Focus-Science and Technology - - Discoveries -

Ne­an­derthals’ off­spring de­vel­oped in a very sim­i­lar way to our own, new re­search has shown – with the dif­fer­ences in rates of de­vel­op­ment thought to ac­count for the phys­i­cal dif­fer­ences be­tween the two species.

A team led by An­to­nio Rosas at the Span­ish Na­tional Re­search Coun­cil stud­ied a male Neanderthal child who died aged around eight years old, and whose re­mains were dis­cov­ered in the El Sidrón cave in Piloña, Spain in 1994. At the time of his death, he was 111cm tall and weighed 26kg. The Span­ish team found that the child had de­vel­oped to al­most ex­actly the same de­gree you’d ex­pect to see in an eight-year- old male child to­day, with two key dif­fer­ences.

First, his brain cav­ity had only reached 87.5 per cent of its adult size, com­pared to a mod­ern hu­man child where the brain cav­ity would al­ready have reached its full size. It’s thought this slightly slower rate of brain de­vel­op­ment en­abled Ne­an­derthals to grow larger.

“De­vel­op­ing a large brain in­volves sig­nif­i­cant en­ergy ex­pen­di­ture and, con­se­quently, this hin­ders the growth of other parts of the body,” said Rosas. “In Homo sapi­ens, the de­vel­op­ment of the brain dur­ing child­hood has a high en­er­getic cost and, as a re­sult, the de­vel­op­ment of the rest of the body slows down.”

Se­cond, the tho­rax area of the skele­ton ap­pears to have more de­vel­oped more slowly. The Neanderthal spec­i­men’s tho­rax re­sem­bled that of a five- or six-year- old hu­man child, with the car­ti­lagi­nous joints of the mid­dle tho­racic ver­te­brae and the top­most ver­te­brae yet to fuse.

“The de­lay of this fu­sion in the ver­te­bral col­umn may in­di­cate that Ne­an­derthals had a de­cou­pling of cer­tain as­pects in the tran­si­tion from in­fancy to the ju­ve­nile phase. Although the im­pli­ca­tions are un­known, this fea­ture could be re­lated to the char­ac­ter­is­tic en­larged shape of the Neanderthal torso, or slower brain growth,” said Rosas.

LEFT: Spain’s El Sidrón caves con­tain Neanderthal fos­sils and tools, which are of great in­ter­est to re­searchers

ABOVE: Skele­ton of the Neanderthal boy

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