crocodile (Crocodylus palustris) is a large reptile of the order Crocodilia, which also includes Alligators y gaviales.

The crocodile is a cold-blooded reptile.

The crocodile is a cold-blooded reptile.


There are 13 species of crocodiles, so there are many different sizes. The smallest crocodile is the dwarf crocodile. It grows to about 1,7 meters in length and weighs 6 to 7 kilograms. The largest is the saltwater crocodile. The largest ever found was 6,17 m long. They can weigh up to 907 kg.

  • C. American ó C. Narigudo (Crocodylus acutus)
  • C. del Orinoco ó C. Llanero (Crocodylus intermedius)
  • C. Australian (Crocodylus johnsoni)
  • Mindoro ó C. Flipino (Crocodylus mindorensis)
  • C. Morelet ó c. Mexican (Crocodylus moreletii)
  • C. del Nile (Crocodylus niloticus)
  • C. of Nueva Guinea (Crocodylus novaeguineae)
  • C. of the marshes, Iranian, hocicudo, Hindu ó lost (Crocodylus palustris)
  • C. Marino (Crocodylus porosus)
  • C. Cuban (Crocodylus rhombifer)
  • C. Siamese (Crocodylus siamensis)
  • C. Dwarf (Osteolaemus tetraspis)
  • C. hociquifino African (Mecistops cataphractus)


Crocodiles may seem quite prehistoric, yet they are the most advanced reptile of our time. Unlike other reptiles, they have a four-chambered heart, diaphragm, and cerebral cortex (a structure within the vertebrate brain with distinct structural and functional properties).

The physical traits of a crocodile allow it to be a successful predator. They have a streamlined body that allows them to swim faster. They also turn on their side while swimming, which helps the crocodile swim fast, decreasing water resistance.

Crocodiles have webbed feet that, although not used to propel the animal through the water, allow it to make quick turns and sudden movements in the water or to initiate swimming. Webbed feet are an advantage in shallow water where crocodiles sometimes move by walking.

Crocodiles are very fast over short distances, even out of water. Crocodiles have extremely powerful jaws and sharp teeth to tear through meat, yet a crocodile cannot open its mouth if it is kept closed. All large crocodiles also have sharp and powerful claws.

Crocodiles have limited lateral movement in their neck, therefore in the protection of the earth even a small tree can be found between the crocodiles' jaws and oneself.

The size varies greatly between species, from the dwarf crocodile to the huge saltwater crocodile. Large species can reach more than 5 or 6 meters in length and weigh more than 1200 kilograms. Despite their large adult size, crocodiles begin life at 20 inches long. The largest species of crocodile, also the largest reptile on Earth, is the saltwater crocodile, found in northern Australia and throughout Southeast Asia.

There is no reliable way to measure the age of a crocodile, although various techniques can be used to obtain a reasonable estimate. The most common method is to measure the laminar growth rings in bones and teeth - each ring corresponds to a change in growth rate that typically occurs once a year between the wet and dry seasons.

Differences between crocodile and alligator

Crocodiles are often mistaken for alligators, but there are some easy-to-spot differences. An alligator's jaw is U-shaped, while a crocodile has a V-shaped jaw. Crocodiles also have teeth that protrude over the upper lip when their mouths are closed.

Another difference between alligators and crocodiles is that crocodiles have salt glands on their tongues. These modified salivary glands help crocodiles tolerate life in salt water. Alligators have lost the ability to secrete excess salt through their tongue glands and therefore prefer to live in freshwater areas.

A crocodile cooling off.

A crocodile cooling off.


They normally live near lakes, rivers, wetlands, and even some saltwater regions. They live in tropical climates for a reason. They are cold-blooded and cannot generate their own heat. During the colder months, they hibernate or fall asleep. Crocodiles also remain dormant during long periods of drought. To create a place to hibernate, they dig a burrow on the shore of a river or lake and settle in for a long sleep.


These large reptiles are found in tropical regions of Africa, Asia, the Americas, and Australia. One of the largest known populations of American crocodiles is found in the Dominican Republic in a large saltwater lake called Lago Enriquillo.


Crocodiles are carnivores, which means that they only eat meat. In their natural habitat, they feast on fish, birds, frogs, and crustaceans. At the zoo, they feed on small animals that have already been euthanized for them, such as rats, fish, or mice. They also eat live lobsters.

In its natural habitat, the crocodile attacks its prey with its huge jaws, crushing them, and then swallowing them whole. They do not have the ability to chew or break small pieces of food like other animals.

To help with digestion, crocodiles swallow small stones that grind up food in their stomachs. Thanks to their slow metabolism, crocodiles can survive for months without food.


