History › Human origins › First hominins: apes that walk upright
Lucy (Australopithecus afarensis)
lived c. 3.2 million years ago; found in Ethiopia, 1974· Person· Life & early humans
Well documentedSolid records, physical evidence or scientific consensus.
Lucy is a 3.2-million-year-old partial skeleton of Australopithecus afarensis, an upright-walking human relative found in Ethiopia in 1974.
See it on the History map →What happened
Donald Johanson and Tom Gray found her at Hadar, Ethiopia, on November 24, 1974; the team named her after the Beatles song playing in camp. About 40% of one skeleton survives. She stood about 1.1 m (3.5 feet), had a brain about the size of a chimpanzee's and long arms, but her hips and knees show she walked upright. In Ethiopia she is called Dinkinesh, 'you are marvelous.'
Why it matters
Her skeleton was the clearest proof yet that walking upright came long before big brains, undercutting the older idea that brain growth led the way.
Legacy and how we know
The bones, dated by volcanic layers, plus hundreds of other afarensis fossils and the 3.66-million-year-old Laetoli footprints in Tanzania. Lucy is kept in Ethiopia's National Museum in Addis Ababa.
Still debated
How she died is debated; a 2016 study proposed a fall from a tree, but critics say the breaks happened after death.
Connections (2)
▸Lucy (Australopithecus afarensis) is the best-known fossil of First hominins: apes that walk uprightWell documented
The connection
Lucy's species, Australopithecus afarensis, lived about 3.9 to 2.9 million years ago and is one of the best-studied early hominins. Her pelvis and knee show she walked upright while keeping long climbing arms, a snapshot of the in-between stage the first hominins went through.
When and how
Hadar, Afar region, Ethiopia, November 24, 1974; Donald Johanson, Tom Gray and the International Afar Research Expedition.
How we know
The skeleton itself: hip, thigh and knee angles match upright walking. The 3.66-million-year-old Laetoli footprints, likely made by her species, confirm it.
Debates and open questions
Older hominins such as Sahelanthropus, about 7 million years old, are known from fewer bones, so how and why upright walking first evolved is still argued.
▸Lucy (Australopithecus afarensis) is a possible ancestor of Homo erectusDebated
The connection
Lucy's species lived just before the genus Homo appeared, in the same part of East Africa, and has the right mix of traits to be its ancestor. If so, she belongs to a population ancestral to Homo erectus, and to us. But other candidates exist.
When and how
The Afar region of Ethiopia, where afarensis fossils about 3 million years old lie close in time and place to the earliest Homo jaw, about 2.8 million years old.
How sure are we?
Only indirect: anatomy, timing and location fit. No DNA survives from fossils this old, so ancestry is inferred from bone shapes.
Debates and open questions
Kenyanthropus, Australopithecus garhi and others are rival candidates, and some researchers think the human line branched off from a species not yet found.