A crocodile is any species belonging to the family Crocodylidae (sometimes classified instead as the subfamily Crocodylinae). The term can also be used more loosely to include all members of the order Crocodilia: i.e. the true crocodiles, the alligators and caimans (family Alligatoridae) and the gharials (family Gavialidae). The crocodiles, colloquially called crocs, are large aquatic reptiles that live throughout the Tropics in Africa, Asia, the Americas and Australia. Crocodiles tend to congregate in freshwater habitats like rivers and lakes and wetlands. Some species, notably the Saltwater Crocodile of Australia and the Pacific islands, have been known to venture far out to sea. They mostly feed on a wide variety of vertebrates like fish, reptiles, and mammals, sometimes with invertebrates like mollusks and crustaceans, depending on species. They are an ancient lineage, and are believed to have changed little since the time of the dinosaurs.
Crocodiles are ambush hunters, waiting for fish or land animals to come close, then rushing out to attack. As cold-blooded predators, they can survive long periods without food, and rarely need to actively go hunting. The crocodile’s bite strength is up to 3,000 pounds per square inch, comparing to just 100 psi for a labrador retriever or 350 psi for a large shark.  Despite their slow appearance, crocodiles are the top predators in their environment, and various species have been observed attacking and killing big cats like lions , large ungulates and even sharks.  A famous exception is the Egyptian Plover which is said to enjoy a symbiotic relationship with the crocodile. According to unauthenticated reports, the plover feeds on parasites that infest the crocodile’s mouth and the reptile will open its jaws and allow the bird to enter to clean out the mouth.
Crocodiles eat fish, birds, mammals and occasionally smaller crocodiles. Wild crocodiles are protected in many parts of the world, but they also are farmed commercially. Their hide is tanned and used to make leather goods such as shoes and handbags, whilst crocodile meat is also considered a delicacy in many parts of the world. 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 crocodile habitat. Crocodiles are more closely related to birds and dinosaurs than to most animals classified as reptiles , the three being included in the group Archosauria (‘ruling reptiles’). See Crocodilia for more information.
The larger species of crocodiles can be very dangerous to humans. The Saltwater and Nile Crocodiles are the most dangerous, killing hundreds of people each year in parts of South-East Asia and Africa. Mugger crocodiles and possibly the endangered Black Caiman, are also very dangerous to humans. American alligators are less aggressive and rarely assault humans without provocation. Crocodiles are the leading cause of animal related deaths as of 2001.
Crocodiles are the largest of all reptiles. Size greatly varies between species. From the exceptionally small dwarf crocodile to the enormous saltwater crocodile, they range in all sorts of sizes. Large species can often reach huge sizes over 5 or 6 metres and weigh well over 1000kg. Despite their large adult size, crocodiles start their life interestingly small. Crocodiles when first hatched are around 20 cm. Sizes vary depending on the season and health and blood composition of the mother. The largest species of crocodile, also Earth’s largest reptile, is the Saltwater Crocodile, found in northern Australia and throughout South-east Asia.According to some scientists, there are no truly reliable records of any non-prehistoric crocodiles over 8.64m In the town of Normanton, Queensland, Australia, there is a fibreglass mould of a crocodile called “Krys the Croc.,” shot in 1958 by Krystina Pawloski, who found the animal on a sandbank on the Norman River. There is a report of a saltwater crocodile in Australia that was 8.2 m long. There is also a skull of a salt water crocodile from Orissa, India that is very large and the animal is estimated to have been 6.4 to 7 m long.
The other two larger certifiable records of complete crocodile are both of 6.2 m crocodiles. The first crocodile was shot in the Mary River in the Northern Territory of Australia in 1974 by poachers and measured by wildlife rangers. The second crocodile was killed in 1983 in the Fly River, Papua New Guinea. In this latter crocodile it was actually the skin that was measured by zoologist Jerome Montague, and as skins are known to underestimate the size of the actual animal, it is possible this crocodile was at least another 10 cm longer.
The largest crocodile ever held in captivity is an Estuarine/Siamese hybrid named Yai (Thai: ใหญ่, meaning big) (born 10 June, 1972) at the famous Samutprakarn Crocodile Farm and Zoo, Thailand. He measures 6 m. in length and weighs 1,114.27 kg.Another huge captive crocodile was a saltie named Gomek. Gomek was captured by George Craig in Papua New Guinea and sold to St. Augustine Alligator Farm in Florida. Although George captured an even larger crocodile with Gomek, it is uncertain whether this animal is still alive on Green Island in Queensland where George Craig now lives. After many years, Gomek unfortunately died of heart disease in February 1997. By this stage, he was a very old crocodile. When he died, he was 5.5 m long – as confirmed by St. Augustine Alligator Farm – and probably between 70 and 80 years old.
On June 16, 2006, A 7.1m giant saltwater crocodile in Orissa, India was crowned the world’s largest living crocodile. It lives in Bhitarkanika Wildlife Sanctuary and in June 2006, was entered in the Guinness Book of World Records. 
Wildlife experts, however, argued that the largest crocodile so far found in the Bhitarkanika was almost 7.62 m which could be traced from the skull preserved by the Kanika Royal Family. The crocodile, probably was shot dead near Dhamara during 1926 and later its skull was preserved by the then Kanika King. The crocodile experts said as per the parameters, the crocodile would be about 7.62 m since the size of the skull was measured one seventh of the total length of the body.
- The crocodile gets its name from the Greeks who observed them in the Nile river. The Greeks called them krokodilos, a compound word from kroke, which means “pebbles” and drilos, which means “worm”. To the Greeks, this “worm of the stones” was so named because of the crocodiles habit of basking in the sun on gravel-covered river banks.
- Petsuchos was the name given by the Greeks to the live crocodile at Crocodilopolis in Ancient Egypt, which was worshipped as a manifestation of the Egyptian god Sobek; the deification of crocodiles.
- Crocodile embryos do not have sex chromosomes, and unlike humans sex is not determined genetically. Sex is determined by temperature, with males produced at around 31.6 degrees celsius, and females produced at slightly lower and higher temperatures. The average incubation period is around 80 days, and also is dependent upon temperature.
- Many of the extinct crocodiles were herbivorous.
[Info from Wikipedia]
Get the stories about Steve Irwin love of crocs and his family’s efforts at crocodilian conservation at his International Crocodile Rescue website!