There were big cats, hyenas, and wolves all along the way, and this may be one reason most of our hominid relatives never made it. It is striking, too, that, unlike so many other species—cats, for example—we are the only branch of our family (Hominidae) who survived the journey. In this sense, we are evolutionary orphans—a broken family of one, and it puts us in strange company: we share our genetic solitude with the platypus, the gharial, and the coelacanth.
