Hobbies And Interests
Instructions
Consider major morphological differences. The Australian freshwater crocodile, for example, gives the impression of extreme slenderness: Its snout is exceedingly narrow almost resembling that of the big fish-eating crocodilians called gharials. The mugger or marsh crocodile of India, by comparison, has thick robust jaws: So broad, in fact, that they resemble those of an American alligator.
Compare the sizes of the different crocodile species. This varies widely between species. The African dwarf crocodile barely reaches 6 feet in length, while some of the biggest species -- the Nile and Indo-Pacific crocodiles, most notably -- may exceed 20 feet and weigh over a ton, though animals of such size are very rare.
Think about the distribution of modern crocodiles, which is restricted to the tropics and subtropics. Certain areas harbor a number of different species. Parts of India host both the mugger crocodile and the Indo-Pacific crocodile, while a given swamp in West Africa might be home to Nile crocodiles, slender-snouted crocodiles and African dwarf crocodiles. The American crocodile is one of the more northerly kinds: It roams the subtropical mangrove swamps and keys of southern Florida, while colder temperatures farther north in the state limit its distribution. Here it is the only true crocodile -- but not the only crocodilian, as it shares space with the American alligator.
Investigate the ecological differences among crocodiles. All share certain basic lifestyle traits: They are most at home in water, they lay their hard-shelled eggs on land, they are wholly carnivorous and all are ectothermic, meaning their body temperature is dependent on that of the ambient environment. But differences in habitat preference do exist. The Indo-Pacific crocodile, also called the estuarine or saltwater crocodile, largest of all living reptiles, readily takes to marine waters; indeed, it may cover hundreds of miles of open ocean by riding prevailing currents. The American crocodile shares this predilection, explaining its presence in the Caribbean and South Florida. Other species are more commonly found in freshwater rivers, swamps and lakes.
Consider crocodiles' predatory strategies and diets. Preferred prey seems mainly dependent on ease of capture and the size of the crocodile. Smaller species consume mainly fish, invertebrates and small mammals, as do younger specimens of larger-growing crocodiles. The biggest animals easily tackle large mammals, employing a sit-and-wait, ambush method of hunting. Nile crocodiles in Africa may target creatures as large as wildebeest, zebra and buffalo, forced to approach crocodile-haunted rivers to drink or during long-distance migrations.