| African Bush Elephant[1] | |
|---|---|
| Conservation status | |
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Mammalia |
| Order: | Proboscidea |
| Family: | Elephantidae |
| Genus: | Loxodonta |
| Species: | L. africana |
| Binomial name | |
| Loxodonta africana (Blumenbach, 1797) |
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| Synonyms | |
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Loxodonta africana africana |
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The African Bush Elephant or African Savanna Elephant (Loxodonta africana) is the larger of the two species of African elephant. Both it and the African Forest Elephant have usually been classified as a single species, known simply as the African Elephant. Some authorities still consider the currently available evidence insufficient for splitting the African Elephant into two species.[3] It is also known as the Bush Elephant.
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The African Elephant is the largest living terrestrial animal, normally reaching 6 to 7.3 metres (19.7 to 24.0 ft) in length and 3.5 to 4 metres (11.5 to 13.1 ft) in height at the head, and weighing between 6,000 to 9,000 kg (13,000 to 20,000 lb).[4]
The largest on record, shot in Angola in 1955,[5] was a bull weighing 12,274 kg (27,060 lb) and standing 4.2 metres (13.8 ft) high, the body of which is now mounted in the rotunda of the National Museum of Natural History in Washington, D.C.. (The museum's website states that the specimen weighs only 8 tons.[6]) The Bush Elephant normally moves at a rate of 6 km/h (4 mph), but it can reach a top speed of 40 km/h (25 mph) 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; 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. The forehead 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.
Little scientific research has been carried out into elephants' cognitive or perceptual abilities. An exception is a recent report that African Bush Elephants are able to use seismic vibrations at infrasound frequencies for communication.[7]
African Bush Elephants are herbivorous. Their diet varies according to their habitat; elephants living in forests, partial deserts, and grasslands all eat different proportions of herbs and tree or shrubbery leaves. Elephants inhabiting the shores of Lake Kariba have been recorded eating underwater plant life.[8] 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 milk 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 vegetable 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. Elephants rip apart all kind of plants, and knock down trees with the tusks if they are not able to reach the tree leaves. Elephants also drink great quantities of water, over 190 liters per day.
In some national parks there is overpopulation, so that managers of overpopulated parks often contact other parks with fewer specimens to transfer excess individuals.
The African Bush Elephant is an intelligent animal. Experiments with reasoning and learning show that they are one of the smartest mammals together with their Asian cousins. This is mostly due to their large brain.
Herds are made up of related females and their young, 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 bachelor herds with other elephants of the same age. Later they lead a solitary life, approaching the female herds only during the mating season. Nevertheless, elephants do not get too far from their families and recognize 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 are 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 recognize 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 becomes receptive, an event that can occur anytime during the year. When she is ready, she starts emitting infrasounds that attract the males, sometimes from kilometers away. The adult males start arriving at the herd during the following days and begin fighting, 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 90 cm 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.
Some African Bush Elephants will attack and kill rhinoceroses. This behavior, when it occurs, is mostly observed with younger adult male elephants who have come into musth prematurely.
The adult African Bush Elephant generally has no natural predators due to its great size,[9] but the calves (especially the newborn) are vulnerable to lion and crocodile attacks, and (rarely) to leopard and hyena attacks. There are prides of lions who prey on both infants and juveniles especially in the drought months. Lions in Chobe National Park in Botswana have been observed for some time taking both infants (23% of elephant kills) and juveniles. Predation, as well as drought, contribute significantly to infant mortality.
Humans are the elephant's major predator. Elephants have been hunted for meat, 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 Bush Elephant for ivory trading was forbidden, after the elephant population fell from several million at the beginning of the 20th century to fewer than 700,000. Trophy hunting continues today. The population of African Bush 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.
A 2010 genetic study confirmed that the African Bush Elephant and the African Forest Elephant are distinct species.[10] By sequencing DNA of 375 nuclear genes, scientists determined that the two species diverged around the same time as the Asian elephant and the woolly mammoth and are as distinct from one another as those two species.[11] As of December 2010[update], conservation organizations such as the United Nations Environment Programme's World Conservation Monitoring Centre and the International Union for Conservation of Nature (IUCN) had not distinguished between the two species of African elephants for purposes of assessing their conservation status. As of March 2010[update], the IUCN Red List classified African elephants as a whole as vulnerable species and the Central African elephant population (forest elephants) as Endangered.[2]
Another possible species or subspecies formerly existed, but although formally described [12][13] it has not been widely recognized by the scientific community. The North African Elephant (Loxodonta africana pharaohensis), also known as the Carthaginian Elephant or Atlas Elephant, was the animal famously used as a war elephant by Carthage in its long struggle against Rome.[14]
While the species is designated as vulnerable,[2] conditions vary somewhat by region within Eastern and Southern Africa.
In 2006, an elephant slaughter was documented in southeastern Chad by aerial surveys. A series of poaching incidents, resulting in the killing of over 100 elephants, was carried out during the late spring and summer of 2006 in the vicinity of Zakouma National Park.[15] This region has a decades-old history of poaching of elephants, which has caused the elephant population of the region, which exceeded 300,000 in 1970, to drop to approximately 10,000 today. The African Bush Elephant officially is protected by Chadian government, but the resources and manpower provided by the government (with some European Union assistance) have proven insufficient to stop the poaching.[16]
Human encroachment into or adjacent to natural areas where Bush Elephants occur has led to recent research into methods of safely driving groups of elephants away from humans, including the discovery that playback of the recorded sounds of angry honey bees are remarkably effective at prompting elephants to flee an area.[17]
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