Impala

The Impala (Aepyceros melampus) is one-of-a-kind antelope. Gracefully built, evenly developed and slender, the species is a highly successful antelope, dominant in its chosen habitat in southern Savanna, from central Kenya and Rwanda to northern Natal, west to Namibia and southern Angola. It prefers open woodland bordering to grassland, well-drained soil with firm footing and no more than moderate slope. Impalas usually live near water but can go without drinking. Being a grazer and browser, the impala grazes while grasses are growing, browses on foliage, herbs, shoots, and seedpods when grasses are dry.

The striking conclusion of a 1984 study is that the species has not been changed for at least 5 million years. The greatest change that can be observed in modern impalas is between the isolated population of Black-faced impalas Aepyceros melampus petersi in Namibia and the Common impala Aepyceros melampus melampus found everywhere else throughout its range. This means that impalas are superbly adapted to their environment and there has not been any selection for any major change in behavior or body structure.

Actively territorial males spend one quarter of their time, shepherding females, time that would be otherwise be spent feeding and digesting, keeping bachelor males away and cutting out juveniles, whose horns betray their sex.

Impalas are famous jumpers. Alarmed impalas can jump 10 feet (3 m) and broad-jump 36 ft (11 m). To escape predators that stalk within pouncing range, a whole herd explodes in all directions. More rarely, impalas perform a unique and equally spectacular high jump. As a runner, the impala is not enduring and depend on cover to escape spotted hyenas, wild dogs, and cheetahs.

Rams are extremely vocal during the mating season and give vent to growls, roars, and snorts. They are only territorial during the rut, from January to May, spending the rest of the time in bachelor herds. The home range of a breeding herd, consisting of ewes and young animals, may overlap with the yerritories of several territorial rams. The rams separate harem herds of 15-20 ewes (with their young) for mating. This disrupts the composition of the herds but they reunite at the conclusion of the rut.

Some mothers bring fawns only 2 to 3 days old into the herd, where they associate with other newborns. They play, move and groom with one another, only seeking mothers to nurse or for protection. Weaning complete as early as 4 to 5 months; by then male horns have emerged, exposing them to increased aggression by breeding males. Males all end up an bachelor herds by 8 months.

References

  1. The Safari Companion: A Guide to Watching African Mammals. Richard D. Estes
  2. Field Guide to Mammals of Southern Africa. Chris Stuart
  3. Mammals of Africa, Volumes 1-6. Jonathan Kingdon, David Happold, Thomas Butynski, Michael Hoffmann, Meredith Happold, Jan Kalina