Why do impala kick?

Impala antelope have unique black glands on their ankles known as metatarsal glands (metatarsal meaning hind limb and a gland being any cell, group of cells or organ producing a secretion). They activate these glands by kicking back their hind legs. When a herd or even a small group of impala reacts to a threat from a predator and they scatter in all directions, they kick back their hind legs and release a scent which makes it easier to find each other again once the threat is over. This behaviour has an added advantage of confusing the predator.