Fossil Hominids: Lucy (AL 288-1)

Discovered by Donald Johanson and Tom Gray in 1974 at Hadar in Ethiopia (Johanson and Edey 1981; Johanson and Taieb 1976). Its age is about 3.2 million years. Lucy was an adult female of about 25 years and was assigned to the species Australopithecus afarensis. About 40% of her skeleton was found, and her pelvis, femur (the upper leg bone) and tibia show her to have been bipedal, although there is evidence that afarensis was also partly arboreal (tree-dwelling). She was about 107 cm (3'6") tall (small for her species) and about 28 kg (62 lbs) in weight.

The humerofemoral ratio, or length of humerus divided by length of femur, is 84.6 for Lucy, compared to 71.8 for humans, and 97.8 and 101.6 for the two species of chimpanzee (all these figures have a standard deviation of between 2.0 and 3.0). In other words, humans have much shorter arms compared to their legs than chimpanzees do, and Lucy falls roughly in the middle. (Korey 1990)

This page is part of the Fossil Hominids FAQ at the talk.origins Archive.