about its
surroundings.[42] This might be why in alligators they are absent on the rest of the body.[43]
Hunting and diet
Nile crocodile attacking wildebeest
Even a cruising crocodile is difficult to locate
Crocodiles are ambush predators, waiting for fish or land animals to come close, then rushing out to
attack. Crocodiles mostly eat fish, amphibians, crustaceans, molluscs, birds, reptiles, and mammals,
and they occasionally cannibalize smaller crocodiles. What a crocodile eats varies greatly with
species, size and age. From the mostly fish-eating species, like the slender-snouted and freshwater
crocodiles, to the larger species like the Nile crocodile and the saltwater crocodile that prey on large
mammals, such as buffalo, deer and wild boar, diet shows great diversity. Diet is also greatly affected
by the size and age of the individual within the same species. All young crocodiles hunt mostly
invertebrates and small fish, gradually moving on to larger prey. Being ectothermic (cold-blooded)
predators, they have a very slow metabolism, so they can survive long periods without food. Despite
their appearance of being slow, crocodiles have a very fast strike and are top predators in their
environment, and various species have been observed attacking and killing other predators such as
sharks and big cats.[44][45] As opportunistic predators, crocodiles would also prey upon young and
dying elephants and hippos when given the chance.[46][47][48] Crocodiles are also known to be
aggressive scavengers who feed upon carrion and steal from other predators.[49] Evidence suggests
that crocodiles also feed upon fruits, based on the discovery of seeds in stools and stomachs from
many subjects as well as accounts of them feeding.[50][51]
Crocodiles have the most acidic stomach of any vertebrate. They can easily digest bones, hooves and
horns. The BBC TV[52] reported that a Nile crocodile that has lurked a long time underwater to catch
prey builds up a large oxygen debt. When it has caught and eaten that prey, it closes its right aortic
arch and uses its left aortic arch to flush blood loaded with carbon dioxide from its muscles directly
to its stomach; the resulting excess acidity in its blood supply makes it much easier for the stomach
lining to secrete more stomach acid to quickly dissolve bulks of swallowed prey flesh and bone.
Many large crocodilians swallow stones (called gastroliths or stomach stones), which may act as
ballast to balance their bodies or assist in crushing food,[20] similar to grit ingested by birds.
Herodotus claimed that Nile crocodiles had a symbiotic relationship with certain birds, such as the
Egyptian plover, which enter the crocodile's mouth and pick leeches feeding on the crocodile's
blood; with no evidence of this interaction actually occurring in any crocodile species, it is most likely
mythical or allegorical fiction.[53]
Bite
Specimen of skull (upper view) prepared by the bone maceration technique.
Since they feed by grabbing and holding onto their prey, they have evolved sharp teeth for piercing
and holding onto flesh, and powerful muscles to close the jaws and hold them shut. The teeth are
not well-suited to tearing flesh off of large prey items as are the dentition and claws of many
mammalian carnivores, the hooked bills and talons of raptorial birds, or the serrated teeth of sharks.
However, this is an advantage rather than a disadvantage to the crocodile since the properties of the
teeth allow it to hold onto prey with the least possibility of the prey animal to escape. Otherwise
combined with the exceptionally high bite force, the flesh would easily cut through; thus creating an
escape opportunity for the prey item. The jaws can bite down with immense force, by far the
strongest bite of any animal. The force of a large crocodile's bite is more than 5,000 lbf (22,000 N),
which was measured in a 5.5 m (18 ft) Nile crocodile, on the field,[54] compared to just 335 lbf
(1,490 N) for a Rottweiler, 670 lbf (3,000 N) for a great white shark, 800 lbf (3,600 N) for a hyena, or
2,200 lbf (9,800 N) for an American alligator.[55][not in citation given] A 5.2 m (17 ft) long saltwater
crocodile has been confirmed as having the strongest bite force ever recorded for an animal in a
laboratory setting. It was able to apply a bite force value of 3,700 lbf (16,000 N), and thus surpassed
the previous record of 2,125 lbf (9,450 N) made by a 3.9 m (13 ft) long American alligator.[56][57]
Taking the measurements of several 5.2 m (17 ft) crocodiles as reference, the bite forces of 6-m
individuals were estimated at 7,700 lbf (34,000 N).[58] The study, led by Dr. Gregory M. Erickson,
also shed light to the larger, extinct species of crocodilians. Since crocodile anatomy has changed
only slightly for the last 80 million years, current data on modern crocodilians can be used to
estimate the bite force of extinct species. An 11 to 12 metres (36–39 ft) long Deinosuchus would
apply a force of 23,100 lbf (103,000 N), twice that of the latest, higher bite force estimations of
Tyrannosaurus.[7] 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 so stiff, it is almost as hard as bone to touch, as if it were the
continuum of the skull. Another trait is that most of the muscle in a crocodile's jaw is arranged for
clamping down. Despite the strong muscles to close the jaw, crocodiles have extremely small and
weak muscles to open the jaw. Crocodiles can thus be subdued for study or transport by taping their
jaws or holding their jaws shut with large rubber bands cut from automobile inner tubes.
