Learn About The
Endangered
CROCODILES
CROCODILES SCIENTIFIC CLASSIFICATION
| KINGDOM |
Animalia |
| PHYLUM |
Chordata |
| CLASS |
Reptilia |
| SUBCLASS |
Archosauria |
| ORDER |
Crocodylia |
| FAMILY |
Crocodylidae |
| GENUS/SPECIES |
COMMON NAME |
| Alligator mississippiensis |
American Alligator |
| Alligator sinensis |
Chinese Alligator |
| Caiman crocodilus (crocodilus) |
Spectacled Caiman |
| Caiman c. apaporiensis |
Rio Apaporis Caiman |
| Caiman c. fuscus |
Brown Caiman |
| Caiman latirostris |
Broad-snouted Caiman |
| Caiman yacare |
Yacare Caiman |
| Melanosuchus niger |
Black Caiman |
| Paleosuchus palpebrosus |
Cuvier's Dwarf Caiman |
| Paleosuchus trigonatus |
Smooth-fronted Caiman |
| GENUS/SPECIES |
COMMON NAME |
| Crocodylus acutus |
American Crocodile
|
| Crocodylus cataphractus |
Slender-snouted Crocodile
|
| Crocodylus intermedius |
Orinoco Crocodile
|
| Crocodylus johnstoni
|
Australian Freshwater Crocodile
|
| Crocodylus mindorensis
|
Phillipine Crocodile
|
| Crocodylus moreletii
|
Morelet's Crocodile
|
| Crocodylus niloticus
|
Nile Crocodile
|
| Crocodylus novaeguineae
|
New Guinea Crocodile
|
| Crocodylus palustris
|
Mugger / Marsh Crocodile
|
| Crocodylus porosus
|
Estuarine / Saltwater Crocodile
|
| Crocodylus rhombifer
|
Cuban Crocodile
|
| Crocodylus siamensis
|
Siamese Crocodile
|
| Osteolaemus tetraspis
|
Dwarf Crocodile
|
| Tomistoma schlegelii
|
False Gharial / Gavial
|
| GENUS/SPECIES |
COMMON NAME |
| Gavialis gangeticus |
Gharial / Gavial |
![[CROCODILES SEQUENCE]](crocseq.gif)
CROCODILES, ALLIGATORS, CAIMANS, and GHARIALS
are all referred to as crocodilians.
They are survivors of a time known as the Age of Reptiles,
dating from 265 million years to about 66 million years ago.
About 210 million years ago, at the end of the Triassic
period, a small reptile appeared which has been named
Terrestrisuchus and is thought to be the direct ancestor
of the modern-day crocodiles.
The terrestrisuchus was primarily a land-dwelling reptile,
having either two or four legs and eating smaller lizards.
There are 23 living species within the crocodilian group,
but crocodylian diversity was much higher in the past.
All four forms of crocodilians resemble each other.
The alligator has a broad, rounded, shovel-like snout
while the gharials snout is long and narrow.
The snouts of the caiman and the crocodiles are between
these extremes, although a long, tapered snout
is most common.
All crocodilians have their eyes and nose on the top
of the skull so that they can see and breathe while
the rest of their body is submerged.
GENERAL CHARACTERISTICS OF ALL CROCODILIANS:
- All crocodilians have powerful jaws.
- They have sharp teeth that are designed for grasping
and tearing. The small prey is swallowed whole,
while larger prey is torn apart and the pieces swallowed. - Their teeth are periodically replaced with up to 50
sets of teeth by the time the crocodilian is old.
- Baby crocodilians feed heavily on insects and small fish.
- They swallow stones to aid in the digestion of food.
- Its digestive system is powerful enough to dissolve
the bones of their prey.
- They store fat in their tails and body.
This fat enables them to go for long periods without eating.
PARTICULAR CHARACTERISTICS OF THE DIFFERENT SPECIES:
ALLIGATORS
Alligators are semiaquatic animals. They spend most of
their time in the water but come out on land to absorb
heat periodically. They eat virtually anything they can
swallow, but are not generally considered dangerous to
humans, as very few attacks have been reported.
