Native Americans have often been portrayed as merely unfortunate victims of European disease and aggression, but data on human stature show—and travelers' accounts and skeletal records confirm—that the equestrian Plains nomads were ingenious, adaptive, and nutritionally successful in the face of exceptional demographic stress. Much of their extraordinary achievement can be attributed to a rich and varied diet, a modest disease load other than epidemics, a remarkable facility at reorganization following demographic disasters, and egalitarian principles of operation.