Wednesday, January 7, 1998
Today we visited the Louisiana Swamp Exhibit at the Audubon Zoo and the Mississippi River Gallery at the Audubon Aquarium of the Americas. We saw many different environments representative of those that line the Mississippi River.
Bayous are marshy creeks or minor river tributaries that branch off from the Mississippi River and wind their way inland. A small boat can usually maneuver along these thin little rivers. Marshes are grassy or weedy wetlands where the soil is generally saturated. Swamps are similar to marshes, but they are also heavily forested and flood seasonally because they are so close to the water table so standing water sticks around for a while.
The most common type of tree found in the forested swamps of the South is the Bald cypress tree. More commonly called the cypress tree, it thrives in this water-soaked region and can grow to be as much as 140 feet tall, over 5 feet in diameter, and live as long as 1,000 years.
The first settlers found the tree to be mystery, calling it "the tree with knees." The cypress tree has a large, fluted buttress-like base with uncommon vertical growths that extend up through the water from the roots. To this day, no one is exactly sure of the benefit of the unusual design of the tree. Some speculate that the cypress "knees" are necessary for support in the saturated soil of the swamp, others believe the curious bumps draw in air to help the roots "breathe."
There are also many curious creatures that inhabit these areas. Among them are playful river otters; unique-looking, long-nosed fish called gars; enormous alligator snapping turtles; and white American alligators.
What we found interesting about the White alligators was that they are not albino as we had guessed. Albinos lack pigment in their skin and eyes. These alligators did not have the pink-colored eyes of a true albino. Instead, their eyes were blue and some had small spots of pigmentation on their heads. These alligators are leucistic, meaning their condition is the result of a genetic mutation of the recessive or "masked" gene. The condition is rare, even more rare than albinism. The white alligators were discovered in 1987, and to this day, they are known to be the only alligators of their kind.
Do you know what the differences are between alligators and a crocodiles?
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