Right off the bat in Last Ape Standing, Chip Walter gives off hints of what eventually grows to become his thesis: that neoteny is the mechanism that defines human evolution. He doesn’t make a big flashy “science journalism” headline out of it—which speaks well to him as a writer, and as an articulator of arguments, as he lets his statements speak for themselves—but it is always there, lurking in the background. It begins with the big toe, with the move to bipedalism, which everyone really agrees is what sets us apart, at least initially, from the other apes. Chimps, gorillas and that ilk have big toes, but they are opposable, thumb-like. It doesn’t start like that, though; no, indeed, it starts straight, and then develops that bend during gestation. What if, instead, it…didn’t? I have to hand it to Walter; it is a pithy and plausible theory.
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