Crocodiles are large reptiles that live in water tropical 

regionsin Africa, Asia, America and Australia. Crocodiles tend to congregate in freshwater habitats like rivers, lakes, wetlands and sometimes in brackish water. They feed mostly on vertebrates - fish, reptiles, and mammals, and sometimes invertebrates - mollusks and crustaceans, depending on species. They first appeared during the Eocene epoch, about 55 million years ago.

Etymology
The word "crocodile" is derived from the Ancient Greek κροκόδιλος (crocodilos), "lizard," used in the phrase ho tou krokódilos Potamou, "the lizard of the (Nile) river."

There are several variant Greek forms of the word attested, including the later form κροκόδειλος (crocodeilos) found cited in many English reference works in the Koine Greek of Roman times. Crocodilos and crocodeilos would have been pronounced identically, and either or both may be the source of the Latin form Crocodilus used by the ancient Romans.

Crocodilos or crocodeilos is krokè compounds ("pebbles"), and drilos / dreilos ("worm"). It is ascribed to Herodotus, supposedly to describe the basking habits of the Egyptian crocodile. However drilos said only proved as a colloquial term for "penis". Meaning krokè explained as describing the skin texture of lizards (or crocodiles) in most sources, but alternately claimed to refer to a supposed habit of (lizards or crocodiles) basking on pebbly ground.

Description
Crocodiles, like dinosaurs, have the abdominal ribs modified into gastralia.
Although they look prehistoric, reptile crocodile is one of the more biologically complex. Unlike other reptiles, crocodiles have a cerebral cortex, a four-chambered heart, and the functional equivalent of a diaphragm, the muscles that are used to enter the water to drive respiration (EGM diaphragmaticus), external morphology, on the other hand, is a sign of water and predatory lifestyle .

Physical characteristics A crocodile is possible to be a successful predator. Slender body that allows for a quick swim, also folded her legs to the side when swimming, which makes it faster by reducing water resistance. Webbed feet, although not used to propel the animal through the water, allow it to make fast corners 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 ceiling has a special path from the nostril to the glottis that passes through the mouth. The nostrils are closed during submergence. As with other archosaurs, crocodile diapsid, although their post-temporal fenestrae reduced. The walls of the braincase are the bones, but it does not have the supratemporal and postfrontal bones [7] their tongues are not free but held in place by a membrane which limits movement;. As a result, the crocodile can not stick its tongue out them.

Crocodile scales have pores believed in sensory function, analogous to the lateral line in fish. They are mainly seen in the upper and lower jaw. Another possibility is that they are secretory, as they produce an oily substance that appears to flush mud off.

Crocodiles are very fast moving, even out of the water. Because they feed by grabbing and holding prey, they have evolved sharp teeth for tearing and holding meat, and strong muscles to close the jaws and hold them shut. These jaws can bite with great force, by far the strongest bite of an animal. Pressure crocodile bite is more than 5,000 pounds per square inch (30,000 kPa), [9] compared to just 335 pounds per square inch (2,300 kPa) for a Rottweiler, 400 pounds per (kPa 2,800) square inch for a large great white shark, 800 pounds per square inch (6,000 kPa) to 1,000 pounds per square inch (7,000 kPa) for a hyena, or 2,000 pounds per square inch (10,000 kPa) for a large crocodile [citation needed]. The jaws opened, however, by a very weak set of muscles. 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. They have limited lateral (side-to-side) movement of the neck.


Biology and Behavior


Crocodiles are ambush hunters, waiting for fish or land animals to get close, then rushing out to attack. As cold-blooded predators, they have a very slow metabolism, so they can survive a long time without food. Despite their appearance being slow, crocodiles are apex predators in their environment, and various species have been observed attacking and killing sharks.

Herodotus claimed that Nile crocodiles have a symbiotic relationship with certain birds, such as the Egyptian plover, which enter the mouth of the crocodile and alligator blood sucking leeches take, with no evidence of this interaction actually occurring in any crocodile species, most likely mythical or allegorical fiction.

Many large stone swallowing crocodile (called gastroliths or stomach stones) which may act as ballast to balance their body or assist destroy food, similar to grit in birds.

Salt glands present in the tongue crocodylids part and they have a pore opening on the surface of the tongue. They seem similar to those in marine turtles, they seem to be absent in Alligatoridae.

Crocodiles can produce sounds during distress and aggressive displays. They can also hear well, but they are hidden by the tympanic membrane flat flaps that can be raised or lowered by muscles.
Crocodiles are protected in many parts of the world, but they are also grown commercially. They hide tanned and used to make leather goods such as shoes and handbags, crocodile meat is also considered delicacies. The most commonly cultivated species is saltwater and Nile crocodiles, while a hybrid of brine and rare Siamese Crocodile is also bred on farms in Asia. 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 preserve their habitat.

Size
A giant saltwater crocodile in captivity in Australia
Size greatly varies between species, from the dwarf crocodile to the saltwater crocodile. Osteolaemus Palaeosuchus species and grow to adult size is only 1 meter (3.3 feet) to 1.5 meters (4.9 feet). Larger species can reach over 4.85 meters (15.9 feet) long and weighing more than 1,200 kilograms (2,600 lb). Crocodile show pronounced sexual dimorphism, with males growing much larger and faster than women. [7] Despite their large adult size, crocodiles start their life at around 20 centimeters (7.9 in) long. The largest species of crocodile is the saltwater crocodile, found in eastern India, northern Australia, throughout Southeast Asia, and in the surrounding waters.

