Image (c) Adam Britton, crocodilian.com
Order: Crocodylia
Family: Crocodylidae
Subfamily: Alligatorinae
Genus & Species: Alligator mississipiensis
APPEARANCE
American alligators and American crocodiles are very similar in
appearance, but can be distinguished by comparing their mouth. In
alligators, the upper teeth lie outside the lower when the mouth is shut,
whereas with crocodiles the upper and lower teeth are in line. In both
species, the fourth lower tooth on either side of the jaw is larger than the
rest. With the American alligator this tooth fits in to a pit in the upper jaw
and cannot be seen when the mouth is closed. With American crocodiles,
the tooth fits into a notch in the upper jaw and is visible when the mouth is
closed. The American alligator's head is also blunter and shorter, and the
snout is blunter as well. The American alligator is larger and stockier than
both the American crocodile and the Chinese Alligator.
American alligators are generally a dark bluish, green, or brown in colour
when fully grown. The juveniles are black with bright yellow crossbands.
The Western population of American alligators differs from the Eastern in
that their young have white speckles on the jaws and the crossbands are
paler. As the young grow, these bands disappear. Across the back is a
protective armour underneath the leathery skin. These form rows of bony
knobs, which disappear at the tail and are replaced by two rows of longer
triangular knobs, which then converge in the center of the tail to form one
row which gets smaller the farther down the tail it goes. Even with the
armour, American alligators are very flexible.
American alligators are very lizard-like in appearance, with a long, stocky
body, a powerful tail, and four stubby, squat legs ending in webbed feet.
The eyes, nostrils, and ears are located on the same plane, allowing all but
them to be submerged underwater. Sexual dimorphism is present, with
males being 11-12 ft (3.3-3.6 m) and females 8-9 ft (2.4-2.7 m) in length.
They weigh between 400-500 lbs (180-228 kg). Larger specimens are rare
today due to overhunting of the large gators in the past.
American alligators have between 74-80 teeth in their mouth. They have a
life span of 30-35 years in captivity, 40-50 in the wild.
They can be quite vocal, and will hiss at intruders. During the mating
season they also make sounds at a frequency to low for us to hear.
HABITAT
American alligators are found in parts of Georgia, Florida, Alabama, Texas,
and South Carolina. They prefer freshwater, but will live in brackish waters.
They can be found in swamps, marshes, rivers, lakes, ponds, wetlands,
mangrove swamps, and manmade bodies of water.
American alligators dig burrows known as "gator holes" which fill with
water and enure them water during the dry season. These underground
hollows reach lengths of 65 ft (19.5 m) and are used to retreat to during the
colder weather.
FOOD
American alligators will feed on almost anything alive. Juveniles feed on
tadpoles, insects, shrimp, and frogs. Adolescents feed on small fish and
snakes. Mature gators eat raccoons, muskrats, fish, birds, turtles, snakes,
deer, other alligators, carrion, etc. They have been known to attack
humans. Larger prey is seized by the alligator and drowned underwater.
ENEMIES
Juvenile alligators are attacked and killed by fish, birds, mammals, and
larger alligators. Their main threat at one time was humans, who hunted
them almost to extinction just to use their hides for clothes and accessories:
coats, shoes, purses, wallets, etc. Today hunting is prohibited. Another
indirect cause to their dwindling population was their use as pets; when they
got too big they were given to zoos, killed, or released into the sewer
system. American alligators have made a comeback. They are today ruled
as threatened.
BREEDING
American alligators reach sexual maturity when they attain a body length of
6 ft (1.8 m). The breeding season is generally in the spring, and they mate
after an elaborate courtship ritual. A nest of rotting vegetation is made on
high ground, and 20-50 eggs are laid in it and then covered with more
vegetation. After an incubation period of 60-65 days, the eggs are ready to
hatch. The female removes the vegetation and carries the hatchlings to the
water's edge. They remain with the females for the next 3 years.
The gender of the young is based on the temperature of the nest during
incubation. Below 30°C- all females. Above 34°C- all male. In between-
both male and female.
RELATIVES
The endangered Chinese alligator is the only other species of alligator.
RESOURCES CITED
1. www.seaworld.org/animal_bytes/alligatorab.html
2. www.csc.noaa.gov/otter/htmls/project/gator.htm
3. Encarta ‘98 CD "Alligator" Microsoft 1996-1998
4. www.flmnh.ufl.edu/natsci/herpetology/brittoncrocs/csp _amis.htm
5. "Alligator" Funk & Wagnall's Wildlife Encyclopedia, 1974, BPC Pub
Ltd, NY, NY
6. "American Alligator" Wildlife Fact File, IM Pub Ltd, USA
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