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| Etymology | |
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Olifant and its variations (ex. oliphant, olyphant) are archaic spellings of elephant. Aside from elephants, the word has been used to refer to ivory, elephant tusks, musical horns made of elephant tusks, or a musical instrument resembling such horns.
It appears in Middle English as olifant or olifaunt, and was borrowed from Medieval French olifanz. The French word owes something to both Old High German olbenta "camel", and to Latin elephantus "elephant", a word of Greek origin.[23] OHG olbenta is a word of old Germanic origin; cf. Gothic ulbandus also meaning "camel". But the form of the OHG and Gothic words suggests it is also a borrowing, perhaps indeed directly or indirectly from Greek "ἐλέφας" (elephas), which in Homer only meant "ivory", but from Herodotus on the word also referred to the animal.[24] The earliest attested form of the word is the Mycenaean Greek e-re-pa-to, written in Linear B syllabic script.[25]
Tags:Elephas,Ivory,Middle English,Greek,Germanic,Gothic,Homer,Herodotus,Mycenaean Greek,Linear B, | |
| Taxonomy and evolution | |
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The African elephant genus contains two or, arguably, three living species; whereas the Asian elephant species is the only surviving member of the Asian elephant genus, but can be divided into four subspecies. The African and the Asian elephants diverged from a common ancestor some 7.6 million years ago.[26]
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| African elephant | |
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Main articles: African elephant, African bush elephant, and African forest elephant
Elephant crossing a river, Kenya.
African bush (savanna) elephant in Etosha National Park, Namibia.
Video of elephants in the wild
The elephants of the genus Loxodonta, known collectively as African elephants, are currently found in 37 countries in Africa.
African elephants are distinguished from Asian elephants in several ways, the most noticeable being their much larger ears.[27] Also, the African elephant is typically larger than the Asian elephant and has a concave back. In Asian elephants, only males have tusks, but both males and females of African elephants have tusks and are usually less hairy than their Asian cousins.
African elephants have traditionally been classified as a single species comprising two distinct subspecies, namely the savanna elephant (Loxodonta africana africana) and the forest elephant (Loxodonta africana cyclotis), but recent DNA analysis suggests that these may actually constitute distinct species.[28] This split is not universally accepted by experts.[3] A third species of African elephant has also been proposed.[29]
The authors of an analysis of nuclear DNA extracted from "African savanna elephant, African forest elephant, Asian elephant, the extinct American mastodon, and the woolly mammoth" concluded in 2010 that African savanna and forest elephants are indeed separate species:
We unequivocally establish that the Asian elephant is the sister species to the woolly mammoth. A surprising finding from our study is that the divergence of African savanna and forest elephants—which some have argued to be two populations of the same species—is about as ancient as the divergence of Asian elephants and mammoths. Given their ancient divergence, we conclude that African savanna and forest elephants should be classified as two distinct species.[30]
This reclassification has implications for conservation. If there are two separate species, each will be less abundant (particularly the rarer) and could be more endangered than a more numerous and wide-ranging single species. There is also a potential danger that if the forest elephant is not explicitly listed as an endangered species, poachers and smugglers might be able to evade the law forbidding trade in endangered animals and their products.
The forest elephant and the savanna elephant can hybridize (interbreed), though their preferences for different terrains reduce such opportunities. As the African elephant has only recently been recognized to comprise two separate species, groups of captive elephants have not been comprehensively classified and some could well be hybrids.
Under the new two species classification, Loxodonta africana refers specifically to the savanna elephant, the largest of all elephants. It is the largest land animal, with males standing 3.2 metres (10 ft) to 4 metres (13 ft) at the shoulder and weighing 3,500 kilograms (7,700 lb) up to a reported 12,000 kilograms (26,000 lb).[31] The female is smaller, standing about 3 metres (9.8 ft) at the shoulder.[32] Most often, savanna elephants are found in open grasslands, marshes, and lakeshores. They range over much of the savanna zone south of the Sahara.
