“Meat Made Us Human” Evolutionary Narrative Starts To Unravel

Homo erectus in East Africa surrounded by up to date fauna. Credit score: Mauricio Anton

New research calls into query the significance of meat-eating in shaping our evolution.

Quintessential human traits reminiscent of giant brains first seem in Homo erectus almost 2 million years in the past. This evolutionary transition in direction of human-like traits is usually linked to a serious dietary shift involving larger meat consumption. A brand new research printed immediately (January 24, 2022) within the Proceedings of the Nationwide Academy of Sciences, nevertheless, calls into query the primacy of meat-eating in early human evolution. Whereas the archaeological proof for meat-eating will increase dramatically after the looks of Homo erectus, the research authors argue that this improve can largely be defined by larger analysis consideration on this time interval, successfully skewing the proof in favor of the “meat made us human” speculation.

“Generations of paleoanthropologists have gone to famously well-preserved websites in locations like Olduvai Gorge searching for — and discovering — breathtaking direct proof of early people consuming meat, furthering this viewpoint that there was an explosion of meat-eating after 2 million years in the past,” W. Andrew Barr, an assistant professor of anthropology on the George Washington College and lead creator on the research, mentioned. “Nonetheless, if you quantitatively synthesize the info from quite a few websites throughout jap Africa to check this speculation, as we did right here, that ‘meat made us human’ evolutionary narrative begins to unravel.”

1.5 million yr outdated fossil bones with reduce marks from Koobi Fora, Kenya. Credit score: Briana Pobiner

Barr and his colleagues compiled printed information from 9 main analysis areas in jap Africa, together with 59 website ranges relationship between 2.6 and 1.2 million years in the past. They used a number of metrics to trace hominin carnivory: the variety of zooarchaeological websites preserving animal bones which have reduce marks made by stone instruments, the overall depend of animal bones with reduce marks throughout websites, and the variety of individually reported stratigraphic ranges.

“Whenever you quantitatively synthesize the info from quite a few websites throughout jap Africa to check this speculation, as we did right here, that ‘meat made us human’ evolutionary narrative begins to unravel.” — W. Andrew Barr

The researchers discovered that, when accounting for variation in sampling effort over time, there is no such thing as a sustained improve within the relative quantity of proof for carnivory after the looks of H. erectus. They observe that whereas the uncooked abundance of modified bones and the variety of zooarchaeological websites and ranges all demonstrably elevated after the looks of H. erectus, the will increase have been mirrored by a corresponding rise in sampling depth, suggesting that intensive sampling – quite than modifications in human conduct – may very well be the trigger.

“I’ve excavated and studied reduce marked fossils for over 20 years, and our findings have been nonetheless an enormous shock to me,” Briana Pobiner, a analysis scientist within the Human Origins Program on the Smithsonian’s Nationwide Museum of Pure Historical past and co-author on the research, mentioned. “This research modifications our understanding of what the zooarchaeological document tells us concerning the earliest prehistoric meat-eating. It additionally exhibits how vital it's that we proceed to ask huge questions on our evolution, whereas we additionally proceed to uncover and analyze new proof about our previous.”

1.5 million yr outdated fossil bones with reduce marks from Koobi Fora, Kenya. Credit score: Briana Pobiner

Sooner or later, the researchers careworn the necessity for different explanations for why sure anatomical and behavioral traits related to trendy people emerged. Attainable different theories embody the provisioning of plant meals by grandmothers and the event of managed hearth for growing nutrient availability by means of cooking. The researchers warning that none of those potential explanations at the moment have a robust grounding within the archaeological document, a lot work stays to be carried out.

“I'd assume this research and its findings could be of curiosity not simply to the paleoanthropology group however to all of the folks at the moment basing their weight-reduction plan selections round some model of this meat-eating narrative,” Barr mentioned. “Our research undermines the concept consuming giant portions of meat drove evolutionary modifications in our early ancestors.”

Reference: “No sustained improve in zooarchaeological proof for carnivory after the looks of Homo erectus” 24 January 2022, Proceedings of the Nationwide Academy of Sciences.

DOI: 10.1073/pnas.2115540119

Along with Barr and Pobiner, the analysis workforce included John Rowan, an assistant professor of anthropology on the College of Albany; Andrew Du, an assistant professor of anthropology and geography at Colorado State College; and J. Tyler Religion, an affiliate professor of anthropology on the College of Utah.