Top 10 Mind-Blowers: Human Butts

Sculpture by Eugene Delaplanche (Prisma/UIG/Getty)

Everyone has a butt, so you've probably seen one before -- maybe even your own. These two, rounded portions of pelvic fat hang out on either side of the anus.

We sit on our buttocks. We spread them when we need to poop. That covers the basics, but we also obsesses about them , reacting even to such an innocuous image as the above with worship or outrage.

So why do we have buttocks? Well, a lot of it just comes down to the sort of lower back that a bipedal ape winds up with over the course of evolution. The underlying muscles are vital to human movement, and buttocks allow primates to sit upright and take the weight off their feet.

Those are the basics, yet there's much more to learn. Let's see what else science can tell us about the butt and humanity's endless fascination with its own rear end.

About the Author: Robert Lamb spent his childhood reading books and staring into the woods — first in Newfoundland, Canada and then in rural Tennessee. There was also a long stretch in which he was terrified of alien abduction. He earned a degree in creative writing. He taught high school and then attended journalism school. He wrote for the smallest of small-town newspapers before finally becoming a full-time science writer and podcaster. He’s currently a senior writer at HowStuffWorks and has co-hosted the science podcast Stuff to Blow Your Mind since its inception in 2010. In his spare time, he enjoys traveling with his wife Bonnie, discussing dinosaurs with his son Bastian and crafting the occasional work of fiction.