Prehistoric diets were maggot heavy, a new study suggests

CNN

3 days ago

Neanderthals had a voracious appetite for meat. They hunted big game and chowed down on woolly mammoth steak as they huddled around a fire. Or so thought many archaeologists who study the Stone Age.
Fresh meat was far from the only thing on the menu, according to a growing body of research that has revealed our archaic cousins ate a varied diet that included pulses and shellfish.
Still, a chemical signature in Neanderthal remains that suggests robust meat eating — observed at higher levels than those seen in top predators such as lions and wolves — has puzzled researchers for decades. Now, new research hints at an unexpected Stone Age food.
Maggots — the larvae of flies, which hatch in and feed on decaying animal tissue — may also have been a staple of prehistoric diets, a study published Friday in the journal Science Advances suggests.
Lead author Melanie Beasley, an assistant professor of biological anthropology at Purdue University in West Lafayette, Indiana, found that a taste for maggots could explain a distinctive chemical signature detected in the bones of prehistoric humans, including Homo sapiens and Neanderthals, a species that went extinct 40,000 years ago.
The findings back up a hypothesis that had been put forward by Beasley's coauthor John Speth, an anthropologist at the University of Michigan, who has for nearly a decade argued that putrid meat and fish would have formed a key part of prehistoric diets. His work was based on ethnographic accounts of the diets of indigenous groups, who he said found rotten meat and maggots acceptable fare.
'Not a lot of people took notice, because it was like this is an out-there idea. And there wasn't any data,' said Beasley, who heard Speth give a talk in 2017 and subsequently decided to test his hypothesis.
To understand past diets and where an animal sat in the ancient food chain, scientists study the chemical signature of different isotopes, or variants, of elements such as nitrogen or carbon, which are preserved in teeth and bones over thousands of years.
Researchers first found in the 1990s that the fossilized bones of Neanderthals unearthed in Northern Europe had particularly elevated levels of the nitrogen-15 isotope, a chemical signature that suggests their meat consumption was on par with hypercarnivores such as lions or wolves.
'Grass will have one (nitrogen) value, but then the deer that eats the grass is going to have a higher value, and then the carnivore that eats the deer is going to have an even higher value,' Beasley explained. 'So you can track nitrogen through this trophic food web system.' Neanderthal remains, she said, had even higher nitrogen values than carnivores.
This was puzzling, however, because modern-day humans, unlike wolves and lions, cannot stomach large quantities of lean meat. Overindulging in it can lead to a potentially lethal form of malnutrition in which the liver fails to break down the protein and rid the body of excess nitrogen.
Known today as protein poisoning, the condition was more common among European explorers of North America — who dubbed the illness 'rabbit poisoning' or 'mal de caribou' — given that wild game was far leaner than today's farmed meat. Archaeologists believe that Neanderthals understood the importance of fatty nutrients, and, at least in one location in what's now Germany, processed animal bones on a large scale to extract the fat.
Rotten meat might be higher in nitrogen than fresh tissue and may have been responsible for boosting nitrogen levels in Neanderthal bones, Speth's research has suggested.
Not long after hearing Speth speak, Beasley, who was previously a postdoctoral fellow at the University of Tennessee, Knoxville, where she conducted research at its Forensic Anthropology Center, decided to investigate. The research facility, sometimes described as a body farm, was established to study how the human body decomposes.
There, she analyzed nitrogen levels in the rotting tissue of donated human corpses left outdoors and the fly larvae that formed in the muscle tissue. The work, conducted over a two-year period, required a strong stomach, she said.
Beasley found that nitrogen levels increased modestly over time in the human tissue. However, she observed much higher nitrogen levels in the fly larvae, suggesting that Neanderthals and early modern humans likely consumed animal meat laced with maggots on a regular basis.
'I started getting the (nitrogen) values back, and they were just astronomically high,' Beasley recalled.
'John (Speth) and I started talking: What if it's not just the putrid meat, but it's the fact that … they're never going to be able to prevent flies from coming and landing on the meat, and so fly larva just become part of the delicacy,' she said.
The data from her work not only provides insight into the Neanderthal diet but also informs modern forensic science, with nitrogen levels in maggots that form in human corpses helping scientists pinpoint time since death, she noted.
It was a 'no brainer' that Neanderthals ate maggots, said Karen Hardy, a professor of prehistoric archaeology at the University of Glasgow in Scotland.
Hardy, who wasn't involved in the study, said the authors provided a 'strong argument in favor of maggot consumption,' although such behavior is unlikely to be conclusively proven because maggot remains do not survive in the archaeological record.
'The surprise element is more to do with our Western perspective on what is edible and what is not,' she added.
Today, at least 2 billion people worldwide are estimated to consume insects as part of traditional diets, according to the United Nations Food and Agriculture Organization.
The study also noted that, according to historical accounts, many indigenous peoples such as the Inuit 'viewed thoroughly putrefied, maggot-infested animal foods as highly desirable fare, not starvation rations.' Many such groups, according to the study, 'routinely, often intentionally, allowed animal foods to decompose to the point where they were crawling with maggots, in some cases even beginning to liquify, and inevitably emitting a stench so overpowering that early European explorers, fur trappers, and missionaries were sickened by it.'
Knud Rasmussen, a polar explorer from Greenland, recorded the following culinary experience, cited in the study, in his 1931 book 'The Netsilik Eskimos: Social Life and Spiritual Culture.'
'The meat was green with age, and when we made a cut in it, it was like the bursting of a boil, so full of great white maggots was it. To my horror my companions scooped out handfuls of the crawling things and ate them with evident relish. I criticised their taste, but they … said, not illogically: 'You yourself like caribou meat, and what are these maggots but live caribou meat? They taste just the same as the meat and are refreshing to the mouth.'
The study also noted that maggots are not unknown in Western culinary traditions, noting the Sardinian cheese casu marzu is replete with the larvae of cheese skipper flies.
Beasley said that Northern latitude groups still process these foods today and consume them safely when prepared following traditional practices.
Beasley's research on modern-day corpses was exploratory and had several limitations, she cautioned.
The work, which involved small sample sizes, focused on human muscle tissue, not the tissue or organs of animals that might have been hunted by Neanderthals. What's more, the fly larvae, which came from three different families, might have differed from those that existed in the late Pleistocene, which ended around 11,000 years ago.
The study also didn't account for the wide variety of climates and temperatures that would have had an effect on stored meat in the Stone Age. She also added that the human body tissue wasn't cooked, processed or prepared in any way.
Beasley has spoken with researchers in Alaska in the hopes of connecting with native groups that would be interested in sharing traditional food preparations. Her goal is to better understand how that might affect the nitrogen level.
The new research has 'opened a fascinating line of inquiry' into the culinary practices of Stone Age hunter-gatherers such as Neanderthals, said Wil Roebroeks, professor emeritus of paleolithic archaeology at Leiden University in the Netherlands. He wasn't involved in the research.
'It certainly gives a fresh — if that is the right word here — perspective on Neanderthal and other Late Pleistocene humans' diets,' Roebroeks added.
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