The other putative species, the forest elephant (Loxodonta cyclotis), is usually smaller and rounder, and its tusks thinner and straighter compared with the savanna elephant. The forest elephant can weigh up to 4,500 kilograms (9,900 lb) and stand about 3 metres (10 ft) tall. Much less is known about these animals than their savanna cousins, because environmental and political obstacles make them difficult to study. Normally, they inhabit the dense African rain forests of central and western Africa, although occasionally they roam the edges of forests, thus overlapping the savanna elephant home ranges and hybridizing. In 1979, Iain Douglas-Hamilton estimated the continental population of African elephants at around 1.3 million animals.[33] This estimate is controversial and is believed to be a gross overestimate,[34] but it is very widely cited and has become a de facto baseline that continues to be incorrectly used to quantify downward population trends in the species. Through the 1980s, Loxodonta received worldwide attention due to the dwindling numbers of major populations in East Africa, largely as a result of poaching. According to IUCN’s African Elephant Status Report 2007,[35] there are between 470,000 and 690,000 African elephants in the wild. Although this estimate only covers about half of the total elephant range, experts do not believe the true figure to be much higher, as it is unlikely that large populations remain to be discovered.[36] By far, the largest populations are now found in southern and eastern Africa, which together account for the majority of the continental population. According to a recent analysis by IUCN experts, most major populations in eastern and southern Africa are stable or have been steadily increasing since the mid-1990s, at an average rate of 4.5% per year.[36][37]
Elephant populations in West Africa, on the other hand, are generally small and fragmented, and only account for a small proportion of the continental total.[38] Much uncertainty remains as to the size of the elephant population in central Africa, where the prevalence of forest makes population surveys difficult, but poaching for ivory and bushmeat is believed to be intense through much of the region.[39] South African elephant population more than doubled, rising from 8,000 to over 20,000, in the thirteen years after a 1995 ban on the trade in elephant ivory.[40] The ban on the ivory trade in southern Africa (but not elsewhere) was lifted in February 2008, sparking controversy among environmental groups.[citation needed]
Tags:Genera,Loxodonta,Extinct,Kenya,Etosha National Park,Namibia,Dna Analysis,Grasslands,Marshes,West Africa,Ivory Trade, | |
| Asian elephant | |
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Main article: Asian elephant
The Asian elephant, Elephas maximus, is smaller than the African. It has smaller ears, and typically, only the males have large external tusks.
The world population of Asian elephants—also called Indian elephants—is estimated to be around 60,000, about a tenth of the number of African elephants. More precisely, it is estimated that there are between 38,000 and 53,000 wild elephants and between 14,500 and 15,300 domesticated elephants in Asia, with perhaps another 1,000 scattered around zoos in the rest of the world.[41] The Asian elephants' decline has possibly been more gradual than the African and caused primarily by poaching and habitat destruction by human encroachment.
A decorated Indian elephant in Jaipur, India.
Elephant orphanage in Sri Lanka
Several subspecies of Elephas maximus have been identified, using morphometric data and molecular markers. Elephas maximus maximus (Sri Lankan elephant) is found only on the island of Sri Lanka. It is the largest of the Asians. There are an estimated 3,000–4,500 members of this subspecies left today in the wild, although no accurate census has been carried out recently. Large males can weigh upward to 5,400 kg (12,000 lb) and stand over 3.4 m (11 ft) tall. Sri Lankan males have very large cranial bulges, and both sexes have more areas of depigmentation than other Asians. Typically, their ears, face, trunk, and belly have large concentrations of pink-speckled skin. There is an orphanage for elephants in Pinnawala, Sri Lanka, which plays a large role in protecting the Sri Lankan elephant from extinction.
Elephas maximus indicus (Indian elephant) makes up the bulk of the Asian elephant population. Numbering approximately 36,000, these elephants are lighter grey in colour, with depigmentation only on the ears and trunk. Large males will ordinarily weigh only about 5,000 kg (11,000 lb), but are as tall as the Sri Lankan. The mainland Asian can be found in 11 Asian countries, from India to Indonesia. They prefer forested areas and transitional zones, between forests and grasslands, where greater food variety is available.
The Sumatran elephant, Elephas maximus sumatranus, found only on Sumatra, is smaller than the Indian elephant. Population estimates for this group range from 2,100 to 3,000 individuals. It is very light grey in colour and has less depigmentation than the other Asians, with pink spots only on the ears. Mature Sumatrans will usually only measure 1.7–2.6 m (5.6–8.5 ft) at the shoulder and weigh less than 3,000 kg (6,600 lb). It is considerably smaller than its other Asian (and African) cousins and exists only on the island of Sumatra, usually in forested regions and partially wooded habitats.
In 2003, a further subspecies was identified on Borneo. Named the Borneo pygmy elephant, it is smaller and tamer than any other Asian elephants. It also has relatively larger ears, longer tail and straighter tusks.
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| Physical characteristics | |
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This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (January 2010)
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| Trunk | |
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The elephant raises its trunk as a sign of warning or to smell enemies or friends
Articulation of elephant trunk.
An elephant can use its trunk for a variety of purposes. This one is wiping its eye.
