Green’s Dictionary of Slang

(Aus.) a prostitute.

[1844		Buffalo Gals 🎵 Buffalo gals won't you come out tonight / And we’ll dance by the light of the moon].
1854		Bell’s Life in Sydney 16 Dec. 2/6: He used such insulting language to her [...] as was likely to incite to a breach of the peace. Mary and Cousin Ellen were passing the Steam Engine Inn, when the defendant pointed to them, exclaiming ‘there go the Buffalo Gals off to Pitt-street’ [...] Ellen complained that not only did the defendant call her and Cousin Mary ‘Buffalo Gals,’ but he also stigmatised them as ‘a couple of titters’.