C. Owen Lovejoy

1943 - present

Why Do We Walk Upright?

C. Owen Lovejoy is an anthropologist at Kent State University. He is best known for his work related to pre-Homo fossils, particularly Ardi and Lucy. Much controversy surrounds various theories as to why these early species developed upright posture and gait at this time. Lovejoy's explanation is that in our shift from primarily tree-dwelling animals to ones requiring longer travel distances each day to find high-energy food, upright posture enabled the male forager to carry back more food from each outing with his freed-up upper limbs. Further, it enabled the female to transport more than one infant at a time enabling more frequent child-bearing. This also precipitated the beginning of the nuclear family and long-term male/female bonding since a male would be less likely to spend long periods away from the female searching food if there was concern about female loyalty.

Other possible explanations for bipedality are discussed including safety from large cat predation, safer conflict resolution, and better heat dissipation. I am not personally convinced that we ever will really know the answer, but I am convinced from the perspective of a physician that upright posture has caused us more problems than it solved. I like the explanation attributed to a Tibetan scholar: "A sense of humor."

To me, this difficulty nailing down the reasons we evolved bipedality is illustrative of a larger issue in studying evolution: not all features selected by natural selection necessarily lead to long-term benefit for a species. In fact, since over 99% of all species have gone extinct, it raises the question whether Darwinian natural selection is a short-term rather than a long-term process. This may apply to the answers.

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