Farming made our ancestors shorter, new study suggests

New study of human bones suggests that shift to agriculture may have initially had negative impact on prehistoric ancestors’ health, Andy Gregory reports

Researchers have analysed prehistoric human bones to shine a light on the impacts of the agricultural revolution (Marija Stojkovic/SWNS)

The switch from hunter-gatherer lifestyles to farming may have made our ancestors shorter, according to new research.

Scientists have long been fascinated by the dramatic impacts of the agricultural revolution upon human health and biology, through its complete transformation of the way in which our ancestors lived and interacted with each other.

Now a new study suggests that during the Neolithic era – which marks the move to agriculture – humans were 1.5 inches shorter than their predecessors in the Upper Paleolithic and Mesolithic eras.

In an attempt to use changes in human stature as a barometer of changes in our ancestors’ health, a global team of scientists studied limb bones from 167 adults, who lived in Europe between 38,000 and 2,400 years ago – which spans from pre-agriculture times to the Iron Age.

The researchers measured the long bones of skeletal remains, which were also sampled for ancient DNA testing, and created a computer model which used adult height, indicators of stress seen in the bones, and gene mapping.

Taking into account these humans’ genetically indicated potential heights, the scientists discovered that individuals from the Neolithic were not only an average of 1.5 inches shorter than their predecessors – but they were also less tall than their descendants.

“Our approach is unique in that we used height measurements and ancient DNA taken from the same individuals,” said lead author Dr Stephanie Marciniak, of Penn State University

In a discovery suggesting that the shift to farming’s seemingly negative impact on health may have been relatively short-lived, the scientists found that – after the dip following the shift to agriculture – heights then steadily increased through the Copper (0.77 inches), Bronze (1.06 inches), and Iron (1.29 inches) eras.

Settled farming communities occurred across Europe at different times, emerging in the Levant more than 10 millennia ago, spreading to France 7,800 years ago and eventually arriving in Britain 1,800 years later.

This period was also marked by significant migration, somewhat complicating the picture for the researchers, whose study has been published in the Proceedings of the National Academy of Sciences journal.

“There was movement of people, generally from east to west,” said Dr Marciniak. “We wanted to account for that migration that perhaps brought different proportions of height-associated genetic variants.”

When the team incorporated ancestral information, they found that for the Neolithic, the height decrease was slightly reduced – placing Neolithic farmers at an average of 1.1 inches shorter than their hunter-gatherer predecessors.

“Right now, what we know is 80 per cent of height is from genetic makeup and 20 per cent is from the environment. Researchers haven’t yet identified all the genetic variants associated with for height,” Dr Marciniak said.

The impacts of the agricultural revolution has fascinated public health experts for decades.

While the move is widely credited with boosting individual fitness and population rates, in addition to laying the grounds for modern societies, the new study is not the first to suggest that it also had negative health consequences.

Diets became monotonous, with the narrower range of food bringing not only a decline in nutrition but also the possibility of disaster from failed harvests.

It has also been linked to a rise in infectious diseases, as humans packed together more densely and in greater numbers, leading to more sedentary lifestyles, and in proximity to domesticated livestock.

The study suggests that both of these factors “may partly underscore” their findings of a drop in height among the first European farmers.

Dr Marciniak added: “This research requires more study with larger datasets. Our work represents a snapshot of something that is very dynamic and very nuanced.

“We need to do more to see what is the cause of the decrease in achieved height versus predicted genetic height during the shift to farming.”

Additional reporting by SWNS