In 1600 they were the largest, most technologically advanced indigenous group in northwest Mexico, but today, though their descendants presumably live on in Sonora, almost no one claims descent from the ?patas. The ?patas seem to have "disappeared" as an ethnic group, their languages forgotten except for the names of the towns, plants, and geography of the Opater?a, where they lived. Why did the ?patas disappear from the historical record while their...