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Lucy (Australopithecus afarensis)
3.2 million years ago (found 1974)· Fossil or site· Human ancestors & us
Well establishedStrong fossil, genetic or geological evidence.
A 3.2-million-year-old partial skeleton from Ethiopia, the most famous early hominin fossil, belonging to Australopithecus afarensis.
See it on the Life map →What happened
Donald Johanson and Tom Gray found her on 24 November 1974 at Hadar, Ethiopia. About 40% of a skeleton was recovered, unusually complete for so old a fossil. That evening the camp played the Beatles' 'Lucy in the Sky with Diamonds', giving her the nickname; in Ethiopia she is Dinkinesh, 'you are marvelous'. She stood about 1.1 meters tall, weighed perhaps 29 kg, and had a chimpanzee-sized brain but hips and legs built for walking upright.
Why it matters
Lucy gave the clearest early picture of a hominin that walked upright with an ape-sized brain, and she became the public face of human evolution.
The evidence (fossils, genes, rocks)
The original bones are kept at the National Museum of Ethiopia in Addis Ababa; argon–argon dating of volcanic layers at Hadar sets her age at about 3.2 million years.
Still debated
How much time she still spent in trees is debated, and a 2016 study proposing she died from a fall out of a tree remains contested.
Connections (2)
▸Lucy (Australopithecus afarensis) is the most famous AustralopithecusWell established
The connection
Lucy belongs to Australopithecus afarensis, the best-known species in the genus. Her skeleton, about 40% complete, gave the first clear picture of a small-brained, upright-walking hominin, and her species became the yardstick for comparing all other australopiths.
When and how
Hadar, Ethiopia, on 24 November 1974, by Donald Johanson and Tom Gray; the species was named in 1978 from her bones and fossils from Laetoli.
The evidence
Hundreds of afarensis fossils from Hadar, Laetoli and Dikika, including the 'First Family' group and the child 'Selam', match her anatomy.
Debates and open questions
Whether afarensis gave rise to later australopiths and Homo, and how it relates to other species living at the same time, such as Kenyanthropus and A. deyiremeda.
▸Lucy (Australopithecus afarensis) shows a skeleton built for Walking on two legsWell established
The connection
Lucy's pelvis is short and wide, and her thighbones angle inward toward the knees, as ours do, placing the feet under the body's center. These are signs of habitual upright walking, yet her long, curved fingers and strong arms suggest she still climbed trees.
When and how
Hadar, Ethiopia: a separate knee joint found there in 1973 first showed the angled thighbone, and Lucy's skeleton, found in 1974, confirmed it.
The evidence
Comparisons with human and ape skeletons, and CT scans of her bones' internal structure, which reflects the loads they carried in life, support upright walking.
Debates and open questions
How efficiently she walked compared with us, and whether her species' climbing traits were still useful or simply leftovers from tree-dwelling ancestors.