The American Crocodile Essays (2399 words) - Crocodylidae

The American Crocodile (Crocodiles acutus) Crocodylus acutus, or more commonly referred to as the American crocodile, ...is the second most widely distributed of the New World crocodiles, ranging from the southern tip of Florida, both the Atlantic and Pacific Coasts of Southern Mexico, as well as the Caribbean islands of Cuba, Jamaica, and Hispaniola (1 Species). These areas provide the perfect climate for these endangered species that have roamed the earth for over 200 million years. Florida is known for its large population of American alligators, which are often confused for the rare American crocodile. However, there are vast differences between the two species. Hunted for their hides and the changing of their habitat to beach front property is slowly pushing the American crocodile out of Florida, the only place it is found in the United States. For 190 million years before the first humans evolved, huge populations of crocodilians, in more or less their present form, inhabited the waters and shorelines of rivers, lakes, swamps, and estuaries of tropical and subtropical lands. Today they represent the last true survivors of the huge reptiles that once dominated the seas and landmasses of Earth for over 200 million years (6 Levy). However, ...It is inappropriate to treat crocodilians as living fossils whose inferiority forced them into a marginal ecological role as amphibious predators in a world now dominated by mammals. In fact, they are highly specialized for their particular mode of life and have undergone considerable changes during their long evolutionary history... (14 Ross). Among living vertebrates, crocodilians are most closely related to birds rather than to lizards (14). Even though these two groups are now adapted to different modes of life, they both have an elongate outer ear canal, a muscular gizzard, and comp lete separation of the ventricles of the heart. Crocodilians are the most advanced of all reptiles. They are elongated, armored, and lizard-like, with a muscular, laterally shaped tail used in swimming. The snout is also elongated, with the nostrils set to the end to allow breathing while most of the body remains submerged under water. The success of the Crocodile is evidenced by the relatively few changes that have occurred since crocodilians first appeared about 200 million years ago. The Crocodile belongs to the family Crocodylinae, which consists of those organisms sharing common crocodilian traits. This Family is further divided into three subfamilies: Alligatorinae (alligators), Gavialinae (gharial), and Crocodylinae (crocodiles). Very often the American alligator (Alligatorinae mississippiensis) is confused for an American crocodile, even though these two species are of the same family they are different in many ways. The alligator has a much broader snout and the crocodile a much narrower snout- ...narrower snouts usually indicating fish eating-species. Another characteristic seen in the American crocodile and not the alligator is the front two teeth that penetrate the upper jaw from below as they grow. These teeth are one of the major differences between crocodiles and alligators. A not so recognizable difference between the American crocodile and alligator is the crocodile's ability to regulate saltwater balance in their body. Crocodiles maintain salt concentrations in their body fluid at the typical level of other vertebrates, which is about one-third that of seawater. The osmoregulatory problems posed by life in fresh or saline waters are related to the amounts of water and salts exchanged across various body surfaces. Loss of salts and water occurs in feces and urine, through respiration, excretion from salt glands in the tongue, and through the skin. The ability of the American crocodile to tolerate salt water is related to their low rate of water loss, low rate of sodium uptake, the ability to excrete excess sodium, and their ability to osmoregulate regularly behaviorally by not drinking saline water or by seeking fresh water after feeding in saline areas. [The American crocodiles will not drink seawater even when they are dehydrated and the American all igator will. However, the alligator does not have the ability to excrete excess sodium]. While the American Crocodile is able to regulate its salinity it is not able to maintain a constant body temperature. Crocodiles, like all reptiles, are cold blooded or pokilothermic. Crocodiles utilize a complex series of physiological and behavioral mechanisms to maintain an even body