Locomotion
A crocodile, in a farm, gaping to thermoregulate
Crocodiles can move quickly over short distances, even out of water. The land speed record for a
crocodile is 17 km/h (11 mph) measured in a galloping Australian freshwater crocodile.[59]
Maximum speed varies between species. Some species can gallop, including Cuban crocodiles,
Johnston's crocodiles, New Guinea crocodiles, African dwarf crocodiles, and even small Nile
crocodiles. The fastest means by which most species can move is a "belly run", in which the body
moves in a snake-like (sinusoidal) fashion, limbs splayed out to either side paddling away frantically
while the tail whips to and fro. Crocodiles can reach speeds of 10–11 km/h (6–7 mph) when they
"belly run", and often faster if slipping down muddy riverbanks. When a crocodile walks quickly, it
holds its legs in a straighter and more upright position under its body, which is called the "high
walk". This walk allows a speed of up to 5 km/h.[60]
Crocodiles may possess a homing instinct. In northern Australia, three rogue saltwater crocodiles
were relocated 400 km (249 mi) by helicopter, but returned to their original locations within three
weeks, based on data obtained from tracking devices attached to them.[61]
Longevity
Measuring crocodile age is unreliable, although several techniques are used to derive a reasonable
guess. The most common method is to measure lamellar growth rings in bones and teeth—each ring
corresponds to a change in growth rate which typically occurs once a year between dry and wet
seasons.[62] Bearing these inaccuracies in mind, it can be safely said that all crocodile species have
an average lifespan of at least 30–40 years, and in the case of larger species an average of 60–70
years. The oldest crocodiles appear to be the largest species. C. porosus is estimated to live around
70 years on average, with limited evidence of some individuals exceeding 100 years.[63]
In captivity, some individuals are claimed to have lived for over a century. A male crocodile lived to
an estimated age of 110–115 years in a Russian zoo in Yekaterinburg.[64] Named Kolya, he joined
the zoo around 1913 to 1915, fully grown, after touring in an animal show, and lived until 1995.[64]
A male freshwater crocodile lived to an estimated age of 120–140 years at the Australia Zoo.[65]
Known affectionately as “Mr. Freshie”, he was rescued around 1970 by Bob Irwin and Steve Irwin,
after being shot twice by hunters and losing an eye as a result, and lived until 2010.[65] Crocworld
Conservation Centre, in Scottburgh, South Africa, claims to have a male Nile crocodile that was born
in 1900. Named Henry, the crocodile is said to have lived in Botswana along the Okavango River,
according to centre director Martin Rodrigues.[66][67]
Social behaviour and vocalization
Captive crocodiles resting together with open jaws.
Crocodiles are the most social of reptiles. Even though they do not form social groups, many species
congregate in certain sections of rivers, tolerating each other at times of feeding and basking. Most
species are not highly territorial, with the exception of the saltwater crocodile, which is a highly
territorial and aggressive species. A mature male will not tolerate any other males at any time of the
year. Most other species are more flexible. There is a certain form of hierarchy in crocodiles: the
largest and heaviest males are at the top, having access to the best basking site, while females are
priority during a group feeding of a big kill or carcass. A good example of the hierarchy in crocodiles
would be the case of the Nile crocodile. This species clearly displays all of these behaviours. Studies
in this area are not thorough, however, and many species are yet to be studied in greater detail.[68]
Mugger crocodiles are also known to show toleration in group feedings and tend to congregate in
certain areas. However, males of all species are aggressive towards each other during mating season,
to gain access to females.
Crocodiles are also the most vocal of all reptiles, producing a wide variety of sounds during various
situations and conditions, depending on species, age, size and sex. Depending on the context, some
species can communicate over 20 different messages through vocalizations alone.[69] Some of these
vocalizations are made during social communication, especially during territorial displays towards
the same sex and courtship with the opposite sex; the common concern being reproduction.
Therefore most conspecific vocalization is made during the breeding season, with the exception
being year-round territorial behaviour in some species and quarrels during feeding. Crocodiles also
produce different distress calls and in aggressive displays to their own kind and other animals;
notably other predators during interspecific predatory confrontations over carcasses and terrestrial
kills.
Specific vocalisations include —
Chirp: When about to hatch, the young make a “peeping” noise, which encourages the female to
excavate the nest. The female then gathers the hatchlings in her mouth and transports them to the
water, where they remain in a group for several months, protected by the female[70]
Distress call: A high-pitched call used mostly by younger animals to alert other crocodiles to
imminent danger or an animal being attacked.
Threat call: A hissing sound that has also been described as a coughing noise.
Hatching call: Emitted by a female when breeding to alert other crocodiles that she has laid eggs in
her nest.
Bellowing: Male crocodiles are especially vociferous. Bellowing choruses occur most often in the
spring when breeding groups congregate, but can occur at any time of year. To bellow, males
noticeably inflate as they raise the tail and head out of water, slowly waving the tail back and forth.
They then puff out the throat and with a closed mouth, begin to vibrate air. Just before bellowing,
males project an infrasonic signal at about 10 Hz through the water, which vibrates the ground and
nearby objects. These low-frequency vibrations travel great distances through both air and water to
advertise the male's presence and are so powerful they result in the water's appearing to
"dance".[71]
Reproduction
Crocodile eggs
Crocodiles lay eggs, which are laid in either holes or mound nests, depending on species. A hole nest
is usually excavated in sand and a mound nest is usually constructed out of vegetation. Nesting
periods range from a few weeks up to six months. Courtship takes place in a series of behavioural
interactions that include a variety of snout rubbing and submissive display that can take a long time.
