Taxonomy, Phylogeny & Etymology |
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Anatomy & Physiology
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(Image: Georgiana Wingard, U.S.
Geological Survey. Public domain.)
Anatomy & Physiology
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
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
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.
in these photographs (above and at left), striking differences of the
head compared to that of the alligator.
(Image at left: National Park
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"
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).
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
(alligators and caimans) are unable to do. This ability is
discussed further in the "Distribution
& Population" and "Ecology"
Like all reptiles (and amphibians), the
crocodile is ectothermic,
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
You may refer to the "Diet"
section for more information on the digestive system of the
on a link from the menu atop this page to navigate this article.