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An '''impala''' (''Aepyceros melampus'' Greek αιπος, ''aipos'' "high" κερος, ''ceros'' "horn" + ''melas'' "black" ''pous'' "foot") is a medium-sized [[Africa]]n [[antelope]]. The name '''impala''' comes from the [[Zulu language]] meaning "[[gazelle]]". They are found in [[savanna]]s and thick ''[[bushveld]]'' in [[Kenya]], [[Tanzania]], [[Swaziland]], [[Mozambique]], northern [[Namibia]], [[Botswana]], [[Zambia]], [[Zimbabwe]], southern [[Angola]], northeastern [[South Africa]] and [[Uganda]]. Impalas can be found in numbers of up to two million in Africa.<ref>{{IUCNlink|550}}</ref>
An '''impala''' (''Aepyceros melampus'') is a medium-sized [[Africa]]n [[antelope]]. The name '''impala''' comes from the [[Zulu language]] meaning "[[gazelle]]," while the scientific name comes from Greek αιπος, ''aipos'' "high" κερος, ''ceros'' "horn" + ''melas'' "black" ''pous'' "foot." They are found in [[savanna]]s and thick ''[[bushveld]]'' in [[Kenya]], [[Tanzania]], [[Swaziland]], [[Mozambique]], northern [[Namibia]], [[Botswana]], [[Zambia]], [[Zimbabwe]], southern [[Angola]], northeastern [[South Africa]] and [[Uganda]]. Impalas can be found in numbers of up to two million in Africa.<ref>{{IUCNlink|550}}</ref>


==Taxonomy==
==Taxonomy==
In the past, [[taxonomist]]s had put impalas in the same tribe as [[gazelle]]s, [[kob]]s and [[hartebeest]]s. However, it was found that the impala was so different from any of these tribes that it was put in its own tribe, ''Aepycerotini''. This tribe has now been elevated to full subfamily status.
In the past, [[taxonomist]]s had put impalas in the same tribe as [[gazelle]]s, [[kob]]s and [[hartebeest]]s. However, the impala is so different from any of these tribes that it was put in its own tribe: ''Aepycerotini''. This tribe has now been elevated to subfamily status.


Usually, two [[subspecies]] are distinguished, which is supported by [[mitochondrial DNA]] analysis:<ref name="Nersting and Arctander 2001">{{cite journal |first=Louise Grau |last=Nersting |first2=Peter |last2=Arctander |title=Phylogeography and conservation of impala and greater kudu |journal=Molecular Ecology |volume=10 |issue=3 |pages=711–719 |year=2001 |doi=10.1046/j.1365-294x.2001.01205.x }}</ref>
Usually, two [[subspecies]] are distinguished, which is supported by [[mitochondrial DNA]] analysis:<ref name="Nersting and Arctander 2001">{{cite journal |first=Louise Grau |last=Nersting |first2=Peter |last2=Arctander |title=Phylogeography and conservation of impala and greater kudu |journal=Molecular Ecology |volume=10 |issue=3 |pages=711–719 |year=2001 |doi=10.1046/j.1365-294x.2001.01205.x }}</ref>

Revision as of 22:03, 14 August 2012

Impala
Young male impala in Serengeti, Tanzania
Female impala in Mikumi National Park, Tanzania
Scientific classification
Kingdom:
Phylum:
Class:
Order:
Family:
Subfamily:
Aepycerotinae

Gray, 1872
Genus:
Aepyceros

Sundevall, 1847
Species:
A. melampus
Binomial name
Aepyceros melampus
(Lichtenstein, 1812)
Subspecies
Distribution of the impala
Red =A. m. melampus
Blue = A. m. petersi

An impala (Aepyceros melampus) is a medium-sized African antelope. The name impala comes from the Zulu language meaning "gazelle," while the scientific name comes from Greek αιπος, aipos "high" κερος, ceros "horn" + melas "black" pous "foot." They are found in savannas and thick bushveld in Kenya, Tanzania, Swaziland, Mozambique, northern Namibia, Botswana, Zambia, Zimbabwe, southern Angola, northeastern South Africa and Uganda. Impalas can be found in numbers of up to two million in Africa.[2]

Taxonomy

In the past, taxonomists had put impalas in the same tribe as gazelles, kobs and hartebeests. However, the impala is so different from any of these tribes that it was put in its own tribe: Aepycerotini. This tribe has now been elevated to subfamily status.

Usually, two subspecies are distinguished, which is supported by mitochondrial DNA analysis:[3]

  • Black-faced impala - Aepyceros melampus petersi
  • Common impala - Aepyceros melampus melampus

Only one species of impala is alive today, but several fossil species are also known, including A. datoadeni, from the Pliocene of Ethiopia.[4]

Appearance

A mature impala ram in Mikumi National Park, Tanzania

Impala range between 75 and 95 cm (30 and 37 in) tall. Average mass for a male impala is 40 to 80 kg (88 to 176 lb), while females weigh about 30 to 50 kg (66 to 110 lb). They are normally reddish-brown in color (hence the Afrikaans name of "Rooibok", not to be confused with rhebok), have lighter flanks and white underbellies with a characteristic "M" marking on the rear. Males, referred to as rams, have lyre-shaped horns, which can reach up to 90 centimeters in length. Females, referred to as ewes, have no horns. The black impala, found in very few places in Africa, is an extremely rare type. A recessive gene causes the black colouration in these animals.

