Crocodile

Scientific name	Crocodylus niloticus (Nile crocodile)
Where they live	Rivers and lakes in Africa
Size	Can grow up to 20 feet long
Diet	Fishes, birds, mammals, and sometimes humans
Interesting fact	Crocodiles have existed since the time of the dinosaurs!

A crocodile (family) is a large, semiaquatic reptile that lives throughout the tropics in Africa, Asia, the Americas and Australia. These fascinating animals are often found in freshwater habitats such as rivers, lakes, and wetlands, but they can also live in brackish or saltwater. Crocodiles are carnivorous, which means they eat other animals. Their diets usually include fish, reptiles, birds, and mammals, and sometimes even invertebrates like molluscs and crustaceans, depending on the species and their age.

All crocodiles share some common traits, even though they come in different sizes and behaviours. They have powerful jaws and tough skin that helps protect them. Unlike alligators, crocodiles are very sensitive to cold and prefer warm, tropical climates. Many crocodile species face threats, and some are at risk of extinction, with a few classified as critically endangered. Learning about crocodiles helps us understand and protect these amazing creatures and their habitats.

Etymology

The word crocodile comes from Middle English, based on a Greek word meaning "stones worm". This word traveled through many languages over time.

Ancient Greek stories and writings, like those by Herodotus, helped shape how people thought about crocodiles. The Latin word crocodilus appeared in writings by Pliny the Elder around the first century AD. Over the centuries, the word changed a little in different languages before becoming the word we use today.

Taxonomy and phylogeny

Species

Distribution of crocodiles

There are 18 different kinds of crocodiles alive today. Scientists are still studying some groups, especially those in the genus Osteolaemus, to learn more about them. If you are interested in the Tomistoma, also known as the false gharial, which is not considered a true crocodile, you can find more information here.

Species name	Distribution	Description/Comments
American crocodile (Crocodylus acutus)	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. Diet consists mostly of aquatic and terrestrial vertebrates. Classified as Vulnerable, but certain local populations under greater threat.
Hall's New Guinea crocodile (Crocodylus halli)	The island of New Guinea, south of the New Guinea Highlands	A smaller species that closely resembles and was long classified under the New Guinea crocodile, which it is now considered to be genetically distinct from. It lives south of the mountain barrier that divides the two species' ranges. It can be physically distinguished from the New Guinea crocodile by its shorter maxilla and enlarged postcranial elements. Cranial elements can still widely vary within the species, with populations from Lake Murray having much wider heads than those from the Aramia River.
Orinoco crocodile (Crocodylus intermedius)	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 johnstoni)	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)	Endemic to the Philippines	This is a relatively small species with a rather broader snout. It has heavy dorsal armour and a golden-brown 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.
Morelet's crocodile (Crocodylus moreletii)	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)	Sub-Saharan 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. This species is listed as Least Concern.
New Guinea crocodile (Crocodylus novaeguineae)	The island of New Guinea, north of the New Guinea Highlands	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)	The 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. Enlarged scutes around the neck make it a heavily armoured species. Prefers slow moving rivers, swamps and lakes. It can also be found in coastal swamps but avoids areas populated by saltwater crocodiles. Feeds on a wide array of vertebrates.
Saltwater crocodile (Crocodylus porosus)	Throughout Southeast Asia, Northern Australia and surrounding waters	The largest on average 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 but with several populations under greater risk.
Borneo crocodile (Crocodylus raninus)	Island of Borneo in Southeast Asia	A freshwater species of crocodile that has been considered a synonym of the saltwater crocodile.
Cuban crocodile (Crocodylus rhombifer)	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. 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, and 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. Today most prey are small to medium sized vertebrates. It is Critically Endangered, and the remaining wild population is under threat of hybridization.
Siamese crocodile (Crocodylus siamensis)	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.
West African crocodile (Crocodylus suchus)	Western and Central Africa	Recent studies revealed that this is distinct species from the larger Nile crocodile. It has a slightly narrower snout and is much smaller compared to its larger cousin.
Osborn's dwarf crocodile (Osteolaemus osborni)	Western Africa	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.
Dwarf crocodile (Osteolaemus tetraspis)	Western Africa	It belongs to its own monotypic genus; however, new studies indicate there might be two or even three distinct species. 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.
West African slender-snouted crocodile (Mecistops cataphractus)	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. It is a Critically Endangered species.
Central African slender-snouted crocodile (Mecistops leptorhynchus)	Central Africa	A medium sized species found in watery areas in dense rainforest. Feeds largely on fish. Insufficient conservation data, but was classified as Critically Endangered when lumped with M. cataphractus, although M. leptorhynchus is doing better in its home range.