Other crocodylians, like the Nile crocodile of Africa
and the Indopacific saltwater crocodile, are genuine
maneaters.
Another kind of alligator is the Chinese alligator
(Alligator sinensis). It is found in China.
CAIMANS
They are closely related to the alligators.
They are found through much of Latin America.
The alligators and caimans form a group called
Alligatoridae.
The word "alligator" is sometimes used to refer to any
member of Alligatoridae. Like other crocodylians,
female alligators lay their eggs on land.
They guard their nests and, when the young alligators
hatch, they protect the hatchlings. Baby alligators
make a grunting sound to attract their mothers when
they sense danger. Alligators are about nine inches
long when they hatch. If fed well, young alligators
grow quickly and can be 3 feet long by the time they
they are three years old.
Like other reptiles, alligators are ectothermic
("cold-blooded") and cannot generate their own body
heat. For this reason, they spend part of their time
basking in the sun to absorb heat.
AMERICAN ALLIGATOR
The American alligator (Alligator mississippiensis) is a
large crocodylian reptile found throughout the southeastern
United States. Individuals as long as 19 feet been
reported, but ten or eleven feet is more typical for large
adults.
The American alligator is a member of the crocodile family.
It can be differentiated from a crocodile by its wider
snout and its bottom teeth which do not show when its
jaw is closed.
Alligators are found throughout the Southeast in wetlands
from the Carolinas to Texas and as far north as Arkansas.
They consume fish, turtles and snails as well as small
animals that come to the waters's edge to drink.
Young alligators feed primarily on insects, crustaceans,
snails, and fish.
They benefit the marsh ecosystem by digging holes that
hold fresh water during the dry season for fish, insects,
crustaceans, snakes, turtles, birds and other animals.
Older males may live 30 years or more and reach lengths
of 14 feet, and weights of 1,000 pounds.
Thirty years ago alligators were depleted from many parts
of their range by market hunting and loss of habitat.
It was believed that this reptile could never recover.
In 1967, this species was listed as an endangered
and alligator hunting was prohibited.
Their numbers were monitored and by 1987 the American
alligator was considered fully recovered and was removed
from the Endangered Species List.
The trade in alligator skins or derived products is still
regulated since some related species, such as crocodiles
and caimans are still in trouble.
CROCODILES
Crocodiles are often referred to as "living fossils."
They have the same basic appearance and lifestyle that
they had nearly 200 million years ago, during the age
of dinosaurs.
They have survived extinction events, ice ages,
climatic changes, and the movement of continents.
Now, habitat loss and overexploitation by humans
have almost eliminated many members of this group.
In North America, the American crocodile endures
only on the southernmost tip of Florida, in and
around the waters of Florida Bay in the Everglades
National Park.
It's estimated that about 500 individuals survive there.
American crocodiles are big reptiles.
Males routinely grow to 15 feet in length.
They're opportunistic predators, feeding at night on
fish, crabs, birds, turtles, snakes, and small mammals.
They're also shy and reclusive, particularly during
their nesting season.
They nest in secluded areas, unlike their close
relatives, the alligators, who will nest almost
anywhere they can find suitable vegetation.
There are very few active crocodile nests in Florida.
To reach adulthood, the young crocodiles need to survive
at least two years, when they'll be large enough to
discourage predators.
Baby crocs are eaten by raccoons, birds, crabs, and
even adult crocodiles. Only a small fraction of the
hatchlings survive.
AMERICAN CROCODILE
Crorodylus acutus, is perhaps the best known of Crocodiles,
because it has the largest range of the four New World
crocodiles.
In North America, its range is restricted to the regions
of the Florida Keys, although it goes up through fresh
water canals around the Everglades.
It is also found on the islands in the Caribbean, Mexico,
Central America, Colombia, Venezuela, Ecuador, and Peru.
A distinguishing feature of all crocodiles is that the
fourth tooth, on either side of the lower jaw, is so long
it protrudes through holes in the upper jaw.
The American crocodile also can be distinguished from all
other crocodiles because it has less bumpy osteoderms
on its back.
It is rare to find any specimens of this crocodile
today that measure over 13 1/2 feet in length.
