Just south of Lake Natron, in northern Tanzania is the Engare Sero site which was was originally discovered by members of a Maasai community living nearby in 2008. Engare Sero lies in the vicinity of two much older hominid footprint sites; the nearly 3.7-million-year-old Laetoli site in Tanzania and the 1.5-million-year-old Ileret site in Kenya. Since 2009, Kevin Hatala of Chatham University in Pittsburgh and his colleagues have excavated the site.
At first, 56 human footprints had already been exposed by natural surface erosion. From 2009 to 2012 the team exposed an additional 175 square meters of the footprint surface, which included at least 352 more human footprints. Ultimately, Engare Sero footprint surface preserves at least 408 human footprints. This makes it the largest collection of Pleistocene footprints of East African hunter-gatherers.
These people walked across a muddy layer of volcanic debris from nearby Ol Doinyo Lengai, which erupted long ago and produced a mudflow which preserved the footprints to dates between around 19,100 and 5,760 years ago, the researchers reported in Scientific Reports. Dating of a thin rock layer that partly overlaps footprint sediment tighten the age range between roughly 12,000 and 10,000 years ago. Because of their apparent human-like morphology and their Late Pleistocene age, they attributed these tracks to Homo sapiens.
One collection of tracks was made by a group of 17 people walking southwest across the landscape, the researchers found. Comparisons with modern human footprint measurements indicate that this group consisted of 14 women, two men and one young boy. In another set of six tracks, the footprints point northeast. Those tracks probably weren’t made by people traveling in a group. Instead, the impressions suggest that two women and a man had ambled along leisurely, a woman and a man had walked briskly, and another woman had run across the area.