Alligator
Overview
 
An alligator is a crocodilian in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Alligator of the family Alligatoridae
Alligatoridae
Alligatoridae is a family of crocodylians that includes alligators and caimans.- True alligators :Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A...

. There are two extant alligator species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

: the American alligator
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

 (Alligator mississippiensis) and the Chinese alligator
Chinese Alligator
The Chinese alligator or Alligator Alligator sinensis) is one of two known living species of Alligator, a genus in the family Alligatoridae. The Chinese alligator is native only to China...

 (Alligator sinensis).

The name alligator is an anglicized form of , the Spanish term for "lizard", which early Spanish explorers and settlers in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

 called the alligator.

Alligators have a variety of successful adaptations to their ecological niche that have allowed these reptiles to remain almost unchanged since the Cretaceous.
The alligator is notorious for its bone-crushing bites.
Encyclopedia
An alligator is a crocodilian in the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Alligator of the family Alligatoridae
Alligatoridae
Alligatoridae is a family of crocodylians that includes alligators and caimans.- True alligators :Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A...

. There are two extant alligator species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

: the American alligator
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

 (Alligator mississippiensis) and the Chinese alligator
Chinese Alligator
The Chinese alligator or Alligator Alligator sinensis) is one of two known living species of Alligator, a genus in the family Alligatoridae. The Chinese alligator is native only to China...

 (Alligator sinensis).

The name alligator is an anglicized form of , the Spanish term for "lizard", which early Spanish explorers and settlers in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

 called the alligator.

Alligators have a variety of successful adaptations to their ecological niche that have allowed these reptiles to remain almost unchanged since the Cretaceous.

Description

The alligator is notorious for its bone-crushing bites. In addition, the alligator has been described as a "living fossil
Living fossil
Living fossil is an informal term for any living species which appears similar to a species otherwise only known from fossils and which has no close living relatives, or a group of organisms which have long fossil records...

", having been extant for 200 million years, beginning in the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...

 Era.

A large adult American alligator's weight and length is 800 pounds (362.9 kg) and 13 feet (4 m) long , but can grow to 14.5 feet (4.4 m) long and weigh over 1000 pounds (453.6 kg). According to the Everglades National Park website, the largest alligator ever recorded in Florida was 17 in 5 in (5.31 m), although according to the Florida Fish and Wildlife Conservation Commission web site the Florida state record for length is a 14 foot male from Lake Monroe
Lake Monroe (Florida)
Lake Monroe is one of the lakes that make up the St. Johns River system. The port city of Sanford is situated along the southern shore, while DeBary and Deltona are located along the northern shore. Two major central Florida roadways that run near the lake are State Road 415 and Interstate 4...

 in Seminole County. The largest specimen ever recorded was found in Louisiana and measured 19 in 2 in (5.84 m). The Chinese alligator is smaller, rarely exceeding 7 feet (2.1 m) in length. Alligators have an average of 75 teeth.

There is no measured average lifespan for an alligator. A specimen named Muja has resided in the Belgrade
Belgrade
Belgrade is the capital and largest city of Serbia. It is located at the confluence of the Sava and Danube rivers, where the Pannonian Plain meets the Balkans. According to official results of Census 2011, the city has a population of 1,639,121. It is one of the 15 largest cities in Europe...

 Zoo in Serbia
Serbia
Serbia , officially the Republic of Serbia , is a landlocked country located at the crossroads of Central and Southeast Europe, covering the southern part of the Carpathian basin and the central part of the Balkans...

 since 1937, making it at least 73 years old. Another specimen, Čabulītis
Cabulitis
Čabulītis was a captive American Alligator residing at the Riga Zoo in Riga, Latvia. At time of his death he was thought to be one of the oldest captive alligators in Europe. Information at the Riga Zoo, dated 1 April 1935, suggests that he was 1 to 3 years old on arrival.-Physical characteristics...

, in Riga Zoo
Riga Zoo
-External links:* - Trip to Riga ZOO...

, Latvia died in 2007 being more than 75 years old.

Habitat

Alligators are only native to the United States and China.

American alligator
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

s are found in the southeast United States: all of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

 and Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...

, the southern parts of Georgia, Alabama
Alabama
Alabama is a state located in the southeastern region of the United States. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its inland...

 and Mississippi
Mississippi
Mississippi is a U.S. state located in the Southern United States. Jackson is the state capital and largest city. The name of the state derives from the Mississippi River, which flows along its western boundary, whose name comes from the Ojibwe word misi-ziibi...

