Ancient Human Footprints Mark the Sands of Time in New Mexico

Just when did humans first enter the New World of the Americas? That question has vexed archeologists. Now, a set of fossilized human footprints found amidst footprints of extinct camels, sloths, and mammoths may help better suggest a date.

The footprints, discovered in sediments of ancient Lake Otero preserved in New Mexico’s White Sands National Park, have been dated at between 23,000 and 21,000 years old. The dating is based on radiocarbon evidence from plants and seeds embedded within the footprints. If humans migrated from Siberia through Alaska—as has been traditionally assumed—then the time needed to reach New Mexico suggests a very early arrival date.

Conventional wisdom is that humans first crossed the Bering land bridge between Asia and North America 13,000 years ago as vast ice sheets began to recede toward the end of the Pleistocene

Epoch, or the Ice Ages, and an ice-free corridor opened through Canada. But the 23,000-yearold footprints throw conventional wisdom out the window and support other hypotheses. For instance, perhaps humans kayaked along the coasts of Siberia and North America without need for an ice-free continental corridor far earlier than ever suspected.

Reporting in the journal Science, geoscientists Matthew Bennett (Bournemouth University, UK) and colleagues say the 61 “ghost tracks” they’ve excavated show humans were well established in New Mexico during the height of the last Ice Age, not the tail end. So much for conventional wisdom? Kim Charlie, a member of the Pueblo of Acoma, points out there is a reason the Native American Acoma language has a word for “camel” long after camels disappeared from North America.