The addax (Addax nasomaculatus), also known as the white antelope and the screwhorn antelope, is an antelope of the genus Addax, that lives in the Sahara desert. It was first described by Henri de Blainville in 1816. As suggested by its alternative name, this pale antelope has long, twisted horns - typically 55 to 80 cm (22 to 31 in) in females and 70 to 85 cm (28 to 33 in) in males. Males stand from 105 to 115 cm (41 to 45 in) at the shoulder, with females at 95 to 110 cm (37 to 43 in). They are sexually dimorphic, as the females are smaller than males. The colour of the coat depends on the season - in the winter, it is greyish-brown with white hindquarters and legs, and long, brown hair on the head, neck, and shoulders; in the summer, the coat turns almost completely white or sandy blond