There's a tricky rule when the conjunction in a compound subject is "or" --
The verb needs to match the subject that is closer to it in the sentence; in this case, "baboon" is closer to the verb, so you use the singular verb form.
Which verb should I use and why?
Either the wild dogs or the baboon makes or make that howling sound.
I think since dogs is plural it should be make?
2 answers
See #5 here:
http://grammar.ccc.commnet.edu/grammar/sv_agr.htm
http://grammar.ccc.commnet.edu/grammar/sv_agr.htm