Crocodylus acutus. By Ken Mayer.



Meet the Alligator's Distant (but Local) Relative



Introduction  |  Taxonomy, Phylogeny & Etymology  |  Distribution & Population  |  Ecology

Anatomy & Physiology  |  Diet & Digestion  |  Reproduction  |  Survival  |  Human Conflict

Cultural & Commercial Impact  |  Suggested Publications  |  References




American crocodile basking.AMERICAN


Crocodylus acutus


Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Superorder: Crocodylomorpha

Order: Crocodilia

Family: Crocodylidae




(Image: Georgiana Wingard, U.S. Geological Survey. Public domain.)



Anatomy & Physiology


An alligator and American crocodile swim by eachother.As a crocodilian, the American crocodile's body is generally similar to the alligator's, so you may refer to the profile of the American Alligator's anatomy and physiology for general reference. Some differences are featured ni this section.


The main anatomical differences are hide color and pattern, scale arrangement and size. This reptile is one of the larger crocodilians, even larger than the alligator, attaining lengths of 16 ft/5 m, though larger sizes have been reported but unconfirmed. The males grow larger than the females. Babies at hatching are a mere 10 in/25 cm. What is perhaps the largest living individual of the species, measuring about 15ft/ 4.6m in length, is kept at Gatorama, a long-standing roadside attraction near Florida's Lake Okeechobee.


In the image above, the crocodilian cousins' physical distinctions are readily seen as an alligator (at top) crosses watery paths with a crocodile.


Another contrast with the alligator is the crocodile's tapered snout, more "acute" than the broad head of the other. The crocodile's 'scutes', those keeled, armor "tiles" on its neck and back, are fewer in number than the alligators, and more irregularly arranged.



Adult captive American crocodile.

The captive adult specimen shown above displays a remarkably unworn hide, rendering its "keels" very sharp. The American crocodile's arrangements of bony plates and hide protrusions are quite distinctive among crocodilians.



American Crocodile at Everglades National Park.Note, in these photographs (above and at left), striking differences of the head compared to that of the alligator.

(Image at left: National Park Service)


The head is of an arrow shape rather than broad and robust; the nostril pair, at the tip, appear as a "button" rather than simply two slits; the fourth tooth of the lower jaw on each side fits into a notch in the upper jaw, a feature of all "true" crocodiles, and its upper teeth show prominently when the jaws are closed, which usually is not the case with the 'gator cousin.


The crocodile's coloration is lighter than the alligator's. Unlike the typically dark coloration of the alligator, the crocodile is olive green in appearance, with darker patches, but water disposition, solar exposure, temperature, and the presence of mud may alter the color. The coloration as camoflage obviously matches a marine-dwelling environment better than the darkwaters of the inland, which the alligator's colors match well. The subject of camoflage is discussed further in the "Survival" section.


Note the slight hump in the snout just in front of the eyes; this feature may have come from genetic mixture with the nearby Cuban Crocodile (Crocodylus rhombifer).


The tip of the tail of an American crocodile, just above the water's surface.The tail of the crocodile holds "keels" or "whorls" which cut through the water as it swims; the tail is the primary means of aquatic propulsion for crocodilians.


The crocodile has the ability to regulate salt in the body (osmoregulation), something that the alligatorids (alligators and caimans) are unable to do. This ability is discussed further in the "Distribution & Population" and "Ecology" sections.


Like all reptiles (and amphibians), the crocodile is ectothermic, specifically poikilothermic, meaning that its body temperature varies because it cannot regulate its own temperature (as a mammal does) and thus is completely at the mercy of climatic conditions of its environment.


You may refer to the "Diet" section for more information on the digestive system of the crocodile.


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