The Collaborative International Dictionary of English v.0.48:

Quagga \Quag"ga\, n. [Hottentot.] (Zool.)
   A South African wild ass (Equus quagga syn. Hippotigris
   quagga). The upper parts are reddish brown, becoming paler
   behind and behind and beneath, with dark stripes on the face,
   neck, and fore part of the body. The species became extinct
   in the late 1800's, largely due to excessive hunting.
   [1913 Webster +PJC]

WordNet (r) 3.0 (2006):

quagga
    n 1: mammal of South Africa that resembled a zebra; extinct
         since late 19th century [syn: quagga, Equus quagga]