Alligator Animals Tiere Natur SelMcKenzie Selzer-McKenzie

Alligator Animals Tiere Natur SelMcKenzie Selzer-McKenzie
Author D.Selzer-McKenzie
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http://www.youtube.com/watch?v=tSUi7Z6-IxY

An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator (Alligator mississippiensis) and the Chinese alligator (Alligator sinensis).
The name alligator is an anglicized form of el lagarto, the Spanish term for "lizard", which early Spanish explorers and settlers in Florida called the alligator.
There are many adaptations for the American alligator. Baby alligators have an egg tooth that helps them get out of their egg during hatching time. They also have a muscular flat tail that propels them forward while they swim.
The alligator is notorious for its bone crushing bites. In addition, the alligator has been described as a "living fossil", having been extant for 200 million years, beginning in the Mesozoic Era.[1]
An average adult American alligator's weight and length is 800 pounds (360 kg) and 13 feet (4.0 m) long[citation needed], but can grow to 14.5 feet (4.4 m) long and weigh 1,032 pounds (468 kg).[2] According to the Everglades National Park website, the largest alligator ever recorded in Florida was 17 feet 5 inches (5.31 m), although according to the Florida Fish and Wildlife Conservation Commission web site the Florida state record for length is a 14 feet 5/8 inches (4.28 m) male from Lake Monroe in Seminole County.[3] The largest specimen ever recorded was found in Louisiana and measured 19 feet 2 inches (5.84 m)[4]. The Chinese alligator is smaller, rarely exceeding 7 feet (2.1 m) in length. Alligators have an average of 75 teeth.[citation needed]
The average lifespan for an alligator is 50 years. A specimen named Muja has resided in the Belgrade Zoo in Serbia since 1937, making it at least 73 years old. Another specimen, Čabulītis, in Riga Zoo, Latvia died in 2007 being more than 75 years old.[citation needed]


Alligators are only native to the United States and China.
American alligators are found in the southeast United States: all of Florida and Louisiana, the southern parts of Georgia, Alabama and Mississippi, coastal South and North Carolina, Eastern Texas, the southeast corner of Oklahoma and the southern tip of Arkansas. According to the 2005 Scholastic Book of World Records, Louisiana is the state with the largest alligator population.[5] The majority of American alligators inhabit Florida and Louisiana, with over a million alligators in each state.
American alligators live in freshwater environments, such as ponds, marshes, wetlands, rivers, lakes, and swamps, as well as brackish environments.[citation needed] Southern Florida is the only place where both alligators and crocodiles live side by side.
The Chinese alligator currently is found only in the Yangtze River 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.
Large male alligators are solitary, territorial animals. Smaller alligators can often be found in large numbers in close proximity 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, they are capable of short bursts of speed, especially in very short lunges. Alligators' main prey is 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 could 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." A hard-wired response developed over millions of years of evolution, even juvenile alligators execute death rolls when presented with chunks of meat. 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 do a death roll.[6]
Most of the muscle in an alligator's jaw evolved to bite and grip prey. The muscles that close the jaws are exceptionally powerful, however the muscles for opening their jaws are relatively weak in comparison. As a result, an adult man can hold an alligator's jaws shut with his bare hands. In general, a strip of duct tape is enough to prevent an adult alligator from opening its jaws and is one of the most common methods used when alligators are to be captured and/or transported.[7] Alligators are generally timid towards humans and tend to walk or swim away if one approaches. Unfortunately, this has led some people to the practice of approaching alligators and their nests in a way that may provoke the animals into attacking. In the state of Florida, 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.[8]
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When young, they eat fish, insects, snails, crustaceans, and worms. As they grow, they take progressively larger prey items, including larger fish such as gar, turtles, various mammals, birds, deer and other reptiles. Their stomachs also often contain gastroliths. They will even consume carrion if they are sufficiently hungry. Adult alligators can take razorbacks and deer and are well known to kill and eat smaller alligators. In some cases, larger alligators are known to ambush dogs, the Florida panther and black bears, making it the apex predator throughout its distribution. As humans encroach onto their habitat, attacks on humans 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.
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Alligator eggs and young.


Baby alligators


A rare albino American alligator
Alligators generally mature at a length of 6 feet (1.8 m). The mating season is in early spring. 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 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 (34 °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 (34 °C)[9]. 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. 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, populations rebounded quickly due to the suppressed number of adults preying upon the new recruits, increasing survival among the young alligators.
Alligators are the only non-avian species shown to have one-way breathing[10], although presumably similar measurements for other crocodilians (not yet done) would show unidirectional air flow in them as well. All other non-avian amnionts 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.[11]
Some alligators are missing inhibited gene for melanin, which makes them albino. These alligators are extremely rare and practically impossible to find in the wild. They could survive only in captivity. As with all albino animals, they are very vulnerable to the sun and predators