Bone analysis of ancient skeletons show humans started eating maize 4,700-years-ago 


Ancient skeletons, found in a remarkably well-preserved state in Central American rock shelters, hold clues to the origins of maize as a staple of the human diet.

The remains were found in the Maya Mountains of Belize and were buried at various points in the past 10,000 years, according to University of Exeter team.

Researchers measured levels of carbon and nitrogen in the bones of 44 skeletons to gather information on their diet – they found the oldest fed on herbs and berries. 

Of the skeletons studied, the first to show signs of maize in their diet would have lived about 4,7000-years-ago, the team said.

The human remains were found in the Maya Mountains of Belize and were buried at various points in the past 10,000 years, according to University of Exeter experts

The human remains were found in the Maya Mountains of Belize and were buried at various points in the past 10,000 years, according to University of Exeter experts

Researchers measured the carbon and nitrogen in the bones of 44 skeletons, to gather information on their diet and found the oldest fed on herbs and berries

Researchers measured the carbon and nitrogen in the bones of 44 skeletons, to gather information on their diet and found the oldest fed on herbs and berries

Of the skeletons studied, the first to show signs of maize in their diet would have lived about 4,7000-years-ago, the team said

Of the skeletons studied, the first to show signs of maize in their diet would have lived about 4,7000-years-ago, the team said

The discovery of dozens remarkably well-preserved ancient skeletons in Central American rock shelters has been described as ‘unparalleled’ by researchers. 

Until now little was known about when humans started eating the crop – once restricted to South America but now a staple of meals around the globe.

The crop has become so vital to the global diet that it now shapes agricultural landscapes and ecosystem biodiversity worldwide. 

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Radiocarbon dating of the skeletal samples helped the team discover the point of transition from pre-maize hunter-gatherer diets to a farmed maize food source. 

Maize made up about a third of people’s diets in the area by 4,700 years ago, rising to 70 per cent just 700 years later.

The discovery of dozens remarkably well-preserved ancient skeletons in Central American rock shelters has been described as 'unparalleled' by researchers

The discovery of dozens remarkably well-preserved ancient skeletons in Central American rock shelters has been described as ‘unparalleled’ by researchers

Until now little was known about when humans started eating the crop - once restricted to South America but now a staple of meals around the globe

Until now little was known about when humans started eating the crop – once restricted to South America but now a staple of meals around the globe

Maize was domesticated from teosinte, a wild grass growing in the lower reaches of the Balsas River Valley of Central Mexico, around 9,000 years ago. 

There is evidence maize was first cultivated in the Maya lowlands around 6,500 years ago, at about the same time that it appears along the Pacific coast of Mexico.

Dr Mark Robinson, from the University of Exeter, who co-directed field excavations, said it’s ‘extremely rare’ to find older human remains in the area due to humidity. 

‘This is the only example of a burial site in the Neotropics used repeatedly for 10,000 years, giving us an unparalleled opportunity to study dietary change over a long time period, including the introduction of maize into the region,’ he said.

‘This is the first direct evidence to show when the change in people’s diets occurred and the rate at which maize increased in economic and dietary importance until it became fundamental to peoples dietary, economic, and religious lives.’

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Experts measured the carbon and nitrogen in the bones of 44 skeletons, which gave information about people’s diet. 

The remains include male and female adults as well as children, providing a wholistic sample of the population and giving a more accurate overview.

The oldest remains date from between 9,600 and 8,600 years ago, with continued burials occurring until about 1,000 years ago, the authors say.

The analysis shows the oldest remains were people who ate herbs, fruits and nuts from forest trees and shrubs, along with meat from hunting terrestrial animals.

These skeletons belonged to hunter gatherers rather than farmers. 

Maize was domesticated from teosinte, a wild grass growing in the lower reaches of the Balsas River Valley of Central Mexico, around 9,000 years ago

Maize was domesticated from teosinte, a wild grass growing in the lower reaches of the Balsas River Valley of Central Mexico, around 9,000 years ago

By 4,700 years ago, diets became more diverse, with some individuals showing the first consumption of maize. 

The isotopic signature of two young nursing infants shows that their mothers were consuming substantial amounts of maize. 

The results show an increasing consumption of maize over the next millennium as the population transitioned to sedentary farming.

By 4,000 years ago, the population was reliant on maize, with the crop forming 70 per cent of their diet. 

The increase in consumption of maize protein was accompanied by a reduction in the consumption of animal protein. 

By 4,700 years ago, diets became more diverse, with some individuals showing the first consumption of maize

By 4,700 years ago, diets became more diverse, with some individuals showing the first consumption of maize

Maize became a dietary staple at a time of broad continental population change, increases in social complexity and social hierarchy, and major subsequent environmental transformations. 

The study shows that as people ate more maize, the associated farming led to an increase in forest clearing, burning and soil erosion across the Maya lowlands.

The spread of maize agriculture across the Americas was likely linked to the spread of distinct cultures, technologies, and languages. 

By the time the highly complex, monumental Maya civilisation developed 2,000 years ago, maize was central to lifeways and cosmology, with their creation story recording that the Maya are made out of maize.

The study has been published in the journal Science Advances.



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