I found this:
What is the origin of the expression: "The Wild Woman of Borneo"? I know it was around as early as the 1940s because I remember it as a child back then, but where did it come from?
I believe this comes from the Victorian circus habit of calling their black show people 'wild' and often attributing their origin to 'Borneo'. They were often displayed wearing only a loin cloth, or similar tropical coverings, wielding a spear, or similar. The crowds were attracted with the call. 'Roll up, roll up, see the wild man of Borneo' The 'wild man of Borneo' was well established as a concept in the UK before WW2, and possibly earlier. The 'woman' version is merely an extension.^
and this image :