Introduction to Crocodile
Crocodile, the largest of living reptiles, found throughout the tropical and subtropical regions of the world. Crocodiles live near swamps and marshes. They spend much of their time basking in the sun.
There are 12 species of crocodiles. The American crocodile, the only species found in the United States, lives in southern Florida, Mexico, Central America, and the Caribbean islands. Most crocodiles are shy; however, the Nile crocodile of Africa and the saltwater crocodile of southeastern Asia, Australia, and the Pacific Islands are dangerous, and unprovoked attacks on humans are common. Crocodiles are hunted for their meat, their skin (which is made into leather), and their musk (which is used in perfumes). Because of hunting and destruction of their habitat most crocodile species are endangered. Some species of crocodiles are preyed upon by lions, leopards, and tigers.
The crocodile has a heavy tail, short legs, and webbed hind feet.Do Any Crocodiles Live in North America?Yes, one kind of crocodile does live in North America. American crocodiles live on islands in the Caribbean (kar uh BEE uhn) and along the coast of Central America. Some also live in the southernmost part of Florida.
American crocodiles can grow to be very large, as large as 20 feet (6.1 meters). But most of these crocodiles are smaller than American alligators.
American crocodiles spend their days resting in sheltered waters, among thick plants, or in their dens. They come out at night to feed. They build nests by digging holes in the sand or in a riverbank. Sometimes, if there is no place to dig, American crocodiles build mound nests.
Description
Crocodiles range from 5 to 25 feet (1.5 to 7.5 m) in length. A crocodile has a long, pointed snout. Some of its lower teeth are exposed when the jaw is closed. It is olive-green with dark crossbands on the back and tail. The skin is protected by large bony plates. The crocodile has a heavy tail, short legs, and webbed hind feet.
The crocodile has protruding eyes and nostrils, raised slightly above the flattened head, allowing the animal to see and breathe while the rest of its body is submerged. The ears have flaps that close when the head is submerged. A fold at the back of the mouth closes off the air passage from the food passage, enabling the animal to breathe even when its mouth is open underwater. The jaws have powerful muscles and sharp, strong teeth that are frequently shed, replaced by new ones that grow in their place. Both sexes have a pair of scent glands under the chin that secretes musk, a strong-smelling substance that attracts a mate.
A crocodile has powerful jaws and sharp, regenerating teeth.How Do You Tell an Alligator from a Crocodile?The easiest way is to look at the animals’ heads. Alligators and caimans have wide, U-shaped snouts. Crocodiles have narrow, V-shaped snouts. But there are other differences, too.
The upper jaws of alligators and caimans are wider than their lower jaws. When the mouth is closed, the teeth in the lower jaw are covered. A crocodile’s upper and lower jaws are nearly the same size. When its mouth is closed, some teeth in the lower jaw are still seen.
Alligators and caimans usually live in fresh water. Crocodiles are found in fresh water and in salt water. Crocodiles have salt glands on their tongues. Extra salt from food or water leaves the crocodile’s body through these salt glands.
Finally, alligators and caimans are shy and will usually avoid humans. Many crocodiles are bold. They are less likely to avoid humans.
Habits
Adult crocodiles feed on crustaceans, fish, small mammals, and water birds; the young feed on frogs and small insects. Adults approach a swimming animal from under water and drag it down until it drowns. Crocodiles do not chew their food; if their prey is too large to be swallowed whole, they grasp it with their teeth and twist their bodies in order to tear chunks of flesh from it. According to a medieval fable, the crocodile sheds tears for its victims as it devours them. Thus the expression "crocodile tears" refers to false sympathy.
The female builds a nest of sand, sticks, and vegetation. The mound of material is usually one foot (30 cm) high and 10 feet (3 m) long. She lays 20 to 60 white eggs in the nest and incubates them for three months. After the young hatch, the mother carries them in her mouth to the nearest body of water. The young are eight to nine inches (20 to 23 cm) long at birth. They mature in five years.
What Do Crocodiles Do in the Dry Season?In tropical areas, seasons can be rainy or dry. During the dry season, many crocodilians must search for places that still have water.
