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| The American Alligator, Alligator mississipiensis (Daudin, 1802). Photographs of a captive (top), two basking in Okeefenokee Swamp, Georgia, and two photographed in central Florida (bottom two). The American Alligator. Inhabits the coastal plain of the southeastern USA.from North Carolina to the Florida Keys and westward to eastern Texas and as far north as Arkansas. Maximum size is 5.84 m, but rarely do they exceed 5 m. Alligators in habitat a variety of bodies of water ranging from large swamps and marshes to rivers, ands man-made ponds. While it usually occurs in freshwater it may enter brackish water, and the ocean. Females construct a nest of vegetation and lay 20-70 eggs (the usual number is about 30). Diet is variable and changes somewhat from one population to another, with eastern populations. Larger vertebrates as well as invertebrates are eaten. |
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| The Spectacled Caiman, Caiman crocodilus (Linnaeus, 1758). Photographs: skull from Trinidad; the following three photos are a juvenile from Costa Rica. The Spectacled Caiman ranges from southern Mexico to northern Argentina. It occurs on several islands including Trinidad and Tobago, and it has been introduced into Cuba, Puerto Rico, and southern Florida. Maximum size is 2.6 m, but specimens over 1.8 m are uncommon. Females construct a nest of vegetation and other debris. Clutches of 18-40 eggs are laid in the nest and the nest is attended. Food includes a variety of vertebrates and invertebrates. |
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| The Salt Water Crocodile, Crocodylus porosus Schneider, 1801. Photographs: Singapore crocodile farm (top); northern Australia; a juvenile from Sabah, Malaysia (bottom two). Salt Water Crocodiles are probably the longest crocodilian species living today, adults may exceed 7 meters, but individuals of that size are rare. They range from Southwestern India and Sri Lanka to Indochina , the Philippines, Australasian, and eastward to the Solomon Islands, Fiji, and Palau, and Ponape. |
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| Crocodiles are more closely related to birds and possibly turtles than to any other living animals. They are part of the Archosauromorpha which includes the dinosaurs as well as phytosaurs, birds, and pterosaurs. Morphology that places crocodilians and birds together includes: cervical ribs with two heads, as well as the concave-convex articulation between the astragalus and calcaneum. These combined with social behavior and parental care suggest a common ancestor. The three subfamilies of Crocodylia are often considered as separate families: Alligatorinae, Crocodylinae, and Gavialinae. The relationships of Tomistoma within the Crocodylia are uncertain because of a conflict between morphology and molecular studies. There are about 23 species of living crocodilians, a small number compared with the diversity of the Mesozoic. They are a group that is in the process of becoming extinct naturally, but this has been enhanced with the help of humans. There is some evidence that individuals may cooperate with each other during hunting, they have complex courtship behavior, and they all show parental care. Sex is determined by the temperature at which the embryo is at during a critical period of development. |
