Mammals
Impala
Aepyceros melampus · also called impala, rooibok
The impala is the antelope you see most on an African safari — a graceful, russet, medium-sized deer-like animal at the edge of the woodland, ready to explode into a series of enormous leaps at the first sign of a predator. It is one of the most abundant antelopes on the continent, and that abundance is down to one advantage: it eats whatever is available.
Overview
Impala live where woodland meets grassland, in savanna and acacia scrub near water, across eastern and southern Africa. They are highly social, forming herds of dozens in the dry season and, in the breeding season, splitting into territorial males, bachelor groups, and female herds. Males carry ridged, lyre-shaped horns; females are hornless.
The mixed feeder
Most antelopes are committed grazers or browsers. The impala is a mixed feeder — it grazes fresh grass in the wet season and browses leaves, shoots, pods, and fruit in the dry season — so it is never short of food. That flexibility, its preference for the productive transition zone, and a high birth rate let it reach densities other antelopes cannot, and persist in human-altered country.
Leaping
An impala clears about 10 metres in length and 3 metres in height in one bound. The leaping breaks a predator’s line of sight, clears obstacles, and — as a stiff-legged “pronk” — signals fitness. Herds sometimes leap for no clear reason at all.
The rut
In the rut, dominant males roar, herd, and chase almost without eating, losing so much condition in two to three weeks that they often lose the territory — and fall to predators — soon after.
Status
The common impala is Least Concern, around 2 million and stable — a staple prey of nearly every large African predator. The distinct black-faced impala of Namibia and Angola is Vulnerable, down to a few thousand.
Impala: common questions
Why can impala jump so far and so high?
An impala can leap about 10 metres in length and 3 metres in height from a standstill or a run, launching itself over bushes, other impala, and open ground. Long, powerful, spring-like hind legs and light bones make it possible. The leaping serves several likely purposes — clearing obstacles quickly during a flight from a predator, breaking a predator's line of sight and pursuit, and startling an ambusher into revealing itself. Impala also "pronk" or "stot," bouncing on stiff legs with the back arched, which is thought to signal to a predator that the animal is fit and fast and not worth chasing. Herds sometimes erupt into leaping for no visible reason at all.
Why is the impala so successful when other antelopes decline?
Its flexible diet. Most antelopes are either grazers (grass eaters, like wildebeest) or browsers (leaf eaters, like kudu), and each struggles when its food type is scarce. The impala is a "mixed feeder" that shifts between the two — it grazes new grass in the wet season and browses leaves, pods, and fruit in the dry season, so it always has something to eat. This, plus its preference for the productive transition zone where woodland meets grassland, its need to stay near water, and its high reproductive rate, lets it reach very high densities and persist in landscapes altered by people and livestock where specialist antelopes disappear.
Do male impala really have a losing strategy in the breeding season?
In a sense. During the rut, which in southern Africa peaks around April–May, dominant males establish and defend territories, and they do it with relentless energy — roaring (a startlingly loud, growling, snorting call), herding females, chasing rivals, and scent-marking, often barely feeding. A territorial male can burn through his fat reserves and lose a large fraction of his body condition in two to three weeks. Exhausted and distracted, he then becomes far more vulnerable to predators and is frequently displaced by a fresher challenger. The most successful long-term strategy for a male is often to time his bid for territory carefully rather than to hold one as long as possible.
What is the black-faced impala?
It is a distinct subspecies, Aepyceros melampus petersi, found only in northwestern Namibia and southwestern Angola, distinguished by a dark blaze down the face and a slightly larger body. It is much rarer than the common impala — reduced by drought, hunting, competition with livestock, and habitat loss to a few thousand animals, mostly in Etosha National Park and on Namibian conservancies and private land. It is listed as Vulnerable, in contrast to the common impala's Least Concern, and there is concern about it hybridising with introduced common impala.