Mating always takes place in water, where the pair can be observed mating several times. Females
can build or dig several trial nests which appear incomplete and abandoned later. Egg-laying usually
takes place at night and about 30–40 minutes.[72] Females are highly protective of their nests and
young. The egg are hard shelled, but translucent at the time of egg-laying. Depending on the species
of crocodile, 7 to 95 eggs are laid. Crocodile embryos do not have sex chromosomes, and unlike
humans, sex is not determined genetically. Sex is determined by temperature, where at 30 °C (86 °F)
or less most hatchlings are females and at 31 °C (88 °F), offspring are of both sexes. A temperature
of 32 to 33 °C (90 to 91 °F) gives mostly males whereas above 33 °C (91 °F) in some species continues
to give males, but in other species resulting in females, which are sometimes called hightemperature females.[73] Temperature also affects growth and survival rate of the young, which
may explain the sexual dimorphism in crocodiles. The average incubation period is around 80 days,
and also is dependent on temperature and species that usually ranges from 65 to 95 days.[74] The
eggshell structure is very conservative through evolution but there are enough changes to tell
different species apart by their eggshell microstructure.[75]
At the time of hatching, the young start calling within the eggs. They have an egg-tooth at the tip of
their snouts, which is developed from the skin, and that helps them pierce out of the shell. Hearing
the calls, the female usually excavates the nest and sometimes takes the unhatched eggs in her
mouth, slowly rolling the eggs to help the process. The young is usually carried to the water in the
mouth. She would then introduce her hatchlings to the water and even feed them.[76] The mother
would then take care of her young for over a year before the next mating season. In the absence of
the mother crocodile, the father would act in her place to take care of the young.[77] However, even
with a sophisticated parental nurturing, young crocodiles have a very high mortality rate due to their
vulnerability to predation.[78] A group of hatchlings is called a pod or crèche and may be protected
for months.[72]
Cognition
Crocodiles possess some advanced cognitive abilities.[79][80][81] They can observe and use patterns
of prey behaviour, such as when prey come to the river to drink at the same time each day. Vladimir
Dinets of the University of Tennessee, observed that crocodiles use twigs as bait for birds looking for
nesting material.[82] They place sticks on their snouts and partly submerge themselves. When the
birds swooped in to get the sticks, the crocodiles then catch the birds. Crocodiles only do this in
spring nesting seasons of the birds, when there is high demand for sticks to be used for building
nests. Vladimir also discovered other similar observations from various scientists, some dating back
to the 19th century.[79][81] Aside from using sticks, crocodiles are also capable of cooperative
hunting.[81][83] Large numbers of crocodiles swim in circles to trap fish and take turns snatching
them. In hunting larger prey, crocodiles swarm in, with one holding the prey down as the others rip
it apart.
Taxonomy and phylogeny
Most species are grouped into the genus Crocodylus. The other extant genus, Osteolaemus, is
monotypic (as is Mecistops, if recognized).
Crocodile farming in Australia
Crocodiles in Costa Rica
American crocodile at La Manzanilla, Jalisco, Mexico
A skull of the extinct Voay robustus
Subfamily Crocodylinae
Genus Crocodylus
Crocodylus acutus, American crocodile
Crocodylus cataphractus, slender-snouted crocodile (studies in DNA and morphology suggest this
species may be more basal than Crocodylus, so belongs in its own genus, Mecistops).[84]
Crocodylus intermedius, Orinoco crocodile
Crocodylus johnsoni, freshwater crocodile, or Johnstone's crocodile
Crocodylus mindorensis, Philippine crocodile
Crocodylus moreletii, Morelet's crocodile or Mexican crocodile
Crocodylus niloticus, Nile crocodile or African crocodile (the subspecies found in Madagascar is
sometimes called the black crocodile)
Crocodylus novaeguineae, New Guinea crocodile
Crocodylus palustris, mugger, marsh or Indian crocodile
Crocodylus porosus, saltwater crocodile or estuarine crocodile
Crocodylus rhombifer, Cuban crocodile
Crocodylus siamensis, Siamese crocodile (may be extinct in the wild)
Crocodylus suchus, West African crocodile, desert or sacred crocodile
Genus Osteolaemus
Osteolaemus tetraspis, dwarf crocodile (There has been controversy as to whether or not this is
actually two species; recent (2010) DNA analysis indicate three distinct species: O. tetraspis, O.
osborni and a third, currently unnamed.)
Genus †Euthecodon
Genus †Rimasuchus (formerly Crocodylus lloydi)
Genus †Voay Brochu, 2007 (formerly Crocodylus robustus)
Phylogeny
The cladogram below follows the topology from a 2012 analysis of morphological traits by
Christopher A. Brochu and Glenn W. Storrs.[85] Many extinct species of Crocodylus might represent
different genera. "Crocodylus" pigotti, for example, was placed in the newly erected genus
Brochuchus in 2013.[86] C. suchus was not included because its morphological codings were
identical to those of C. niloticus. However, the authors suggested that the lack of differences was
due to limited specimen sampling, and considered the two species to be distinct. This analysis found
weak support for the clade Osteolaeminae.[85] Brochu named Osteolaeminae in 2003 as a subfamily
of Crocodylidae separate from Crocodylinae, but the group has since been classified within
Crocodylinae. It includes the living genus Osteolaemus as well as the extinct species Voay robustus
and Rimasuchus lloydi.