, coastal South
South Carolina
South Carolina is a state in the Deep South of the United States that borders Georgia to the south, North Carolina to the north, and the Atlantic Ocean to the east. Originally part of the Province of Carolina, the Province of South Carolina was one of the 13 colonies that declared independence...

 and North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...

, Eastern Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

, the southeast corner of Oklahoma
Oklahoma
Oklahoma is a state located in the South Central region of the United States of America. With an estimated 3,751,351 residents as of the 2010 census and a land area of 68,667 square miles , Oklahoma is the 28th most populous and 20th-largest state...

 and the southern tip of Arkansas
Arkansas
Arkansas is a state located in the southern region of the United States. Its name is an Algonquian name of the Quapaw Indians. Arkansas shares borders with six states , and its eastern border is largely defined by the Mississippi River...

. According to the 2005 Scholastic Book of World Records, Louisiana
Louisiana
Louisiana is a state located in the southern region of the United States of America. Its capital is Baton Rouge and largest city is New Orleans. Louisiana is the only state in the U.S. with political subdivisions termed parishes, which are local governments equivalent to counties...

 is the state with the largest alligator population. The majority of American alligators inhabit Florida and Louisiana, with over a million alligators in each state.

American alligators live in freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...

 environments, such as ponds, marsh
Marsh
In geography, a marsh, or morass, is a type of wetland that is subject to frequent or continuous flood. Typically the water is shallow and features grasses, rushes, reeds, typhas, sedges, other herbaceous plants, and moss....

es, wetland
Wetland
A wetland is an area of land whose soil is saturated with water either permanently or seasonally. Wetlands are categorised by their characteristic vegetation, which is adapted to these unique soil conditions....

s, rivers, lakes, and swamp
Swamp
A swamp is a wetland with some flooding of large areas of land by shallow bodies of water. A swamp generally has a large number of hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodical inundation. The two main types of swamp are "true" or swamp...

s, as well as brackish environments. Southern Florida is the only place where both alligators and crocodile
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...

s live side by side.

The Chinese alligator
Chinese Alligator
The Chinese alligator or Alligator Alligator sinensis) is one of two known living species of Alligator, a genus in the family Alligatoridae. The Chinese alligator is native only to China...

 currently is found only in the Yangtze River
Yangtze River
The Yangtze, Yangzi or Cháng Jiāng is the longest river in Asia, and the third-longest in the world. It flows for from the glaciers on the Tibetan Plateau in Qinghai eastward across southwest, central and eastern China before emptying into the East China Sea at Shanghai. It is also one of the...

 valley and is extremely endangered, with only a few dozen believed to be left in the wild. Indeed, far more Chinese alligators live in zoos around the world than can be found in the wild. Rockefeller Wildlife Refuge in southern Louisiana has several in captivity in an attempt to preserve the species. Miami MetroZoo in Florida also has a breeding pair of Chinese alligators. The St. Augustine Alligator Farm Zoological Park has successfully reproduced Chinese Alligators and been fortunate enough to release some of their offspring back into the wild in China.

Behavior

Large male alligators are solitary territorial
Territory (animal)
In ethology the term territory refers to any sociographical area that an animal of a particular species consistently defends against conspecifics...

 animals. Smaller alligators can often be found in large numbers close to each other. The largest of the species (both males and females), will defend prime territory; smaller alligators have a higher tolerance of other alligators within a similar size class.

Although alligators have a heavy body and a slow metabolism
Metabolism
Metabolism is the set of chemical reactions that happen in the cells of living organisms to sustain life. These processes allow organisms to grow and reproduce, maintain their structures, and respond to their environments. Metabolism is usually divided into two categories...

, they are capable of short bursts of speed, especially in very short lunges. Alligators' main prey are smaller animals that they can kill and eat with a single bite. Alligators may kill larger prey by grabbing it and dragging it into the water to drown. Alligators consume food that can not be eaten in one bite by allowing it to rot, or by biting and then spinning or convulsing wildly until bite-size chunks are torn off. This is referred to as a "death roll." Critical to the alligator's ability to initiate a death roll, the tail must flex to a significant angle relative to its body. An alligator with an immobilized tail cannot perform a death roll.

Most of the muscle in an alligator's jaw evolved to bite and grip prey. The muscles that close the jaws are exceptionally powerful, but the muscles for opening their jaws are comparatively weak. As a result, an adult human can hold an alligator's jaws shut barehanded. It is common today to use several wraps of duct tape
Duct tape
Duct tape, or duck tape, is cloth- or scrim-backed pressure sensitive tape often sealed with polyethylene. It is very similar to gaffer tape but differs in that gaffer tape was designed to be cleanly removed, while duct tape was not. It has a standard width of and is generally silver or black...

 to prevent an adult alligator from opening its jaws when handled or transported.

