Written in Bone Volume 60 Number 3, May/June 2007 by Brenda Fowler How radioactive isotopes reveal the migrations of ancient people A molar from the city of Campeche in Mexico (Courtesy Douglas Price) In the late thirteenth century, drought ravaged the American Southwest, withering the corn, squash, and beans upon which ancient inhabitants relied for survival. Across the region people abandoned their homes in a desperate search for arable land. Some were lucky enough to find a moist Arizona valley where they built a settlement now known as Grasshopper Pueblo. At its peak, the pueblo consisted of 500 rooms housing...