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Fossil footprints of early modern humans found in Tanzania

This article was published in Scientific American’s former blog network and reflects the views of the author, not necessarily those of Scientific American


MINNEAPOLIS—Newly discovered fossil footprints at a site in northern Tanzania on the shore of Lake Natron capture a moment in time around 120,000 years ago when a band of 18 humans—early members of our own species, Homo sapiens—traipsed across wet volcanic ash to an unknown destination. Brian Richmond of George Washington University unveiled the stunning find here on April 13 at the annual meeting of the Paleoanthropology Society.

Footprints are extremely rare in the human fossil record, and highly prized for the unique information they can reveal about the anatomy and behavior of our ancient relatives. Richmond and his colleagues found the new prints—more than 350 in all—in 2010 at the site, called Engare Sero. No animal prints were among them.

Richmond reported that one group of prints head east and, judging from the stride lengths evident in the trails, appear to have been left by individuals who were variously walking, running, or moving at an intermediate pace.* The different speeds indicate that these people were not traveling together. The other group of prints, however, were made by 18 individuals walking together to the west.


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To learn more about the these early travelers, Richmond and his colleagues compared the fossil footprints to a set of prints obtained experimentally from modern-day men and women from Ileret, Kenya, moving at a variety of speeds. Based on these measurements, the team concluded that the ancient human group was composed of men, women and children, with more women than men.

"This is evidence of what an early modern human social group traveling together looked like," Richmond said. "It offers a glimpse of actual behavior in the fossil record."

 

*An earlier version of this story stated incorrectly that the prints heading east were made by 14 people.

Kate Wong is an award-winning science writer and senior editor at Scientific American focused on evolution, ecology, anthropology, archaeology, paleontology and animal behavior. She is fascinated by human origins, which she has covered for more than 25 years. Recently she has become obsessed with birds. Her reporting has taken her to caves in France and Croatia that Neandertals once called home, to the shores of Kenya's Lake Turkana in search of the oldest stone tools in the world, to Madagascar on an expedition to unearth ancient mammals and dinosaurs, to the icy waters of Antarctica, where humpback whales feast on krill, and on a "Big Day" race around the state of Connecticut to find as many bird species as possible in 24 hours. Kate is co-author, with Donald Johanson, of Lucy's Legacy: The Quest for Human Origins. She holds a bachelor of science degree in biological anthropology and zoology from the University of Michigan. Follow Wong on X (formerly Twitter) @katewong

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