To understand how we evolved, we have to understand where we evolved. Natural selection exists because the environment is kinder to some individuals than others. Depending on the species, that environment may be a lake miles underneath Antarctic ice, an alpine meadow near the top of a mountain, or an oxygen-free swamp in the sweltering tropics. Each habitat creates its own set of conditions in which individuals thrive or die. We humans are no different. We are the product of where we have lived.

A century ago, paleontologists thought humans evolved in Central Asia. At the time the only known fossils of an ancient human relative (what we now call a hominin) came from Indonesia. The idea of humans evolving in