Crocodylinae
†"Crocodylus" pigotti
†"Crocodylus" gariepensis
†Euthecodon arambourgii
†Euthecodon brumpti
Osteolaeminae
†Rimasuchus lloydi
†Voay robustus
Osteolaemus osborni
Osteolaemus tetraspis
Mecistops cataphractus
Crocodylus
†C. checchiai
†C. palaeindicus
†C. anthropophagus
†C. thorbjarnarsoni
C. niloticus
C. siamensis
C. palustris
C. porosus
C. johnsoni
C. mindorensis
C. novaeguineae
C. raninus
C. acutus
C. intermedius
C. rhombifer
C. moreletii
A 2013 analysis by Jack L. Conrad, Kirsten Jenkins, Thomas Lehmann, and others did not support
Osteolaeminae as a true clade but rather a paraphyletic group consisting of two smaller clades. They
informally called these clades "osteolaemins" and "mecistopins". "Osteolaemins" include
Osteolaemus, Voay, Rimasuchus, and Brochuchus and "mecistopins" include Mecistops and
Euthecodon.[86]
Relationship with humans
Danger to humans
Main article: Crocodile attacks
Crocodile warning sign, Trinity Beach, Queensland, Australia
The larger species of crocodiles are very dangerous to humans, mainly because of their ability to
strike before the person can react.[87] The saltwater crocodile and Nile crocodile are the most
dangerous, killing hundreds of people each year in parts of Southeast Asia and Africa. The mugger
crocodile and American crocodile are also dangerous to humans.
Crocodile products
Main article: Crocodile farm
Crocodile leather wallets from a Bangkok crocodile farm
Crocodiles are protected in many parts of the world, but they also are farmed commercially. Their
hides are tanned and used to make leather goods such as shoes and handbags; crocodile meat is also
considered a delicacy.[88] The most commonly farmed species are the saltwater and Nile crocodiles,
while a hybrid of the saltwater and the rare Siamese crocodile is also bred in Asian farms. Farming
has resulted in an increase in the saltwater crocodile population in Australia, as eggs are usually
harvested from the wild, so landowners have an incentive to conserve their habitat. Crocodile
leather can be made into goods such as wallets, briefcases, purses, handbags, belts, hats, and shoes.
Crocodile oil has been used for various purposes.[89] Crocodiles were eaten by Vietnamese while
they were taboo and off limits for Chinese. Vietnamese women who married Chinese men adopted
the Chinese taboo.[90] Crocodile meat is occasionally eaten as an "exotic" delicacy in the western
world.[91]
In religion
Statue of Sobek from the mortuary temple of Amenemhat III.
circa 1810 BC. Ashmolean Museum, Oxford.
Brooklyn Museum - Plaque with Crocodile Deity, ca. 700–900.,33.448.12
Crocodiles have appeared in various forms in religions across the world. Ancient Egypt had Sobek,
the crocodile-headed god, with his cult-city Crocodilopolis, as well as Taweret, the goddess of
childbirth and fertility, with the back and tail of a crocodile.[92] The Jukun shrine in the Wukari
Federation, Nigeria is dedicated to crocodiles in thanks for their aid during migration.[93]
Crocodiles appear in different forms in Hinduism. Varuna, a Vedic and Hindu god, rides a partcrocodile makara; his consort Varuni rides a crocodile.[83] Similarly the goddess personifications of
the Ganga and Yamuna rivers are often depicted as riding crocodiles.[94][95][96] Also in India, in
Goa, crocodile worship is practised, including the annual Mannge Thapnee ceremony.[97]
In Latin America, Cipactli was the giant earth crocodile of the Aztec and other Nahua peoples.[98]
Crocodile tears
Main article: Crocodile tears
The term "Crocodile tears" (and equivalents in other languages) refers to a false, insincere display of
emotion, such as a hypocrite crying fake tears of grief. It is derived from an ancient anecdote that
crocodiles weep in order to lure their prey, or that they cry for the victims they are eating, first told
in the Bibliotheca by Photios I of Constantinople.[99] The story is repeated in bestiaries such as De
bestiis et aliis rebus. This tale was first spread widely in English in the stories of the Travels of Sir
John Mandeville in the 14th century, and appears in several of Shakespeare's plays.[100] In fact,
crocodiles can and do generate tears, but they do not actually cry.[101]
The Surabaya Shark and Crocodile
Fighting shark and crocodile, the emblem of Surabaya city applied since colonial times, derived from
local folk etymology
The name of Surabaya, Indonesia, is locally believed to be derived from the words "suro" (shark) and
"boyo" (crocodile), two creatures which, in a local myth, fought each other in order to gain the title
of "the strongest and most powerful animal" in the area. It was said that the two powerful animals
agreed for a truce and set boundaries; that the shark's domain would be in the sea while the
crocodile's domain would be on the land. However one day the shark swam into the river estuary to
hunt, this angered the crocodile, who declared it his territory. The Shark argued that the river was a
water-realm which meant that it was shark territory, while the crocodile argued that the river flowed
deep inland, so it was therefore crocodile territory. A ferocious fight resumed as the two animals bit
each other. Finally the shark was badly bitten and fled to the open sea, and the crocodile finally
ruled the estuarine area that today is the city.[102]
Another source alludes to a Jayabaya prophecy — a 12th-century psychic king of Kediri Kingdom —
as he foresaw a fight between a giant white shark and a giant white crocodile taking place in the
area, which is sometimes interpreted as a foretelling of the Mongol invasion of Java, a major conflict
between the forces of the Kublai Khan, Mongol ruler of China, and those of Raden Wijaya's
Majapahit in 1293.[103] The two animals are now used as the city's symbol, with the two facing and
circling each other, as depicted in a statue appropriately located near the entrance to the city zoo
(see photo on the Surabaya page).
