Impalas are active during the daytime, especially at dawn and dusk, but also have a feeding period in the middle of the night. They are highly gregarious animals living in groups, called herds, of up to 100 animals. The larger herds are mainly composed of females; subdominant males also form herds. The smallest herds comprise of around 10 animals. A dominant male usually owns a certain amount of territory and has access to the females in the herds which use his territory. Dominant males are frequently challenged and territories may change hands every three to six months. After resting, the previously dominant male may rechallenge for the territory.

Males have a scent gland on their head with which they mark their territory. Males also make aggressive noises (snorts and grunts) when challenged by another male. On defending their territories, males will first resort to characteristic rituals of intimidation, their nose extended forward, head down, tail outstretched and snorting. When confronted with another male, a dominant male yawns widely at the intruder, who often turns and walks away. If this intimidation process does not work a fight will begin.

Male impalas advertise their territory by their behaviour, often standing on a locally high point of land to do so. Other males, coming upon the scent of a dominant male, will attempt to cover the scent with their own. Fights are thus avoided in many instances, even though changes of ownership of a territory are common occurrences. Within the male herd, individuals may signal ties by rubbing heads and exchanging scents produced by glands on their faces. These relationships break down in the breeding season.

Impalas are often seen associated with giraffes, kudus, zebras, wildebeests, and baboons. Such associations are broken off when the lambs are born, as baboons are known to prey on young impala lambs.

Diet

The impala is both a grazer and a browser, feeding on leaves, grass, small plants and seeds. They like to live near water, but can exist without drinking. Antelopes are true ruminants and, like cows, they chew the cud and have a four-chambered stomach.

Adaptations

Their complex digestive system allows antelopes to eat a large quantity of food quickly and then digest it at leisure in a safe place. They have a mobile tongue to grasp their food, which is then cut against the sharp lower incisors. Another adaptation is the impala┐s ability to jump very well. It can reach 3 metres (10 feet) into the air, and 11 metres (36 feet) across the ground. They do this to escape predators but also jump in play. The first jumper alerts the rest of the herd. When jumping, the herd is a spectacular sight.