There’s a dirty little secret in paleoanthropology: What we know about human evolution is that we don’t know much of the story.
Let’s be clear: That Homo sapiens evolved from earlier hominin species isn’t in question. Although the fossil record is incomplete, we have more than enough to see that, in broad terms, our big-brained, long-limbed, built-for-distance-walking species evolved from arboreal ancestors with smaller brains, larger teeth and broader chests. We can also say, more confidently than even a few decades ago, that our family tree isn’t a tall pine, with a single trunk progressing upward to a lone pinnacle (us). Instead, the story of hominin evolution is a gnarly tree with multiple branches, some of them tangled through interbreeding.
“Our provisional family tree shows typically several hominids were living at the same time,” says paleoanthropologist and best-selling author Ian Tattersall. “It’s only very recently that we’ve had the planet to ourselves. ‘Normal’ is having more than one hominid running around.”