Crocodile (walking)
In the UK, a row of schoolchildren walking in pairs, or two by two is known as 'crocodile'.[104][105]
See also
Amphibians and reptiles portal
Alligator meat
The Crocodile Hunter
Crocodilian armor
Game (hunting)
Sewer alligator
Sobek – an ancient Egyptian deity associated with the Nile crocodile
References
"Crocodilian Biology Database - FAQ - What's the difference between a crocodile and an alligator".
Flmnh.ufl.edu. Retrieved 5 April 2009.
Guggisberg, C.A.W. (1972). Crocodiles: Their Natural History, Folklore, and Conservation. Newton
Abbot: David & Charles. p. 195. ISBN 0-7153-5272-5.
Buchanan, L.A. (2009). "Kambara taraina sp. nov (Crocodylia, Crocodyloidea), a new Eocene
mekosuchine from Queensland, Australia, and a revision of the genus". Journal of Vertebrate
Paleontology. 29 (2): 473–486. doi:10.1671/039.029.0220.
http://perseus.mpiwg-berlin.mpg.de/cgi-bin/vor?lookup=krokodeilos&lang=greek
"Crocodile | Define Crocodile at Dictionary.com". Dictionary.reference.com. Retrieved 26 April
2013.
"Online Etymology Dictionary". Etymonline.com. Retrieved 16 March 2010.
"American Crocodiles, American Crocodile Pictures, American Crocodile Facts - National
Geographic". Animals.nationalgeographic.com. 15 April 2013. Retrieved 25 April 2013.
McAliley, Willis, Ray, White, Brochu & Densmore (2006). Are crocodiles really monophyletic?—
Evidence for subdivisions from sequence and morphological data. Molecular Phylogenetics and
Evolution 39: 16–32.
(2011-09-06). "Pictures: Biggest Crocodile Ever Caught?". National Geographic Daily News.
"IUCN-SSC Crocodile Specialist Group". Crocodilian.com. Retrieved 25 April 2013.
[1]. Crocodile Species List. Retrieved on 2013-04-13.
Crocodile Specialist Group (1996). "Crocodylus porosus". The IUCN Red List of Threatened Species.
IUCN. 1996: e.T5668A11503588. doi:10.2305/IUCN.UK.1996.RLTS.T5668A11503588.en. Retrieved 23
December 2017.
"Mark O'Shea - The Official Website".
Alexander, Marc (1 January 2006). "Last of the Cuban crocodile?". Americas (English Edition).
Organization of American States. ISSN 0379-0940. Retrieved 9 July 2010.
"Hybrid Cuban-American Crocodiles on the Rise". 26 June 2011.
Simpson, Boyd; Bezuijen (2010). "Siamese Crocodile Crocodylus Siamensis" (PDF). Crocodiles. Third
Edition. Retrieved 13 January 2018.
Nile crocodile is two species, Nature.com
Schmitz, A.; Mausfeld, P.; Hekkala, E.; Shine, T.; Nickel, H.; Amato, G. & Böhme, W. (2003).
"Molecular evidence for species level divergence in African Nile crocodiles Crocodylus niloticus
(Laurenti, 1786)". Comptes Rendus Palevol. 2 (8): 703–12. doi:10.1016/j.crpv.2003.07.002.
Eaton, Mitchell J.; Andrew Martin; John Thorbjarnarson; George Amato (March 2009). "Species-level
diversification of African dwarf crocodiles (Genus Osteolaemus): A geographic and phylogenetic
perspective". Molecular Phylogenetics and Evolution. 50 (3): 496–506.
doi:10.1016/j.ympev.2008.11.009. PMID 19056500.
Grigg, Gordon and Gans, Carl (1993) Morphology And Physiology Of The Crocodylia Archived 20 July
2005 at the Wayback Machine., in Fauna of Australia Vol 2A Amphibia and Reptilia, chapter 40, pp.
326–336. Australian Government Publishing Service, Canberra.
Huchzermeyer, Fritz (2003). Crocodiles: Biology, Husbandry and Diseases. CABI Publishing. p. 13.
ISBN 978-0-85199-656-1.
[2]. Crocodilian Species List. Retrieved on 2012-04-14
Guinness Book of World Records. Retrieved on 2013-04-08.
The Guinness Book of Records. Largest Captive Crocodile, Worldcrocodile.com
Britton, Adam. "Lolong officially the world's largest crocodile in captivity". Crocodilian.com.
Retrieved 12 July 2012.
"Displaced Species". PhilStar. Retrieved 12 July 2012.
GMA News with Ben Serrano & Paterno Esmaquel. "NatGeo team confirms Lolong the croc is
world's longest". GMA News Online Top Stories. GMA Network Inc. Retrieved 15 November 2011.
Nuwer, Rachel. "Solving an Alligator Mystery May Help Humans Regrow Lost Teeth".
