06 February 2012

How to Feed a Pregnant Neanderthal


200,000 years of eating for two.

It's hard to imagine what 200,000 years means in human lifetimes but, between ca. 250,000 and 40,000 years ago, the only human beings living in Europe were Neanderthals.  From the Ukraine across to southern Spain, this land was their land.  Then, in an archaeological flash, ca. 28,000 BP (Before Present), the world had utterly changed.  Populations of anatomically modern Homo sapiens were everywhere on the continent -- and the Neanderthals had entirely disappeared.

What happened?

One answer may simply be the consequence of different rates of fertility and mother-and-child mortality between Neanderthals and Anatomically Modern Homo sapiens (AMHS).  While many factors are involved, it now seems we can point an accusing finger at defects in Neanderthal nutrition.  What a mother-to-be eats has possibly the greatest impact on both her survival and her fetus, as well as, of course, on the new-born and infant child later feeding at her breast. 

What was the daily diet for a pregnant Neanderthal woman?  Or, to put it personally, what was Wilma eating (above, read about Wilma here) when she had a bun in her oven?

Hunter-Gatherer Calories

Producing and breast-feeding offspring requires an awful lot of energy, especially in large-brained species like Neanderthals and Homo sapiens.  Even more so when, like recent hunter-gatherers, you're physically active most of the time. When translated into calories, healthy gestation in such circumstances requires the mama-to-be to eat an extra 1750 calories per day (whereas a pregnant woman in cushy modern Europe needs only 300 extra daily calories).  Neanderthal pregnant women required much, much more: their  average daily caloric intake was hugely above even what is needed by modern human foragers. 

So how did Wilma cope with that?


She went on hunting, I'm afraid.

A new study tells us that she was eating too much of the wrong kinds of food:*
... from the perspective of a modern fast food diet, a pregnant Neanderthal women would need to eat 10 large burgers per day (or three in the morning, three at mid-day, and four in the evening).
Wilma had to consume a whopping 5,500 calories each day.  That is an enormous quantity to supply, especially for a hunter-gatherer, and very much more than was needed by the anatomically modern Homo sapiens then making their way into Europe. The difference is due to such factors as the Neanderthal's more robust and massively muscular body, higher metabolic rates, less efficient body-temperature regulation, a lifestyle of constantly pursuing large game animals in close-range encounters, and reduced sexual division of labour.

Would Wilma have been better off staying in the cave, sewing warm clothing, than going out hunting like a lioness?

For a quarter of a million years, Neanderthals -- men and women -- were highly effective hunters.  Throughout this enormous period of time, the next meal depended on killing large to medium-sized land animals (red deer, ibex, roe deer, wild boar, tahr, and chamois, together with larger game such as bison, horse, rhino, and elephant).  Most of the time, Neanderthals would probably have enjoyed adequate calorie and protein intake.  Their highly carnivorous diet, however, lacked adequate intake of micronutrients such as vitamins A, C, and E, which means that many Neanderthal women probably had high incidences of abortions, miscarriages, and stillbirths resulting in high fetal-to-infant mortality.
This means that no matter what land mammals they would have hunted, Neanderthals would still have not been able to get the micronutrients to stay alive, especially with the metabolic needs of a pregnant Neanderthal.
This was clearly not a winning strategy, but Neanderthals weren't stupid: we have plenty of archaeological indications that they also routinely consumed other kinds of foods (plants, shellfish, and even sea mammals** -- all of which are rich in various essential nutrients not found in terrestrial mammals) when these were available.  Given the cold environments of Pleistocene Europe before ca. 40,000-30,000 BP, the Neanderthals were probably doing the best they could.  And that was good enough as long as the competition consisted of non-human predators such as wolves, lions, and hyenas. 

It's the Demographic Payoff that counts.  

Virtual reconstruction of Neanderthal child skeletons
left: age 1 week; right age 19 months
In a nutshell, the Neanderthals may have been doomed by their subsistence strategy when they were simultaneously confronted with a warming climate and the newly arriving Anatomically Modern Homo sapiens.  Compared to the wider range of foods consumed by AMHS, yummy Neanderthal meals of mammal meat and organs didn't look so good.  Humans need more than just calories to thrive, and none more so than pregnant women and lactating mothers, and their newborn and infants.  Regardless of the protein and fat provided, the Neanderthal diet was inferior to the more diverse, greener diets of the AMHS, especially in the essential micronutrients that decrease maternal and fetus-to-infant mortality, as well as increase average life expectancy.  The proof of the pudding is that fewer people would be added to the breeding stock in succeeding generations.  Healthier, longer-living AMHS populations would thus, sooner or later, swamp the Neanderthals.

