Elephant
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- This page is about the animal, see elephant (disambiguation) for more meanings.
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ElephantFrom open-encyclopedia.com - the free encyclopedia.
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An elephant's most obvious characteristic is the trunk, a much elongated combination of nose and upper lip, which can be used to grab objects such as food. Elephants also have tusks, large teeth coming out of their upper jaws. Elephant tusks are the major source of ivory, but because of the increased rarity of elephants, hunting and ivory trade is now illegal.
Elephants have three premolars and three molars in each quadrant. They erupt in order from front to back, then wear down as the elephant chews its highly fibrous diet. When the last molar has worn out, the elephant typically dies of malnutrition; elephants in captivity can be kept alive longer than that by feeding them preground food. The molars of the African elephant are loxodont, hence the genus name.
Skin diseases often occur, from which they try to protected themselves by taking mud baths, shower one another with water from the trunk, and rolling in dust. The skin can therefore appear brown or reddish, but the natural color is light gray. Their significant coarse and wrinkled skin is about 1 in. thick, sparsely bristled (with varieties for the Asian and the African kinds), a thickness they disadvantageousely developed instead of pigment which causes the color. There are also rare white elephants, who often have blue eyes. Otherwise elephants have brown, surrounded by long lashes.
They have large ears that wave for cooling, and a relatively small tail with a brush at its tip.
Walking at a normal pace an elephant covers about 2 to 4 miles an hour but they can reach 24 miles an hour at full speed.
Elephants are vegetarians, spending 16 hours a day collecting plant food from all levels. Their diet is at least 50% grasses, supplemented with leaves, twigs, bark, roots, and small amounts of fruits, seeds and flowers. Because elephants only use 40% of what they eat they have to make up for their digestive system's lack of efficiency in volume. An adult elephant can consume 300 to 600 pounds of food a day. 60% of that food leaves the elephant's body undigested.
It has long been known that African and Asian elephants were separate species. African elephants tend to be larger than the Asian species (up to 4m high and 7500kg) and have bigger ears (which are rich in veins and thought to help in cooling off the blood in the hotter African climate). Female African elephants have tusks, while female Asian Elephants don't. African elephants have a dipped back, as compared with the Asian species, and have two "fingers" at the tip of their trunks, as opposed to only one.
There are two populations of African elephants, savanna and forest, and recent genetic studies have led to a reclassification of these as separate species, the forest population now being called Loxodonta cyclotis, and the savanna or bush population termed Loxodonta africanus. This reclassification has important implications for conservation, because it means where there were thought to be two small populations of a single endangered species, there may in fact be two separate species, each of which is even more severely endangered. There's also a potential danger in that if the forest elephant isn't explicitly listed as an endangered species, poachers and smugglers might thus be able to evade the law forbidding trade in endangered animals and their body parts.
Poaching has had some unexpected consequences on elephant anatomy as well. African ivory hunters, by killing only tusked elephants, have given a much larger chance of mating to elephants with small tusks or no tusks at all. The propagation of the absent-tusk gene has resulted in the birth of large numbers of tuskless elephants, now approaching 30% in some populations (compare with a rate of about 1% in 1930). Tusklessness, once a very rare genetic abnormality, has become a widespread hereditary trait. [1] It is possible, if unlikely, that continued poaching could bring about a complete absence of tusks in African elephants, a development normally requiring thousands of years of evolution. The effect of tuskless elephants on the environment, and on the elephants themselves, could be dramatic. Elephants use their tusks to root around in the ground for necessary minerals, tear apart vegetation, and spar with one another for mating rights. Without tusks, elephant behavior could change dramatically. [2]
Elephants have been used in various capacities by humans. War elephants were used by armies in the Indian sub-continent, and by the Persian empire. This use was adopted by Hellenistic Ptolemaic and Seleucid kingdoms. The Carthaginian general Hannibal took elephants across the Alps when he was fighting the Romans. Hannibal brought too few elephants to be of much military use, although his horse cavalry was quite successful. Hannibal probably used a now extinct third African species, the North African elephant, smaller than its two southern cousins.
African elephant (left) and Indian elephant at an English zoo.
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Asian elephants have been used for transportation and entertainment, and are common to circuses around the world. Throughout Siam, India, and most of South Asia they were used in the military, used for heavy labor, especially for uprooting trees and moving logs, and were also commonly used as executioners to crush the condemned underfoot.
However, elephants have never been truly domesticated: the male elephant in heat is dangerous and difficult to control; elephants used by humans have typically been female. War elephants were an exception, however, as female elephants in battle will run from a male, only males could be used in war. It's more economical to capture wild young elephants and tame them than breeding them from scratch.
African elephants are usually thought not domesticable, but some entrepreneurs have succeeded by bringing Asian mahouts to Africa.
In the wild elephants exhibit complex social behavior and strong family bonds. Most females will stay with their original natal group for a lifetime. Social hierarchy in calf-cow groups is based on size and age, with the largest and oldest females at the top and the smallest and youngest coming in last. Adolescent males determine their own ranking order through head-butting contests, where strength and temperament are as important as size and age. They communicate with very low and long-ranging subsonic tones.
Although the fossil evidence is extremely murky, some scientists believe there is genetic evidence that the elephant family shares distant ancestry with the Sirenians (sea cows) and the hyraxes. In the distant past, members of the hyrax family grew to large sizes, and it seems likely that the common ancestor of all three modern families was some kind of amphibious hyracoid. One theory suggests that these animals spent most of their time under water, using their trunks like snorkels for breathing. It has recently been discovered that modern elephants can still swim using their trunks in that manner.
In the past, there was a much wider variety of elephant genera, including the mammoths, stegodons and deinotheria.
The elephant is also the symbol for the United States Republican Party (often pictured with the Democratic party's donkey). The first depiction of the Republican party appeared in a cartoon by Thomas Nast of Harper's Weekly in 1874.
af:Olifant
ast:Elefante
ca:Elefant
da:Elefant
de:Elefanten
es:Elefante
eo:Elefanto
fr:Éléphant
ms:Gajah
nl:Olifant
ja:ゾウ
pl:Słoniowate
ru:Слон
simple:Elephant
sv:Elefanter
zh:象
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