A grazer during rains that switches to browse in the dry season, the Impala out competes pure grazers and browsers within its habitat, reaching high population densities. Herds of females and young often number 50 to 100.
When food is plentiful, and during the rutting season, the dominant male becomes highly territorial and will round up any females that enter its territory. They mark their territory with urine, dung heaps(middens) and with a scent that is excreted from facial glands. The dominant male will defend its territory aggressively with bodily postures, threatening behaviors and loud vocalizations.
Matting takes place between March and June and lasts for three weeks . Dominant males are highly territorial during the rutting season. They will try to separate and keep the females that are in oestrus, that wander into their territory so that they can mate with them. The males are able to detect females that are in oestrus by smelling and tasting their urine.