Mammoths excavated in New Mexico provide the best evidence of early human presence in North America

In 2013, a neighbor noticed a tusk protruding from a mound on Rowe’s land in New Mexico. DWhen Rowe went to investigate, he found a crushed mammoth skull and other bones that had been deliberately broken.

He appeared to have discovered a site where mammoths had been slaughtered, but early human sites are shrouded in uncertainty. It can be very difficult to determine whether one is created by nature or by human hands.

That uncertainty has fueled debate in the anthropological community about when humans first appeared in North America.

Long thought to be an indigenous human culture dating back 16,000 years, the Clovis culture left behind carefully crafted stone tools. These make it possible to assign certain sites to people in an objective way.

But at older sites without stone tools, traces become more subjective, said Mike Collins, a retired professor at Texas State University who was not involved in the study. Collins led the investigation at Gault, a well-known archaeological site near Austin where many Clovis and pre-Clovis artifacts have been found.