In Africa and Asia, crocodiles often have to compete with lions, tigers, and leopards for food, territory, and life; it is true that felines, being the most important apex predators, are large and strong enough to take on even a large crocodile, although the tiger seems to be responsible for most of the attacks.

Due to their small size which often makes them vulnerable, small crocodile species, such as the Australian freshwater crocodile, must run to escape the deadly jaws of larger (and much more dangerous) species, such as the famous marine crocodile. .

Some individual crocodiles can be hunted by large pythons, but only if the snake was long, large, and strong enough to constrain the deadliest reptile on earth.

Nile crocodiles must often share their river domains with the famous hippopotamus, and must give way to hippos whenever these massive beasts are within reach. Hippos are very aggressive, probably the most aggressive living animals, equipped with strong jaws and the ability to open their mouths wide, as well as a very short temperament - skills that make the job of killing a large crocodile very short.

Elephants also do not hesitate to attack crocodiles on sight, either to defend themselves or to protect their young.


The crocodile breeding season is from January to May. In the case of males, the onset of sexual maturity occurs when they are about 3 meters long, while in the case of females, it occurs when they are between 2 and 2,5 meters long. This takes approximately 10 years for crocodiles, both male and female, to reach these lengths under normal conditions.

During mating season, males attract females by yelling, slapping the water, blowing water from their noses, and making a variety of vocalizations. The larger males in a population tend to be more successful. Once a female has been attracted, the pair gurgles and rubs the bottom of their jaws.

After the crocodiles mate, the female lays 20 to 40 eggs (one clutch) in a nest she makes near a riverbank once a year. Cover the nest with leaves and other vegetation. Rotten vegetation keeps the eggs warm and the nest moist. The incubation temperature of crocodile eggs is 28 - 32 degrees centigrade, the relative humidity is 95 - 100 percent, the incubation period is 70 - 80 days. The female stays and looks after the nest until the eggs hatch. The hatchlings scream and the female crocodile opens the nest and carries it into the water, where they immediately begin to feed on crabs, shrimp, and insects. About half will not survive the first year due to predators.

Older crocodiles are estimated to have lived around 71 years on average and there is limited evidence that some individuals can exceed 100 years. One of the oldest recorded crocodiles died in a zoo in Russia, apparently at 115 years of age.

Crocodiles lay 10 to 60 eggs at a time. The young remain in their eggs for 55 to 110 days. They are born with a size of 17.8 to 25.4 centimeters long and do not mature until 4 to 15 years. The lifespan of a crocodile depends on its species. Some only live for about 30 years, while others live up to 75 years.

State of conservation

The Cuban crocodile is one of the most threatened crocodile species in the world. It is considered critically endangered and has a population of only about 4.000. Poaching is a constant threat to crocodile species.

The American crocodile is also considered vulnerable by the International Union for Conservation of Nature and Natural Resources, but its populations are increasing.

Relationship with humans

Larger species of crocodile can be very dangerous to humans. Saltwater and Nile crocodiles are the most dangerous, killing hundreds of people each year in parts of Southeast Asia and Africa. Thieving crocodiles, and possibly the endangered black caiman, are also very dangerous to humans. American alligators are less aggressive and rarely attack humans without provocation.


When a crocodile loses a tooth, it is quickly replaced. These reptiles can go through 8.000 teeth in their lifetime.

Crocodiles don't sweat. To stay cool, they open their mouths in a process called "gaping," which is much like panting.

"Crying crocodile tears" refers to a person who expresses insincere remorse. It is a saying that dates back to the XNUMXth century. Crocodiles DO produce tears. Your tear glands secrete a fluid behind your third eyelid, called nictitating membrane. The liquid helps clean the eye, lubricate it, and reduce bacteria. Crocodile tears are generally not noticeable unless the crocodile has been out of the water for a while and the eyes begin to dry out.

The jaws of a crocodile can apply more than 2000 kilos of pressure per square centimeter. This means that they can bite an arm or a leg without any problem. The jaw of a human only produces 45 kg of pressure. However, the crocodile jaw has very little opening force. For example, the mouth of a crocodile can be kept closed with an elastic band.

In addition to their strong jaws, crocodiles also have very sharp hearing. It is so good that they can hear their babies making noise from inside the egg.

Crocodiles swim very fast, which helps them catch their prey. They can swim up to 32 miles per hour and can hold their breath underwater for about an hour. On land, crocodiles are not that fast. They can only run up to 17.6 kph for a short distance.

It is illegal to hunt crocodiles for their skin. This makes their skin very rare. A bag made of crocodile skin can cost a fortune.

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