Starvation is not nearly as common an occurence as “common sense” would suggest. As Bernard Angier puts it in the first line of his How to Stay Alive in the Woods, “It’s impossible to starve to death in a forest.” You’re surrounded by life, all the time–and as omnivores, we can eat almost all of it. So why is it that people starve to death? Most commonly, people starve to death surrounded by edible matter–just no food. There is the essential issue, because “food” is not just edible matter, it’s the culturally constructed subset of edible matter. That mismatch has garnered a small fortune for the producers of “Fear Factor.” Bull’s penis is entirely edible–it’s even a high-priced delicacy consumed by China’s elites to bestow sexual potency–but it isn’t “food.” At least not in our culture.

Some of the examples of this mismatch are simply astounding. The single most famous example of cannibalism in American history is that of the Donner party–a group of 31 settlers bound for California who became trapped in the Sierra Nevadas in the winter of 1947. As Wikipedia tells the story:

Cannibalism is the best known feature of the Donner Party story but the facts are often misrepresented. The emigrants ate everything else they could — animals, rawhide, bones, leather — before finally turning to the only food source that remained, the bodies of the dead. The documentary record makes it clear that cannibalism occurred among the snowshoers and at the Donner Lake camp; the evidence from the Alder Creek camp, though not as good, is still strong. Several survivors spoke or wrote of their own consumption of human flesh and dozens of people who visited the remains of the lake camp between 1847 and 1849 reported seeing the physical evidence.

But the Donner party died in the middle of a large pine grove. They used the pine trees for fuel and even cut many of them down–but they never used them for food. Pine bark and pine nuts are entirely edible. Nor were they unaware of this:

On 12th January, Eddy’s group reached a Paiute village. They took pity on the travellers and gave them a corn meal. This gave them the strength to move on and five days later found another village. This time they were given a meal of pine nuts. Eddy then paid a warrior a pouch of tobacco to act as a guide to Sutter’s Fort.

Despite this, and despite their desperation, they never ate the pine. Pine had long been a “starvation food” for Native Americans in these areas; when all else failed, you could always eat the pine. It was rarely the first choice, but in desperate circumstances, it would suffice. The Donner party was desperate, and ate every “food” they could think of–even rawhide, bones and leather. But they didn’t eat things that weren’t “food”–and pine simply wasn’t “food,” even though they had been fed a meal of pine nuts a short time before.

Or, consider the plight of the Viking colonists of Greenland, as related by Jared Diamond in Collapse. As Malcolm Gladwell relates it in his review for The New Yorker:

Diamond writes, for instance, of the fact that nobody can find fish remains in Norse archeological sites. One scientist sifted through tons of debris from the Vatnahverfi farm and found only three fish bones; another researcher analyzed thirty-five thousand bones from the garbage of another Norse farm and found two fish bones. How can this be? Greenland is a fisherman’s dream: Diamond describes running into a Danish tourist in Greenland who had just caught two Arctic char in a shallow pool with her bare hands. “Every archaeologist who comes to excavate in Greenland . . . starts out with his or her own idea about where all those missing fish bones might be hiding,” he writes. “Could the Norse have strictly confined their munching on fish to within a few feet of the shoreline, at sites now underwater because of land subsidence? Could they have faithfully saved all their fish bones for fertilizer, fuel, or feeding to cows?” It seems unlikely. There are no fish bones in Norse archeological remains, Diamond concludes, for the simple reason that the Norse didn’t eat fish. For one reason or another, they had a cultural taboo against it.

…

When archeologists looked through the ruins of the Western Settlement, they found plenty of the big wooden objects that were so valuable in Greenland–crucifixes, bowls, furniture, doors, roof timbers–which meant that the end came too quickly for anyone to do any scavenging. And, when the archeologists looked at the animal bones left in the debris, they found the bones of newborn calves, meaning that the Norse, in that final winter, had given up on the future. They found toe bones from cows, equal to the number of cow spaces in the barn, meaning that the Norse ate their cattle down to the hoofs, and they found the bones of dogs covered with knife marks, meaning that, in the end, they had to eat their pets. But not fish bones, of course.

The Greenland Vikings knew that fish was edible. They lived in full view of the Inuit, who lived happily as they starved to death. They called them skraelings–”wretches”–because they were naught but ignoble savages. Savages who survived–and quite happily–while the civilized Europeans died a long, agonizing death.

