Holes in the ‘Hyper-Carnivore’ Theory
Anthropologist Melanie Beasley led research that set out to solve a lingering mystery about the Neanderthal diet. Did ancient humans exclusively eat meat, and if so, how did they survive?
“As primates, our bodies cannot process meat in the same way a carnivore can, like a lion or a hyena or a wolf,” says Beasley. “We can't consume that level of pure meat protein in our diet.”
Yet that’s what lab research was showing. When researchers analyzed collagen from Neanderthal bones in the 1990s, they found incredibly high levels of nitrogen isotopes. That seemed to be a clear sign that Neanderthals were at the very top of the food chain.
“Neanderthals were higher than hyenas in nitrogen,” says Beasley. “They were higher than cave bears. They were higher than wolves, basically any carnivore. And so there was this popular idea that Neanderthals were ‘hyper-carnivores.’”
But if primate bodies can’t process a meat-only diet, then how could Neanderthals have lived exclusively on the flesh of big game animals?
Various theories were floated. Maybe Neanderthals supplemented their diets with grasses and other simple carbohydrates. Maybe they consumed a lot of fish and marine mammals. Then in 2017, one of Beasley’s co-authors, John Speth, made a radical proposal—what if ancient man wasn’t eating freshly killed meat but putrid, rotten meat?
For Beasley, who studies the origins and evolution of the human diet, rotten meat was a revelation. Putrid meat was essentially “fermented,” meaning that bacteria did some of the difficult work of breaking down and “pre-digesting” the proteins. That partially explained how humans could eat such a meat-heavy diet, but it didn’t fully explain those high nitrogen levels.
That’s when Beasley’s attention shifted from putrid meat itself to the maggots living inside it.
In Traditional Cultures, Steaks Were for the Dogs
Some of the strongest evidence that ancient hominins ate putrid meat and maggots comes from the “ethnohistorical” record. Over the past several hundred years, Europeans and other Westerners recorded interactions with traditional hunting and foraging cultures in which meat-eating had a very different meaning.
"If you’re cooking Sunday dinner, you might have a roast or steak, but those were not considered great cuts of meat by these traditional societies,” says Beasley. “That’s what they fed to the dogs or left on the carcass. Humans can’t eat pure muscle tissue. You have to complement that protein with fats and other things to have a more complete diet.”
In written accounts of Native American and Inuit hunts, the “choice parts” of a kill were the brain, tongue, briskets, ribs, fatty organs, entrails, marrow and even partly digested stomach contents. Lean meat from muscle tissue was only harvested in times of scarcity.
Instead of eating the freshly killed meat, food was often stored for later consumption through drying or smoking. But since flies can lay eggs even in smoking meat, there was no escaping the presence of fly larvae (maggots). Although it may be stomach-churning to most modern humans, maggots were considered a delicacy in many traditional societies.
The disgust response doesn’t form in humans until 5 to 7 years old, Beasley says, so if children grow up around adults eating putrid, maggot-filled meat, “they grow up thinking, ‘Oh, that’s yummy!’”
The Nutritional Value of Maggots
It's not a great leap to think that ancient hominins like Neanderthals had the same approach to meat-eating as Indigenous and traditional hunting cultures. Neanderthals would have prized fatty organs and brains as the choicest parts of a kill, but they also would have used as much of the carcass as possible to hedge against future hunger.
That's where Beasley thinks maggots would have played a critical nutritional role.
“If you think about lean game meat that they would have been hunting and storing, the fly larvae are actually converting that lean game meat into their own fatty substance,” says Beasley. “By eating the fatty fly larvae along with the lean meat, Neanderthals were getting a more complete food.”
The evidence for maggot-eating is right in the data collected from Neanderthal bones. Those sky-high nitrogen isotope levels that were once seen as a sign of “hyper-carnivorism” in Neanderthals can also be explained by widespread maggot consumption.
For the grisliest part of their research, Beasley and her team analyzed the nitrogen levels of fly larvae grown in the decomposing tissue of 34 human donors. After feeding on rotting flesh for months, the lab-grown maggots were rich in nitrogen isotopes.
“To put it in perspective, most foods on the high end of nitrogen values—seals and whales, for example—have numbers in the range of 18 to 21 parts per million,” says Beasley. “For the fly larvae, we got nitrogen values as high as the low 40s.”
According to this new research, the high nitrogen values found in Neanderthal bones isn't proof that ancient hominins fed exclusively on freshly killed game. Like most traditional hunting and foraging societies, Neanderthals had a highly developed taste for maggots.