Eye of an Asian elephant.
The proboscis, or trunk, is a fusion of the nose and upper lip,[42] elongated and specialized to become the elephant's most important and versatile appendage. African elephants are equipped with two fingerlike projections at the tip of their trunk, while Asians have only one. The elephant's trunk is sensitive enough to pick up a single blade of grass, yet strong enough to rip the branches off a tree.
Most herbivores (plant eaters, like the elephant) possess teeth adapted for cutting and tearing off plant materials. However, except for the very young or infirm, elephants always use their trunks to tear up their food and then place it in their mouths. They will graze on grass or reach up into trees to grasp leaves, fruit, or entire branches. If the desired food item is too high up, the elephant will wrap its trunk around the tree or branch and shake its food loose or sometimes simply knock the tree down altogether.
The trunk is also used for drinking. Elephants suck water up into the trunk—up to 14 litres (15 quarts) at a time—and then blow it into their mouths. Elephants also suck up water to spray on their bodies during bathing. On top of this watery coating, the animals will then spray dirt and mud, which dries and acts as a protective sunscreen. When swimming, the trunk makes an excellent snorkel.[43][44]
This appendage also plays a key role in many social interactions. Familiar elephants will greet each other by entwining their trunks, much like a handshake. They also use them while play-wrestling, caressing during courtship and mother-child interactions, and for dominance displays; a raised trunk can be a warning or threat, while a lowered trunk can be a sign of submission. Elephants can defend themselves very well by flailing their trunks at unwanted intruders or by grasping and flinging them.
An elephant also relies on its trunk for its highly developed sense of smell. By raising the trunk up in the air and swiveling it from side to side, like a periscope, it can determine the location of friends, enemies, and food sources.[citation needed]
Some elephants have been afflicted by floppy trunk syndrome.
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| Tusks | |
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This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (May 2010)
Tusks of African and Asian elephants.
The tusks of an elephant are its second upper incisors. Tusks grow continuously; an adult male's tusks grow about 18 cm (7 in) a year. Tusks are used to dig for water, salt, and roots; to debark trees to eat the bark; to dig into baobab trees to get at the pulp inside; and to move trees and branches when clearing a path. In addition, they are used for marking trees to establish territory, and occasionally as weapons.
Like humans who are typically right- or left-handed, elephants are usually right- or left-tusked. The dominant tusk, called the master tusk, is generally shorter and more rounded at the tip from wear. Both male and female African elephants have large tusks that can reach over 3 m (10 ft) in length and weigh over 90 kg (200 lb). In the Asian species, only the males have large tusks. Female Asians have tusks which are very small or absent altogether. Asian males can have tusks as long as the much larger Africans, but they are usually much slimmer and lighter; the heaviest recorded is 39 kg (86 lb). The tusk of both species is mostly made of calcium phosphate in the form of apatite. As a piece of living tissue, it is relatively soft (compared with other minerals such as rock), and the tusk, also known as ivory, is strongly favoured by artists for its carvability. The desire for elephant ivory has been one of the major factors in the reduction of the world's elephant population.
Some extinct relatives of elephants had tusks in their lower jaws in addition to their upper jaws, such as Gomphotherium, or only in their lower jaws, such as Deinotherium.[45]
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| Teeth | |
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This section needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. (May 2010)
Elephants' teeth are very different from those of most other mammals. Over their lives they usually have 28 teeth. These are:
The two upper second incisors: these are the tusks.
The milk precursors of the tusks.
12 premolars, 3 in each side of each jaw.
12 molars, 3 in each side of each jaw.
Replica of an Asian elephant's molar, showing upper side.
This gives elephants a dental formula of:
Unlike most mammals, which grow baby teeth and then replace them with a permanent set of adult teeth, elephants have cycles of tooth rotation throughout their entire lives. The tusks have milk precursors, which fall out quickly and the adult tusks are in place by one year of age, but the chewing teeth are replaced five[46] or, very rarely, six[47] times in an elephant's lifetime.
