American Alligator at Circle B Bar Reserve in Florida.

Meet the Amazing Alligator



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

  Anatomy & Physiology  |  Diet & Digestion  |  Thermoregulation  |  Reproduction  |  Neonate Care  |  Ethology

Survival  |  Human Conflict  |  Cultural & Commercial Impact  |  Conservation


Prime Observation Locations  |  Bibliography  |  Filmography  |  Suggested Publications  |  References



An alli gator afloat in water reflecting the gold of a sunset.AMERICAN ALLIGATOR

Alligator mississippiensis


Kingdom: Animalia

Phylum: Chordata

Class: Reptilia

Superorder: Crocodylomorpha

Order: Crocodilia

Family: Alligatoridae

Genus: Alligator


(Image: istockphoto/LarryLynch)



4. Ecology


A view of the Sante Fe River in Florida.The semi-aquatic reptile makes its home at almost any body of water and on the immediate surrounding land. Major factors affecting its choice include (in no particular order):


Salinity level, since it is not well capable of secreting salt from the body (via salivary glands) as a true crocodile does, in the expulsion process known as osmoregulation. The reptile may settle in brackish waters that contain a tolerable salt volume, though freshwater is optimal. This condition of limited osmoregulation limits the animal's range, as it does not traverse oceans to other land masses as some crocodiles do.


The image above shows the Sante Fe River, Alachua County, northern Florida. This slow-moving river remains a constant 72°F/ 22°C, especially attractive to the swimming reptiles during the winter. (Image Ronald Dupont Jr.)


Proximity to humans, as this condition can serve as a major stressor. However, its desire for a home in limited, untouched habitat may force conditioned behavior in the alligator that desensitizes it to human company, resulting in a willingness to share habitat with people.


Availability of prey. The alligator will take fish, mammals, mollusks, other reptiles, birds - anything in the area that offers a meal of meat.


Access to features that allow it to hide on land, hide in water, such as in dense aquatic vegetation, bask in solar warmth, and rest in shade. An alligator will also excavate soil and mud from the bank of a water body to create a burrow, which may be used for hiding, especially during the winter months when they must lay still under the freezing or near-freezing effect of the cold, and ideal domicile for a mother and her brood. Ideally, a burrow includes a tunnel which may rise above the water's surface to keep its resident from drowning. A burrow may be extensive - 10ft/ 3m to 16.4ft/ 5m - and have multiple rooms.

An alligator burrow in a canal bank.

This burrow complex in a canal in central Florida,  photographed during a dry season at low water level, was constructed under tree roots. While erosion may have revealed the roots, the potential of the site has been exploited into a multi-entry construction, the roots trusses for reinforcement.


• For mature females, access to suitable nesting area.


• For breeding males, water bodies with females. A bull alligator will travel a distance in search of a mate, crossing over dry land or navigating channels of water.


Water movement and temperature. The alligator does not prefer fast-moving water, since this condition makes navigation, hunting, and breeding more difficult. A warm water body is obviously much more appealing to a gator than a chillier, spring-fed one; though, at 72F/22C, a chilly river may feel better than the chilly air during winter. Hence, the alligator's resilience and ability to A Louisiana Bayou.adapt, although limited, renders its comfort relative. Testament to the 'gator's robust manner is its ability to live through a freezing event, practically shutting down its body; read about the gator's fascinating ability to survive in subfreezing temperatures, here.


Seen at right  is a bayou in Louisiana. Water in a habitat such as this tends to move slowly, making it desirable to alligators. Water darkened by natural tannins (from leaves, branches, etc.) provides security for hiding 'gators, especially smaller ones.

(Image: istockphoto/pmstephens)


The reptile's importance to its habitat is so high that it may be referred to as a "keystone" species for multiple reasons, including these discussed below.


An alligator floats beneath nesting birds.The alligator is a dominant predatory species and regulates animal populations when it takes prey. Natural elements and the balance of their use are sent awry without an apex predator that can eat practically any prey. Too many of a species, such as rabbits or turtles, places burdens on other populations affected, as well as on parts of the habitat. Balance is sought by nautre.


As a "hydrologist" the 'gator will dig water holes during the dry season, providing much-needed hydration for animal life. Using its powerful muscular body, it will manipulate mud and dirt around it, displacing it in order to tap the water beneath, thus maintaining water depth. This achievement provides available water to other animals.


The image at left shows an alligator floating beneath nesting birds at a rookery in north-eastern Florida.


The alligator may serve as a sentry to nesting birds. A curious aspect of its regulatory work is it presence among bird nesting habitat. Birds will nest in trees and brush over the water's edge to secure a distance from would-be predators seeking to eat their eggs or young. A hungry raccoon, for instance, may only approach such a limb from the water, but dares not, lest he become alligator food.


The nests of alligators are sometimes shared by aquatic turtles. A turtle will lay her eggs in the lower section of a nest, and leave them. Her eggs will incubate in optimum levels of temperature and moisture, and of course, will be guarded by a fierce mama alligator. Some species of turtle may hatch up to 200 babies, which will enter the ecosystem and play their own role in it.


POLLUTION. Chemicals and natural waste material proliferate in waterways in the the alligator's range, especially Florida, where the robust human population -- its residential developments and vegetable and cattle famring -- have polluted the water with chemical toxins as well as great amounts of the nutrients  phosphorus and nitrogen, which is derived from fertilizers, cattle manure, human sewage and other sources. Nutrient pollution, called eutrophication, is an issue throughout the United States and in other parts of the world.


An algal bloom in a marsh.Decades of such unchecked activity have resulted in dense masses of algae literally choking oxygen from waterways, lakes and springs, aquatic systems which are vital, absolutely vital, to the health of ecology and human environmental well-being.


Algae is a green-colored microorganism which resembles thick sludge when it is abundant in water. The formerly healthy waters are being depleted of oxygen and sunlight, thus destroying aquatic life, including the animal prey the alligator feeds on, and the plant life the prey subsists on. Even the endangered manatee is threatened by it.


In some cases the algal "blooms" caused by an overabundance of nutrients are so volumninous that swimming in them can cause serious illness in humans and animals. The unique and famous waters of Florida, for example, are especially endangered, due to warm temperatures, abundant sunlight and prevalent human activity throughout.


A marsh invaded by algal bloom is shown in the image above.

(Image: Eric Vance, Courtesy of U.S. Environmental Protection Agency.)


YOUR ROLE. You can play an important role in the long-term curing of the environment of this bio-disorder, wherever it occurs. Please visit the links provided below to learn more, and you are encouraged to expand your reading on the subject and to share your learning with family, friends and neighbors.


Protect Florida's Water. Stop! Pointless Personal Pollution, a brochure by the Environmental Protection Agency. PDF


Understanding Algal Blooms, by St. Johns River Water Management District. HTML


Nutrient Pollution, an infographic by Environmental Protection Agency. PNG Image


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