Characteristics

Crocodiles are large reptiles that live in warm places around the world. They look similar to alligators and caimans but have some special traits that help them survive in water. Their bodies are shaped for swimming fast, and they have webbed feet that help them turn quickly in the water. Crocodiles can close their noses and mouths when they are underwater.

Crocodiles come in different sizes. Some, like the dwarf crocodile, are small, growing only about 1.5 meters long. Others, like the saltwater crocodile, can grow over 6 meters and weigh more than a ton! Most crocodiles start very small, about 20 centimeters long, when they are born. They grow quickly, especially the males, who become larger than females. Their skin has special scales that protect them and help them stay healthy.

Biology and behaviour

Crocodiles are closely related to birds and dinosaurs. They are biologically complex reptiles, with a brain structure similar to other reptiles and a four-chambered heart. Unlike other reptiles, they have structures that help with breathing underwater and special salt glands on their tongues.

Crocodiles have excellent senses. Their eyes, ears, and nostrils are on top of their heads, letting them see and hear while mostly hidden underwater. They see well at night and can detect colours. Their jaws have special sensors that feel even the smallest changes in water, helping them find food and stay safe.

Crocodiles are ambush predators, waiting for the right moment to catch fish, birds, mammals, and more. They can survive long periods without eating because they don’t need much food. Their strong jaws can bite very hard—much harder than many other animals. They can move quickly on land and in water, and some can even run short distances.

Crocodiles often gather in groups, especially when eating or basking in the sun. They make many different sounds, like chirping when their babies are hatching, and loud bellows during mating season. Mothers take care of their young for over a year, teaching them to swim and protecting them. Even though they care for their babies, many young crocodiles don’t survive because other animals might eat them.

Relationship with humans

Danger to humans

Some large crocodiles can be very dangerous to people because they can strike very quickly, faster than a person can react. The saltwater crocodile and Nile crocodile are the most dangerous, and they can harm many people each year in parts of Southeast Asia and Africa. The mugger crocodile and American crocodile can also be dangerous.

Crocodile products

Crocodiles are protected in many places, but some are also farmed for their skin and meat. Their hides are used to make leather goods like shoes and handbags. Crocodile meat is eaten in some countries, such as Australia, Ethiopia, Thailand, South Africa, China, and Cuba. Because there is a lot of demand for crocodile products, many crocodile skins have been exported from Africa over the years.

Crocodile hunting and conservation

Aboriginal Australians have harvested crocodile eggs and hunted crocodiles in a sustainable way for thousands of years. In the past, many crocodiles were hunted for their skin, especially from the 1940s to the 1960s. Laws were later passed to protect crocodiles, and they have been a protected species since the 1970s. Today, their numbers have grown, but there are still rules to make sure they stay safe.

In religion and mythology

Further information: Crocodilia § Cultural depictions

Crocodiles have been important in many religions and stories around the world. In Ancient Egypt, there was a crocodile-headed god named Sobek. In Madagascar, some people believe crocodiles are spirit ancestors. In Hinduism, some river goddesses are shown riding crocodiles. In Indonesia, the city of Surabaya has a story about a shark and a crocodile fighting, which is why the city uses both animals as symbols.

In language and as symbols

The phrase "crocodile tears" means pretending to feel sorry, like someone who cries but doesn’t really mean it. In schools in the UK, a line of children walking two by two is called a "crocodile". In politics, calling someone a crocodile can mean they are clever and strong, or that they are greedy and unfair.

Fashion logos

The French clothing company Lacoste uses a crocodile in its logo. The American shoe company Crocs also uses a crocodile in its logo.