American Crocodile: Species Profile
Crocodiles and alligators belong to a group of reptiles called crocodilians, which are the largest of the living reptiles. Of the 23 different species of crocodilians in the world, 2 species are native to the United States, and south Florida is the only place where both of these species coexist. The American alligator (Alligator mississippiensis) ranges throughout the southeastern United States, and Everglades alligators exist at the southern extreme of their range. American Crocodiles (Crocodylus acutus), on the other hand, inhabit coastal areas of south Florida where they are at the northern extreme of their range. American crocodiles also can be found on the islands of Cuba, Jamaica, and Hispaniola, as well as along both coasts of southern Mexico and Central America, south to Ecuador on the Pacific coast of South America, and Venezuela on the Atlantic coast.
At first glance crocodiles can be difficult to distinguish from alligators, but closer inspection reveals several important differences. The American crocodile is lizard-shaped with a long, muscular tail and four short legs that have five toes on the front feet and four on the back feet. Adults have grayish-green backs and tails and white to yellowish undersides. Their narrow snout is triangular in shape, and the fourth tooth on both sides of the lower jaw is visible when the mouth is closed. The ear drums are protected by moveable flaps of skin at the top of the head behind the eyes, and the nostrils are at the end of the elongated snout. Because of the location of the eyes, ears, and nostrils, a crocodile can be submerged with only the top of its head exposed and still be able to see, hear, and breathe. Male crocodiles are larger than females and can reach about 20 feet in length but rarely exceed 14 feet in the wild. Breeding females are about 8 to 12 feet in length.
Alligators are more numerous in Florida than crocodiles, are darker, have a broader snout, and are typically found in freshwater habitats. Crocodiles, on the other hand, are rare and secretive creatures that inhabit coastal, brackish, and salt-water habitats. Although the aggressive reputation earned by the American crocodile’s distant, larger, man-eating cousins in Australia and Africa may inspire fear of crocodiles inhabiting the Everglades, conflict with humans rarely occurs because of the shy nature of American crocodiles. Like alligators, crocodiles are ectothermic, meaning they rely on external sources of heat to regulate their body temperature by basking in the sun or by moving to an area with warmer or cooler water. A basking crocodile may be surprised by an approaching person and quickly (and noisily) enter the water. This behavior might startle the person, but it should not be misunderstood. Crocodiles normally enter the water quietly; splashing away indicates that the crocodile is frightened and feeling stressed. Crocodiles sometimes can be seen sunning with their mouths open. This behavior is also a way of regulating body temperature and does not mean that the crocodile is acting aggressively toward people.