David of Gene Expression broke the news of a new study of skulls from a Yorkshire village, which ‘deepens’ a

“long-standing mystery over the way men’s skulls changed from long to round during medieval Europe.”

Why men? I’ve never heard of the claim that male bones are more sensitive to environmental change during their development than those of women, which is what this the Guardian article quotes. Does anyone out there have a paper which studies this? I have, however, been taught that rounder skulls have less surface area, a common physiological adaptation seen in all animals.

The data of 700 skeletons from the Wharram Percy sites complicates what and how changes in skull shape happened during the 11th and 13th century. Currently there are two hypotheses, one where round skulls are due to gene flow from immigrant populations and the other is one that suggest round skulls were selected and influenced by climate change. But,

“neither [hypotheses] makes sense of the 700 Yorkshire skeletons…

The leading theory, that Scandinavian incomers brought new racial characteristics to the rest of Europe, does not make sense at Wharram, a lonely valley in the Wolds near Malton. Its natural isolation was reinforced during the 200 years of the skull change by plague and sheep blight which soon after led to its abandonment.

The skulls also show that only men were affected, which would not have applied if its cause was new genetic stock. Simon Mays, the human skeletal biologist in charge of the English Heritage study, said: “If immigration was responsible we would expect both sexes to be affected. There’s also the puzzle of why male skull shapes eventually reverted back, becoming similar to those we have today… But the climate at Wharram during the critical period rose by 0.5C and was actually warmer than it is today,” said Mr Mays. “Further, as the weather got much colder in the later medieval period skulls started to become longer and narrower again.”

Because neither gene flow nor climate change can explain why humans skulls became rounder during this time period, people are considering the effects of plague on selecting round skulls. The plague,

“repeatedly devastated Wharram along with many other parts of western Europe. Villagers finally called it a day around 1500, leaving only mounds and the ruined St Martin’s church today.

The study, the latest of 14 volumes on 40 years of excavation at Wharram, also shows that left-handedness was much more common in medieval times, at 15% compared with 8% today. Infant mortality was also unexpectedly low, possibly because illness and poor diet set in only after weaning off breast milk.”

But as David of Gene Expression, “the change between the 11th and 13th centuries precedes the Black Death.”

So what’s going on with these skulls? I wish I had a photo to see just how round these skulls. In my forensic anthropology education, white people, like Europeans, are generally characterized by a doliocephalic shape, which is a fancy way of saying the skull is long. The doliocephalic shape is calculated by taking a ratio of the breadth of the head to its length. Sure there is a lot of variation in populations, but the consensus is that Europeans have longer skulls than round, broad ones as compared to other humans.

I guess the jury is still out on what happened at Wharram Percy and the round skull phenomenon.