The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Who We Are Today

by Rob Dunn

  The students worked hard. In a time before Google, their first step was to travel to a basement—the map room of the New York Public Library—to figure out the surface area of the roofs of Manhattan. They needed to know how much roof could be farmed. As they gathered and measured roof after roof, the answer seemed as though it was a great deal. They were not just finding roofs—there were also balconies, abandoned lots, and old railway lines. The city, for all its modernity, was filled with layers and levels of dirt, and so too the possibility of layers and levels of life. The students came back to class, week after week, ever more excited, until they found the total amount of farm that was possible in Manhattan.

  The students summed and resummed. They calculated pounds of crops. What they were not able to do was turn those pounds of crops and other benefits of rooftop gardens into dollar values. A recent three-year million-dollar Toronto study, however, provided help. The study by the Department of Architectural Science at Ryerson University found that if all of the rooftops in Toronto were greened, the economic value would be substantial. Storm-water capture would lead to a net benefit initially of $118 million. Reduction in sewer overflow would save an additional $46 million. In cold Toronto and probably also in cold New York, tens of millions more would be saved in energy costs. All told, Toronto’s savings was roughly $300 million initially, and then tens of millions of dollars each year.3 Although no one had calculated it, the much greater surface area of New York’s buildings would produce, undoubtedly, a much bigger savings. This was all on top of the benefits of actually producing food.

  But then Despommier, still with a bit of realism’s doom in his heart, asked, “How many of the people in New York City would it feed? How many of these eight million individual primates could eat from the city’s vines and trees?” The answer they were looking for was a big number, 3 million or even more, maybe all of the city. The reality was humbling. It was just 2 percent, 2 percent of the food of the city. Two percent was meager—an organic mango where what was needed was miles of grains.

  Despommier could have left the students to wallow in the realities of the magnitudes, the big numbers of demand and the small numbers of supply. Something compelled him, though, to do otherwise. He asked a new question. “What if we turned whole buildings into farms? What if we used hydroponics and made abandoned buildings into biomes and grew vertical farms, up walls or even inside walls, in the way that forests grow vertically?” The students were still high on hope, and so this sort of nudge was all they would need to take a wild leap.

  Until this point, Despommier had played a passive role in the students’ endeavors. He helped and guided, but the students’ obsession was not his, not at all. He had another class to think about and he was still, privately, imagining all of the projects he still wanted to do on worms. If the National Science Foundation had funded him at that point, he might even have abandoned his class midstream. They did not, and so he kept at the class, more involved at each stage, until he found himself sucked into the students’ questions. He found himself actually wondering, as he talked to his wife across the dinner table, what one could do with a little hope and some seeds.

  Despommier had begun to think about the project all the time. He looked up at the buildings around him in Manhattan. The buildings were filled with human bodies and the species that lived off of them—worms, mites, bacteria, and flies—but they did not give back, not life anyway. They just took. Each day, thousands of pounds of food and millions of gallons of water were shipped and carried up elevators, staircases, and pipes, and near-equal amounts of waste were shipped down toilets. Each building sucked the juices out of the land outside the city, sucked at the land around the world. This was what he knew and had known—the gloom of the world, the dark and foreboding realities of our condition, the beaten down farm fields, the plowed-under forests, and the poor farmers from India to Brazil. He knew this and yet ideas turned through his head like windmills. Here he was, caught up in the dreams of students, and all he could think to do, rather than slowing down, was to raise his wooden sword and charge.

  What would one really need to do to grow food in cities, lots of food, and in doing so make them like any other ecosystem that produces instead of simply taking? He began to make sketches on napkins. He was done submitting grants for his science on worms. His life was changing under him—the landscape he had known for all his professional life was substituted for something else entirely, a terrain as new and different as the canals once thought to exist on Mars. Hopefully, it was not also as illusory.

  There were models for what Despommier and the students were working on (other than Don Quixote), but not many. There was the landscape architect Fredrick Olmsted, who came back from the Civil War and built the greatest parks of the United States in Chicago, New York, New Jersey, and elsewhere. Olmsted, though, was different from Despommier. He built the parks as public goods, paid for with public money. He built them in such a way as to appeal purely and directly to our ancestral preferences for grass, a smattering of grovelike trees and water, but his parks did not make money. Nor did they feed people. Like museums, they relied on public funds forever. Someone will always have to pay to trim the trees and keep the paths open for walking. The grass too needs to be mowed, a task that was once accomplished by one of our mutualists, sheep, but that eventually gave way to machines and the price of their gas. This model was not quite what Despommier wanted, though it was recognizable in its grandness. After all, that Olmsted was able to transform entire cities suggested that it was possible. It suggested that a single woman or man with a plan could shape the interactions of people with each other and the rest of life for tens, hundreds, or even thousands of years.

