Sept. 23, 2021
According to a paper published today in the journal Science, now-fossilized footprints were pressed into mud near an ancient lake at White Sands, New Mexico, between 21,000 and 23,000 years ago, a time when many scientists think that massive ice sheets walled off human passage into North America. Unlike other pre-Clovis sites, there's no doubt humans left tracks at White Sands: "It's just screamingly obvious," says study author Vance Holliday, an archaeologist and geologist at the University of Arizona.