Wu, Ping; Wu, Xiaoshan; Jiang, Ting-Xin; Elsey, Ruth M.; Temple, Bradley L.; Divers, Stephen J.;
Glenn, Travis C.; Yuan, Kuo; Chen, Min-Huey; Widelitz, Randall B.; Chuong, Cheng-Ming (28 May
2013). "Specialized stem cell niche enables repetitive renewal of alligator teeth". PNAS. 110 (22):
E2009–E2018. Bibcode:2013PNAS..110E2009W. doi:10.1073/pnas.1213202110. PMC 3670376 Freely
accessible. PMID 23671090 – via www.pnas.org.
Specialized stem cell niche enables repetitive renewal of alligator teeth Archived 4 November 2013
at the Wayback Machine.
Uriona TJ, Farmer CG (2008). "Recruitment of the diaphragmaticus, ischiopubis and other
respiratory muscles to control pitch and roll in the American alligator (Alligator mississippiensis)".
Journal of Experimental Biology. 211 (Pt 7): 1141–1147. doi:10.1242/jeb.015339. PMID 18344489.
Anitai, Stefan. "14 Amazing Facts About Crocodiles – Living dinosaurs". Softpedia. Retrieved 1 April
2008.
Dinets, Vladimir; Britton, Adam; Shirley, Matthew (2013). "Climbing behaviour in extant
crocodilians" (PDF). Herpetology Notes. 7: 3–7.
evergreen. "Reptiles". Retrieved 29 April 2013.
Land, M.F. (2006). "Visual optics: the shapes of pupils". Current Biology. 16 (5): R167–R168.
doi:10.1016/j.cub.2006.02.046. PMID 16527734.
Encyclopædia Britannica. "Crocodile". Retrieved 29 April 2013.
Hansen, A (2007). "Olfactory and solitary chemosensory cells: two different chemosensory systems
in the nasal cavity of the American alligator, Alligator mississippiensis". BMC Neuroscience. 8: 64.
doi:10.1186/1471-2202-8-64.
Gans, C.; Clark, B. (1976). "Studies on ventilation of Caiman crocodilus (Crocodilia: Reptilia)". Respir.
Physiol. 26 (3): 285–301. doi:10.1016/0034-5687(76)90001-3. PMID 951534.
Putterill, J.F.; Soley, J.T. (2006). "Morphology of the gular valve of the Nile crocodile, Crocodylus
niloticus (Laurenti, 1768)". J. Morphol. 267 (8): 924–939. doi:10.1002/jmor.10448.
Schwenk, K. (2008). Comparative anatomy and physiology of chemical senses in nonavian aquatic
reptiles. In, Sensory Evolution on the Threshold: Adaptations in Secondarily Aquatic Vertebrates.
J.G.M Thewissen and S. Nummels (Eds). University of California Press, Berkeley. pp. 65–81
CBCnews (2002). "Alligators detect silent ripples when hunting". CBC News. Retrieved 29 April 2013.
Jackson, K.; Brooks, D.R. (2007). "Do crocodiles co-opt their sense of "touch" to "taste"? A possible
new type of vertebrate sensory organ" (PDF). Amphibia-Reptilia. 28 (2): 277–285.
doi:10.1163/156853807780202486.
"Crocodilian Biology Database - Integumentary Sense Organs". Crocodilian.com. Retrieved 26 April
2013.
"Saltwater Crocodile, Saltwater Crocodile Profile, Facts, Information, Photos, Pictures, Sounds,
Habitats, Reports, News – National Geographic". Animals.nationalgeographic.com. Retrieved 16
March 2010.
"Crocodilian Species - Nile Crocodile (Crocodylus niloticus)". Crocodilian.com. Retrieved 26 April
2013.
Damien Gayle. "When two tribes go to war: Incredible moment legion of hippos turn and flee after
stand-off with more than 100 crocodiles in epic Zambian river battle". Daily Mail. April 16, 2014
Darren Naish. "Crocodiles attack elephants". Scientific American. February 4, 2013
Simon Tomlinson. "Tragic hippo tot is tossed around by crocodile after young animal is snatched
while its mother had her back turned". Daily Mail. August 5, 2014
"Saltwater Crocodile Profile". Australian Animal.
Jon Tennant. "ARE CROCODILES SECRET FRUIT-LOVERS?". Popular Science. November 13, 2013
Charles Q. Choi. "Crikey! Crocodiles and Alligators Snack on Fruit". Live Science. August 27, 2013
BBC channel 1 program Inside The Perfect Predator, Thursday 25 March 2010
Adam Britton (6 September 2009). "Croc Blog: Crocodile myths #1 – the curious trochilus".
Crocodilian.blogspot.com. Retrieved 26 April 2013.
National Geographic documentary; "Bite Force", Brady Barr.
"National Geographic's Dr. Brady Barr's Bite Pressure Tests | Dog Facts". Dogfacts.wordpress.com.
Retrieved 26 April 2013.
Erickson, Gregory M.; Lappin, A. Kristopher; Vliet, Kent A. (2003). "The ontogeny of bite-force
performance in American alligator (Alligator mississippiensis)" (PDF). Journal of Zoology. 260 (3):
317–327. doi:10.1017/S0952836903003819.
"Australian saltwater crocodiles are world's most powerful biters". Sciencedaily.com. 16 March
2012. doi:10.1371/journal.pone.0031781. Retrieved 26 April 2013.
