The Newsletter of the Minnesota Herpetological Society
August 2004
The alligator walks with the body mass high off the ground, the only thing dragging being the tail, and the legs are vertical under the body. The walking sequence is much like mammals in that they alternate front left to rear right and front right to rear left. When the gator is frightened, physics works to it’s disfavor and it is not able to support the weight while moving quickly. This results in the legs splaying out to the side and it dragging it’s belly on the ground while being propelled across land by the legs and the tail. In the water, the limbs are held to the sides and the alligators is propelled by the graceful side to side sweeping of it’s powerful tail.
Osteoderms The back of the alligator is covered with boney scutes or osteoderms, giving them their bumpy appearance. One function of these scutes is to provide protection to the alligator in the event of an attack as well as to serve in temperature regulation. These scutes contain hundreds of
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reverse effect takes place. Additional thermal regulation is accomplished by holding the mouth open much like a panting dog.
Osmoregulation Alligators, while able to live in somewhat brackish waters, do not possess the advanced abilities of the American or saltwater crocodile to osmoregulate, or rid their bodies of excess salts. Glands on the tongue are used for this purpose but with limited capability. Alligators (and crocodiles for that matter) can not drink salt water for the same reasons as humans.
The Brain The brain of crocodilians includes a cerebral cortex, the area of the brain where thought occurs, unique among reptiles. This advanced brain pushes the crocodilians to the front of the reptilian line where intelligence is concerned. There are many documented and anecdotal stories about the ability of the crocodilians to adapt to new situations, including learning habits of animals around them and learning and responding to a name or other stimuli such as a noise, light or regular, recurring events.
Circulation
The osteoderms are the boney scutes prominant on the backs of all crocodilians. They are used for protection and thermo-regulation
tiny holes through which blood passes. When the alligator is laying in the early morning Sun trying to warm up, the dark skin on it’s back absorbs the heat and transfers it into the scutes which act as little radiators by quickly warming the blood that is flowing through them. This blood is then circulated deep into the body mass thereby quickly warming the animal to it’s preferred body temperature of 88 degrees F. Conversely, if the alligator gets too hot, it can either move to the shade or the water where the
All Crocodilians have a four-chambered heart, as do mammals, other reptiles have only two. This advancement allows better efficiency of blood circulation and separates oxygenated blood from deoxygenated blood. Alligators, as all crocodilians, can control to a certain degree either by speeding up, or slowing down, blood flow to various parts of their body. It is advantageous, for example, that the alligator slow the blood flow to organs such as the lungs during extended periods of time under water. This preserves oxygenated blood for the heart and brain during a time when the lungs are not in use.
Dentition and Bite Force Alligators, as are all the members of the family “Alligatorinae” (American and Chinese alligators and all caimans) can easily be differentiated from their distant cousins, crocodiles, by the presence of an overbite. The top jaw is larger than the lower jaw so when the jaws are closed, the top teeth close over the lower jaw. The fourth tooth in the upper jaw of the alligators and their cousins, the caimans, is the largest tooth in the mouth. This is different than the Page 9