Anthropologists describe the first skeleton of a Homo naledi child

The excavation was a mixture of spelunking expedition and paleontology field trip yet provided enough power to run lights and computers. (credit: National Geographic)

A Homo naledi child’s skeleton could shed some light on the evolutionary origins of our own species’ lengthy childhoods. Humans take much longer to grow up than other great apes, which may be related to our larger brains and more complex cognitive skills. Anthropologists are still trying to understand exactly when and how that reality came about. To do so, they’ve been working with juvenile skeletons from just a handful of species besides our own: Neanderthals, Homo erectus, Australopithecus afarensis, A. sediba. But now they can also look at Homo naledi.

In 2013 and 2014, paleoanthropologists unearthed the partial skeleton of a Homo naledi child dating from 335,000 to 226,000 years ago. Now called DH7, the skeleton has most of a left leg with the bones still articulated—even several of the tarsals, the small bones that make up the ankle. The bones also included a right thighbone (femur) and hipbone (ischium), a right arm, and part of a lower right jaw and a few teeth. The shafts of the long bones hadn’t completely fused with their ends, or epiphyses, which is a sign that the young hominin was still growing when they died.

It’s hard to say exactly how old DH7 was, though, since we don’t know how quickly Homo naledi children matured. If child development was fairly quick, like in earlier hominin species, then DH7 was probably between eight and 11 years old. But if Homo naledi children developed more slowly, like Neanderthals and modern humans, the bones could look the same at 11 to 15 years old.