Grain Consumption Caused Neanderthal Extinction: An Alternative Hypothesis

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A new study, ‘Microfossils in calculus demonstrate consumption of plants and cooked foods in Neanderthal diets‘, got a brief writeup in Scientific American today under the title,
Fossilized food stuck in Neandertal teeth indicates plant-rich diet‘. I haven’t seen the inevitable spin-off articles proclaiming the death of the paleo diet, but I can hear the echoes of vegans clickity-clacking away on their keyboards this very moment. Melissa McEwen’s brain is apparently wired directly into the internet and she’d already written that this study is convincing, but doesn’t really offer anything new before I’d finished two paragraphs. By the time I got distracted and returned to writing this, Richard Nikoley had also mentioned it and referenced a post from two years ago bolstering his commitment to remaining nonplussed by the onslaught of non-news. On most days, that would leave me only to ponder whether Newton or Leibniz first discovered microfossils in calculus. Not today my friends!

Without further ado, it is with extreme excitement that I release my contribution to this discussion by way of an alternative hypothesis. It is currently in-press for the Journal of Applied Paleonthropological Hyperbole.

Abstract

The nature and causes of the disappearance of Neanderthals and their apparent replacement by modern humans are subjects of considerable debate. Many researchers have proposed biologically or technologically mediated dietary differences between the two groups as one of the fundamental causes of Neanderthal disappearance. Some scenarios have focused on the apparent lack of plant foods in Neanderthal diets. Here we report direct evidence for Neanderthal consumption of a variety of plant foods, in the form of phytoliths and starch grains recovered from dental calculus of Neanderthal skeletons. Some of the plants are typical of recent modern human diets, including legumes, and grass seeds (Triticeae), whereas others are known to be edible but are not heavily used today. Many of the grass seed starches showed damage that is a distinctive marker of cooking. Our results indicate that in both warm eastern Mediterranean and cold northwestern European climates, and across their latitudinal range, Neanderthals made use of the diverse plant foods available in their local environment and transformed them into more easily digestible foodstuffs in part through cooking them, suggesting that the extinction of Homo neanderthalensis may have been caused by introduction of food sources sufficiently deleterious to individual health.

The obvious question then becomes: How long do we have to wait before proclaiming Neanderthals were vegans? Why would Neanderthals continue to eat substances that were toxic?

For that, we need look no further than modern humans. When ingested items provide an observable short-term benefit in terms of calories, they are assumed to be beneficial. When the negative effects of toxic inputs are cumulative over a period of weeks, months, or years, individuals are incapable of isolating the confounding variables. This is further complicated by not being limited to dietary inputs, but also those of microbial, genetic, or other environmental factors such as shortages or overages of vitamins, minerals, and myriad chemical compounds. This problem has not been solved with modern scientific methods, and it is reasonable to assume that Neanderthals were less capable of determining cause and effect during the Pleistocene.

When the introduction of toxins does not manifest with sufficiently deleterious symptoms for a duration in excess of nine months in females, and nine seconds in males, significant adaptive pressure may not be placed on reproduction for that individual. Thus, the combination of an inability to disambiguate dietary toxins across a relevant period of time with the lack of strong selection pressure in delayed onset cumulative symptoms may result in both poor health and reproductive success, especially in the short-term. However, over time, the inability to recognize the delayed onset cumulative symptoms of the introduction of dietary toxins may lead to an increase in the consumption of the toxic sources. While a disconnect in the causal relationship between dietary input and its negative health outcomes persists, we may see a paradoxical increase in the consumption of such toxins which are believed to be beneficial. As consumption spreads through a population, the negative health consequences would come earlier in life, and with more frequency. Since we have no reason to assume adaptation in all cases (to the contrary, we must assume non-adaptation as the null hypothesis), it is possible that the paradoxical increase in consumption lead to unsustainable population levels within the species.

We are certain of two points: Neanderthals ate grains, and Neanderthals are extinct. To date, there is a complete lack of evidentiary support for hypotheses involving any benefits to the introduction of grains into the Neanderthal diet. Thus, we find all hypotheses of our colleagues that indicate grain consumption provided any survival or reproductive benefits to Neanderthals to be strange and unfounded. Since Homo neanderthalensis is extinct, and the deleterious effects of grain consumption can still be seen in the modern Homo lineage, it is more reasonable to conclude that increased consumption of grains in the Neanderthal diet played a role in their extinction.

Discussion

Grain consumption may result in death and subsequent fossilization of you and your species. Further research is required.

Acknowledgements

This research was funded by evolvify.com in connection with the upcoming book, ‘The Extinction Diet: How to Lose Weight and Save the Planet Through Individual Death and Species Extinction’.