The world’s most famous early human ancestor could walk upright like modern humans thanks to fully bendable knee joints, research shows.
“Lucy” comes from an extinct species of ape that lived in Africa three million years ago.
Excavated in Ethiopia in 1974, she was the most complete early human ancestor known at the time.
But it’s only now that researchers have fully digitally reconstructed the muscles of her lower body, hoping to end a decades-long debate among scientists about how she walks.
Lucy could straighten her knees, stand upright and walk on two legs like we do today, according to findings published in the Royal Society Open Science journal by a team from the University of Cambridge.
But her legs were also found to be much larger and more powerful than ours, allowing her to live in trees like an ape, meaning she was just as capable of living in open grasslands as in dense forests.
Scientists at the University of Cambridge said the findings could help shed light on how human body movement evolved, “including those abilities we have lost”.
How Lucy’s Leg Was Rebuilt
A team led by Dr Ashleigh Wiseman created 3D models of Lucy’s leg and pelvic muscles, with 36 pieces for each leg.
The major muscles of her calves and thighs were more than twice as large as those of modern humans—the only living animal capable of standing on straight knees.
Dr Wiseman, from the MacDonald Institute of Archeology at the University of Cambridge, said: “Lucy’s ability to walk upright can only be understood by reconstructing the paths and spaces occupied by muscles in the body.”
She added: “Lucy’s muscles suggest that she is as proficient at bipedal walking as we are, while also possibly being comfortable in the trees.”
Lucy’s leg and pelvic muscles were digitally recreated.Photo: University of Cambridge
Lucy’s History
Lucy’s discovery in the 1970s was a landmark because her skeleton was 40 percent complete, with 47 of 207 bones intact.
It includes parts of her arms, legs, spine, ribs, pelvis, jaw and skull.
She was found to belong to the species Australopithecus afarensis and was given her name because the archaeologist who found her was listening to the Beatles’ “Lucy in the Sky with Diamonds.”
Researchers said she should have died as a young adult, just over a meter tall and weighing less than 30kg.
Since then, some experts believe she would have crouched and wobbled like a chimpanzee, while others believe she would have been more human-like.