As a U.S. slang term, *moke* has a very problematic history. Though its earliest slang meaning (going back at least to 1839), was "donkey or mule," it was also used for decades as a disparaging term for "a black or dark-skinned person" (starting not later than 1847) and "a foolish or inconsequential fellow" (starting not later than 1855).

J.E. Lighter, *Random House Historical Dictionary of American Slang* (1994) identifies three basic meanings of the term in connection with living creatures:

>**moke** *n.* {orig[in] unk[nown]} **1.a.** a donkey or mule. *Rare* in U.S. b. a horse. [Citations range from 1839 to 1960.] ...

>**2.a.**  a black person.—usu. used contemptuously.—usu. considered offensive. ... b. a dark-skinned person of any race. —usu. used contemptuously.—usu. considered offensive. [Citations range from 1847 to 1967.] ...

>**3.** a foolish or inconsequential fellow. Cf. MOOK. [Citations range from 1855 to 1915] ...

So historically in U.S. usage, a *moke* could refer to a beast of burden; a black or dark-skinned person; or a fool or lightweight.

[I will continue to research the term and add to this answer, but I wanted to post this initial bit of information in case the question gets closed before I can complete it.]