Coat colour in sable antelope changes with age and sex. Calves are a uniform tan or reddish brown with faint markings. Young animals of both sexes resemble the cows. As bulls mature over several years the coat darkens progressively through dark brown to a deep glossy black, while the white facial markings and belly remain, producing the sharp contrast the species is known for.
Cows vary geographically. In many southern populations they stay chestnut throughout life; in some eastern populations older cows become considerably darker, which can make sexing at a distance unreliable without checking horn thickness and length. Both sexes carry ringed, backward-curving horns, longer and heavier in bulls.
The darkening is best read as a signal tied to social status. Sable are territorial, with bulls holding ground and herds of cows moving through, and a jet-black coat with high-contrast face markings is visible at distance across open woodland. The species is also a notably determined fighter, using its horns from a kneeling position when cornered.