 Usually, all species of the Alcelaphinae, Antilopinae, Hippotraginae, Reduncinae, Cephalophinae, many Bovinae, the grey rhebok, and the impala are called antelopes.More species of antelope are native to Africa than to any other continent, almost exclusively in savannahs, with 20-35 species co-occurring over much of East Africa.Because savannah habitat in Africa has expanded and contracted five times over the last three million years, and the fossil record indicates this is when most extant species evolved, it is believed that isolation in refugia during contractions was a major driver of this diversification.