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January 11, 2012
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Scicurious is a PhD in Physiology, and is currently a postdoc in biomedical research. She loves the brain. And so should you. Follow on Twitter @Scicurious.
Scicurious is a PhD in Physiology, and is currently a postdoc in biomedical research. She loves the brain. And so should you. Follow on Twitter @Scicurious.
The paleolithic diet is pretty popular among Americans right now. The basic idea is that humans during the Paleolithic (about 2.5 million years ago to 10,000 years ago), were healthier (and presumably skinnier) than we are now, and so if we eat what THEY ate (based on “hunter-gatherer” diets rather than our modern agriculturally based model), we might be healthier too. The diet consists of veggies, fruit, grass fed meat, and nuts, but with very little dairy or grains. And the diet is VERY heavy in FISH.
I’m not going to opine on whether or not the Paleolithic diet works. What I want to know is…is it very Paleolithic? SHOULD it be heavy in fish? Could early humans fish? And if so, how early are we talking about? Does the paleolithic diet really have room for tuna?
O’Conner et al. “Pelagic Fishing at 42,000 Years Before the Present and the Maritime Skills of Modern Humans” Science, 2011.
Modern humans mastered the art of the boat pretty quickly, around 50,000 years ago, and used it to do little piddly things like colonize Australia. But for all the evidence of boats, there is relatively little evidence of FISHING. Evidence of fishing before about 12,000 years ago (giving you only 2,000 years of a fish-centered Paleo diet) is extremely rare, and restricted mostly to shallow water species that wouldn’t require boats or a lot of technology to catch.
But now there are a group of new sites around Papua New Guinea and the surrounding islands which show some evidence for, not just fishing of shallow species, but deep sea species as well.
This area had variations in sea level during human development, but was always a set of islands. On some of these islands, there are caves with evidence of human habitation, often with shells and some shallow water fish (those which can be speared, for example), but no evidence of systematic fishing of deeper water species.
But in a cave on the island of East Timor, the site called Jarimalai has something a little different. The cave holds evidence of a VERY long period of human habitation, with carbon dating showing artifacts as old as 42,000 years before present all the way to the modern period (or at least around 5,000 years ago). Among the shells, beads, stone artifacts, and bone points, are fish bones. LOADS of fish bones. The authors recovered over 38,000 fish bones, representing almost 800 species of fish. And not all of these fish were shallow water specimens. In fact, there were a lot of Scombridae specimens, the tuna group, and these specimens reached back almost to the base of the bone pile, estimated to be, at the bottom, around 42,000 years old.
And it looks like tuna was a favorite dish. In the oldest portions of the site, 50% of the fish bones are tuna, and this continues up until around 9,000 years ago. After that, the tuna percentage drops off over time to about 25%, and instead the fish bones are dominated by shallow water species like parrotfish and grouper. There was even evidence of sharks and rays.
So now we know that humans as far back as 42,000 years ago were able to reliably eat tuna, a fish which is characteristic of the deep sea rather than the shallows. The question is, how were they caught? In the oldest layers, there is no evidence of fish hooks or other direct evidence (though they did uncover what is possibly the world’s oldest known fish hook, at around 16-23,000 years old). The authors hypothesize that the tuna might have been caught using nets, as tuna are in fact caught today. The tuna specimens are mostly juveniles (tuna tend to school within their own size, which means fish of the same age group will tend to go together), and the authors think that they could have been lured into shallower water using floating logs (a method known to attract tuna), and then netted. The shallower water specimens might have been speared instead, and later caught using fish hooks.
Possibly the world's oldest fishhook.
Of course this doesn’t rule out something like a massive, really lucky beaching of a young tuna school, but it may mean that humans as far back as 42,000 years ago had the technology and seafaring skill to net some pretty big fish. After all, have you ever SEEN a tuna?
That’s one major meal. And this could have been very important to the peoples of the region, as the islands tend to be small and don’t have a lot of large animals around for the eating. Most of the land-dwelling animals found in the remains are small things like bats, lizards, and snakes, and so fishing could have been pretty important for survival. And it means that yes, your Paleolithic diet merits the inclusion of some tuna. Early humans were dining on the chicken of the sea long before we first thought.
O’Connor, S., Ono, R., & Clarkson, C. (2011). Pelagic Fishing at 42,000 Years Before the Present and the Maritime Skills of Modern Humans Science, 334 (6059), 1117-1121 DOI: 10.1126/science.1207703
Acknowledgements:
Today’s post would not be possible without the help and insight of Brian Switek of Laelaps and Eric Michael Johnson of the Primate Diaries. They helped me to decipher the terms I wasn’t used to and made me consider new and interesting caveats to the research. Thanks guys!
About the Author: Scicurious is a PhD in Physiology, and is currently a postdoc in biomedical research. She loves the brain. And so should you. Follow on Twitter @Scicurious.
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The paleo diet encourages people to give up or cut back on foods containing grains and processed sugar. I can answer your question about whether it works or not – I’ve been paleo for two years and it does. There are endless quibbles about what cavemen really ate, but we know for sure that they did not start their day with a bagel.
