he Centro Nacional de Investigación sobre la Evolución Humana (CENIEH) is involved in a study published today in the journal Proceedings of the National Academy of Sciences (PNAS) that provides new insights into the technology, environment, and remains of early modern humans who lived in the Afar Rift (Ethiopia) around 100,000 years ago.

The research, led by archaeologist Yonas Beyene, focuses on the Halibee Member of the Dawaitoli Formation, where thousands of stone tools and three partial Homo sapiens fossil skeletons, dated to approximately 100,000 years ago, have been recovered. Research into the African Middle Stone Age—a period when modern humans first appear in the continent’s fossil record—has been limited by the vast geographic extent of Africa and gaps in both the fossil and archaeological records.

Geological analysis and the study of more than 3,000 vertebrate fossil remains indicate that the sediments at the site were deposited by seasonal flooding of the Awash River in a wooded environment. This setting would have provided shade, water, and other key resources within an otherwise arid savanna, offering important context for understanding the living conditions of these human populations.

The Middle Stone Age tools, identified through surveys and excavations, were made from a wide range of volcanic rocks and were likely produced and discarded on the ancient floodplain during short-term human occupations. Analysis of the human fossils has revealed different postmortem processes: one individual was rapidly buried by accumulating sediments, another shows extensive carnivore damage, and a third presents evidence of exposure to high temperatures.

CENIEH researcher Leslea Hlusko participated in this study, leading the paleontological analysis of the primates recovered from Halibee. Her work demonstrates the presence of two monkey species—a vervet and a black-and-white colobus—representing ancestors of species still living in Ethiopia today. “Fortunately, the large assemblage of monkey fossils provided clear evidence that numerous trees must have been present in the area, as both species spend much of their time in trees, especially the black-and-white colobus,” says Hlusko.

CENIEH-affiliated researcher Tim White, co-director of the Middle Awash research project, highlights the significance of these findings: “These results are the outcome of many years of work. The Middle Awash project has been conducting fieldwork in the Afar Region of Ethiopia for decades, and this long-term, multidisciplinary research provides a ‘paleo’ snapshot of how and where our African human ancestors lived 100,000 years ago.”

According to the authors, this study contributes to a better understanding of the technologies, environments, and occupation dynamics of early Homo sapiens in Africa, offering a more complete picture of their behavior and adaptation during the Middle Stone Age.