WASHINGTON DC- Quintessential human traits such as big brains appear for the first time in homo erectus nearly 2 million years ago. This evolutionary transition to human traits is often linked to a major dietary change involving greater meat consumption. A new study published in the Proceedings of the National Academy of Sciences, however, questions the primacy of meat consumption in early human evolution. While archaeological evidence for meat consumption increases dramatically after the appearance of homo erectus, the study authors argue that this increase can largely be explained by greater research attention to this period, effectively skewing the evidence in favor of the “meat made us human” hypothesis.
“Generations of paleoanthropologists have traveled to reputedly well-preserved sites in places like the Olduvai Gorge in search and discovery of jaw-dropping direct evidence of early humans eating meat, bolstering this view. that there was an explosion in meat consumption 2 million years ago,” W. Andrew Barr, assistant professor of anthropology at George Washington University and lead author of the study, said. “However, when you quantitatively synthesize data from many sites across East Africa to test this hypothesis, as we have done here, the evolutionary narrative that ‘meat made us human’ begins to unravel. to do.”
Barr and his colleagues compiled published data from nine major research areas in East Africa, including 59 levels of sites dating between 2.6 and 1.2 million years ago. They used several measures to track the hominid carnivore: the number of zooarchaeological sites preserving animal bones that have cut marks made by stone tools, the total number of animal bones with cut marks on the sites and the number of stratigraphic levels reported separately.
The researchers found that, when accounting for variation in sampling effort over time, there is no sustained increase in the relative amount of carnivore evidence after the appearance of H. erectus. They note that while the raw abundance of altered bones and the number of zooarchaeological sites and levels all clearly increased after the appearance of H. erectus, the increases were mirrored by a corresponding increase in sampling intensity, suggesting that intensive sampling—rather than changes in human behavior—might be the cause.
“I’ve excavated and studied marked fossils for more than 20 years, and our discoveries have always come as a big surprise to me,” said Briana Pobiner, researcher with the Smithsonian’s National Museum of Natural History’s Human Origins program and co -author on the study, says. “This study changes our understanding of what zooarchaeological records tell us about the first prehistoric meat eaters. It also shows how important it is that we continue to ask big questions about our evolution, while continuing to discover and analyze new evidence about our past.
Going forward, researchers have pointed to the need for alternative explanations for why certain anatomical and behavioral traits associated with modern humans have emerged. Possible alternative theories include the provision of plant foods by grandmothers and the development of a controlled fire to increase nutrient availability through cooking. The researchers warn that none of these possible explanations currently have a firm basis in the archaeological record, so much work remains to be done.
“I think this study and its findings would be of interest not just to the paleoanthropological community, but to anyone who is currently basing their diet decisions on some version of this meat-eating narrative,” Barr said. “Our study undermines the idea that eating large amounts of meat caused evolutionary changes in our earliest ancestors.”
In addition to Barr and Pobiner, the research team included John Rowan, assistant professor of anthropology at the University of Albany; Andrew Du, assistant professor of anthropology and geography at Colorado State University; and J. Tyler Faith, associate professor of anthropology at the University of Utah.
– This press release originally appeared on the George Washington University website