Although no single reptile can be considered typical of all reptiles, the alligator is as good a representative as any, since it has a backbone, is cold-blooded, lays eggs with shells and has a reptilian skin--i.e. slated, scaled or shell-like. Nevertheless it has advanced features which are peculiar to it. Its four-chambered hearts of other reptiles, which tend to mix freshly oxygenated blood with unoxygenated blood. Its respiratory system is better. The nostrils are separated from the mouth by a hard palate. When the alligator swallows a struggling victim there is no danger that a damage its brain. The alligator has well-developed lungs in comparison to the more primitive sac-like structure of snakes. It has the most highly developed brain of any reptile, and is one of the few to have its teeth firmly set in its jaws.
On the other hand, the alligator lacks a well-developed Jacobson's organ, which means that its ability to detect tastes and odours is not nearly so acute as a snake's. It has the well-developed digestive system which works so efficiently for all reptiles, but lacks a bladder, although most turtles and lizards have one. As a result, the alligator must pass its urine, along with solid wastes, into a chamber called the cloaca, which opens to the outside of the body.
Significant features of the Alligator are given below,
Mouth: To achieve its characteristic gape, the alligator does not merely drop its lower jaw but raises its head and upper jaw. The teeth are used for seizing and holding prey. Teeth are not for chewing.
Stomach: Because an alligator cannot chew, its stomach has two parts, which are a muscular gizzard and a digestive section. The gizzard's grinding of food is aided by swallowing hard objects.
Heart: Blood passes from the right ventricle through the pulmonary artery for oxygenation by the lungs; it returns through the left atrium to left ventricle, and is pumped out to the body.
Scales: The alligator's armour is composed of horny scales, each developing on it's own and replaced by layers from below. Those shielding the back and tail have bony plates beneath them.
