They are medium-sized antelopes with a striking reddish-brown to purplish-red coat. Distinct black patches appear on their face, their upper forelegs, and on their hips and thighs. To complete their singular appearance, the topi’s yellowish-tan legs look like they are encased in stockings.
Although not quite as large as their relative the hartebeest (kongoni), topis have a similar body shape. However, it does not have such a long, narrow head, nor are they as high at the shoulder. Female topis are usually lighter in color than the males. Both sexes have thick, heavily ringed, lyre-shaped horns that are about 30 to 40 centimeters long (11 to 16 inches). Topis have good sight and hearing and can run quite fast with a bounding gait.
Topis are exceptionally gregarious and live in herds of 15 to 20. In some places, it is possible to see herds of hundreds. They have a flexible social structure. Sedentary populations display the usual residence pattern — small herds led by a dominant male. During migratory periods, large numbers of animals congregate together indiscriminately. When the group stops, even if for just a few hours, males establish small, temporary territories in which they shepherd the females.
They also spend much of their time with other antelopes, such as wildebeest, and also with zebras and ostriches
Calving normally occurs once a year and is timed for periods when grass supplies are plentiful. Nonetheless, topis are almost as flexible in their reproduction as they are in social organizations. If food supplies are particularly good, then they will conceive at different times of the year, with shorter intervals between calves. Females have also developed the ability to stall the labor process if they sense immediate danger.
They only eat grass — their narrow muzzle being well-adapted for selecting the most tender growth. They graze for a while and then rest and chew their cud before continuing feeding. These antelopes can go without water for long periods of time only if they have access to green pastures. If green grazing is not available, the topi must drink daily.