Only four chewing teeth (premolars and/or molars), one on each side of each jaw, are in primary use at any given time (or two, as one replaces the other at each location). Adult teeth do not replace milk teeth by emerging from the jaws vertically as human teeth do. Instead, new teeth grow in at the back of the mouth, pushing older teeth toward the front, where the latter break off in pieces until they are gone. In African elephants, the first two sets of chewing teeth (premolars) are in place when an elephant is born. The first chewing tooth on each side in each jaw falls out when the elephant is about two years old. The second set of chewing teeth falls out when the elephant is about six years old. The third set is lost at 13 to 15 years of age, and set four lasts to approximately 28 years of age. The fifth set of chewing teeth (molars) lasts until the elephant is in its early 40s. The sixth (and usually final) set must last the elephant the rest of its life. If an elephant lives to more than 60 years of age, the last set of molars is worn to stumps, and it can no longer feed properly. Moss reports a female elephant in its sixties whose final set of molars were worn smooth and about one-quarter of their original size and who survived "with extra chewing and longer feeding bouts." Abscesses of chewing teeth, as well as of tusks and jaws, are common in elephants, and may lead to premature death.[48]
Tusks in the lower jaw are also second incisors. These grew out large in Deinotherium and some mastodons, but in modern elephants they disappear early without erupting.
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| Skin | |
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Skin of an African (left) and Asian (right) elephant.
African elephant bathing
Elephants are colloquially called pachyderms (from their original scientific classification), which means thick-skinned animals. An elephant's skin is extremely tough around most parts of its body and measures about 2.5 centimetres (1.0 in) thick. However, the skin around the mouth and inside of the ear is considerably thinner. Normally, the skin of an Asian is covered with more hair than its African counterpart. This is most noticeable in the young. Asian calves are usually covered with a thick coat of brownish red fuzz. As they get older, this hair darkens and becomes more sparse, but it will always remain on their heads and tails.
The species of elephants are typically greyish in colour, but the Africans very often appear brown or reddish from wallowing in mud holes of colored soil. Wallowing is an important behaviour in elephant society. Not only is it important for socialization, but the mud acts as a sunscreen, protecting its skin from harsh ultraviolet radiation. Although tough, an elephant's skin is very sensitive. Without regular mud baths to protect it from burning, as well as from insect bites and moisture loss, an elephant's skin would suffer serious damage. After bathing, the elephant will usually use its trunk to blow soil on its body to help dry and bake on its new protective coat. As elephants are limited to smaller and smaller areas, there is less water available, and local herds will often come too close over the right to use these limited resources.
Wallowing also aids the skin in regulating body temperatures. Elephants have difficulty in releasing heat through the skin because, in proportion to their body size, they have very little of it. The ratio of an elephant's mass to the surface area of its skin is many times that of a human. Elephants have even been observed lifting up their legs to expose the soles of their feet, presumably in an effort to expose more skin to the air. Since wild elephants live in very hot climates, they must have other means of getting rid of excess heat.
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| Legs and feet | |
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Elephant using its feet to crush a watermelon before eating it.
An elephant's legs are roughly shaped like columns or pillars, as they must be to support its bulk. The elephant needs less muscular power to stand because of its straight legs and large padded feet. For this reason, an elephant can stand for very long periods of time without tiring. In fact, African elephants rarely lie down unless they are sick or wounded. Indian elephants, in contrast, lie down frequently.
The feet of an elephant are nearly round. African elephants have three nails on each hind foot, and four on each front foot. Indian elephants have four nails on each hind foot and five on each front foot. Beneath the bones of the foot is a tough, gelatinous material that acts as a cushion or shock absorber. Under the elephant's weight, the foot swells, but it gets smaller when the weight is removed. An elephant can sink deep into mud, but can pull its legs out readily because its feet become smaller when they are lifted.[citation needed]
Elephants swim well, but cannot trot, jump, or gallop. They do have two gaits: a walk and a faster gait that is similar to running.
In walking, the legs act as pendulums, with the hips and shoulders rising and falling while the foot is planted on the ground. With no "aerial phase", the faster gait does not meet all the criteria of running, as elephants always have at least one foot on the ground. However, an elephant moving fast uses its legs much like other running animals, with the hips and shoulders falling and then rising while the feet are on the ground. In this gait, an elephant will have three feet off the ground at one time. As both of the hind feet and both of the front feet are off the ground at the same time, this gait has been likened to the hind legs and the front legs taking turns running.[49] Tests at the Thai Elephant Conservation Centre are reported to show that fast-moving elephants 'run' with their front legs, but 'walk' with their hind legs.[50]
Although they start this "run" at only 8 km/h,[51] elephants have been reported to reach speeds up to 40 km/h (25 mph),[52] all the while using the same gait. In tests at the Thai Elephant Conservation Centre, the fastest elephants reached a top speed of 18 km/h (11 mph).[50] At this speed, most other four-legged creatures are well into a gallop, even accounting for leg length. Spring-like kinetics could explain the difference between the motion of elephants and other animals.[53]
See also: Comparative foot morphology#Elephant foot
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