Black sable antelope (Hippotragus niger) rivals even the greater kudu as the most handsome of all antelope, with its powerful, robust build, vertical mane and fantastically long, curved horns, which arch majestically backwards. Newborn calves are born with a camouflaging, sandy-brown coat, but as they grow and achieve herd status their coats continually darken. Mature females eventually become a rich chestnut-brown to dark brownish-black and fully mature males are a glossy brownish-black to pitch-black, varying with the subspecies. Coat colour appears to be controlled hormonally, with castrated males losing their black colour to become brown again, and it is thought to help communicate age, and therefore social status, to others. Both sexes have sharply contrasting white abdominal, rump, and facial patches, and black facial stripes running down the bridge of the nose and from the eyes to the nostrils. The semi-circular, ridged horns are longer and thicker in males, growing up to an incredible 165 centimetres in length, while those of females reach a worthy 100 centimetres. These massive horns are very effective defensive weapons against natural predators and are used in dominance fighting.