It’s not a lack of desperation that’s at fault here; it’s a lack of imagination. It’s the cultural construction of food. We like to point to such stories with modern pride, and think, “My, how stupid people were in those unenlightened days before my time! Why, to think they would starve to death just for cultural pride!” But consider what you might honestly have done in their place. If there was no bread to be found, and all you had were fields and fields of dandelions. Would it ever honestly occur to you that you can eat dandelions? Or would you starve, desperate for anything to eat.

In many ways, our cultural revulsion at the idea of cannibalism makes us more prone to actually do it, not less. It is part of our vision of “the savage.” Yet, because this floats around in our culture, we know that humans are food. Other people are, for us, the same kind of starvation food that pine nuts were for the Amerindians. It’s certainly not our first choice, but in a pinch, we know we can eat each other.

We don’t know that we can eat pine bark, or dandelions, or plantain, or burdock root, or any of the other thousands of plant and animal species that surround us–even in the middle of the city. Walking to work every day, I pass an enormous stand of Lady’s Thumb, growing up out of the cracks around a parking meter. It would be enough to feed Giuli and I for a week, if it weren’t so close to the road and choked with exhaust fumes (and why we haven’t gathered it). That doesn’t stop us from collecting acorns from the nearby parks, leeching the tannin and making a delicious, honey-covered and nutritious candy out of them. But when we do gather food, we get lots of dirty looks. The reactions range from shock to horror, generally. What? How can you do such a thing? That could be poisonous! How can you eat that? That’s not food!

It makes sense that we would feel food tabboos so deeply. Evolutionarily, our brains have adapted to incorporate culture on a very deep level, and beliefs about food are extremely important. A feeling of disgust can be the only thing that keeps you from dying of poison. The same way that a computer is built to take an ephemeral piece of software and express it on physical hardware, we have adapted to take whatever arbitrary food tabboos our culture has developed and feel them on a very deep level, such that most of us have a difficult time understanding how such reactions can be anything but universal instinct. There are people in the world who eat insects? Gross! Don’t they know that’s disgusting?

No; because it’s only disgusting to us. To them, it’s food.

Usually, food tabboos are about staying alive. Most of the Jewish kosher laws can be understood in this dimension. Pork is difficult to prepare properly, and may lead to food poisioning–so it’s best left alone entirely. Cooking meat and dairy together can lead to all kinds of problems. But this doesn’t explain all the kosher laws. Many can only be understood as cultural identification. As the Wikipedia article on “Kashrut” puts it:

According to the Biblical book of Leviticus, the purpose of the laws is related to ritual purity and holiness. Indeed, the Hebrew word for “holiness” is etymologically related to the Hebrew word for “distinction” or “separation.” This idea is generally accepted by most Jews today, and by many modern biblical scholars. Cultural anthropologist Mary Douglas has written an important work on just how the Israelites may have used the idea of distinction as a way to create holiness. Her seminal work, Purity and Danger (1966), is still studied today. One theory widely accepted today is that the laws serve as a distinction between the Israelites and the non-Israelite nations of the world. Gordon Wenham writes: “The laws reminded Israel what sort of behaviour was expected of her, that she had been chosen to be holy in an unclean world.”

Why would any culture so limit their possible food choices, though? Why would any culture run the risk of annihilation–like the Greenland Vikings, or the Donner party–for something as petty as food taboos? Cultural identity is very important. It solidifies group cohesion just as much as tribalism. It acts as a counter-force to group fissioning, and gives individuals an incentive to stay in the group and work out their problems. That makes it important in making sure society doesn’t fly apart at the seams.

But this understanding of food tabboos and their adaptive purpose only makes sense if the tabboos are relatively random and benign–if there are only a few foods that are banned, but still a wide range of possibilities left. This is not the case with our own culture. While we have a large periphery, nearly all the food consumed in the world today is either wheat, corn or rice. For meat, we have very little beyond the cow and the chicken. We look askance on anything that is not domesticated and grown on a farm.

We still have the same kind of narrow definition of “food” that killed the Vikings in Greenland. Slightly different–different enough for us to feel a misplaced bit of superiority for their reluctance to eat fish–but generally on the same order. How many of us would think we could eat rattlesnake? Or that bear liver is such a nutritious and tasty meal?

Why would a culture restrict their definition of “food” to such a narrow range of the wide diversity of possibilities? Why would we limit ourselves only to a tiny handful of closely related domesticates, and thus become the only adaptive strategy susceptible to wide-spread famine?

The answer to that is simple.

Control.