American crocodiles use their hind feet to make a hole
in the peat in which to lay their eggs.
The female lays from 40 to 60 eggs.
She then makes a tunnel for herself close to the nest
to stand guard over the eggs.
After a 3 month period of incubation she will help
the young to hatch by opening the nest.
WHAT'S THE DIFFERENCE BETWEEN an ALLIGATOR and a CROCODILE?
There are 23 living species of crocodylian, and in fact
not all are properly alligators or crocodiles,
as the Indian gharial (Gavialis gangeticus) is in a
separate crocodylian lineage.
While some books use the word "crocodile" specifically
for one of the crocodylids or "true crocodiles"
(members of Crocodylus and Osteolaemus), others use
"crocodile" to refer to any crocodylian, or even to
a larger group of animals including Crocodylia and
some extinct creatures not beloning to Crocodylia in the
strictest sense.
So, the question "what's the difference between an
alligator and a crocodile?" can be difficult to answer.
A crocodile should be considered to be one of the the
eleven living species of Crocodylus.
HOW ARE CROCODILES DIFFERENT FROM ALLIGATORS???
Many popular books state that alligators have blunt
snouts, and crocodiles have narrow, pointed snouts.
To tell a crocodile from an alligator, look at the
lower front teeth. On both sides of the lower jaw
of crocodiles, the fourth tooth from the front of the
snout is visible, when the animal's mouth is closed.
When an alligator's mouth is closed, you can't see any
of its lower teeth.
The alligators' coloring is darker than that of
crocodiles.
If you hear one of these big reptiles bellowing,
it's an alligator. Crocodiles don't bellow and are
less vocal in general.
Conservation biologists have urged that alligators be
kept on the Endangered Species List until the crocodile
can also come back. In that way, the crocodile won't
suffer from so many cases of mistaken identity.
WHY ARE THESE GIGANTIC REPTILES ENDANGERED?
An Endangered Species is one that is in immediate
danger of becoming Extinct.
For these species, immediate intervention and action is
required
in order for them to survive.
- Of the 22 remaining species of crocodilians (crocodiles,
alligators and gharials), 17 are considered to be in
grave danger of extinction.
- Historically, alligators were depleted from many parts
of their range as a result of market hunting and loss
of habitat.
- 30 years ago many people believed this unique reptile
-
would never recover.
- In 1967, the alligator was listed as an endangered
species (under a law that preceded the Endangered Species
Act of 1973), because it was considered in danger of
extinction throughout all or a significant portion of
its range.
- A combined effort by the U.S. Fish and Wildlife Service
and state wildlife agencies in the South saved these unique
animals.
- Alligator hunting was prohibited, allowing the species
to rebound in numbers in many areas where it had been
depleted.
- As the alligator began to make a come back, states
established alligator population monitoring programs
to ensure alligator numbers continued to increase.
- In 1987, the American alligator fully recovered and was
removed from the list of endangered species.
- Although the American alligator is secure, some related
animals are still in trouble.
- Because of this, the Fish and Wildlife Service still
regulates the legal trade in alligator skins, or products
made from them, in order to protect these endangered
animals with skin that is similar in appearance, but
illegal in the commercial market.
- The populations of the American crocodile have greatly declined.
- One reason is that it was hunted for it skin.
- Its habitat has been destroyed.
- Human population pressures in southern Florida take an
additional toll on young crocodiles.
- Dams built to supply water for homes, cities and farms
greatly reduce the flow of fresh water from Lake
Okeechobee into Florida Bay.
- The salt content of the bay is rising dramatically.
- Adult crocodiles can tolerate salt water, but
hatchlings can't. They need fresh water to survive.
- Alligators are one of the principal threats to
crocodiles. But the threat is not directly from the
alligators themselves, but from people.
- As most people can't tell the difference between the
crocodiles and alligators, many a crocodile has been killed
because it was confused with an alligator.
TO HELP PROTECT THE CROCODILES
What is Being Done:
- There are several organizations that are working hard to
help by educating the public on the protective measures.
- Help the captive-breeding programs.
- Help the wildlife refuges.
- Help enforce the CITES trade restrictions.
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