Grévy's zebra
The Grévy's zebra is the largest of all wild equines. It is from head to tail with a tail, and stands high at the withers. These zebras weigh . Grévy's zebra differs from the other two zebras in its more primitive characteristics. It is particularly mule-like in appearance; the head is large, long, and narrow with elongated nostril openings; the ears are very large, rounded, and conical and the neck is short but thick. The zebra's muzzle is ash-grey to black in colour with the lips having whiskers. The mane is tall and erect; juveniles have a mane that extends to the length of the back and shortens as they reach adulthood.
Plains zebra
The quagga was originally classified as a separate species, "Equus quagga", in 1778. Over the next 50 years or so, many other zebras were described by naturalists and explorers. Because of the great variation in coat patterns (no two zebras are alike), taxonomists were left with a great number of described "species", and no easy way to tell which of these were true species, which were subspecies, and which were simply natural variants. The quagga was the first extinct creature to have its DNA studied. Recent genetic research at the Smithsonian Institution has demonstrated that the quagga was in fact not a separate species at all, but diverged from the plains zebra, between 120,000 and 290,000 years ago, and suggests that it should be named "Equus burchellii quagga". However, according to the rules of biological nomenclature, where two or more alternative names are given to a single species, the name first used takes priority. As the quagga was described about 30 years earlier than Burchell's zebra, the correct terms apparently are "E. quagga quagga" for the quagga and "E. quagga burchellii" for the plains zebra, unless ""Equus burchellii"" is officially declared to be a "nomen conservandum".