from Google: With their large pendulous nose, giant bellies, and permanent erect penis, the proboscis monkey has one of the most unusual appearances of all primates. Their most distinctive trait is their large protruding nose. Although females already have a very large nose for a primate, the nose of males is so long it often hangs over their mouth, exceeding 10cm in length. Why males have such a large nose is still a matter of dispute but may be a form of sexual selection, with females preferring males with large noses because the nose amplifies vocalisations.
------------------------------------------------------------------------------------------------------------------------------------------------------
not from Google: I  think females prefer not only a large nose but also a male with " permanent erect penis";  lol;