Free Wanderlust: A History of Walking by Rebecca Solnit

hominids became bipedal, the males used their now-exposed penises as a “threat display organ” to intimidate opponents, and we speculated on the origins of human laughter. The following day, after he came home from guiding clients up and down rock faces all day and was lounging with a drink, I read him anthropologist Dean Falk’s attack on Lovejoy. Lovejoy’s term “copulatory vigilance” caught his attention, and he laughed more at the strange stuff I was immersed in. Not that his world was exactly a bastion of seriousness: while he was climbing for pleasure the day before, I had lain in the shade idly flipping through his guidebook and been entertained by some of the names of the climbing routes up and down the park’s myriad giant boulders: “Presbyterian Dental Floss” was right next to “Episcopalian Toothpick,” while “Boogers on a Lampshade” mocked the climb genteelly called “Figures in a Landscape,” and innumerable poodle, political, and anatomical jokes described other vertical routes up the rocks. That evening, as I read bipedal theory to him and the quail bobbed about the backyard and the setting sun pushed the shadows of the hills farther and farther across the valley, he swore he would get his friends who founded and named many of the park’s climbing routes to name the next one “Copulatory Vigilance,” an obscure monument to a theory that we had lost our ability to climb and to his opinion of the more far-flung theories of human origins. Lovejoy’s theory has become famous, if only because no one can resist attacking it.
    Among the earlier critics were the anatomists Jack Stern and Randall Sussman at the State University of New York at Stonybrook, who I visited. Two unathletic men with identical clipped gray mustaches, they looked something like the Walrus and the Carpenter, with Stern as the compact Carpenter and Sussman the expansive Walrus. They talked to me for hours in an office full of bones and books, and periodically one or the other would grab a chimp pelvis or a cast of a fossil femur to illustrate a point. Obviously enthusiastic about their work, they often went off on conversational tangents with each other that left me far behind, and they delighted too in dishing their colleagues in this contentious field. Theyhad argued that Johanson’s Lucy-era Australopithecus afarensis fossils were those of apprentice walkers who, based on the evidence—big arms and smallish legs, curved fingers and toes—continued climbing trees well and frequently for a long time afterward. Another feature of the afarensis fossils they took up was gender size: if the large and small skeletons Johanson and company had found in Ethiopia were the same species (which Richard Leakey and others contest), then the sizes must represent small females and large males, which made it unlikely they practiced Lovejoy’s monogamous arrangement. Living primate species where the males are far larger—baboons, gorillas—are usually polygamous; only those without size differences, such as gibbons, are monogamous. So their version of Lucy was that she was a lousy walker with big floppy feet, a pretty good climber with long, strong arms, and probably part of a polygamous group in which small females spent more time in the trees than large males.
    Sussman said, “Back when we started this work, and I don’t think it’s unhumble to say it, the majority of the people in the field would say we evolved in the savannah, in the open country of the veldt of South Africa or the savannah of East Africa. I think that’s a load of crap. I think that what happened was that afarensis was living in forest and open country mosaics like you see today in places like the French Congo or along rivers where there’s a lot of trees. I mean, that probably went on for a million years when you had an animal that was climbing and an apprentice