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.

[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).

[13][14][15][16][8] Below is a cladogram showing the relationships of the major extant crocodile groups based on molecular studies, excluding separate extinct taxa: Caiman Melanosuchus Paleosuchus Alligator Crocodylus Mecistops Osteolaemus Gavialis Tomistoma Below is a more detailed cladogram of Crocodylidae, based on a 2021 study using paleogenomics that extracted DNA from the extinct Voay.

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.

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.

When above water, crocodiles enhance their ability to detect volatile odorants by gular pumping, a rhythmic movement of the floor of the pharynx.

[55] Cranial: 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.

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.

The BBC TV[64] reported that a Nile crocodile that has lurked a long time underwater to catch prey builds up a large oxygen debt.

Cutting teeth, combined with the exceptionally high bite force, would pass through flesh easily enough to leave an escape opportunity for prey.

Since crocodile anatomy has changed only slightly over the last 80 million years, current data on modern crocodilians can be used to estimate the bite force of extinct species.

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.

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.

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.

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 — Crocodiles lay eggs, which are laid in either holes or mound nests, depending on species.

This behaviour was exhibited with conspecifics and mammals and is apparently not uncommon, though has been difficult to observe and interpret in the past due to obvious dangers of interacting with large carnivores.

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.

[103] Crocodile meat is consumed in some countries, such as Australia, Ethiopia, Thailand, South Africa, China, and Cuba (in pickled form).

The Brinkin people (aka Marrithiyal) of the Daly River in the Northern Territory (NT) used harpoons and bamboo, and even their own hands to capture crocodiles for food.

[106] After settlement of northern Australia, in the late-19th and early 20th centuries, non-Indigenous people killed individual crocodiles, mostly by locals to protect the population, or novelty-seeking visitors, or just opportunistically, so numbers were not noticeably reduced.

The federal government later banned the export of crocodile skins, which brought commercial hunting to an end in Queensland.

In 2021, after several attacks on humans by the "salties" and an estimated population of around 200,000 had been reached, Queensland politician Bob Katter called for the reintroduction of hunting.

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.

[122] 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.

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.

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.