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.

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!