Alligators are generally timid towards humans and tend to walk or swim away if one approaches. This has led some people to the practice of approaching alligators and their nests in a manner that may provoke the animals into attacking. In the state of Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...

, it is illegal to feed wild alligators at any time. If fed, the alligators will eventually lose their fear of humans and will learn to associate humans with food, thereby becoming a greater danger to people.

Diet

When young, alligators eat fish, insects, snail
Snail
Snail is a common name applied to most of the members of the molluscan class Gastropoda that have coiled shells in the adult stage. When the word is used in its most general sense, it includes sea snails, land snails and freshwater snails. The word snail without any qualifier is however more often...

s, crustacean
Crustacean
Crustaceans form a very large group of arthropods, usually treated as a subphylum, which includes such familiar animals as crabs, lobsters, crayfish, shrimp, krill and barnacles. The 50,000 described species range in size from Stygotantulus stocki at , to the Japanese spider crab with a leg span...

s, and worm
Worm
The term worm refers to an obsolete taxon used by Carolus Linnaeus and Jean-Baptiste Lamarck for all non-arthropod invertebrate animals, and stems from the Old English word wyrm. Currently it is used to describe many different distantly-related animals that typically have a long cylindrical...

s. As they mature, progressively larger prey is taken, including larger fish such as gar
Gar
In American English the name gar is strictly applied to members of the Lepisosteidae, a family including seven living species of fish in two genera that inhabit fresh, brackish, and occasionally marine, waters of eastern North America, Central America, and the Caribbean islands.-Etymology:In...

, turtles, various mammals, birds, deer and other reptiles. Their stomachs also often contain gizzard stone
Gastrolith
A gastrolith, also called a stomach stone or gizzard stones, is a rock held inside a gastrointestinal tract. Gastroliths are retained in the muscular gizzard and used to grind food in animals lacking suitable grinding teeth. The grain size depends upon the size of the animal and the gastrolith's...

s. They will even consume carrion
Carrion
Carrion refers to the carcass of a dead animal. Carrion is an important food source for large carnivores and omnivores in most ecosystems. Examples of carrion-eaters include vultures, hawks, eagles, hyenas, Virginia Opossum, Tasmanian Devils, coyotes, Komodo dragons, and burying beetles...

 if they are sufficiently hungry. Adult alligators can take razorbacks
Razorback
Razorback is an Americanism, loosely applied to any type of feral pig or wild boar in North America. The term has also appeared in Australia, to describe said animals in that country.-Introduction to the Americas:...

 and deer and are well known to kill and eat smaller alligators. In some cases, larger alligators are known to ambush dogs, Florida panther
Florida Panther
The Florida panther is an endangered subspecies of cougar that lives in forests and swamps of southern Florida in the United States. Its current taxonomic status is unresolved, but recent genetic research alone does not alter the legal conservation status...

 and black bears
American black bear
The American black bear is a medium-sized bear native to North America. It is the continent's smallest and most common bear species. Black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in...

, making it the apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...

 throughout its distribution. As humans encroach onto their habitat, attacks are few but not unknown. Alligators, unlike the large crocodiles, do not immediately regard a human upon encounter as prey, but may still attack in self-defense if provoked.

Reproduction

Alligators generally mature at a length of 6 feet (1.8 m). The mating season is in late spring. In April and May, alligators form so-called "bellowing choruses". Large groups of animals bellow together for a few minutes a few times a day, usually one-three hours after sunrise. The bellows of male American alligators are accompanied by powerful blasts of infrasound
Infrasound
Infrasound is sound that is lower in frequency than 20 Hz or cycles per second, the "normal" limit of human hearing. Hearing becomes gradually less sensitive as frequency decreases, so for humans to perceive infrasound, the sound pressure must be sufficiently high...

 produced by sacs in their chins.
Another form of male display is a loud head-slap. Recently it was discovered that on spring nights alligators gather in large numbers for group courtship, the so-called "alligator dances".

