New research suggests that our closest extinct cousins may have been feasting on fly larvae as routinely as they ate meat, and those squirming snacks could explain why Neanderthal bones show nitrogen levels rivaling lions and wolves. By analyzing nitrogen isotopes in maggots raised on decomposing tissue, researchers at Purdue University propose that these protein‑ and fat‑rich larvae, long considered detritus, were an overlooked dietary staple that skewed isotope records.
Nitrogen isotope ratios in bone collagen serve as molecular footprints of where an animal sits in the food web. Late Pleistocene Neanderthals consistently yield nitrogen values at or above those of hypercarnivores, leading archaeologists to conclude they subsisted primarily on mammoth, bison, and other large game.
Yet humans cannot tolerate the extreme protein loads of true predators. Melanie Beasley, the lead author of the study, instead, point to fly larvae—maggots—that swarm putrefying meat caches and boast nitrogen values far higher than the flesh itself.
To test this, the team collected 389 larvae from three fly families (Calliphoridae, Piophilidae, Stratiomyidae) feeding on human muscle tissue left to decompose over two years at the University of Tennessee’s Anthropology Research Facility. While the underlying muscle tissue saw modest nitrogen increases of −0.6 to 7.7‰, the maggots registered a striking 5.4 to 43.2‰ enrichment—up to four times higher than herbivores and well above the expected 3–5‰ trophic jump per level.
Ethnohistoric records reveal that indigenous foragers prized maggot‑infested meat. One 17th‑century Netsilik observer recalled, “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”. In fact, dishes like Sardinia’s casu marzu cheese show that larvae consumption persisted as delicacy rather than desperation.
Comparing these insect values to fossil data, the authors note that 75.3% of their maggot samples exceed the highest nitrogen ratio recorded for a Pleistocene herbivore (11.2‰), and many align with the hypercarnivore range. If Neanderthals regularly consumed maggot‑laced fat and organ tissues—tongue, brisket, kidneys—they would have ingested not just decomposed meat but a potent isotope signature carried by larvae.
“It is the maggots, more so than the carcass tissues themselves, that gave Late Pleistocene hominins both a rich source of fat and a very highly N‑enriched source of protein,” the team concludes.
Still, Beasley caution that quantifying how much maggot biomass Neanderthals ate remains elusive without macronutrient data or clear analogs in modern foragers. Northern populations did indulge in putrid meat, but marine‑rich diets confound comparisons. Future work will need to model dietary contributions of larvae, test different decomposition contexts, and examine how various insect instar stages affect the Nitrogen values.
The study has been published in Science Advances.
