when cavemen had sex the high iq ones were disgusted if they saw poop on the butt. the females with brown buttholes were bred out because brown looks like poop plus it hides real poop and makes it harder to see. so the smart ones evolved pink buttholes to make it easy to ensure it was clean, while the dumb ones kept their poopy brown buttholes. this is an easy way to tell if someone has good genetics it's the color of the butthole
