Today there are something like twenty-two species of reptile that make up the Order Crocodylia. Of these species; only thirteen are actually true crocodiles, the remainder are Alligators, Caiman and the extremely rare and endangered, long-snouted gavials, sometimes referred to as gharials. We often get asked how to tell the difference between a crocodile and an alligator. There are a number of anatomical differences between crocodiles and alligators, when observing these reptiles look for a large, fourth tooth in the lower jaw. When the mouth is closed this tooth fits into a notch in the upper jaw and the tooth remains visible even when the mouth is closed. If you can see this tooth, then you are looking at a crocodile. There are only two species of Alligator left in the world. Firstly, as most people know, there is the American alligator (alligator mississipiensis), which can be found widely distributed across the south-eastern United States, most typically in the Florida Everglades. There is also a second extant species of alligator, although this one is much rarer and confined to the upper Yangtse River valley in China. Scientists had thought that the less aggressive alligator had been "weeded out" of its range by crocodiles, leaving the only representatives of the Alligatoridae family in these isolated pockets. The more efficient crocodiles grew faster and may have been better at consuming food but this is generally regarded as speculation - as in the case of the American alligator, this species competes with the native American crocodile (C. acutus). The American alligator can withstand cold spells far better than the American crocodile, and as a result, has a much more extensive range in the United States. Article Source: http://EzineArticles.com/6470054
