Ancient human footprints, once attributed to bears, reveal unique walk

December 3, 2021

Rain pattered in freshly laid volcanic ash across northern Tanzania some 3.66 million years ago. Before the ground had fully dried—the volcano perhaps still smoldering in the distance—a trio of ancient human relatives strolled across the damp sediments, casting their prints in the slowly cementing ash.

A fresh analysis of a set of long-forgotten prints nearby hints that these early humans weren't alone. If the scientists are right, a mysterious upright-walking hominin also left its mark in the ash.

"You can almost imagine them looking across the landscape seeing one another," says Ellie McNutt, a paleoanthropologist from Ohio University and lead author of a new study documenting the prints in the journal Nature.

British paleoanthropologist Mary Leakey led a team that discovered the five curious hominin-like traces 45 years ago. The prints' odd arrangement seemed to have been left by a biped that crossed one foot in front of the other as it walked in a "somewhat shambling" gait, Leaky and her colleague Richard Hay later described.

Though often more graceful, "the extreme version of this would be like model walking," McNutt says.

Who this ancient trackmaker was—and whether its model walk was a few off-kilter steps or a regular strut—remains uncertain. And some scientists are not yet convinced there's enough evidence to suggest another human species walked alongside A. afarensis.

Walking on two feet was once viewed as a behavior borne from a particular combination of physical features. But scientists have slowly realized there's more than one way to be bipedal, and this new study hints at even more diversity, says paleoanthropologist William Harcourt-Smith, of the City University of New York, who was not part of the study team.

Source - https://www.nationalgeographic.com/science/article/ancient-footprints-hint-at-mysterious-human-relative-with-a-strange-walk