Ecology

Impala leaping in Kenya

Impalas are an ecotone species "living in light woodland with little undergrowth and grassland of low to medium height".[5] They have an irregular distribution due to dependence on relatively flat lands with good soil drainage and water.[5] While they stay near water in the dry season, they can go weeks without drinking if there is enough green fodder.[5]

Impalas are adaptable foragers. They usually switch between grazing and browsing depending on the season. During wet seasons when grasses are fresh they graze.[5] During dry seasons they browse foliage, shoots, forbs and seeds.[5] They may switch between grazing and browsing depending on the habitat.[6] Leopards, cheetahs, lions and wild dogs prey on impala.

Impala, as well as other small- to medium-sized African antelopes, have a special dental arrangement on the front lower jaw similar to the toothcomb seen in strepsirrhine primates,[7] which is used during grooming to comb the fur and remove ectoparasites.[8]

Social structure and reproduction

Male impalas rutting (fighting during the breeding season)

Females and young form herds of up to 200 individuals. When food is plentiful, adult males will establish territories. Females pass through the territories that have the best food resources.[9] Territorial males round up any female herds that enter their grounds,[5][9] and will chase away bachelor males that follow.[5][9] They will even chase away recently weaned males. A male impala tries to prevent any female from leaving his territory. During the dry seasons, territories are abandoned, as herds must travel farther to find food. Large, mixed tranquil herds of females and males form. Young male impalas who have been made to leave their previous herd form bachelor herds of around 30 individuals. Males that are able to dominate their herd are contenders for assuming control of a territory.

Aepyceros melampus petersi, female (Namibia)

The breeding season of impalas, also called rutting, begins toward the end of the wet season in May. The entire affair typically lasts approximately three weeks. While young are usually born after six to seven months,[10] the mother has the ability to delay giving birth for an additional month if conditions are harsh. When giving birth, a female impala will isolate herself from the herd,[10] despite numerous attempts by the male to keep her in his territory.[11] The impala mother will keep the fawn in an isolated spot for a few days or even leave it lying out in hiding for a few days, weeks, or more before returning to the herd.[5] There, the fawn will join a nursery group and will go to its mother only to nurse or when predators are near.[5] Fawns are suckled for four to six months.[5] Males who mature are forced out of the group and will join bachelor herds.[5]

When frightened or startled, the whole herd starts leaping about to confuse their predator. They can jump distances of more than ten meters (33 ft) and three meters (9 ft) high. Impalas can reach running speeds of about 90 km/h (56 mph),[12][13] to escape their predators. When escaping from predators, they can release a scent from their glands on their heels, which can help them stay together. This is done by performing a high kick of their hind legs.[citation needed]

Status

The common impala is one of the most abundant antelopes in Africa, with about one-quarter of the population occurring in protected areas.[1] The largest numbers occur in areas such as the Masai Mara and Kajiado (Kenya); Serengeti, Ruaha and Selous (Tanzania); Luangwa Valley (Zambia); Okavango (Botswana); Hwange, Sebungwe and the Zambezi Valley (Zimbabwe); Kruger National Park (South Africa) and on private farms and conservancies (South Africa, Zimbabwe, Botswana and Namibia).[14] The rare Black-faced impalas survive in Etosha National Park and private farms in Namibia.[1]

References

  1. ^ a b c Template:IUCN2008 Database entry includes a brief justification of why this species is of least concern
  2. ^ http://www.iucnredlist.org/details/full/550/0
  3. ^ Nersting, Louise Grau; Arctander, Peter (2001). "Phylogeography and conservation of impala and greater kudu". Molecular Ecology. 10 (3): 711–719. doi:10.1046/j.1365-294x.2001.01205.x.
  4. ^ Geraads, D.; et al. (2012). "Pliocene Bovidae (Mammalia) from the Hadar Formation of Hadar and Ledi-Geraru, Lower Awash, Ethiopia". Journal of Vertebrate Paleontology. 32 (1): 180–197. doi:10.1080/02724634.2012.632046. {{cite journal}}: Explicit use of et al. in: |author= (help)
  5. ^ a b c d e f g h i j k Estes, R. (1991). The Behavior Guide to African Mammals, Including Hoofed Mammals, Carnivores, Primates. Los Angeles, University of California Press. pgs. 158-166
  6. ^ Smithers, R. H. N. (1983) The Mammals of the Southern African Subregion. University of Petoria.
  7. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1111/j.1096-3642.1990.tb00564.x, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1111/j.1096-3642.1990.tb00564.x instead.
  8. ^ Attention: This template ({{cite doi}}) is deprecated. To cite the publication identified by doi: 10.1016.2F0031-9384.2895.2902186-8, please use {{cite journal}} (if it was published in a bona fide academic journal, otherwise {{cite report}} with |doi= 10.1016.2F0031-9384.2895.2902186-8 instead.
  9. ^ a b c Nowak, R. M. (1991). Walker's mammals of the world. Baltimore, Johns Hopkins University press.
  10. ^ a b Estes, R.D. (1999). The Safari Companion. Rev. Ed. Chelsea Green Publishing Company: White River Junction.
  11. ^ Jarman, M. (1979). "Impala Social Behaviour: Territory, Hierarchy, Mating, and the Use of Space". Beihefte Z. Tierpsychol. 21:1-92.
  12. ^ Safari Photo Zebre Impala
  13. ^ Impalas Réserve Africaine de Sigean
  14. ^ East, R. 1999. African Antelope Database 1999. IUCN, Gland, Switzerland and Cambridge, UK.