Neanderthals Might Have Eaten Maggot-Infested, Putrefying Meat, Explaining a Mysterious Chemical Signature in Their Remains

Maggots might have helped our long-extinct relatives avoid protein poisoning by providing a nutritious source of fat, a new study suggests

August 4, 2025

maggots in a bucket — New research suggests Neanderthals ate rotten flesh and maggots, explaining why the levels of nitrogen-15 found in their remains are so high. Cory Doctorow via Wikimedia Commons under CC BY-SA 2.0

Unexpected chemical traces in Neanderthal remains had previously led experts to suggest our long-extinct relatives were eating more meat than humanly possible. But a study published in July in the journal Science Advances offers a new potential explanation: Neanderthals were chowing down on a whole lot of maggots, or fly larvae.

Researchers can investigate the prehistoric diets of humans and animals by analyzing nitrogen-15—a version of nitrogen that accumulates in greater quantities higher up the food chain.

“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,” Melanie Beasley, lead author of the study and a bioanthropologist at Purdue University, tells CNN’s Katie Hunt. “So, you can track nitrogen through this trophic food web system.”

The amount of nitrogen-15 in Neanderthal remains from the late Pleistocene (which spanned 11,700 to 129,000 years ago), however, was high enough to make many researchers raise their eyebrows. It was higher than that of hyenas, wolves, cave bears and “basically any carnivore,” Beasley tells History’s Dave Roos.

To explain those numbers, some researchers had suggested Neanderthals were “hyper-carnivores” that ate an astronomical amount of meat. But that idea had one main flaw: protein poisoning. Also known as “rabbit starvation” or “mal de caribou,” it occurs when humans eat too much protein without enough fat or carbohydrates, such that the liver and kidneys can’t process it. And yet, remains from prehistoric Homo sapiens have similar nitrogen chemical signatures to those of Neanderthals. So, how were these human groups thriving with such high nitrogen-15 values?

Key concept: What was included in Neanderthal diets?

Once thought to solely eat vast amounts of game meat, Neanderthals seem to have had more varied diets than expected. Research has revealed the early humans ate shellfish such as crabs and cooked complex meals including lentils, nuts and grasses.

Nearly a decade ago, John Speth, an anthropologist at the University of Michigan and senior author of the new study, suggested prehistoric diets relied on putrid meat and fish after studying ethnographic accounts of Indigenous diets that included such meals. Often, these putrefied carcasses were crawling with maggots, which offer a key source of fat. But Beasley tells CNN that many people didn’t pay attention to the hypothesis, because it was an “out-there idea” without supporting data.

Could maggots be the source of Neanderthals’ mysterious nitrogen-15 levels? To answer this question, the team repurposed scientific resources—donated human flesh that spent two years putrefying at the Forensic Anthropology Center at the University of Tennessee, Knoxville. Originally, these cadavers were intended for another research goal—to understand how decomposition affects nitrogen values.

“While the data can assist modern forensic death investigations, in our current study we repurposed it to test a very different hypothesis,” Beasley writes in the Conversation. “We found that stable nitrogen isotope values increase modestly as muscle tissue decomposes.”

This suggests Neanderthals would have gained greater quantities of nitrogen-15 by eating rotting meat. But what was most surprising was the level of nitrogen-15 in the fly larvae that naturally colonized the rotting flesh. In muscle tissue, researchers registered the ratio of nitrogen-15 to the more abundant nitrogen-14 at up to 7.7 parts per thousand. In contrast, the nitrogen ratio in the flesh-eating maggots was up to 43.2 parts per thousand, according to the study, and that number also increased with the time the flesh spent rotting.

In other words, Neanderthals’ mysteriously high nitrogen-15 values could have been caused by eating maggots.

“Fly larvae are a fat-rich, nutrient-dense, ubiquitous and easily procured insect resource, and both Neanderthals and anatomically modern humans, much like recent foragers, would benefit from taking full advantage of them,” Beasley tells Gizmodo’s Ed Cara. Some Sardinians already do take advantage—thanks to their infamous (albeit widely banned) cheese, called casu marzu, which contains live maggots.

Amanda Henry, a bioarchaeologist at Leiden University in the Netherlands who was not involved in the research, tells Nature’s Jenna Ahart that the study would be more significant if the team also investigated the flesh and maggots of animals that Neanderthals actually ate, rather than just human flesh. It’s worth noting, however, that some evidence suggests early humans practiced cannibalism.

Either way, the work suggests today’s trendy paleo diet may not be completely true to its namesake, Beasley explains to New Scientist’s Michael Le Page. “All the people who want to go true ‘paleo,’ they need to start thinking about fermenting their meat and letting the flies access them.”

Yum.

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