What is the purpose of brow ridges in primates? Why are they universal in anthropoids but not prosimians? Why don’t humans have them? How do they affect perception, notably vision? Do they protect the eyes more than not having brow ridges? What other anatomical structures are linked with brow ridges? I don’t have much background here, but my best guess is that brow ridges have something to do with absorbing shock or pressure from chewing with shorter muzzles? Please enlighten. Thanks!