Queens College Professor Thomas Plummer is Lead Author of International Study That Recasts Story of Human Evolution

–Two Queens College alumnae participated in research as CUNY graduate students–

March 3, 2023—Working at Nyayanga on Kenya’s Homa Peninsula, an international team that included Queens College Anthropology Professor Thomas Plummer and two alumnae participating as City University of New York (CUNY) graduate students, has excavated stone tools, animal bones, and hominin teeth from about 2.9 million years ago. The find challenges our picture of the origins of toolmaking, suggesting that—contrary to current thinking—early humans may not have been the sole makers or users of stone tools. Plummer served as lead study author on the study that was published February 9 in Science. He was assisted on-site by then-CUNY graduate student Frances Forrest, who earned a BA in anthropology from the college, and CUNY PhD candidate Raquel Lamela-Lopez, also an anthropology graduate of the college. Forrest and Lamela-Lopez were among seven CUNY students who participated in the research.

“A critical element of any educational experience is the opportunity to conduct hands-on research alongside faculty who are making—as in this case—game-changing scientific discoveries,” says Queens College President Frank H. Wu. “The strong Queens College presence in the Nyayanga findings isn’t surprising, it’s just one of several examples of how our faculty mentor students, guiding them toward impactful postgraduate study and careers. The findings themselves show us how urgent it is to come to terms with our history as a toolmaking species and to better understand our place within the rest of life on earth as we assess how our adaptability to changeable conditions has taxed the sustainability of the planet.”

The Nyayanga site revealed a treasure trove of finds in surprising combination. They include 330 artifacts that represent the oldest known appearance of the Oldowan toolkit, one of the world’s most important technological innovations. The oldest known stone tools (found near Lake Turkana in Kenya) dated from 3.3 million years ago, well before the Homo genus emerged—and they were very large and less portable. By contrast, the Oldowan toolkit—consisting of handheld tools and stones for making tools—was made using more sophisticated techniques and identified with early Homo species that predated modern humans.

The site also yielded 1,776 bones—including from hippos and antelope—with deep cuts that indicated butchering. Wear patterns on the stone tools showed that they had been used to cut, scrape, and pound both animals and plants. More than likely the animals were not hunted, but were scavenged by early humans who would have had to extract and eat meat and marrow without benefit even of fire. Oldowan tools enabled their users to cut through tough animal hides and bones—including those of fat- and protein-rich large animals like hippos—successfully securing a wide variety of food across the climatologically volatile and ecologically diverse environments of prehistory. Such an adaptation could have given early humans an evolutionary advantage, and the Nyayanga site reveals that it occurred 600,000 years earlier than has been believed. 

Forrest helped with surface collection, taxonomic identification and looking for stone tool damage on the bones. Lamela-Lopez helped with making a topographic map at Nyayanga and excavating. “Our project was good training for the students, and the expedition in turn benefited greatly from their detailed, high-quality analyses,” says Plummer. “They were involved in a range of tasks, including surveying for fossils and artifacts eroding from the ground, mapping and excavating sites, identifying bones, describing stone tools, looking for butchery damage on fossils, and reconstructing the diet of extinct animals from the chemistry of their teeth.” Forrest is now an assistant professor of Sociology and Anthropology at Fairfield University. Lamela-Lopez is a PhD candidate in Anthropology at the CUNY Graduate Center.

Finally, anthropologists have long attributed the Oldowan toolkit to members of the Homo genus only, but the team discovered two molars belonging to the hominin Paranthropus, a different genus but close evolutionary relative of humans. Because of their large teeth and jaws (Paranthropus has been nicknamed the Nutcracker), scientists had thought that they would have no need for tools to secure tough foods. However, the molars’ presence at Nyayanga raises many questions. Could Paranthropus have made Oldowan tools? Did Paranthropus merely use the stone tools made by our human ancestors? Who among the large group of hominins—humans and humanlike primates—invented the Oldowan toolkit, and what kinds of relations existed between early humans and their primate relatives?

“There are multiple species of hominin living on the landscape of Africa between 3 and 2 million years ago. It’s widely been assumed that the oldest stone tools were made by our lineage, the genus Homo, fossils of which go back to 2.8 million years,” says Plummer. “The association of these Nyayanga tools with Paranthropus may reopen the case as to who made the oldest Oldowan tools. Perhaps not only Homo, but other kinds of hominins were processing food with Oldowan technology.”

Plummer, who has a PhD from Yale University, holds appointments as a professor of anthropology at Queens College and the CUNY Graduate Center. He is a specialist in the Oldowan toolkit, and teaches biological anthropology, human paleontology, the human skeleton, faunal analysis, ancient technology, and other courses related to the prehistoric record and human evolution. Plummer, who has over 54 publications to his credit, leads the Homa Peninsula Paleoanthropological Project at Queens College and is a research associate at the Smithsonian’s Human Origins Program, which partners with Queens. In addition, he is a member of the New York Consortium in Evolutionary Primatology.

The Nyayanga excavation has been conducted since 2015. Funding has been provided by the Smithsonian, the L. S. B. Leakey Foundation, the National Science Foundation, the Wenner-Gren Foundation, the Professional Staff Congress City University of New York Research Award, the William H. Donner Foundation, and the Peter Buck Fund for Human Origins Research.


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Maria Matteo

Media and College Relations