"Crocodiles Have Strongest Bite Ever Measured, Hands-on Tests Show".
News.nationalgeographic.com. 15 March 2012. Retrieved 26 April 2013.
Britton, Adam. "Crocodilian Biology Database FAQ, "How fast can a crocodile run?"". Retrieved 2
February 2008.
Walters, Martin; Johnson, Jinny. Encyclopedia of Animals. Marks and Spencer p.l.c. p. 145. ISBN 184273-964-6.
Read M. A.; Grigg G. C.; Irwin S. R.; Shanahan D.; Franklin C. E. (2007). Lusseau, David, ed. "Satellite
Tracking Reveals Long Distance Coastal Travel and Homing by Translocated Estuarine Crocodiles,
Crocodylus porosus". PLoS ONE. 2 (9): e949. Bibcode:2007PLoSO...2..949R.
doi:10.1371/journal.pone.0000949. PMC 1978533 Freely accessible. PMID 17895990.
"Crocodilian Biology Database, FAQ. "How long do crocodiles live for?"". Flmnh.ufl.edu. Retrieved
26 April 2013.
"Crocodilian Biology Database - FAQ - How long do crocodiles live for?". Crocodilian.com. Retrieved
26 April 2013.
Associated Press (16 February 1995). "Crocodile at Russian zoo dies; on display since czars". The
News–Journal. 70 (47). Daytona Beach, Florida: News–Journal Corporation.
Campbell, Kieran (24 March 2010). "Freshie the croc dies at age 140". Sunshine Coast Daily.
"Johannesburg: World's oldest crocodile turns 114". IBN Live. December 16, 2014. Retrieved
December 19, 2014.
"Celebran cumpleaños del cocodrilo más longevo del mundo". El Nuevo Día. December 16, 2014.
Retrieved December 19, 2014.
"Crocodilian Species List". Crocodilian.com. Retrieved 26 April 2013.
"Crocodilian Communication". Crocodilian.com. Retrieved 29 April 2013.
Arkive. "Nile crocodile (Crocodylus niloticus)". Retrieved 29 April 2013.
Hays, J. (2008). "Crocodiles: Their history, characteristics and behavior". Retrieved 31 May 2013.
K. Richardson; G. Webb; C. Manolis (2000). Crocodiles: Inside and Out.
G. Webb; C. Manolis (1989). Crocodiles of Australia.
Sfetcu, Nicolae (10 January 2011). Reptiles: Crocodiles, Alligators, Lizards, Snakes, Turtles. Lulu.com.
ISBN 9781470933203.
Marzola, M.; Russo, J.; Mateus, O. (2015). "Identification and comparison of modern and fossil
crocodilian eggs and eggshell structures". Historical Biology. 27 (1): 115–133.
doi:10.1080/08912963.2013.871009.
Darren Naish. "Do crocodilians (sometimes) feed their young?". Science Blogs. November 8, 2008
"10 Delightful Baby Animals that Grow up to Be Fatal Predators". Odd Stuff. February 3, 2012
Jasey Kelly. "THE LIFE CYCLE OF ALLIGATORS AND CROCODILES". Demand Media.
Amina Khan. "Scary smart! Clever crocodiles, alligators use sticks to lure prey". Los Angeles Times.
December 06, 2013
Jason G. Goldman. "Crocodiles and their ilk may be smarter than they look". Washington Post.
December 9, 2013
"Scary smart! Clever crocodiles, alligators use sticks to lure prey". Phys Org. October 13, 2014
"Crocodiles are cleverer than previously thought: Some crocodiles use lures to hunt their prey".
ScienceDaily. December 4, 2013. Retrieved December 8, 2013.
"The Crocodile Files". One World Magazine.
McAliley, Willis, Ray, White, Brochu & Densmore (2006). Are crocodiles really monophyletic?—
Evidence for subdivisions from sequence and morphological data. Molecular Phylogenetics and
Evolution 39:16–32.
Brochu, C. A.; Storrs, G. W. (2012). "A giant crocodile from the Plio-Pleistocene of Kenya, the
phylogenetic relationships of Neogene African crocodylines, and the antiquity of Crocodylus in
Africa". Journal of Vertebrate Paleontology. 32 (3): 587–602. doi:10.1080/02724634.2012.652324.
Conrad, J. L.; Jenkins, K.; Lehmann, T.; Manthi, F. K.; Peppe, D. J.; Nightingale, S.; Cossette, A.;
Dunsworth, H. M.; Harcourt-Smith, W. E. H.; McNulty, K. P. (2013). "New specimens of "Crocodylus"
pigotti (Crocodylidae) from Rusinga Island, Kenya, and generic reallocation of the species". Journal of
Vertebrate Paleontology. 33 (3): 629–646. doi:10.1080/02724634.2013.743404.
"Crocodilian Attacks". IUCN Crocodile Specialist Group (iucncsg.org). Retrieved 3 February 2013.
Lyman, Rick (30 November 1998). "Anahuac Journal; Alligator Farmer Feeds Demand for All the
Parts". The New York Times. Retrieved 13 November 2013.
Elisabeth Janos (2004). Country Folk Medicine: Tales of Skunk Oil, Sassafras Tea and Other Old-Time
Remedies. Globe Pequot Press. p. 56. ISBN 978-1-59228-178-7.
