Wilford, John Noble. "Even Couch Potatoes May Have Been Born to Run". The New York Times. 2004 November 17.

[T]here was the gluteus maximus, the muscle of the buttocks. Earlier human ancestors, like chimpanzees today, had pelvises that could support only a modest gluteus maximus, nothing like the strong buttocks of Homo.

"Have you ever looked at an ape?" Dr. Bramble said. "They have no buns."