Thomson's gazelle (Eudorcas thomsonii), named after Joseph Thomson (1858-1895), a Scottish geologist and explorer, is easily identified by its tail motion – it swings side to side like a windshield wiper. One of the smaller species of gazelles, it has a white belly, a white rump patch that extends up to the tail, and a horizontal black side stripe. Thomson's gazelles (called Tommies) live in buck or doe herds of up to 100 individuals, or mixed groups of up to 700. It is the most common type of gazelle in East Africa.
