American alligator
American alligatorAlligator mississippiensis is in the family Crocodylidae. This family has existed since the upper Triassic period, but the modern family members appear in the fossil record as little as 80 million years ago. There are three subfamilies, Alligatorinae, Crocodylinae, and Gavaialinae. Some people also include a fourth subfamily, Tomistominae, which contains a single species, the False Gharial. Alligatorinae includes the American and Chinese alligators and the caimans. Crocodylinae includes the crocodiles. Gavaialinae contains the gharials (or gavials). The alligators are unusually tolerant of cold and have been found frozen in ice at the most northern parts of their ranges (Beck).
PROTECTION STATUS
All of the family Crocodylidae is endangered. However, the American alligator has undergone a dramatic population resurgence because of human protection. Restrictions are still in place on capturing alligators from the wild (Beck). Studies have shown that using hormones such as norethindrone can be used to feminize alligator embryos at the male producing temperature (Lance, 79). This could lead to a way to help alligators increase in numbers of both sexes as well as help other members of the family Crocodylidae. Alligators are important ecologically and are dependent on the spatial and temporal patterns of water fluctuations. Patterns of courtship, mating, nesting, and habitat use are all dependent on marsh water levels. Alligators are a great study organism to study the adaptations and responses to the seasonal changes to the hydrological conditions in the everglades. Alligators seem to be able to adjust the height of the nest egg cavity based on the spring water levels, which historically indicated the water levels later in the nesting season. Water levels also determine the availability of food therefore affecting the patterns of growth and survival. Alligators are most abundant in central sloughs, which is probably due to recommendations regarding managing hydrological conditions for alligators focused on maintaining alligators in central slough habitats (Mazzotti, 485).
PRIMARY HABITATS
The American alligator is one of the keystone species in the Florida everglades and other marsh systems. It is the only large, abundant, widespread nonmarine carnivore left in the southeastern United States (Mazzotti, 485). They are spread as far west as reserves in Texas, and their northern boundary is in South Carolina.
REPRODUCTION
The interesting thing about alligators is the temperature determination of sex. At 29�C all females will be produced. At 32�C all males are produced. Temperatures in-between will produce mixed sets of young. The lower the temperature the less yolk there is for the young, there fore the young turns out smaller and female (Allsteadt, 76). It would be the opposite for warmer temperatures. The female alligator chooses the nest site, which in turn determines the sex of the young. The sex of the young is determined in the first two-thirds of incubation. During the final third of incubation the quality of the...
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