Snapshots of human anatomy, locomotion, and behavior from Late Pleistocene footprints at Engare Sero, Tanzania

Kevin G Hatala,Brian W Zimmer,David J Green,Vince Rossi,Brian G Richmond,Briana L Pobiner,Adam Metallo,Adam D Gordon,Cynthia M Liutkus-Pierce,William E H Harcourt-Smith

doi:10.1038/s41598-020-64095-0

Abstract

Fossil hominin footprints preserve data on a remarkably short time scale compared to most other fossil evidence, offering snapshots of organisms in their immediate ecological and behavioral contexts. Here, we report on our excavations and analyses of more than 400 Late Pleistocene human footprints from Engare Sero, Tanzania. The site represents the largest assemblage of footprints currently known from the human fossil record in Africa. Speed estimates show that the trackways reflect both walking and running behaviors. Estimates of group composition suggest that these footprints were made by a mixed-sex and mixed-age group, but one that consisted of mostly adult females. One group of similarly-oriented trackways was attributed to 14 adult females who walked together at the same pace, with only two adult males and one juvenile accompanying them. In the context of modern ethnographic data, we suggest that these trackways may capture a unique snapshot of cooperative and sexually divided foraging behavior in Late Pleistocene humans.

Highlights

We report on Late Pleistocene human footprints discovered at Engare Sero, Tanzania
While our previous publications focused on the geological context and preservation of this site[24,25], we explore the paleoanthropological implications of this remarkable assemblage of more than 400 human footprints
Our team has built upon radioisotopic results to further constrain the likely age of the footprint surface to the latest Pleistocene, as we identified in previous analyses a calcite cement in an overlying sedimentary layer that was likely produced during a highstand of Lake Natron that occurred www.nature.com/scientificreports between 12 and 10 ka[24]

Summary

Introduction

We report on Late Pleistocene human footprints discovered at Engare Sero, Tanzania. While our previous publications focused on the geological context and preservation of this site[24,25], we explore the paleoanthropological implications of this remarkable assemblage of more than 400 human footprints. This includes inferences regarding the body sizes, locomotor behaviors, and composition of the group of humans who generated these tracks. All of the footprints appear to have been produced by barefoot humans, as individual toe impressions are distinguishable (Fig. 3) Because of their apparent human-like morphology and their Late Pleistocene age, we have attributed these tracks to Homo sapiens. Excavation of additional sediments has been halted until a long-term site conservation plan is implemented, as we know the exposed portion of the site is subject to erosion[25]

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Discussion

Conclusion