African bush elephant: Difference between revisions
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The adult African Bush Elephant lacks natural predators thanks to its great size, but the calves (especially the newborn) are vulnerable to [[lion]], [[leopard]], [[Nile crocodile|crocodile]], and, more rarely, [[hyena]] attacks. Adult females of a group will attack approaching predators. Predation, as well as drought, contribute significantly to infant mortality. |
The adult African Bush Elephant lacks natural predators thanks to its great size, but the calves (especially the newborn) are vulnerable to [[lion]], [[leopard]], [[Nile crocodile|crocodile]], and, more rarely, [[hyena]] attacks. Adult females of a group will attack approaching predators. Predation, as well as drought, contribute significantly to infant mortality. |
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Humans are the elephant's major predator. Elephants have been hunted for meat as well as the rest of the body, including skin, bones, and tusks. Elephant trophy-hunting increased in the 19th and 20th centuries, when tourism and plantations increasingly attracted sport hunters. In 1989, hunting of the African elephant and ivory trading were forbidden, after the elephant population fell from several million at the beginning of the 20th century to fewer than 700,000. The population of African elephants was halved during the 1980s. Scientists then estimated that, if no protective measures were taken, the wild elephant would be extinct by 1995. The protection that the elephant now receives has been partially successful, but despite increasingly severe penalties imposed by governments against illegal hunting, poaching is still common. [[CITES]] still considers this species as threatened with extinction. |
Humans are the elephant's major predator. Elephants have been hunted for meat as well as the rest of the body, including skin, bones, and tusks. Elephant trophy-hunting increased in the 19th and 20th centuries, when tourism and plantations increasingly attracted sport hunters. In 1989, hunting of the African elephant and ivory trading were forbidden, after the elephant population fell from several million at the beginning of the 20th century to fewer than 700,000. The population of African elephants was halved during the 1980s. Scientists then estimated that, if no protective measures were taken, the wild elephant would be extinct by 1995. The protection that the elephant now receives has been partially successful, but despite increasingly severe penalties imposed by governments against illegal hunting, poaching is still common. [[CITES]] still considers this species as threatened with extinction. |
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==Species differences== |
==Species differences== |
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Revision as of 06:28, 10 August 2006
| African Bush Elephant[1] | |
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| Scientific classification | |
| Kingdom: | |
| Phylum: | |
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| Genus: | |
| Species: | L. africana
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| Binomial name | |
| Loxodonta africana (Blumenbach, 1797)
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The African Bush Elephant (Loxodonta africana) is the better-known and larger of the two species of African elephants. Both it and the African Forest Elephant were previously classified as a single species, known simply as the African Elephant. It is also known as the Bush Elephant or Savanna Elephant.
Description
The African Bush Elephant is the largest land dwelling animal, normally reaches 6 to 7.3 m (20 to 24 ft) in length and 3 to 3.5 meters in height, although a 4-meter elephant, the body of which is mounted in the rotunda of the National Museum of Natural History in Washington, D.C., was discovered in Angola in 1955. Weighing between 7,000 and 10,000 kg (15,000-22,000 lb), it is the largest land animal in the world. It moves at a rate of 6 km/h, but it can reach a top speed of 40 km/h when scared or upset.
The animal is characterized by its large head; two large ears that cover its shoulders and radiate excess heat; a large and muscular trunk; two prominent tusks, which are well-developed in both sexes, although more commonly in males; a short neck; a large, barrel-like body; four long and heavy legs that resemble columns; and a relatively short tail.
The animal is protected by a heavy but flexible layer of gray-brown skin, dotted with mostly undeveloped patches of hair and long, black hair at the tip of its tail. Its back feet have three toes that form a hoof, while the number of toes on the front feet have varied between four and five, in different instances. The front is smoother and less convex than that of the Asian Elephant.
The trunk is the most characteristic feature of the African Bush Elephant. It is formed by the fusion and elongation of the nose and upper lip, forming a flexible and strong organ made purely of muscle.
Relatively little scientific research has been carried out into elephants' cognitive or perceptual abilities. An exception is a recent report that African elephants are able to use seismic vibrations at infrasound frequencies for communication.[3]
Diet
African elephants are herbivorous. The diet of the African Bush Elephant varies according to its habitat; elephants living in forests, partial deserts, and grasslands all eat different proportions of herbs and tree or shrubbery leaves. In order to break down the plants they consume, the African Bush Elephant has four large molars, two in each mandible of the jaw. Each of these molars is 10 cm wide and 30 cm long. Over time, these molars are worn away and new ones are grown to replace them as the elephant ages. Around the age of 15 their deciduous teeth are replaced by new ones that last until the age of 30, and then by another set which wear off past the age of 40, being replaced by the last set of teeth that last approximately until the age of 65–70. Not much later, the animal dies of starvation from not being able to feed correctly. There are known cases of over 80 year old specimens in captivity.
These animals typically ingest an average of 225 kg of vegetal matter daily, which is defecated without being fully digested. That, combined with the long distances that they can cover daily in search of more food, contributes notably to the dispersion of many plant seeds that germinate in the middle of a nutrient-filled feces mound. In their feeding-oriented whereabouts, elephants rip apart all kind of plants, and knock down trees with the tusks if they are not able to reach the tree leaves not even standing up straight, as actual living bulldozers. It can be said that they carry devastation with them. That causes deep trouble for other species and to the elephants themselves in national parks where there is overpopulation, so that managers of overpopulated parks often contact other parks with fewer specimens to transfer excess individuals.
