Humans
PUBLISHED
There’s something about Neanderthals that doesn’t quite add up. Based on the type of nitrogen detected in their collagen, they appear to have been hypercarnivores, eating way more meat than apex predators like wolves and hyenas.
But humans simply can’t consume that much meat without getting seriously ill - so what on Earth were the extinct hominins eating?
Herbivore muscle meat is high in nitrogen-15 isotopes, and elevated levels of this element in ancient remains usually point towards a carnivorous diet. Gray wolves and spotted hyenas, for instance, typically show values of between 7.9 and 8.4 percent nitrogen-15, reflecting their meaty menus.
Yet Neanderthals often display values of between 12 and 14 percent, which suggests that their lust for flesh was absolutely off the scale.
However, in modern humans, consuming more than 300 grams of lean protein per day typically leads to a potentially fatal condition called rabbit starvation. This form of malnutrition occurs because, while the calorie consumption is high, there is simply not enough fats or carbohydrates.
Last year, researchers offered an explanation for this “trophic anomaly” in Neanderthals.
Maggots for breakfast, lunch, and dinner
They suggested that Neanderthals may have feasted on maggots obtained from rotting flesh. By eating the decaying meat, these grubs would have accumulated high levels of nitrogen isotopes, which were then passed on to the Neanderthals and may therefore account for the values seen in the collagen samples.
However, a new study challenges this idea by calculating the quantity of maggots that Neanderthals would need to eat in order to achieve the nitrogen levels found in archaeological specimens.
Depending on the amount of nitrogen the larvae were able to absorb, the simulations suggest that they would need to make up between 40 and 100 percent of the Neanderthal diet to generate the types of isotopic signatures we’re talking about.
In some cases, the required contribution of maggots to Neanderthal protein intake exceeded 100 percent.
Ultimately, then, study author José Luis Guil-Guerrero from the University of Almería concludes that “the consumption of insect larvae - even highly enriched specimens - would require entirely implausible dietary proportions to independently drive Neanderthal collagen signals so far beyond the apex carnivore baseline.”
Looks like meat's back on the menu, boys
Instead, he suggests that these high isotopic values may be more parsimoniously explained by the consumption of mammoth meat, which has a high nitrogen content.
“The targeted hunting of megafauna, particularly mammoths, remains a leading hypothesis for these extreme trophic elevations,” writes Guil-Guerrero.
“However, it must be acknowledged that no single explanatory model - whether mammoth hunting, aridity, physiological stress, or larval consumption - has yet proven universally applicable,” he adds.
In light of this lingering uncertainty, the author argues that “the ultimate cause of these elevated values likely involves a complex, regionally variable mosaic of behaviors and environments that we are still working to fully explain.”
The study has been published in the American Journal of Biological Anthropology.
