Lucy’s Feet Were Arched and Stiff, Just Like Ours
By Brian Switek
How did Lucy walk? Although the famous 3.2-million-year-old skeleton shows that she was undoubtedly an upright walker, our incomplete knowledge of her feet has fed a long-running debate about the mechanics of her stride. Now, thanks to the discovery of a single bone, scientists have found important similarities between Lucy’s feet and our own.
Reported Feb. 10 in the journal Science by University of Missouri anthropologist Carol Ward and co-authors William Kimbel and Donald Johanson of Arizona State University, the single foot bone was discovered in 2000 and comes from Hadar, Ethiopia. Of the same age as Lucy herself, this site contains the remains of many Australopithecus afarensis individuals who died under mysterious circumstances.
The bone is a fourth metatarsal; one of the bones of the mid-foot, just behind the toes. In modern humans, metatarsals create the distinctive arch of the foot and act as a shock absorber while keeping the foot stiff. Earlier research has shown, however, that the degree of the arch has varied during human history.
Like the same bone in our foot, but unlike that seen in chimpanzees or gorillas, the fourth metatarsal of this A. afarensis individual angled down to contact the ground, creating a strong, weight-bearing arch along the outside edge of the foot. Also telling were two facets on the bone’s end where it connected with the rest of the foot, trading the flexibility seen in ape feet for strength and stability.
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