In summer, the female builds a nest of vegetation where the decomposition of the vegetation provides the heat needed to incubate the eggs. The sex of the offspring is determined by the temperature in the nest
Temperature-dependent sex determination
Temperature-dependent sex determination is type of environmental sex determination in which the temperatures experienced during embryonic development determine the sex of the offspring. It is most prevalent and common among amniote vertebrates that are classified under the reptile class, but is...

 and is fixed within 7 to 21 days of the start of incubation. Incubation temperatures of 86 °F (30 °C) or lower produce a clutch of females; those of 93 °F (33.9 °C) or higher produce entirely males. Nests constructed on leaves are hotter than those constructed on wet marsh and, thus, the former tend to produce males and the latter, females. The natural sex ratio at hatching is five females to one male. Females hatched from eggs incubated at 86 °F (30 °C) weigh significantly more than males hatched from eggs incubated at 93 °F (33.9 °C). The mother will defend the nest from predators and will assist the hatchlings to water. She will provide protection to the young for about a year if they remain in the area. The largest threat to the young are adult alligators. Baby alligators have an egg tooth
Egg tooth
In some egg-laying animals, the egg tooth is a small, sharp, cranial protuberance used by offspring to break or tear through the egg's surface during hatching...

 that helps them get out of their egg during hatching time. Predation by adults on young can account for a mortality rate of up to fifty percent in the first year. In the past, immediately following the outlawing of alligator hunting
Hunting
Hunting is the practice of pursuing any living thing, usually wildlife, for food, recreation, or trade. In present-day use, the term refers to lawful hunting, as distinguished from poaching, which is the killing, trapping or capture of the hunted species contrary to applicable law...

, populations rebounded quickly due to the suppressed number of adults preying upon the new recruits, increasing survival among the young alligators.

Anatomy

Alligators are the only non-avian
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

 species shown to have one-way breathing, although presumably similar measurements for other crocodilians (not yet done) would show unidirectional air flow in them as well. All other non-avian amnionts
Amniote
The amniotes are a group of tetrapods that have a terrestrially adapted egg. They include synapsids and sauropsids , as well as their fossil ancestors. Amniote embryos, whether laid as eggs or carried by the female, are protected and aided by several extensive membranes...

 have dead-end breathing. In dead-end breathing the air flows into the lungs through branching bronchi which terminate in small dead-end chambers called alveoli. The air moves in both directions through the bronchi. In alligators the air makes a circuit through the lungs moving in only one direction through the bronchi. The air first enters the outer branch, moves through the lungs in small tubes called parabronchi, and exits the lung through the inner branch. The parabronchi are where the oxygen exchange takes place.

They have a muscular flat tail that propels them while swimming.

Albino

There are two kinds of white alligators, albino and leucistic. These alligators are extremely rare and practically impossible to find in the wild. They could survive only in captivity. As with all white animals, they are very vulnerable to the sun and predators.

Albino alligators have a non-functional gene
Gene
A gene is a molecular unit of heredity of a living organism. It is a name given to some stretches of DNA and RNA that code for a type of protein or for an RNA chain that has a function in the organism. Living beings depend on genes, as they specify all proteins and functional RNA chains...

 for melanin
Melanin
Melanin is a pigment that is ubiquitous in nature, being found in most organisms . In animals melanin pigments are derivatives of the amino acid tyrosine. The most common form of biological melanin is eumelanin, a brown-black polymer of dihydroxyindole carboxylic acids, and their reduced forms...

, which makes them albino
Albinism
Albinism is a congenital disorder characterized by the complete or partial absence of pigment in the skin, hair and eyes due to absence or defect of an enzyme involved in the production of melanin...

. The is the common trait of all albino vertebrates
Vertebrate
Vertebrates are animals that are members of the subphylum Vertebrata . Vertebrates are the largest group of chordates, with currently about 58,000 species described. Vertebrates include the jawless fishes, bony fishes, sharks and rays, amphibians, reptiles, mammals, and birds...

.

In leucistic alligators all of the pigment genes are defective not just the melanin gene. This makes them white with blue eyes. The Aquarium of the Americas
Aquarium of the Americas
The Audubon Aquarium of the Americas is a renowned aquarium in New Orleans, Louisiana, USA.Recognized as one of the leading aquariums in the United States, it is run by the Audubon Institute, which also supervises the Audubon Zoo and Audubon Park...

 in New Orleans has leucistic alligators found in a Louisiana swamp in 1987.

Human uses

Alligators are raised commercially for their meat and skin, which is used for bags and shoes.

See also

  • Alligatoridae
    Alligatoridae
    Alligatoridae is a family of crocodylians that includes alligators and caimans.- True alligators :Alligators proper occur in the fluvial deposits of the age of the Upper Chalk in Europe, where they did not die out until the Pliocene age. The true alligators are now restricted to two species, A...

  • American Alligator
    American Alligator
    The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

  • American Crocodile
    American Crocodile
    The American crocodile is a species of crocodilian found in the Neotropics. It is the most widespread of the four extant species of crocodiles from the Americas. Populations occur from the Atlantic and Pacific coasts of southern Mexico to South America as far as Peru and Venezuela. It also lives...

  • Caiman
  • Crocodiles
  • List of fatal alligator attacks in the United States by decade

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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