Impala

Impala

The graceful impala is a slender, medium-sized antelope so adaptable that it is found from southern Africa to the northern limits of East Africa. In the rainy season, when food is plentiful, they may gather in large herds of several hundred animals to browse on grasses and herbs, bushes, shrubs, and shoots.

Physical Characteristics

The body is reddish-brown with white hair inside the ears, over each eye and on the chin, upper throat, underparts and buttocks.
A narrow black line runs along the middle of the lower back to the long tail, and a vertical black stripe appears on the back of each thigh.
Unlike other antelopes, impalas have large, brush like tufts of long, coarse black hair that cover a scent gland located just above the heel on each hind leg.

Habitat

Impalas are found at grassland and woodland edges, usually very close by water.

Behavior

Their social organization allows impalas to adapt to prevailing environmental conditions.
When food is plentiful, the males become territorial. In home ranges averaging 3 square miles, six to eight dominant males set up territories.
They stand with erect posture, rub scent from face glands and make dung heaps to mark their territory.
The females form herds of 10 to 50 or more and wander in and out of male territories.
If they start to leave the territory, the male tries to herd them back to the center, or he feigns danger just beyond his boundary by taking a stance normally used as a warning sign.
Bachelor males are allowed to remain in male territories if they ignore the females.
The territorial male's challenger will have worked his way up through the hierarchy of the bachelor group until he becomes the dominant male.
He then leaves the group and challenges a territorial male through horn duels, in which the males approach one another with slow, deliberate steps.
At a signal, such as swiveling the eyeballs to show the whites or slightly nodding the head, they rush forward and clash horns, attempting to throw one another off balance.
Although fighting can be fatal, males are protected by exceptionally thick skin over vulnerable areas.
It is not the length of horn that gives a male the advantage but his condition and weight.
When a territorial male begins to lose weight from his frantic activity, he is defeated and must return to the bachelor group to recuperate.
There are times, however, when this territorial system is not maintained.
In drier years the animals have to travel further to obtain food, and many smaller herds of females’ form.
They move in and out of the territories so often that the males are very quickly exhausted.
When this happens, territories are abandoned, and large, mixed tranquil herds of females and males form.
When feed conditions improve, impalas revert to the territorial system.

Diet

Impalas eat tender young grass shoots in the wet season and herbs and shrubs at other times. During the dry season they must drink daily.

Caring for the young Impala

In East Africa young are born year-round, but birth peaks usually coincide with the rains. The female leaves the herd and seeks a secluded spot to bear her fawn. After giving birth she cleans the fawn and eats the afterbirth. If the fawn is born at a time when there are few other young around, the mother will stay with it in seclusion spot for a few days or even leave it lying out for a week or more before returning to the herd. If there are many other fawns, she may take hers back to the herd in a day or two, where a nursery group may form. Because predators have more difficulty selecting an individual from a nursery group, the fawns are safer there.

The young are suckled for 4 to 6 months and grow rapidly, reaching maturity at a little over a year. The young males, however, are evicted from their mothers' groups when they are 6 months old, staying around the edges of the herd until they join a bachelor group. During this transition period they are most vulnerable to predators. Males will not be mature enough to hold a territory until they are 5 or 6 years old.

Predators

The young are killed by jackals and the smaller cats, baboons, eagles and pythons. When in danger, impalas will "explode" in a magnificent spectacle of leaping. In their zig-zag leaps, they often jump over and across their companions, probably to confuse predators. They perform a high kick of the hind legs, a movement thought to release scent from the glands on the heels, making it easier for them to stay together. Herds offer protection from predators, such as lions. An alert impala will bark out an alarm that puts the entire herd to flight—and a fleeing impala is no easy prey.

Impalas are fleet runners who are able to leap distances of up to 33 feet. They use this technique to escape predators and sometimes, apparently, simply to amuse themselves. The impala can also clear bushes and other obstacles by soaring some 10 feet in the air. Typically, a running impala will simply jump over anything in its path.

Did you know?

The female is similar to the male but does not have horns. The male's graceful lyre-shaped horns are 18 to 37 inches long.
During periods of intense mating the male vocalizes loudly, making a sound between a lion's roar and a dog's bark. Exhausted by such activity, males seldom can hold their territories for more than a few months at a time.
The impala is one of the most common and most graceful of all Africa’s antelopes. A slender, agile creature, it can clear formidable obstacles and run at speeds faster than 60km/h.
They are fleet runners who can leap up to 10m in length and 3m in height. They use their tremendous speed and agility to avoid predation, and seemingly for pure enjoyment.
Males are known as rams, while females are referred to as ewes and have no horns. Male impalas have Lyre-shaped and ringed horns, up to 75cm long.
The male’s horns can take many years to reach full length, which is why young animals are unlikely to establish a dominant position and breeding territory.
Male impalas produce a scent from a gland on their foreheads to advertise their status to rivals. When he loses his rank, a male produces less scent.
Males will fight for status and territory throughout the mating season, using their antlers as weapons.
Impalas decrease their chances of attack when living in herds. They leap and scatter in all directions when being attacked to confuse the predator.
As they also must drink every day and knowing that predators, such as the lion, frequently lie in wait around waterholes at dusk, they often drink during the hottest part of the day. At this time, the predators are at their most sluggish.
The impala is rarely seen on its own. Females and young animals form herds of up to 100 individuals, while males live in a bachelor group of about 60 animals. They occupy a large range and make seasonal migrations from high to lower ground according to the availability of suitable food.
Predators include lions, leopards and cheetahs. Like other antelope, the impala is constantly alert to danger and has extremely acute senses of hearing, sight and smell. 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.
The name ‘Impala’ come from the Zulu language meaning ‘gazelle’.

Sources:

http://www.nationalgeographic.com/animals/mammals/i/impala/

http://www.onekindplanet.otg/animal/impala/

http://www.outtoafrica.nl/animals/engimpale.html

IMPALA