The Orinoco (ohr uh NOH koh) crocodiles of South America are one example. During the rainy season, their grassland homes are flooded. Rivers flow in places that are dry at other times of the year. There are many places to swim, bask, and feed. But in the dry season, many of these areas dry up. The crocodiles must return to their watery burrows or search for new watery pools.
Orinoco crocodiles are very protective parents. At night, hatchlings may wander off by themselves to look for food. But during the day, their mother stays with them in a group called a pod. She protects them for a good reason. In South America, giant otters prey on young crocodiles. These otters can reach lengths of 7 feet (2 meters).
Which Crocodiles Set Traps?Crocodilians have many different ways to catch prey. Nile crocodiles of Africa even set traps to catch fish.
A good time to watch trap-setting is when great numbers of fish are found in one area. This happens when fish are searching for food. It also happens when fish swim upstream to spawn, or lay eggs.
Nile crocodiles use their bodies to set traps. They line up next to each other in a stream. As fish swim by, the crocodiles catch them with a snap of their jaws. A single crocodile may also use its body to block a part of a stream. This forces fish to swim around the crocodile and—snap! The crocodile swings its head sideways and grabs the fish.
Do Crocodiles Share Their Food?Crocodiles do seem to share food, but probably not out of kindness. The real reason they share is out of need. Often, crocodiles need other crocodiles to help them eat prey that can’t be swallowed whole.
The Nile crocodile eats fish. But it also preys on large animals such as zebras and wildebeests (WIHL duh beests). Once a crocodile sights its prey, it submerges and swims in close for the attack. Then it grabs the animal, drags it into the water, and drowns it. The noise and splashing of the kill attracts other crocodiles.
Even though one crocodile does the killing, several crocodiles help eat the prey. The crocodiles take turns biting, twisting, turning, and rolling to tear off bite-sized pieces. After a few bites, a crocodile may swim away. Another crocodile takes its place. Larger, more dominant crocodiles usually get most of the food.
Why Are Mugger Parents So Unusual?Like all crocodilians, the female mugger defends her nest, helps the eggs hatch, and protects the hatchlings. But with mugger pairs, the male helps.
Male muggers are very good fathers. They help the females uncover nests when the hatchlings begin to chirp. Males help hatch eggs by rolling the eggs in their mouths. They also help carry hatchlings to the water. A male mugger may even chase away a female so that he can hatch the nest of eggs on his own.
Mugger crocodiles form family groups. In this way, both parents can care for and protect the young. Mugger parents may protect their hatchlings for up to two years.
Which Crocodiles Are at Home in the Sea?Many crocodiles can live in fresh water and in salt water. But Australian saltwater crocodiles spend more time in salt water than any other crocodile. Salties, as they are called, can even swim hundreds of miles to reach new territories. Some spend so much time at sea that they have barnacles, a kind of sea animal, growing on them.
Australian saltwater crocodiles are the largest reptiles in the world. They can reach lengths of 23 feet (7 meters). Still, these giant crocodiles can leap high out of the water. When this happens, it looks as if they are walking on their tails.
Salties are very territorial, and they will attack to defend their territories from other crocodiles. Salties also have attacked and killed humans. This makes the Australian saltwater crocodile one of the most feared crocodilians.
Which Crocodile Runs the Fastest?Two kinds of crocodiles live on the continent of Australia. And both hold crocodilian records. The Australian saltwater crocodile is the largest. The Johnston’s crocodile, or Australian freshwater crocodile, is the fastest.
Johnston’s crocodiles are small and shy. They avoid humans and run if they feel threatened. Sometimes a run turns into a bounding gallop. First, the back legs push the animal forward. Then the front legs hold it up while the back legs swing forward for another push. Johnston’s crocodiles can gallop as fast as 10 miles (16 kilometers) an hour.
Johnston’s crocodiles live in freshwater lakes, streams, and swamps. These small crocodiles have long, narrow snouts and very sharp teeth—perfect for catching and eating fish.
Crocodiles belong to the family Crocodylidae. The American crocodile is Crocodylus acutus; the saltwater, C. porosus; the Nile, C. niloticus.