Two notes grade greater than 6.2 meter second (20 feet) crocodile. The first shot in the Mary River in the Northern Territory of Australia in 1974 by poachers and measured by wildlife rangers [citation needed]. The second crocodile was killed in 1983 in the Fly River, Papua New Guinea. In the case of the second crocodile, it's really the skin as measured by zoologist Jerome Montague, and as skins are known to underestimate the size of the actual animal, it is possible the crocodile was at least 10 cm longer [citation. required]

Largest crocodile ever held in captivity is mouth-Siamese hybrid named Yai (Thai: ใหญ่, meaning big) (born June 10, 1972) at the famous Samutprakarn Crocodile Farm and Zoo, Thailand. This animal measures 6 m (19.69 ft) (19 ft 8 in) in length and weighs 1114.27 kg. [17]

Meanwhile, the longest crocodile captured alive is wailed, measured at 6.17 meters (20.24 ft) and weighs in at 1075 pounds by a team of National Geographic in the province of Agusan del Sur, Philippines [18]. [19] [20]

Wildlife expert, however, believes the largest crocodile so far found in the Bhitarkanika nearly 23 feet (7.0 m) long, which can be traced from the skull preserved by the Kanika Royal Family. Crocodile was shot near Dhamara in 1926 and then the skull preserved by the then Kanika King. Crocodile experts estimate the animal was between 20 feet (6.1 m) and 23 feet (7.0 m) long, because the size of the skull was measured one-ninth of the total length of the body. [Citation needed]

Age

Measuring unreliable crocodile age, 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 according to changes in the growth rate which typically occurs once a year between dry and wet seasons [21] Given these inaccuracies in mind., The oldest crocodile species seems to be the biggest . C. porosus is estimated to live around 70 years on average, with limited evidence of some individuals exceeding 100 years. One of the oldest crocodiles recorded died in a zoo in Russia. A male freshwater crocodile at the Australia Zoo is estimated 130 years. He was rescued from the wild by Bob Irwin and Steve Irwin after being shot twice by hunters. As a result of the shootings, this crocodile (known fondly as "Mr. Freshy") has lost his right eye. [22]

Skin                                                                                                    Crocodiles have smooth skin on the belly and side, while their dorsal surface armored with large osteoderms. Leather armor and has a thick, rough scales, provide protection. They are still able to absorb heat through this armor, as a network of small capillaries allows blood through the scales to absorb heat ....

Crocodiles are large reptiles that live in water tropical regions in Africa, Asia, America and Australia. Crocodiles tend to congregate in freshwater habitats like rivers, lakes, wetlands and sometimes in brackish water. They feed mostly on vertebrates - fish, reptiles, and mammals, and sometimes invertebrates - mollusks and crustaceans, depending on species. They first appeared during the Eocene epoch, about 55 million years ago.

Etymology
The word "crocodile" is derived from the Ancient Greek κροκόδιλος (crocodilos), "lizard," used in the phrase ho tou krokódilos Potamou, "the lizard of the (Nile) river."

There are several variant Greek forms of the word attested, including the later form κροκόδειλος (crocodeilos) found cited in many English reference works in the Koine Greek of Roman times. Crocodilos and crocodeilos would have been pronounced identically, and either or both may be the source of the Latin form Crocodilus used by the ancient Romans.

Crocodilos or crocodeilos is krokè compounds ("pebbles"), and drilos / dreilos ("worm"). It is ascribed to Herodotus, supposedly to describe the basking habits of the Egyptian crocodile. However drilos said only proved as a colloquial term for "penis". Meaning krokè explained as describing the skin texture of lizards (or crocodiles) in most sources, but alternately claimed to refer to a supposed habit of (lizards or crocodiles) basking on pebbly ground.

Description
Crocodiles, like dinosaurs, have the abdominal ribs modified into gastralia.
Although they look prehistoric, reptile crocodile is one of the more biologically complex. Unlike other reptiles, crocodiles have a cerebral cortex, a four-chambered heart, and the functional equivalent of a diaphragm, the muscles that are used to enter the water to drive respiration (EGM diaphragmaticus), external morphology, on the other hand, is a sign of water and predatory lifestyle .

Physical characteristics A crocodile is possible to be a successful predator. Slender body that allows for a quick swim, also folded her legs to the side when swimming, which makes it faster by reducing water resistance. Webbed feet, although not used to propel the animal through the water, allow it to make fast corners 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 ceiling has a special path from the nostril to the glottis that passes through the mouth. The nostrils are closed during submergence. As with other archosaurs, crocodile diapsid, although their post-temporal fenestrae reduced. The walls of the braincase are the bones, but it does not have the supratemporal and postfrontal bones [7] their tongues are not free but held in place by a membrane which limits movement;. As a result, the crocodile can not stick its tongue out them.

Crocodile scales have pores believed in sensory function, analogous to the lateral line in fish. They are mainly seen in the upper and lower jaw. Another possibility is that they are secretory, as they produce an oily substance that appears to flush mud off.

Crocodiles are very fast moving, even out of the water. Because they feed by grabbing and holding prey, they have evolved sharp teeth for tearing and holding meat, and strong muscles to close the jaws and hold them shut. These jaws can bite with great force, by far the strongest bite of an animal. Pressure crocodile bite is more than 5,000 pounds per square inch (30,000 kPa), [9] compared to just 335 pounds per square inch (2,300 kPa) for a Rottweiler, 400 pounds per (kPa 2,800) square inch for a large great white shark, 800 pounds per square inch (6,000 kPa) to 1,000 pounds per square inch (7,000 kPa) for a hyena, or 2,000 pounds per square inch (10,000 kPa) for a large crocodile [citation needed]. The jaws opened, however, by a very weak set of muscles. 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. They have limited lateral (side-to-side) movement of the neck.

Skin
Crocodiles have smooth skin on the belly and side, while their dorsal surface armored with large osteoderms. Leather armor and has a thick, rough scales, provide protection. They are still able to absorb heat through this armor, as a network of small capillaries allows blood through the scales to absorb heat ....