HUMANS are unusual mammals. Along with bipedalism, naked skin and our unusually large size, there is also the uncomfortable fact that we are the only living member of our genus.
Most mammals have at least one or two close living relatives; some, like the house mouse, have over three dozen. But genetically speaking, modern humans are alone on the planet. And as the authors of The Last Human point out, we become more isolated every day as we push our closest relatives, the great apes, to the edge of extinction.
This action, Sarmiento and his colleagues believe, is just the…
