Alligators and Crocodiles
Alligators and crocodiles are reptiles that have four
short legs and a long tail. These animals look alike but one way to tell the
difference is to look at their mouths. When a crocodile’s mouth is closed, you
can see its bottom teeth (left). An alligator’s teeth don’t show when its
mouth is closed (right).
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Scientific
Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft
Corporation. All rights reserved.
Alligators and Crocodiles
Alligators and crocodiles are reptiles that have four
short legs and a long tail. These animals look alike but one way to tell the
difference is to look at their mouths. When a crocodile’s mouth is closed, you
can see its bottom teeth (left). An alligator’s teeth don’t show when its
mouth is closed (right).
Alligators and Crocodiles
Alligators and crocodiles are reptiles that have four
short legs and a long tail. These animals look alike but one way to tell the
difference is to look at their mouths. When a crocodile’s mouth is closed, you
can see its bottom teeth (left). An alligator’s teeth don’t show when its
mouth is closed (right).
Alligators and Crocodiles
What is the difference between an
alligator and a crocodile? That’s kind of a trick question. “Crocodile” is a
common name for an order, or large group, of animals called crocodilians.
Alligators, caimans, and gavials are all crocodilians—but so are
crocodiles.
HOW ARE THEY DIFFERENT?
One way to tell the difference
between alligators and crocodiles is by looking at their snouts. Alligators and
their close relative, the caiman, have broad, rounded snouts. Crocodiles have
longer, sharper snouts that are shaped like triangles.
Crocodiles have a tooth on each
side of their lower jaw that sticks up when their mouth is closed. Alligators do
not show any teeth when their mouths are closed.
The Indo-Pacific, or saltwater,
crocodile is one of the biggest reptiles. It is about 23 feet (7 meters) long
and weighs more than 2,000 pounds (more than 1,000 kilograms). The American
alligator is smaller. It can grow to 20 feet (6 meters) long.
Crocodiles live in warm, tropical
places. Alligators can live in cooler places as well as warm environments.
HOW ARE THEY THE SAME?
All crocodilians are reptiles.
They are cold-blooded. This means they must warm up by lying in the sun. They
cool off by staying in the shade.
Crocodilians breathe through
lungs. They spend most of their time in water but must come to the surface to
breathe.
The thick skin of crocodilians is
made up of bony plates. These animals have about 30 to 40 teeth in each jaw. The
teeth lock together when their jaws are closed—kind of the way a zipper’s teeth
fit together.
HUNTING AND EATING
Alligators and crocodiles float
with their bodies almost totally underwater. Only their nostrils, eyes, and part
of their backs stick out. They look scary as they silently stalk their
prey (animals they hunt and eat).
Alligators and crocodiles have
long, powerful tails. They sometimes swat prey with their tails. They also use
their tails to push prey into deeper water, where it is easier to attack.
The powerful jaws of crocodilians
slam shut on small animals and crush their bones. They eat fish, frogs, snakes,
turtles, birds, and mammals. Crocodiles sometimes attack humans.
NOISY REPTILES
Alligators and crocodiles make all
kinds of sounds. They hiss softly. They make fearsome roars and bellows. Males
roar and bellow loudest during the mating season. Scientists don’t know exactly
what the roars mean. Maybe the males are trying to call females. Maybe they are
trying to scare other males away.
SWIMMING AND WALKING
Alligators and crocodiles use
their tails for swimming. They swish their strong tails back and forth.
On land, crocodilians sometimes
crawl on their bellies. They can also gallop and walk fast on all four legs,
just as many mammals do.
WHERE ALLIGATORS LIVE
There are two species (kinds) of
alligators: the American alligator and the Chinese alligator. The American
alligator lives mainly in swamps, lakes, and bayous in the southeastern United
States. American alligators live as far west as the Rio Grande in Texas. The
Chinese alligator lives along the Yangtze River in China.
Chinese alligators are much
smaller than American alligators. They are usually less than 8 feet (2.5 meters)
long. American alligators will attack people. Chinese alligators almost never
attack people.
During cold winters, alligators
bury themselves in mud. There they can hibernate until spring.
WHERE CROCODILES LIVE
Four species of crocodiles live
in the Americas. These crocodiles are found in southern Florida, Cuba and other
Caribbean islands, southern Mexico, Central America, and northern South
America.
The Indo-Pacific crocodile lives
along the seacoasts of India, southern China, Malaysia, and Australia. The swamp
crocodile is found in the lakes and rivers of India. The Nile crocodile lives in
parts of Africa.
LIFE CYCLE
Females crocodilians lay from 20
to 90 eggs. They lay their eggs in nests made of sand, mud, or rotting plant
parts. Baby crocodilians hatch from the eggs.
Most female crocodilians watch
over their young. Alligator mothers may help the babies break out of the egg.
They sometimes carry the newborn alligators in their mouths. They put the babies
into the water. Some mothers stay near their young for at least a year. If the
young alligator gets in trouble, its mother is there to help.
No one is really sure how long
alligators and crocodiles live. Scientists estimate that smaller species can
live from 30 to 50 years, while larger crocodilian species can live to be 70 or
even 80 years old.
THREATS TO CROCODILIANS
Alligators and crocodiles are
threatened by hunting. People hunt them mainly for their eggs and for their
skin. Many crocodile species are endangered.
The American alligator became an
endangered species in 1967. Laws protected it from being hunted. As a result,
the species made a comeback. By the late 1970s, people could again hunt the
American alligator in some states.
Microsoft ® Encarta ® 2009. © 1993-2008 Microsoft
Corporation. All rights reserved.
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