Examination of the chemical composition of the teeth of people interred in ancient Cahokia has determined that a considerable portion of the population grew up elsewhere:
Teeth that form in infancy, for example, like the first permanent molars, will reveal a person’s location as a newborn, while those that form in the early teens, like the third molars, will bear the chemical traces of their home in adolescence.
Armed with this technique, Slater’s team studied 133 teeth from 87 people, found in 13 different burial contexts throughout American Bottom.
The results showed that 38 of the teeth, about 29 percent, had strontium ratios that were outside the local range, indicating that those people had been born and raised elsewhere and migrated to Cahokia as adults.
Interestingly, the remains of those believed to have been sacrificial offerings are more likely to be those of locals than other remains.
The Cahokia mounds, which flourished between about 600 BCE to 1400 CE, constitute the largest and most complex pre-Columbian North American city north of Mexico. Artifacts found there suggest that it traded over an enormous area, from the Gulf of Mexico to the Great Lakes. And, as we are learning, it may have attracted people from an equally great range.
If you ever find yourself in downstate Illinois, it’s well worth a visit.