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Roger Weller, geology instructor

by Patrick Ransford
Physical Geology
Spring 2013



Crocodiles are large aquatic tetrapods that live throughout the tropics in Africa, Asia United states and Australia. Crocodilians, which all members are considered true crocodiles are a biological subfamily.  Tomistoma, alligators and caimans are all part of the subfamily of the crocodiles.  Crocodiles have narrower and longer heads, with a more V-shaped than a U-shaped snout compared to alligators and caimans. The upper and lower jaws are the same width, also the teeth in the lower jaw fall along the edge of the upper jaw when the mouth is closed. 





Crocodiles have more webbing on the toes of there hind feet. They can also tolerate salt water better than any others of the family because they have specialized salt glands just for filtering salt water. There also known as archosaurs, which means they are genetically closer to birds and extinct dinosaurs than other reptiles are.  Crocodiles are biologically similar but there size behavior and ecology differs between species.  They tend to congregate in fresh water such as rivers, lakes and wetland, but also go into saltwater.                                                                                                                                                                                


The size of the dwarf crocodiles gets up to 4.9ft to 6.2ft at the adult age.  A saltwater crocodile get up to 23ft long and can weigh up to 4,400 pounds. Several other species can get up to 17ft long and weigh up to 2000 pounds also.  The largest species of crocodile is the saltwater crocodile as you can see which are found in eastern India, northern Australia surrounding waters. The largest crocodile ever held in captivity is an estuarine–Siamese hybrid that measured in at 20ft long and 2,456 pounds.  These large predators have acute senses that gives them an amazing advantage in hunting. They have very good night vision and are mostly nocturnal hunters. Their sense of smell is also very strong, aiding them to detect prey or animal carcasses that are on land or in water, from far away. They also have nerve fibers that respond to the slightest disturbance in surface water, which detect vibrations and pressure changes in water. This makes them able to detect prey, danger and intruders in total darkness.




            Crocodiles are ambush predators, waiting for fish or land animals to come close and then rushing to attack. Crocodiles mostly eat fish, amphibians, birds, reptiles, mammals and blooded predators which gives them a slow metabolism. Their evolved with sharp teeth for piercing and holding onto there prey. Having very strong muscles in there jaw to make sure that nothing breaks loose from the grip. There teeth are actually now well suited like occasionally turn into a cannibal on smaller crocodiles. They would even attack on very large animals themselves such as buffalo wild boar and deer. The young crocodiles hunt very small invertebrates and fish, gradually moving onto larger prey. They are also cold- sharks or other mammals and you would think this is a disadvantage but this is an advantage. Causing them to never lose grip of there prey and a very small chance of getting away. Crocodiles have immense force when biting down, giving them the strongest by far of any animal.



The saltwater crocodile is very territorial and an aggressive species. A mature male will not tolerate any other male at any time of the year. Usually the largest and heaviest males are at the top, giving it the best basking site. Crocodiles reproduce by laying eggs, which are either laid in a hole or in a mound nests. A holes nest is usually a hole of sand and a mound nest is made of vegetations. The time of nesting goes up to a few weeks up to six months. The relationships between the two have behavioral interactions like snout rubbing and submissive display that can last a very long time. This by one female, also sex is determined by temperature instead of genetically like humans. always takes place in water. The females lay their eggs at night, which takes up to 40 minutes. They are also very protective of their nests and eggs. Crocodiles can have up too 7-95 eggs laid.