When the first members of our species ventured out of Africa, they walked into a world that earlier hominins, such as Homo erectus, had first explored a million years earlier. According to a recent study of a 1.5 million-year-old vertebra, those earlier hominins may have expanded beyond Africa in several waves—each following different environments and equipped for different ways of life.

Taking a second look

Anthropologists found a single vertebra from the lower back of a hominin child who died 1.5 million years ago. Mixed with the fossilized bones of hippos, mammoths, giraffes, saber-toothed tigers, and warthogs, the bone had sat among the remains of Pleistocene fauna since the 1966 excavation that unearthed it. But when University of Tulsa anthropologist Miriam Belmaker, a co-author on the recent study, looked through the animal fossils as part of another recent study (an effort to narrow down the age of the site), she recognized the vertebra as belonging to a member of our genus, Homo.

And the fact that the pieces of the vertebra hadn’t all fused together into a single hard, bony piece meant that it came from a child who hadn’t yet finished growing and maturing. They were probably somewhere between 6 and 11 years old when they died.