Neandertal Child Gives Clues to How They Developed

Gizmodo is running a story about the discovery and examination of a Neandertal child, from El Sidrón Cave, in Spain, who died under mysterious circumstances:

The first step was to determine the chronological age of death by performing a dental analysis. The specimen, dubbed El Sidrón J1, exhibited a mix of baby and adult teeth. Incremental markings on the teeth, which are counted like rings on a tree, showed that the boy died at 7.7 years of age. The skeletal remains exhibited no signs of trauma, no signs of sickness, or any other physical abnormalities. El Sidrón J1, aside from experiencing an untimely death, appears to have been a perfectly normal and healthy Neanderthal child.

The researchers then compared the skeleton’s biological stage of development with what would be expected in a modern human of the same age. To their surprise, they found few differences between the two human subspecies in terms of the pace of growth.

“The comparison...indicate(s) that there was no noticeable difference in the growth and maturation of this Neanderthal juvenile in comparison with modern human juveniles,” said study co-author Luis Rios, a Member of the Paleoanthropology Group at Museo Nacional de Ciencias Naturales, at a press conference held yesterday.

Research has generally shown that Neandertals developed a bit more quickly than modern humans but, in one critical area, this study did not back up that claim.

Perhaps more significantly, analysis of the Neanderthal skull shows that El Sidrón J1's brain was roughly 87.5 percent the size of an average adult Neanderthal at the time of death. The brains of modern humans, on the other hand, reach 95 percent the size of an adult at that age. Previous studies have suggested that the larger brains of Neanderthals underwent rapid growth during these formative years, yet this new research would seem to contradict such claims.

There is a bit of circularity going on here, though because the child is being aged based on dental development and, if for some reason, the dental development does not completely track with either the current estimates or there were some developmental insults, the age might be off.  This is speculation on my part, though.  In any event, it gives us more to understand the developmental biology and ontogeny of these very, very close relatives.