Scientists Discover Oldest Human Ancestor who Lived 4.4 Million Years Ago

Analysis of a near-complete skeleton of a human ancestor found in Ethiopia changes scientists' thinking about the appearance and behavior of our distant forebears.

Photo: Scientists Discover Oldest Human Ancestor who Lived 4.4 Million Years Ago

A treasure trove of 4.4-million-year-old fossils from the Ethiopian desert is dramatically overturning widely held ideas about the early evolution of humans and how they came to walk upright, even as it paints a remarkably detailed picture of early life in Africa, researchers reported Thursday, Los Angeles Times reports.

The analysis of Ardipithecus ramidus (it means "root of the ground ape"), reported in the journal Science, changes the notion that humans and chimps, our closest genetic cousins, both trace their lineage to a creature that was more like today's chimp. Rather, the research suggests that their common ancestor was a walking forest forager more cooperative in nature than the competitive, aggressive chimp and that chimps were an evolutionary offshoot of this creature, USA Today reports.

According to The Associated Press, the story of humankind is reaching back another million years as scientists learn more about "Ardi," the 110-pound, 4-foot female roamed forests a million years before the famous Lucy, long studied as the earliest skeleton of a human ancestor. This older skeleton reverses the common wisdom of human evolution, said anthropologist C. Owen Lovejoy of Kent State University.

"This is not that common ancestor, but it's the closest we have ever been able to come," said Tim White, director of the Human Evolution Research Center at the University of California, Berkeley. The lines that evolved into modern humans and living apes probably shared an ancestor 6 million to 7 million years ago, White said in a telephone interview.