[I]f the czigithai is not the ſame with the zebra, it may be the Aſiatic animal called onager or wild aſs. The onager ſhould not be confounded with the zebra; but I am uncertain whether the ſame remark is applicable to the onager and czigithai; for, from comparing the relations of travellers, it appears, that there are different kinds of wild aſſes, of which the onager is the moſt remarkable. […] The ſwiftneſs of the onager is mentioned by travellers, who remark, that he runs with ſuch rapidity as to eſcape the hunters, though mounted on horſes; […]
Source: wiktionary