The orgin of the Wolf whistle!?

Well this must be a stupid thing to blog about, but I’m looking for the origin of certain whistle tones. That is, how did the two note ascending and descending whistle (“wolf whistle”) become the sound of appreciation for a female and also another male these days? I been trying to search on the internet but the only thing i found was that  during the Roman time they did so as well;

“Unfortunately the evidence for the existence of the notorious wolf-whistle, communicating sexual interest mainly by males of the human species, is very scant for the Greek and Roman past. It consists of only one episode in Plautus’ Mercator (403-408). Here the father Demipho says to his son Charinus with reference to the beautiful slavegirl they both secretly love and whom the son pretends to have bought for his mother: “I can’t permit it. She is hardly the proper sort of person to attend your mother.” Char.: “Why not?” Dem.: “Because it would cause scandal if such a beauty were the attendant of a wife and mother; when she passes through the streets all the men would look at her, leer, nod and wink and whistle (sibilent).”

Well yes maybe someone else has an answer to my question!? Here is at least a video of how to make the notorious whistle sound! good luck..