The Human Body Is Built for Distance

The next time somebody asks if the body is built for distance running or sitting on the couch of doom eating cheezy poofs, send em here.  
...And the gluteus maximus, the largest muscle in the human body, is primarily engaged only during running. “Your butt is a running muscle; you barely use it when you walk,” Dr. Lieberman said. “There are so many features in our bodies from our heads to our toes that make us good at running.”

So, finally the answer to why our butts are so big...

-Larry