Originally posted by Madman_V3N0M
Uhh... they remind us of the ass? I think that's the scientific explanation of why human females developed large mamary glands...
This butt-resemblance supposedly encouraged face-to-face mating, which strengthened male-female pairing (making it longer lasting), an advantage when raising human young, since humans take a long time before they can be out on their own, foraging 'n' stuff.