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| CROCODILES
AND ALLIGATORS |
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| SCIENTIFIC
CLASSIFICATION |
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| COMMON
NAME: |
crocodile, croc; alligator, gator |
| KINGDOM: |
Animalia |
| PHYLUM: |
Chordata |
| CLASS: |
Reptilia |
| ORDER: |
Crocodylia |
| FAMILY: |
Crocodylidae (crocodiles), Alligatoridae (alligators) |
| GENUS
SPECIES: |
23 living species |
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| DESCRIPTION: |
Crocodilians are large, lizard-shaped reptiles
with four, short legs and a long, muscular tail.
Their hide is rough and scaled.
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| The
difference between alligators and crocodiles is
often easy to spot once you get the hang of it.
Alligators are dark colored with a broad, rounded
snout and are usually found in fresh water. Crocodiles
are grayish-green and prefer coastal, brackish and
salt-water habitats. They have a narrow, tapered,
triangular snout. Also, the fourth tooth on either
side of the lower jaw of an alligator fits into
an internal socket in the upper jaw so that these
teeth are hidden when the mouth is closed. In a
crocodile, the fourth tooth is always exposed. |
| MALE |
For all species of crocodilian, mature males grow
larger than females. |
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| SIZE: |
The largest species of crocodilian is the saltwater
crocodile, Crocodylus porosus, which can
measure more than 6 m (20 ft.). The smallest species
is the Cuvier's dwarf caiman; adult males only reach
a maximum length of about 1.6 m (5.2 ft.). |
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| WEIGHT: |
900-1360 kg (1-1.5 tons) maximum; most species approximate
454 kg (0.5 ton) or less |
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| DIET: |
Crocodilians are predatory and depending on their
size and habitat may feed upon a variety of fishes,
reptiles (including other crocodilians), amphibians,
aquatic invertebrates and even birds, mammals and
carrion. |
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| INCUBATION: |
No
data |
| CLUTCH
SIZE |
No
data |
| BREEDING
PERIOD |
No
data |
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| LIFE
SPAN: |
Probably very long-lived - at least 50 to 60 years. |
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| RANGE: |
Two species of crocodilians are native to the United
States - the American alligator (Alligator mississippiensis)
and the American crocodile (Crocodylus acutus).
American alligators are restricted to the southeastern
United States, while the highly endangered American
crocodile is found only in the southern tip of Florida.
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| HABITAT: |
Mostly found in tropical and subtropical freshwater
and saltwater habitats. |
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| POPULATION: |
GLOBAL |
No
data |
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| STATUS: |
IUCN |
13 species are listed, 4 of which are listed as
critically endangered |
| CITES |
Nearly all species of crocodilians are listed |
| USFWS |
The American alligator is listed as threatened and
the American crocodile as endangered. Many other
species are listed. |
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| 1. |
Alligators and crocodiles are one of the oldest
and most successful groups of predators. A noteworthy
extinct crocodile was Deinosuchus, or "terrible
crocodile." The only fossil recovered from
this species was a skull found in Texas, which measured
more than 2 m (6.6 ft.) in length. Based on this
skull size, researchers believe this enormous predator
was 15 m (49 ft.) long and large enough to eat most
dinosaurs living at the time. |
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| 2. |
Crocodilians, like the American alligator, have
vertical pupils that open wide in low light, which
allows them to be impressive nocturnal hunters.
Their throat (gular) pouch blocks water so that
they can eat prey under water as well as on land. |
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| 3. |
The 23 living species of crocodilians have changed
little since the appearance of their prehistoric
relatives, although this does not mean they are
not advanced compared to other reptiles. Unlike
other living reptiles, for example, crocodilians
have efficient four-chambered hearts (like birds
and mammals). |
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Crocodilians are vital to the overall health of
their ecosystems. For example, Nile crocodiles (Crocodylus
niloticus) control the barbel catfish population.
If crocodiles were hunted to extinction, the voracious
catfish could wipe out other fish populations, which
are food sources to more than 40 species of birds.
The birds, in turn, are necessary because their
droppings recycle nutrients back into the system.
Crocodiles are also scavengers that feed on dead
carcasses found along the waterways, effectively
cleansing the environment. Without crocodilians,
many ecosystems would suffer. |
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Conant, Roger and Joseph T. Collins. Reptiles
and Amphibians: Eastern and Central North America.
Boston. Houghton Mifflin Co., 1991.
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Haliday, T. and K. Adler, eds. Encyclopedia of
Reptiles and Amphibians. New York: Facts on
File, Inc., 1987. |
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Ross, C., ed. Crocodiles and Alligators.
New York: Facts on File, Inc., 1989.
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| Steel,
Rodney. Crocodiles. London. Christopher Helm
Ltd., 1989. |
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| http://www.flmnh.ufl.edu/cnhc/cbd.html |
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