Elephants also drink great quantities of water, over 190 liters per day.
Social behaviour
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The African Bush Elephant is a notably intelligent animal. In fact, experiments about reasoning and learning applied on them show that they are the smartest ungulates together with their Asian cousins. This is mostly due to their large brain.
Herds are made up of related females and their younglings of assorted ages, directed by the eldest female, called the matriarch. Infrequently, an adult male goes with them, but those usually leave the pack when reaching adolescence to form herds with other elephants of the same age. Later, they spread out, carrying out a lonely life, approaching the female herds only during the mating season. Nevertheless, elephants don't get too far from their families and recognise them when re-encountered. Sometimes, several female herds can blend for a period of time, reaching even hundreds of individuals.
The matriarch is the one who decides the route and shows to each other member of the herd all the water sources she knows, which the rest will memorize in the future. The relations among the members of the herd is very tight; when a female gives birth to a baby the rest go to acknowledge it touching her with the trunk; and when an old elephant dies the rest of the herd will stay by the corpse for a while. The famous elephant graveyards are a myth, but it is true that these animals can recognise a carcass of its species when they find one during their trips, and even if it is a stranger, they form around it and sometimes they even touch its forehead with their trunk.
Mating happens when the female feels ready, an event that can occur anytime during the year. When she is ready, she starts emitting infrasounds that attract the males, sometimes many kilometers away. The adult males start arriving to the herd during the following days and begin fighting head-to-head between them, causing some injuries and even broken tusks. The female shows her acceptance of the victor by rubbing her body against his. They mate, and then both go their own way. After 22 months of gestation (the longest among mammals), the female gives birth to a single 90cm-high calf which weighs more than 100 kg. The baby feeds on the mothers milk until the age of 5, but also eats solid food from as early as 6 months old. Just a few days after birth the calf can follow the herd by foot, and so the herd resumes its course.
Some African Bush Elephants will attack and kill rhinoceroses. This behaviour, when it occurs, is mostly observed with younger adult male elephants who have come into musth prematurely.
Predators
The adult African Bush Elephant lacks natural predators thanks to its great size, but the calves (especially the newborn) are vulnerable to lion, leopard, crocodile, and, more rarely, hyena attacks. Adult females of a group will attack approaching predators. Predation, as well as drought, contribute significantly to infant mortality.
Humans are the elephant's major predator. Elephants have been hunted for meat as well as the rest of the body, including skin, bones, and tusks. Elephant trophy-hunting increased in the 19th and 20th centuries, when tourism and plantations increasingly attracted sport hunters. In 1989, hunting of the African elephant and ivory trading were forbidden, after the elephant population fell from several million at the beginning of the 20th century to fewer than 700,000. The population of African elephants was halved during the 1980s. Scientists then estimated that, if no protective measures were taken, the wild elephant would be extinct by 1995. The protection that the elephant now receives has been partially successful, but despite increasingly severe penalties imposed by governments against illegal hunting, poaching is still common. CITES still considers this species as threatened with extinction.
Species differences
The African elephant genus Loxodonta is composed of two species, the African Bush Elephant (Loxodonta africana) and the African Forest Elephant (Loxodonta cyclotis). The African Forest Elephant has a longer and narrower mandible, rounder ears, a different number of toenails, different tusks, and considerably smaller size.
Another possible species (or subspecies) existed, but it has not been recognised yet as it by the scientific community: The North African Elephant (Loxodonta pharaonensis), also known as Carthaginian Elephant or Atlas Elephant. This species, extinct nowadays, lived between the Magreb and the Nile mouth, and had a smaller size than the Savanna Elephant, probably similar to the Forest Elephant. It is also possible that it was more docile that the Savanna Elephant, letting the Carthaginians tame it with an unknown method. To this species belonged the elephants with whom Hannibal crossed the Pyrenees and the Alps in order to invade Italy during the Second Punic War. These elephants were also trained and used by the Ptolemies of Egypt. The historian Polybius (Histories 5.83) describes their inferiority in battle against the larger Indian elephants used by the Seleucid kings. A remaining Ptolemaic inscription does in fact speak about three types of war elephants, the Troglodytic (probably Libyan) and Ethiopian, as well as Indian. The Ptolemaic king prides himself with being the first to tame the Ethiopian elephants, a stock which should be identical to one of the two extant African species.
After the conquest of Sicily, the Romans seemed to gain interest in capturing some specimens that have been left behind in the middle of the island, but failed eventually. The species must have become extinct some decades after the Roman conquest of North Africa.
References
- ^ Shoshani, J. (2005). Wilson, D.E.; Reeder, D.M. (eds.). Mammal Species of the World: A Taxonomic and Geographic Reference (3rd ed.). Johns Hopkins University Press. p. 91. ISBN 978-0-8018-8221-0. OCLC 62265494.
- ^ Template:IUCN2006 Database entry includes a range map and a lengthy justification of why this species is vulnerable
- ^ Günther, R. H., O'Connell-Rodwell, C. E., & Klemperer, S. L. (2004). "Seismic waves from elephant vocalizations: A possible communication mode?". Geophysical Research Letters. 31: L11602.
{{cite journal}}: CS1 maint: multiple names: authors list (link)
External links
- Elephant Information Repository - An in-depth resource on elephants
- African Bush Elephant (Loxodonta africana) facts and picture - Wild Animals Online encyclopedia
- ARKive - images and movies of the African elephant (Loxodonta africana)