Between them they muster 22 living species. Although they have been around for about 300 million years, none of the ancient crocodiles survives today - perhaps just as well for those humans living in crocodile habitats. As someone has said, if you jump into a river full of crocodiles, you can expect to be killed. However, the Indian mugger crocodiles, although growing up to 12ft in length, are normally placid and have a good temperament. Crocodiles are found mainly in Africa, Asia and northern Australia, with one species found in North America.
Alligators are very similar to crocodiles, although generally less aggressive.
In the other families, this tooth fits into a socket in the upper jaw and is thus concealed when the jaws are shut. In the US, alligators are normally protected species, but inevitably conflict with humans has occurred as the latter have encroached on alligator habitats with new homes. The Chinese alligator is a smaller species, only reaching 6 ft, but is rarely seen outside its natural habitat, let alone for sale in the West. The snout appears abnormally elongated and armed with rows of sharp teeth, but in fact this creature is largely harmless to man as it feeds exclusively on fish. Though growing up to 20 ft long, gavials are in fact quite shy, and the jaws themselves somewhat delicate considering their appearance.