Neanderthals either did not or could not initiate the lifestyle changes that would have allowed them to compete demographically with the newcomers.  So, our ancestors certainly weren't stronger and maybe not even smarter than Neanderthals; just hungrier.

Still, Wilma's not to blame for misjudging the effects of climate change.  And a reign of a quarter of a million years in Europe is nothing to sneeze at.  We should be so lucky.



* Bryan Hockett, 'The consequences of Middle Paleolithic diets on pregnant Neanderthal women', Quaternary International, 19 July 2011 (abstract available at ScienceDirect). I am especially grateful to Julien Riel-Salvatore, blogging at A Very Remote Period Indeed, for alerting me to this paper and for his incisive discussion of its significance.  Other sources include B. Hockett & J.A. Haws, 'Nutritional ecology and the human demography of
Neandertal extinction', Quaternary International 137 (2005) 21–34; available online; A.W. Froehle & S.E. Churchill, 'Energetic Competition Between Neandertals and Anatomically Modern Humans' PaleoAnthropology 112, 2009.

** On plants in their diet, see '
The Raw and the Cooked: Caveman Redux'; shellfish, see 'Neanderthals Shellfishing 150,000 years ago', and 'Shellfish gathering, paleoanthropologicalstrawman'; sea mammals: Modern Is As Modern Does?'.

Illustrations


Above left: Wilma, a Neanderthal reconstruction based on both fossil anatomy and ancient DNA. Reconstruction by Kennis and Kennis, photo credit: Joe McNalley.  Via
National Geographic website.

Centre: Wilma, dressed-up for summer hunting.  Credits as above.


Below left: from 'Childbirth was already difficult for the Neanderthals'. Photo credit: University of Zurich, via Science Centric News, 9 Sept. 2008.
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5 comments:

Vicky Alvear Shecter said...

Fascinating! Going to repost on FB and Twitter.

Julien Riel-Salvatore said...

Thanks for the link-back, and I agree that it's a really interesting way to look at the issue! I think some of these dietary estimates look intuitively satisfying because of how they're calculated, but breaking them down in term of actual things that people would have needed to eat really drives home the point that we may still be quite a way from the answer.

JRS

Nick Savage said...

"Applying a nutritional ecology perspective to the issue, a modeled diet consisting of 5500 calories per day derived exclusively from large, terrestrial herbivores indicates that such a diet would kill a pregnant Neanderthal woman and her developing fetus." according to Mr Hocking.
But they race seems to have survived 210,000 years.
There must be a mistake.

Judith Weingarten said...

@ Nick, thanks for commenting. Exactly, that's the point made by Julien Riel-Salvatore in his blog post (first footnote) and his comment, above. Also, there is new evidence that Neanderthals had a more varied diet (second footnote) than previously thought. Keep in mind, too, that the 5500 daily calories is a theoretical calculation - subject to modification - since there is no Neanderthal 'Otzi' whose stomach contents can be studied. Judith

Anonymous said...

This is faulty and un-informed reasoning.
If all meat/animal protein & fat diets will kill off a human species then why do tribes such as the eskimo, the dinka, the mongols and other nomadic hunting people survive and even thrive?
Homo sapiens are omnivores and yet are quite adaptable, they can adjust and thrive on most diets granted that they contain important proteins and fats for biological functions.
This is an agenda piece - we beat the primitive and physically stronger Neanderthals because they didn't eat their veggies.
I would submit the opposite theory: The Neanderthals died out over time due to malnutrition as the climate changed and their hunting ranges diminished. Chances are that they had to forage for lower nutritiona value food such as vegetable greens, roots and fruits. But the lack of high quality proteins and fats in their diets contributed to reproductive and hormonal problems. Add in increased pressure for hunting space from Homo sapiens and possible out-breeding with the same Homo Sapiens and over millenia they fade out as a Human species. They're not quite gone, modern humans contain some Neanderthal DNA.

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