The scientists thought for a long time that the Neanderthals were eager consumers of meat. According to the chemical analysis of Neanderthals, it seemed that they had given themselves a feast with as much meat as the predators of the apex as the lions and the hyenas. But as a group, hominids, that is, the Neanderthals, our species and other extinct close relatives, are not specialized carnivores. Rather, they are more omnivorous and also eat many plant foods.
It is possible that humans subsist with a very carnivorous diet. In fact, many traditional northern hunters-gatherers, such as the Inuit, subsist mainly with animal foods. But hominids simply cannot tolerate the consumption of high protein levels that great predators can consume. If humans eat as much protein as hypercarnivores for long periods without consuming other nutrients, it can cause protein poisoning, a weakening, even lethal condition, historically known as “rabbit starring.”
So what could explain the chemical firms found in the bones of the Neanderthals that seem to suggest that they were eating tons of meat in a healthy way?
I am an anthropologist who uses elements such as nitrogen to study the diets of our very old ancestors. A new investigation that my colleagues and I do suggests a secret ingredient in the Neanderthal diet that could explain what was happening: worms.
Isotope proportions reveal what an animal ate
The proportions of several elements in the animals of the animals can provide information about what they ate while they were alive. Isotopes are alternative forms of the same element that have slightly different masses. Nitrogen has two stable isotopes: nitrogen-14, the most abundant, and nitrogen-15 form, the heaviest and least common form. Scientists denote the proportion of nitrogen-15 to nitrogen-14 as δ¹⁵n and measure it in a unit called permil.
As it rises in the food chain, organisms have relatively more of the nitrogen-15 isotope. The grass, for example, has a very low δ¹⁵n value. A herbivore accumulates nitrogen-15 that consumes eating grass, so its own body has a value of δ¹⁵n slightly higher. Carnivorous animals have the highest nitrogen proportion in a food network; The nitrogen-15 of its prey is concentrated in their bodies.
When analyzing the stable proportions of nitrogen isotopes, we can rebuild the Diets of the Neanderthals and the first Homo sapiens During the late Pleistocene, which extended for 11,700 to 129,000 years. The fossils of several sites tell the same story: these hominids have high values of δ¹⁵n. The high values of δ¹⁵n would generally place them at the top of the food network, along with hypercarnivores such as the lions of caverns and hyenas, whose diet is more than 70% of meat.
But maybe something else about his diet was inflating the δ¹⁵n values of the Neanderthals.
Discovering the Neanderthal Menu
We suspect that worms could have been a different potential source of nitrogen-15 enriched in the Neanderthal diet. The worms, which are fly larvae, can be a fat -rich food source. They are inevitable after killing another animal, easily collectible in large quantities and nutritionally beneficial.
To investigate this possibility, we use a data set that was originally created with a very different purpose: a forensic anthropology project focused on how nitrogen could help estimate the time elapsed since death.
Originally samples of modern muscle tissue and associated worms had collected at the Center for Forensic Anthropology of the University of Tennessee, Knoxville, to understand how nitrogen values change during decomposition after death.
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While data can help modern death investigations, in our current study we reuse them to test a very different hypothesis. We find that stable nitrogen isotope values increase modestly as muscle tissue decomposes, oscillating between -0.6 per thousand.
This increase is more dramatic in worms that feed on decomposition: 5.4 per thousand to 43.2 per thousand. To put the values of worms in perspective, scientists estimate that the values of δ¹⁵n for the herbivores of the Pleistocene range between 0.9 per thousand and 11.2 per thousand. The worms measure up to almost four times more.
Our research suggests that the high values of δ¹⁵n observed in the hominids of the late Pleistocene may be inflated by consumption throughout the year of worms enriched with ¹⁵n that are found in dry foods dry, frozen or stored in cache.
Cultural practices shape diet
In 2017, my collaborator John Speth proposed that the high values of δ¹⁵n in the Neanderthals were due to the consumption of rotten or rotten meat, based on the historical and cultural evidence of the diets in the collection of the North of the Arctic.
Traditionally, indigenous peoples saw almost universally food of animal origin completely rotten and infested with worms as highly desirable foods, not as rations of hunger. In fact, many of these people allowed routine often intentionally that food of animal origin broke down to the point where they dragged with worms, in some cases even beginning to blend.
This inevitably rotten food would emit a stench so overwhelming that the first explorers, fur hunters and European missionaries became ill to it. However, indigenous peoples considered that these foods were good to eat, even a delicacy. When asked how they could tolerate the nauseating stench, they simply replied: “We do not eat the smell.”
The cultural practices of the Neanderthals, similar to those of indigenous peoples, could be the response to the mystery of their high values of δ¹⁵n. The ancient hominids sacrificed, stored, retained, cooked and cultivated a variety of articles. All these practices enriched their paleo menu with food in forms that non -hominid carnivores do not consume. The research shows that the δ¹⁵n values are higher for cooked food, the posterid muscle tissue of terrestrial and aquatic species and, with our study, for fly larvae that feed on decomposition tissue.
The high values of δ¹⁵n of the worms associated with the posterid foods of animal origin help to explain how the Neanderthals could have included many other nutritious foods beyond the meat, while registering values of δ¹⁵n that we are accustomed to see in the hypercarnivores.
We suspect that the high values of δ¹⁵n observed in the Neanderthals reflect the routine consumption of fatty tissues of animals and fermented stomach content, a large part of them in a semi -suputeal or district state, together with the inevitable advantage of living and dead worms enriched with ¹⁵n.
What is not yet known
Flying larva Homo sapienslike recent collectors, they would have benefited from making the most of them. But we cannot say that worms alone explain why Neanderthals have δ¹⁵n so high values in their remains.
Several questions about this old diet are still unanswered. How many worms would you need to consume someone to take into account an increase in the values of δ¹⁵n above the expected values due only to the consumption of meat? How do the nutritional benefits of worms consumption change the longer a food is stored? More experimental studies on changes in the δ¹⁵n values of processed, stored and cooked foods following the traditional indigenous practices can help us better understand the dietary practices of our old relatives.
*Melanie Beasley is an assistant professor of Anthropology at the University of Purdue.
This article was originally published in The Conversation/Reuters
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