Talk:Forever/@comment-27595907-20160112040959/@comment-26653902-20161015201342

Actually, with Sumatran orangutans, not all males have the flaps. Subordinate males look similar to females.

Sources:

http://www.iflscience.com/plants-and-animals/male-orangutans-cheek-pads-father-more-offspring/

http://beheco.oxfordjournals.org/content/13/5/643.full