|Mature male impala in Serengeti National Park, Tanzania|
|Female impala in Mikumi National Park, Tanzania|
|Distribution of the impala
Red =A. m. melampus
Blue = A. m. petersi
It is found in savannas and thick bushveld in Kenya, Tanzania, Swaziland, Mozambique, northern Namibia, Botswana, Zambia, Zimbabwe, southern Angola, northeastern South Africa, and Uganda. It can be found in numbers of up to two million.
Taxonomy and etymology
The name impala comes from the Zulu language meaning "gazelle". The scientific name, Aepyceros melampus, is derived from Greek words αιπος aipos ("high"), κερος ceros ("horn") and melas ("black"), pous ("foot").
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, it was put in its own tribe, Aepycerotini. This tribe has now been elevated to subfamily status.
- Black-faced impala (A. m. petersi)
- Common impala (A. m. melampus)
The impala is sexually dimorphic. It is around 75 and 95 cm (30 and 37 in) tall. The average mass for a male impala is 40 to 75 kg (88 to 165 lb), while females weigh about 30 to 50 kg (66 to 110 lb). The coat is short and glossy, normally reddish-brown in colour (hence the Afrikaans name rooibok, not to be confused with rhebok). It has lighter flanks and a white underbelly with a characteristic "M" marking on the rear.
Only the male, referred to as the ram, has lyre-shaped horns, which can reach up to 45–92 cm (18–36 in) in length. The female, referred to as the ewe, lacks horns. Both have distinctive black and white stripes running down the rump and tail. The black impala, found in very few places in Africa, is an extremely rare type. A recessive gene causes the black coloration in these animals. The impala has scent glands covered in the fur of the back feet and sebaceous glands on the head.
The impala is an ecotone species "living in light woodland with little undergrowth and grassland of low to medium height". It has an irregular distribution due to dependence on relatively flat lands with good soil drainage and water. While it stays near water in the dry season, it can go weeks without drinking if enough green fodder is available.
The impala is an adaptable forager. It usually switches between grazing and browsing depending on the season. During wet seasons when grasses are fresh, it grazes. During dry seasons, it browses foliage, shoots, forbs, and seeds. It may switch between grazing and browsing depending on the habitat. Leopards, cheetahs, lions and wild dogs prey on the impala.
The impala, like other small- to medium-sized African antelope, has a special dental arrangement on the front lower jaw similar to the toothcomb seen in strepsirrhine primates, which is used during grooming to comb the fur and remove ectoparasites.
Social structure and reproduction
Females and young form herds of up to 200 individuals. When food is plentiful, adult males will establish territories. Females pass through the territories with the best food resources. Territorial males round up any female herds that enter their grounds, and will chase away bachelor males that follow. 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 which 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.
The breeding season of the impala, also called the rut, begins toward the end of the wet season in May. The entire affair typically lasts about three weeks. While young are usually born after six to seven months, the mother has the ability to delay giving birth for an additional month if conditions are harsh. When giving birth, the female will isolate herself from the herd, despite numerous attempts by the male to keep her in his territory. The female 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. There, the fawn will join a nursery group and will go to its mother only to nurse or when predators are near. Fawns are suckled for four to six months. Males which mature are forced out of the group and will join bachelor herds.
When frightened or startled, the whole herd starts leaping about to confuse their predator. Able to jump distances of more than 10 m (33 ft) and 3 m (9 ft) into the air, threatened impalas will explode in a magnificent spectacle of leaping. Sometimes this is done with the animals holding their leg stiffly and the neck arched downwards, a behaviour known as stotting or pronking. The impala can reach running speeds in a zig-zag of about 60 km/h (37 mph) on average with the peak on 80 km/h (50 mph), to escape its predators. When escaping from predators, it can release a scent from glands on its heels, which can help it stay with the group. This is done by performing a high kick of its hind legs.
The common impala is one of the most abundant antelopes in Africa, with about one-quarter of the population occurring in protected areas. The largest numbers occur in areas such as the Masai Mara and Kajiado (Kenya); Serengeti, Ruaha and Selous (Tanzania); Luangwa Valley (Zambia); Okavango Delta (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). The rare black-faced impala survives in Etosha National Park and private farms in Namibia.
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- Trek Nature Impala
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