Green’s Dictionary of Slang

orangutan n.

(US) a derog. term for a black person.

[US]Whip & Satirist of NY & Brooklyn (NY) 28 May n.p.: One of the Congo breed of Orang Otangs of whom there is a great many at present in the city.
[US]Bentley & Corbett Prison Sl. 55: Orangutan A black person.