Erica J. Peters (2012). Appetites and Aspirations in Vietnam: Food and Drink in the Long Nineteenth
Century. Rowman Altamira. pp. 142–. ISBN 978-0-7591-2075-4.
Armstrong, Hilary (8 April 2009). "Best exotic restaurants in London". London Evening Standard.
Retrieved 4 September 2016.
Catherine C. Harris. "Egypt: The Crocodile God, Sobek". Tour Egypt.
Fidelis Mac-Leva. "Nigeria: How Giant Crocodiles Guided Jukun to Kwararafa". All Africa. June 24,
2009
"Holy Rivers, Lakes, and Oceans". Heart of Hinduism. ISKCON Educational Services. 2004. Most rivers
are considered female and are personified as goddesses. Ganga, who features in the Mahabharata,
is usually shown riding on a crocodile (see right).
Kumar, Nitin (August 2003). "Ganga The River Goddess - Tales in Art and Mythology". The second
distinguishing aspect of Ganga's iconography is her animal mount, which is often shown serving as a
pedestal for her. This is the makara, a hybrid creature having the body of a crocodile and the tail of a
fish. The makara in Hindu thought corresponds to the star sign of Capricorn in western astrology.
The crocodile is a unique animal in that it can live on both land and sea. It thus denotes the wisdom
of both the earth and waters.
"Hindu gods and their holy mounts". Sri.Venkateswara Zoological Park. Archived from the original
on 23 June 2014. The river goddesses, Ganga and Yamuna, were appropriately mounted on a
tortoise and a crocodile respectively.
"The Crocodile is God in Goa" (PDF). Crocodile Specialist Group Newsletter. 14 (1): 8. January–
March 1995.
John Black. "Cipactli and Aztec Creation". Ancient Origins. May 19, 2013
PHOTIUS (1977). Bibliothèque. Tome VIII : Codices 257–280 (in French and Ancient Greek). Texte
établi et traduit par R. Henry. Paris: Les Belles Lettres. p. 93. ISBN 978-2-251-32227-8.
John Ashton (2009). Curious creatures in zoology. ISBN 978-1-4092-3184-4.
Britton, Adam (n.d.). Do crocodiles cry 'crocodile tears'? Crocodilian Biology Database. Retrieved
March 13, 2006 from the Crocodile Specialist Group, Crocodile Species List, FAQ.
Irwan Rouf; Shenia Ananda (2013). Rangkuman 100 Cerita Rakyat Indonesia: Dari Sabang Sampai
Merauke. AnakKita. p. 60. ISBN 978-602-9003-82-6.
"Welcome to Surabaya City, East Java". Surabaya Tourism, EastJava.com. Retrieved 17 November
2014.
Martin H. Manser, Turton and Nigel D. Turton Advanced Learner's Dictionary, p. 164, at Google
Books
Angela Brazil The Nicest Girl in the School, p. 50, at Google Books
Further reading
Iskandar, DT (2000). Turtles and Crocodiles of Insular Southeast Asia and New Guinea. ITB, Bandung.
Crocodilian Biology Database, FAQ. FLMNH.ufl.edu, "How long do crocodiles live for?" [sic] Adam
Britton.
Crocodilian Biology Database, FAQ. FLMNH.ufl.edu, "How fast can a crocodile run?" Adam Britton.
External links
Look up crocodile in Wiktionary, the free dictionary.
Wikispecies has information related to Crocodilia
Wikiversity has learning resources about Crocodile
Media related to Crocodilia at Wikimedia Commons
Crocodilian Online
Crocodilian Biology Database
Crocodile Attacks in Australia
BBC news finds powerful agent in crocodile blood
World’s most expensive handbag sells in Hong Kong for over US$377,000 – a Hermès white crocodile
(31 May 2017), South China Morning Post
[show] v t e
Extant Crocodilian species
[show] v t e
Related articles on alligators, caimans, crocodiles and gharials
[show] v t e
Meat
Taxon identifiers
Wd: Q2535664 EoL: 42334959 Fossilworks: 63119
Authority control
BNF: cb11964877v (data)
Categories: CrocodylidaeReptiles of AsiaReptiles of AfricaCrocodiles of AustraliaReptiles of North
AmericaReptiles of South AmericaExtant Ypresian first appearances
Navigation menu
Not logged inTalkContributionsCreate accountLog inArticleTalkReadView sourceView historySearch
Search Wikipedia
Main page
Contents
Featured content
Current events
Random article
Donate to Wikipedia
Wikipedia store
Interaction
Help
About Wikipedia
Community portal
Recent changes
Contact page
Tools
What links here
Related changes
Upload file
Special pages
Permanent link
Page information
Wikidata item
Cite this page
Print/export
Create a book
Download as PDF
Printable version
In other projects
Wikimedia Commons
Wikispecies
Languages
اﻟﻌرﺑﯾﺔ
বাংলা
ﻓﺎرﺳﯽ
Français
മലയാളം
Nederlands
Scots
اردو
Tiếng Việt
13 more
Edit links
This page was last edited on 11 May 2018, at 00:21.
Text is available under the Creative Commons Attribution-ShareAlike License; additional terms may
apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia® is a registered
trademark of the Wikimedia Foundation, Inc., a non-profit organization.
Privacy policyAbout WikipediaDisclaimersContact WikipediaDevelopersCookie statementMobile
viewWikimedia Foundation Powered by MediaWiki