麻豆传媒

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STOP me if you have heard this one before: the transition to farming was a cataclysmic turn for the worse. Beginning around 12,000 years ago, some of our ancestors started cultivating crops, abandoning the egalitarian and sustainable hunter-gatherer lifestyle that had worked for hundreds of thousands of years. The result was poor health, limited diets, new diseases and unsustainable practices that have culminated with climate change and a sixth mass extinction.

This narrative has become well established. But like so many stories about our prehistory, I am not sure we should believe it.

Traditionally, anthropologists thought of prehistory in terms of progress. This meant the advent of farming was seen as an advance over hunting and gathering, which was older and so more primitive.

However, in the late 20th century, the assumption of progress came in for criticism: why is a farming society 鈥渂etter鈥� than a hunter-gatherer one? Around the same time, research suggested that the first farmers had poor health compared with their hunter-gatherer ancestors.

Key evidence of this came from studies of changes to average height. People who are well nourished and healthy tend to grow taller than those who often go hungry. Crucially, the archaeological record indicated that .

The idea was summed up in a 1999 article by Jared Diamond. He described farming as the , which is pretty unambiguous. The idea of farming as progress had been overturned.

You know there is a 鈥渂ut鈥� coming, right? Last month, the journal PNAS published . It included by in London, Canada, and his colleagues. The research dramatically reframes the question of how switching to farming affected our health.

Stock鈥檚 team compiled data on 3577 skeletons from 366 archaeological sites in Europe, Asia and North Africa. The remains span the period from 34,300 years ago to the present. There is obviously a lot of variation, but average body size gradually declines from 34,300 years ago until about 6000 years ago, when it increases again. This isn鈥檛 what you would expect if switching from hunting and gathering to farming was bad for our ancestors.

The increase in body size around 6000 years ago might be linked to mutations enabling adults to drink milk. But why were people getting smaller for thousands of years before they started farming?

Let me state upfront that the paper doesn鈥檛 offer a clear answer for this and I don鈥檛 have one either. The researchers point out that communities didn鈥檛 switch to farming overnight. Many early farmers still did some hunting and foraging. This muddies the picture.

We might also invoke climate change. Between about 110,000 and 12,000 years ago, Earth was in a colder phase. Temperatures reached their lowest point around 20,000 years ago. It is possible that the frigid climate made it harder for hunter-gatherers to get by. But that doesn鈥檛 explain why body size kept shrinking after temperatures started warming up again.

I have one more hypothesis: that humans got smaller because they had overhunted big animals like mammoths, leading to a shortage of nutritious meat. In 2021, I reported on the work of Miki Ben-Dor at Tel Aviv University in Israel and his colleagues, who claimed that overhunting of large animals forced humans to gradually switch to other food sources.

It is conceivable that hunter-gatherers gradually denuded their environments of large animals, forcing them to rely more on smaller prey and on managing wild plants. This could explain why humans shrank for thousands of years. But just like the other hypotheses, this comes with major uncertainties. In particular, Ben-Dor and his team鈥檚 claim that early humans drove megafauna declines is very much up for discussion.

Putting these difficulties aside, I do think the new study of human body size should prompt a rethink of our ideas about the impact of farming on our health. Diamond鈥檚 claim it was the worst mistake our ancestors ever made now seems at best an exaggeration (I am pretty sure the invention of absolute monarchy was a worse idea).

We shouldn鈥檛 take this argument too far. Farming didn鈥檛 prompt an immediate increase in body size, so I don鈥檛 think the study would support the opposite narrative of farming being unambiguous 鈥減rogress鈥�. But maybe, instead of it being a silly mistake we then became locked into, it was the best possible choice at the time.

Michael Marshall is a science writer based in Devon, UK. He writes 麻豆传媒鈥檚 monthly email newsletter Our Human Story, which is about human evolution. His book The Genesis Quest is about the origin of life on Earth and is now available in paperback.