Ancient human footprints found in a dried-up New Mexico lakebed present a remarkably detailed snapshot from more than 10,000 years ago. An adolescent or small adult female carries a young child nearly a mile across muddy terrain frequented by mammoths, giant sloths, saber-toothed cats and dire wolves. Then the traveler turns around and makes the journey back, without the child in tow, perhaps having delivered the toddler to its destination.
The prints, believed to be the longest known trackway of early-human footprints, tell a dramatic story of danger and perseverance. A new study in the online edition of Quaternary Science Reviews details how the tracks at White Sands National Park were discovered and studied, and what they add to the ichnological (trace fossil) record -- and show us about our Ice Age forebears.
"This research is important in helping us understand our human ancestors, how they lived, their similarities and differences," said Sally Reynolds, senior lecturer in hominin paleoecology at the UK's Bournemouth University and co-author of the study about the archaeological finding. "We can put ourselves in the shoes, or footprints, of this person (and) imagine what it was like to carry a child from arm to arm as we walk across tough terrain surrounded by potentially dangerous animals."
An international team working with staff from the National Park Service found the footprints in a lakebed that contains other prints going back between 11,550 and 13,000 years. As the lakebed dried up, it preserved footprints for thousands of years.
Smaller prints that appear at points along the shores of ancient Lake Otero indicate the caregiver occasionally put down the child, believed to be 3 or younger. The prints show the person carrying the child made a return journey along the same path a few hours later, though the shape of the prints suggest the child was no longer present. Taken together, the prints tell the story of a taxing journey, but each track offers even more specific details: of the pace of stride, a slip here, a stretch there to avoid a puddle.
"The ground was wet and slick with mud and they were walking at speed, which would have been exhausting," Reynolds and fellow Bournemouth researcher Matthew Robert Bennett write in a piece about the discovery in The Conversation.
White Sands National Park contains a treasure trove of fossilized human and animal footprints. Last year, a team led by Cornell University published a study on to investigate the movements of mammoths, humans and giant sloths there from 12,000 years ago. One mammoth track showed a human footprint left in the same spot later, giving a rare glimpse into how people and megafauna may have interacted so many years ago.
"We never thought to look under footprints," Thomas Urban of Cornell, who contributed to the 2018 study as well as the new one, said at the time. "But it turns out that the sediment itself has a memory that records the effects of the animal's weight and momentum in a beautiful way. It gives us a way to understand the biomechanics of extinct fauna that we never had before."