African Bush Elephant

African Bush Elephant

Taxobox
name = African Bush ElephantMSW3 Shoshani|pages=91]
status = NT
status_system = iucn3.1
status_ref = IUCN2006|assessors=African Elephant Specialist Group|year=2004|id=12392|title=Loxodonta africana|downloaded=11 May 2006 Database entry includes a range map and a lengthy justification of why this species is near threatened]
trend = unknown



image_width = 250px
regnum = Animalia
phylum = Chordata
classis = Mammalia
ordo = Proboscidea
familia = Elephantidae
genus = "Loxodonta"
species = "L. africana"
binomial = "Loxodonta africana"
binomial_authority = (Blumenbach, 1797)

The African Bush 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. [IUCN African Elephant Specialist Group (AfESG): Statement on the Taxonomy of extant Loxodonta (February, 2006)] It is also known as the Bush Elephant or Savanna Elephant.

Description

The African Bush Elephant is the largest living land dwelling animal, normally reaching 6 to 7.3 meters (19.7 to 24.0 feet) in length and 3 to 3.5 meters (9.8 to 11.5 feet) in height at the shoulder, and weighing between 6,000 and 9,000 kg (13,228-19,843 lb).

The largest on record, shot in Angola in 1955, was a bull weighing 12,274 kg (27,060 lb) and standing 4.2 meters (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 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 genders, 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 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.

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. [cite journal|author = Günther, R. H., O'Connell-Rodwell, C. E., & Klemperer, S. L. | year = 2004 | title = Seismic waves from elephant vocalizations: A possible communication mode? | journal = Geophysical Research Letters | volume = 31 | pages = L11602|doi = 10.1029/2004GL019671]

Diet

African 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. [ [http://www.animalcorner.co.uk/wildlife/elephants/elephant_african.html] ] 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 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 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. Elephants rip apart all kind of plants, and knock down trees with the tusks if they are not able to reach the tree leaves. In some national parks 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.

ocial behavior

The African Bush Elephant is an intelligent animal. Experiments with reasoning and learning 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 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 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 do not get too far from their families and recognize them when reencountered. 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 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.

Predators

The adult African Bush Elephant generally has no natural predators thanks to its great size [ [http://animaldiversity.ummz.umich.edu/site/accounts/information/Loxodonta_africana.html ADW: Loxodonta africana: Information ] ] , but the calves (especially the newborn) are vulnerable to lion and crocodile attacks, and (rarely) to leopard and hyena attacks. Predation, as well as drought, contribute significantly to infant mortality. Contrary to the ordinary capacities of lions, a pride including over 30 lions have been reported as preying on adult female elephants at Chobe National Park. [ [http://darrennaish.blogspot.com/2006/11/giant-killers-macropredation-in-lions.html Darren Naish: Tetrapod Zoology: Giant killers: macropredation in lions ] ]

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 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 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.

pecies differences

The African Elephant genus "Loxodonta" is nowadays generally considered to be 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, straighter and downward tusks, and considerably smaller size. With regard to the number of toenails: the African Bush Elephant normally has 4 toenails on the frontfoot and 3 on the hindfoot while the African Forest Elephant normally has 5 toenails on the frontfoot and 4 on the hindfoot (like the Asian Elephant), but hybrids between the two species occur.

Another possible species or subspecies existed, but although formally described [Nowak, Ronald M. (1999), "Walker's Mammals of the World", 6th edition, Baltimore and London: The Johns Hopkins University Press, pp 1002.] [Yalden, D.W., M.J. Largen and D. Kock (1986), "Catalogue of the Mammals of Ethiopia.6. Perissodactyla, Proboscidea, Hyracoidea, Lagomorpha, Tubulidentata, Sirenia, and Cetacea", Italian J. Zool., Suppl., n.s., 21:31-103.] 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. This was the animal famously used as war elephants by Carthage in its long struggle against Rome.

Conservation

While the species is designated as vulnerable, 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. [cite web | title = African Elephants Slaughtered in Herds Near Chad Wildlife Park | url = http://news.nationalgeographic.com/news/2006/08/060830-elephants-chad.html | author = Handwerk, Brian | date = 2006-08-30 | accessdate = 2006-09-01 | work = [http://www.nationalgeographic.com/index.html NationalGeographic.com] ] 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 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. [cite web | title = 100 Slaughtered Elephants Found in Africa | url = http://www.livescience.com/animalworld/060830_chad_elephants.html | author = Goudarzi, Sara | date = 2006-08-30 | accessdate = 2006-08-31 | work = [http://LiveScience.com LiveScience.com] ]

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. [Lucy E. King, Iain Douglas-Hamilton, Fritz Vollrath (2007) African elephants run from the sound of disturbed bees. "Current Biology" 17: R832-R833]

References

External links

* [http://elephant.elehost.com/About_Elephants/about_elephants.htm Elephant Information Repository] - An in-depth resource on elephants
* ARKive - [http://www.arkive.org/species/GES/mammals/Loxodonta_africana/ images and movies of the African elephant "(Loxodonta africana)"]


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