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When
thinking about animals and how they impact a particular habitat, probably the
first to come to mind is the beaver and the dams they create flooding areas to
create their own swimming pool and restaurant.
Although they cause more changes than most, they are not the only form of
wildlife to do this. Another animal
that does this is the American alligator as they do their own water management
control, creating deep-water pools called "alligator holes."
On
occasion, alligators will move into existing holes at the downstream end of a
slough or into an acid-created pothole on a tree island, but more often than not
they create these holes by digging one where their instinct tells them the water
table is close to the surface. They
enlarge and deepen their holes by breaking the ground with their powerful tails
and using their snouts to shovel debris up onto the rim of the pool.
This
action benefits the whole area. Over
time, a dense thicket of willows and other plants begin growing on this
tossed-up mulch. While beneficial to the habitat, this is not the main reason
the alligators create these holes.
The
pools are much like a beaver pond in that other animals are attracted to the
area. By keeping the center open
and free of choking vegetation, this open water attracts fish, frogs and other
edibles, which in turn attract birds and mammals that also become part of the
alligators' menu.
These
alligator pools, during the very dry times of the year, can remind you of the
water holes in the African Serengeti. These
are excellent areas to look for when out shooting in locations such as the
Everglades as you can see concentrations of raccoons, river otters, spiny
softshell turtles and a wide variety of snakes and waterbirds.
Without
these alligator holes, many groups of fish and aquatic invertebrates would not
be able to withstand the droughts, thus they are able to wait these periods out
and emigrate in the spring to repopulate the flooded plains.
Alligator
holes are not the only unique behavior offered up by these animals that have
survived from pre-historic times. After
mating, the females build a nest that rivals any in the natural world using
decaying vegetation as a natural composter where the heat of the decomposition
keeps the eggs warm.
The
female begins the process by clearing a site for her nest by tearing vegetation
out by the roots, mashing it down or scissoring it off with her large jaws.
She then piles the vegetation into a cone-shaped mound, using her snout
and tail to push it tightly into place.
She
makes frequent trips to the nearby water to gather additional water plants to
build up the cone, which she finally levels at the top.
Then, to form a bowl-shaped hollow in the top of the mound, she begins to
pinwheel on her belly, pushing off with one foot.
Into the hollow, she packs mud and more aquatic plants until it is filled
to the top again.
She
then hollows out a small depression in this liner, just large enough to lay her
eggs, which number between 25 and 60. Using
debris she has pulled from the nest, she covers the eggs and then smoothes the
large cone with her body.
When
finished, the nest measures 5-7 feet in diameter and 1 1/2 to 3 feet high.
The
eggs incubate for nine weeks, with the female standing guard nearby.
NOTE - Although coming across one of these nests may give you some
interesting photo opportunities be careful as the females are very protective
and more dangerous now than at any other time and will attack without notice.
The
compost serves a vital role in the birthing process.
Research has found that if the eggs are kept below 86 degrees F they will all
turn out female and if kept above 93 degrees F they will all be male.
The female helps control the temperature of the nest by alternately
letting it dry out and wetting it. More
often than not she does a good job as most broods appear to be an even mix of
males and females. The 8" to
10" hatchlings stay with their mother for up to a year and a half until
they reach adult size.
Behavior
DIET
- Their primary food is fish, but they also eat waterfowl and small mammals that
venture next to the water's edge. You
can also see them under heron colonies, waiting for a nestling to fall out of
the nest and into the water.
When
eating a meal underwater they are able to seal their air passage with their
tongue so as not to drown while eating. If
their prey is too large to be swallowed on a single gulp, they may shake it
violently until it breaks apart.
CALL
- Male alligators have a throaty, bellowing roar during breeding season.
As he roars, glands under his chin spray out a musky fluid that can be
smelled by other alligators for several miles.
The female bellows too, but not as loudly as the male. Young alligators have more of a muted moaning type of grunt.
Hot
Spot
A
trip to Myakka State Park in southwest Florida will provide you with all of the
alligators you'll ever want to find. Just
after you enter the park look around the bridge area as they can be found here
at most any time of the day as well as many other shoreline locations,
especially near the boat docks. Myakka
State Park is located off of I-75 south of Sarasota.
__________________________
Andy Long is a freelance
photographer and writer based in Lakewood, CO.
He has been leading workshops throughout North America for five years,
offering hands-on help and area expertise.
An assistant editor of Nature Photographer magazine, he has credits in
more than 30 books and publications including Montana Outdoors, Audubon Field
Guides, Wildlife Detectives, Colorado Division of Wildlife, and Outdoor &
Nature Photographer as well as having his work featured on National Geographic
Television International. He has
also conducted seminars as part of Nature First Photo Seminars, New England
Council of Camera Clubs annual seminar and others.
His work has also been part of the Art Wolf Invitational Exhibit and the
Rosewater Network travelling exhibit. To
view and purchase prints of his work you can go to: www.prophotoprints.com/Search.asp?PhotographerID=46
For information on his workshops you can contact him at firstlightfoto@aol.com
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