|An American alligator in captivity at the Columbus Zoo|
Alligator is a genus in the order Crocodilia. There are two living species: the American alligator and the smaller Chinese alligator. Together with the caimans, the gharials, and the crocodiles, they make up the order Crocodilia.
An average adult American alligator weighs 360 kg (790 lb) and is 4.0 m (13.1 ft) long. However, they can grow to 4.4 m (14 ft) long and weigh over 450 kg (990 lb).
The largest alligator ever recorded, found in Louisiana, was 5.84 m (19.2 ft) long.
The Chinese alligator is smaller. It is rarely longer than 2.1 m (6.9 ft). In addition, it weighs considerably less than the American alligator. Male Chinese alligators rarely weigh over 45 kg (99 lb).
Nobody knows how long alligators live, on average. An 80-year-old alligator named Muja, living in the Belgrade Zoo in Serbia, is thought to be the oldest alligator living in captivity.
Differences between alligators and crocodiles
- See also: Crocodile
Alligators and crocodiles are different in many ways. For example, in general:
- Crocodiles have salt glands, so they can live in saltwater habitats. Alligators usually live in freshwater habitats.
- Most alligators have wide snouts that are shaped like a U. Usually, crocodiles' snouts are longer, narrower, and are shaped like a V. However, some crocodiles do have wide snouts.
- When its mouth is closed, you can see the fourth tooth on a crocodile's jaw. You cannot see that tooth when an alligator's mouth is closed.
Although the alligator often moves slowly, it can run very fast for short times, especially in very short lunges. Usually, alligators' main prey are smaller animals they can kill and eat with a single bite. If the prey is not big enough to eat in one bite, they may drag the animal into the water to drown. They may also bite they prey and then spin or wildly until bite-sized chunks are torn off. This is called a "death roll".
Alligators are generally timid towards humans and tend to walk or swim away if a human comes near them. However, they will attack humans to protect their nests. In Florida, feeding wild alligators at any time is illegal. If fed, the alligators will eventually lose their fear of humans and will learn to associate humans with food, thereby becoming both a greater danger to people, and at greater risk from them.
Alligators are native only to the United States and China.
American alligators live mostly in the southeast United States. According to the 2012 Scholastic Book of World Records, Louisiana has the largest alligator population, with about two million. Most American alligators live in Louisiana or Florida, which is home to about 1.3 million alligators. Southern Florida is the only place where both alligators and crocodiles live side by side.
American alligators cannot live in saltwater very long because they do not have salt glands. Because of this, they live in freshwater environments, such as ponds, marshes, wetlands, rivers, lakes, and swamps, as well as in brackish environments.
The Chinese alligator is extremely endangered. Scientists believe that only a few dozen Chinese alligators are left in the wild. Indeed, far more Chinese alligators live in zoos around the world than 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.
Large male alligators are solitary (individual) territorial animals. Smaller alligators can often be found in large numbers close to each other. The largest of the species (both males and females) defend prime territory; smaller alligators have a higher tolerance for other alligators within a similar size class.
Alligators move on land by two forms of locomotion referred to as "sprawl" and "high walk". The sprawl is a forward movement with the belly making contact with the ground and is used to transition to "high walk" or to slither over wet substrate into water. The high walk is an up on four limbs forward motion used for overland travel with the belly well up from the ground. Alligators have also been observed to rise up and balance on their hind legs and semi step forward as part of a forward or upward lunge. However they can not walk on their hind legs for long distances.
Although the alligator has a heavy body and a slow metabolism, it is capable of short bursts of speed, especially in very short lunges. Alligators' main prey are smaller animals they can kill and eat with a single bite. They 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-sized 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 bare-handed. It is common today to use several wraps of duct tape to prevent an adult alligator from opening its jaws when being 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 Florida, feeding wild alligators at any time is illegal. If fed, the alligators will eventually lose their fear of humans and will learn to associate humans with food, thereby becoming both a greater danger to people, and at greater risk from them.
Alligators generally mature at a length of 6 ft (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 to three hours after sunrise. The bellows of male American alligators are accompanied by powerful blasts of infrasound. Another form of male display is a loud head-slap. Recently, on spring nights alligators were found to 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 and is fixed within seven 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, so the former tend to produce males and the latter, females. The baby alligator's egg tooth helps it get out of its egg during hatching time.
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). The mother defends the nest from predators and assists 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 50% 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 juveniles, increasing survival among the young alligators.
Alligators, much like birds, have been shown to exhibit unidirectional movement of air through their lungs. Most other amniotes are believed to exhibit bidirectional, or tidal breathing. For a tidal breathing animal, such as a mammal, air flows into and out of the lungs through branching bronchi which terminate in small dead-end chambers called alveoli. As the alveoli represent dead-ends to flow, the inspired air must move back out the same way it came in. In contrast, air in alligator lungs makes a circuit, moving in only one direction through the parabronchi. The air first enters the outer branch, moves through the parabronchi, and exits the lung through the inner branch. Extensive vasculature around the parabronchi are where oxygen exchange takes place.
They have muscular, flat tails that propel them while swimming.
The two kinds of white alligators are albino and leucistic. These alligators are practically impossible to find in the wild. They could survive only in captivity and are few in number. The Aquarium of the Americas in New Orleans has leucistic alligators found in a Louisiana swamp in 1987.
Alligators are raised commercially for their meat and skin, which is used for bags and shoes. They also provide economic benefits through the ecotourism industry. Visitors may take swamp tours, in which alligators are a feature. Their most important economic benefit to humans may be the control of coypu and muskrats. Louisiana spends millions of dollars of bounty money to control coypu using alligators.
Alligator meat is also consumed by humans. The Archbishop of New Orleans ruled in 2010 that for purposes of Catholic church discipline in relation to abstention from meat, the flesh of the alligator is characterised as fish.
American alligators were once an endangered species in the United States.
Today, the American alligator is no longer endangered, but it is still a "protected species." It is protected because the alligator looks like some species of crocodiles and caimans, which are still endangered. Because of this, the Fish and Wildlife Service categorizes the American alligator as “threatened due to similarity of appearance.” Their goal is to prevent people from killing endangered crocodiles and caimans because they have mistaken an alligator for a crocodile or caiman. Because of this, killing alligators, and trading in products made from alligator meat or skin, are all regulated by the Fish and Wildlife Service.
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