WE have our broad-hipped ancestors to thank for our big brains. The capacious birth canal of a newly unearthed Homo erectus fossil shows we evolved to accommodate a bulging brain as long as 1.2 million years ago.
“Brain size is driving the whole system here,” says Scott Simpson of Case Western Reserve University in Cleveland, Ohio, who was part of the team that uncovered the nearly complete fossil. “The most successful individuals in these populations will have positive selection for [big] brains and large pelvises.”
The new fossil offers a glimpse into the female influences on evolution, say the researchers,…
