A new study co-authored by a University of Arizona anthropology professor documents some surprising uses of fire by Native Americans in the northern Great Plains.

The research was conducted through a partnership with the Blackfeet Tribe in northern Montana.

Co-author María Nieves Zedeño and her colleagues examined river beds containing bone deposits that showed evidence of charcoal.

She said the findings showed that human-made fire was used for two main purposes.

“In the case of bison hunting specifically, fire was used both to drive bison into this funnel-shaped drylands and to renew the grasslands. So, if you think of a funnel, the narrowest portion of the funnel is going to be right at the top of a precipice where the bison are going to jump to their death."

The study is published in Proceedings of the National Academy of Sciences.