Link to thisYou’ve made the common mistake of assuming the Paleo diet advocates ONLY foods that were regularly eaten before the advent of agriculture. While that may be the belief of some, the general consensus of the modern Paleo community is that we should use the suspected diet of Paleolithic man to give us clues as to what our optimal diet may be. As it turns out, for the most part the scientific data backs up the benefits of what we can learn from our ancestor’s diets. But that is simply a starting point, and we have to use our modern scientific capabilities to take it further. One of the biggest points of the paleo diet is to drastically reduce our Omega-6 intake, to bring our Omega-3 to Omega-6 ratios back into balance. There’s not much argument that Omega-3 is beneficial, but it’s really the balance of O-3:O-6 that is more important than the quantities themselves. Fish, to varying degrees by species, are a great source of O-3, and studies have shown that we absorb O-3 far better from whole food sources than from supplements, sometimes up to 9 times better, due to other nutrient cofactors found in the meat and fat (goes back to the “whole foods are better” argument). The Paleo diet seeks to cut back on O-6 (found in high concentration in grains, nuts, and particularly seed oils) rather than to simply band-aid the problem by trying to force more O-3 into the body. Of course, that’s just one of the many benefits of cutting back on grains and eating more fish.
So whether our ancestors ate tuna regularly is pretty much irrelevant.
Link to thisCould evidence of sea fishing be rare simply because most Paleolithic coastline sites are now undersea?
Link to thisBTW – I thought that to help solving world’s overpopulation and overuse of natural resources, one should encourage unhealthy foods, smoking, drinking, substance abuse, lack of exercise etc. among people around?
Link to thisJarzy New: Certainly a possibility. The sea levels have changed a lot, and they authors were very lucky in that this cave is above sea level, but near the coastline, and was STILL above sea level and near the coastline 42,000 years ago. There was a period of time when it was not near the coastline, and during that time it was apparently unoccurpied (between 32,000 and 17,000 years ago). So I imagine there might be sites that are not near coastlines at all now, but where you might find evidence of fishing, that may not have been investigated yet. And of course some of them might be underwater.
Link to thisIt’s an interesting finding, but doesn’t really tell us much. Human history goes back 3 million years or more. The Paleolithic period can be dated 2.6 million years ago to 10,000 years ago. So evidence of a small amount of fish eating 42,000 years ago is a start, but doesn’t really tell us what people ate.
But a few reasons this doesn’t matter to paleos (myself included). A central idea is that while we can’t know exactly what our ancestors were eating, we certainly know what they weren’t. The diet is largely about restricting foods (e.g. grains), eating more nutritional variants of foods (e.g. grassfed meat), adopting more natural behaviors (e.g. outdoor exercise), and then tinkering.
We also have found that there is no single ‘right’ paleo diet. It depends on people’s genetics and environment. Even today we see huge variation in hunter-gatherers diets. Some are high carb, while others high fat and protein. I myself can tolerate a small amount of dairy and prefer to restrict my fruits to maybe a couple pieces a week due to the high sugar content.
Link to thisAh, excellent! breachingblue said what I wanted to say: “We also have found that there is no single ‘right’ paleo diet. It depends on people’s genetics and environment. Even today we see huge variation in hunter-gatherers diets.”
This is one of the primary mistakes new Paleo Diet eaters make: that they think they are supposed to eat meat, tubers and little else, because that is what they learned was the traditional forager diet. But that’s not the traditional forager diet. That’s the traditional forager diet of a particular subset of foragers that we anthropologists LOVE to trot out whenever we ancestral humans, as though they are living fossils. Other foragers survive mostly on blubber. Still others eat a huge quantity of fruit. It mostly depends on what food you have access to where you live.
The other thing that’s neat about diet is that your body does adjust over time (and there may be genetic/epigenetic/maternal effects things going on too). So someone who eats one kind of diet (say, mostly whale blubber) for many years may not take well to a totally different diet (nuts, tubers and seeds). So those who used to eat very processed, American diets may want to ease into the “Paleo” diet.
Finally (and then I promise I’ll stop) it seems to me like the bigger issue, and the great thing that Paleo promotes, is eating real food that is minimally processed. So, eating an orange instead of orange juice, oatmeal from rolled oats rather than instant/cold cereal, etc. This should warn people away from products marketed to be Paleo-friendly that are, say, cookies (I have seen chocolate chip Paleo cookies sold, and they use almond meal instead of flour – makes it technically Paleo but not in the spirit of Paleo).
Thanks for covering this cool topic and new results, Sci!
Link to thisSo If I interpret this all correctly,people 42,000 years ago..give or take.. knew more about food, when the average lifespan was less than 40 years, by the way, and ate only what was locally available to avoid all the diseases associated with starvation. Sounds like the cult of the noble savage all over again..doesnt it?
Link to this@dclarke50
Link to thisOf course they new what to eat, the problem was not getting eaten while picking up some paleo fast food