Alcelaphus pygarga

from The Collaborative International Dictionary of English v.0.48

Bontebok \Bon"te*bok\ (b[o^]n"t[-e]*b[o^]k), n. [D. bont a sort
   of skin or fur, prop. variegated + bok buck.] (Zool.)
   The pied antelope of South Africa ({Alcelaphus pygarga}). Its
   face and rump are white. Called also {nunni}.
   [1913 Webster]