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 describe by Henri de Blainville in 1816. As suggested by its alternative name, this pale antelope has long, twisted horns – typically 22 to 31 inches in females and 28 to 33 inches in males. Males stand from 41 to 45 inches at the shoulder, with females at 37 to 43 inches.