  The other models came from other animals rather than architecture, agriculture, or design. Leaf-cutter ants have grown entirely reliant on their farmed food, without alternative, fallback, or recourse. The same is true for leaf-farming termites and the many fungus-farming beetles. None of these societies can return to hunting or gathering any more than we can. They are dependent on the fungus that grows on the leaves they bring back to their nest or the wood in which they tunnel. They feed it to their larvae and nymphs, scattered in colonies throughout the tropics, one small white clump at a time. What is interesting about the farming by leaf-cutter ants, termites, and all the animals that farm successfully is that they do it where they live, at the heart of their cities. They farm in the realm in which they have the most control and in which pathogens are kept most easily at bay. One can speculate as to the specific evolutionary forces that created this scenario. It is hard to imagine, in a way, an ant species ever farming a fungus outside of its nest for the very reasons that our own farms face such difficulties. Outside the nest, pathogens abound. Outside of the nest, the distance between food and child is greater. Outside of the nest, it gets too hot or too cold. Inside the nest, the fungus can be tended to, nursed the way one might a chosen child. Suffice it to say that for some or all of these reasons, every time farming has evolved, species have farmed where they live—every time except in our own societies. We are the only animals that farm far from where we live. In doing so, we have divided our world into the places that produce and, separately (in our cities), the places where we consume food and make waste. No animals have ever chosen to live beside their waste rather than beside their food. If there were ever any ants, beetles, or termites that ran their cities in the way we do, they are gone. They became extinct.

  What the class and Despommier would come to propose was a thirty-story tower, or in the parlance of ant nests, a garden chamber. The tower would be the beginning of what would someday be a series of towers that would produce fruit, veggies, grains, and all the rest. It was to be a tower of food, much like the leaf-cutter ants’ and leaf-farming termites’ towers of fungi. Despommier and his class would design these buildings in such a way that they cleaned wastewater, generated energy, and provided other services to society. Despommier and the class estimated that 150 of
these buildings could provide sustenance to all of New York City, a city in which there are many more than 150 abandoned buildings being used for nothing at all.

  The math was crude, the ideas coarse, and yet the amount of food that such a building seemed capable of producing was astounding. The more Despommier thought about it, particularly the more he thought about in the context of the doom and gloom he was used to, the more it seemed to make sense, and the more it seemed as though it would make even more sense in the future. Despommier knew that by 2050, the earth will house no fewer than 2 billion more people than it houses today, 2 billion people for whom we must find plots of land to produce food. Doing more of what we are doing today will not feed those people, not without cutting down most of the remaining forest on Earth. At the same time, most of those humans will be in cities, and so we need that food in cities. We also need forests and grasslands, wherever they might be. We need them for many reasons, but especially now to remove some of the carbon dioxide from the air, carbon dioxide produced in no small part by our traffic of food from where it is grown to where we consume it. Here then, at least on paper, was a kind of panacea.

  The idea was not totally without precedent. Crops have been grown in buildings for years, particularly in water (rather than soil) as hydroponics. As a New York Magazine article pointed out in one particularly telling example, a family in Florida farmed strawberries on a thirty-acre farm in Florida.4 They farmed strawberries there until Hurricane Andrew wiped them out. After the hurricane, they started fresh by growing strawberries indoors in a hydroponic system, in which the strawberries were stacked one layer on top of another. Indoors, they could grow the same quantity of strawberries on one acre that they used to grow on thirty. One thirtieth of the land was occupied in their new endeavor and the rest, from all appearances, lay fallow, each acre returning, slowly to forests, birds, and bees.

  Farming an entire thirty-story building hydroponically was a grand and, in some ways, quixotic vision. The popular press immediately became caught up in the mood of Despommier’s ideas and what, at some point during this journey, had become his hopefulness. Each time a new article ran, more people wrote in to say how excited they were. There were always cynics. The devil, they would claim, is in the details. The critics made some reasonable points. The buildings in major cities would have to compete for land with commercial properties. The land would be expensive. Yet it seemed possible to build a green building, somewhere, on some scale and maybe many places on many scales, maybe.

  Two things seemed to go missing in the discussion of the vision of Despommier and his students. The first was that Despommier did not really know what he was doing. He was a worm guy who also worked in farms, but the idea of designing an entire building, much less one in a major metropolitan area, was forty steps beyond what he really knew. The other was that what Despommier was proposing offered resolution not just to the problem of food, but, at least in part, to many of the problems humans face. They were the problems associated with a disconnect between our modern lives and the ones we once lived, but more specifically our disconnect with other species. In essence, what Despommier had proposed was to consciously build back into our lives one set of those species that benefit us, our food plants. He would do so while keeping at bay those species that would do us harm, or at least those that would do our crops harm, by creating his farms indoors. In theory, no pesticides would even be necessary. Despommier stopped at farming food. That was enough of a vision for one man, but when his vision is combined with those of others, one can look forward to an urban landscape in which key elements of our lives are resurrected around us.

  Despommier’s vision, though, was still that of a worm man dreaming big. He did not know architecture. He did not know plumbing. He did not know solar power. He did not know any of what he would need to know to make this new dream more tangible. Then big architectural firms started to call him and help with the logistics of designs. The designs have improved, and logistical necessities have been tended to. What was more, other people started to run with his ideas. The Internet is now populated with hundreds of images of plans for vertical gardens or farms, bits and pieces of which appear to be popping up in actual buildings, if not yet at the scale Despommier envisioned. Finally, Despommier was invited to meet the mayor of Newark, New Jersey. New Jersey, for all of its downsides, is the garden state, though it would be hard to call Newark the garden city. The mayor wanted to make changes. The worm man whose name means “of the apple tree (Des pommier),” had an idea that just might take seed.

  Before we come back to the meeting in Newark, it seems worth revisiting not just where we are ecologically, but where we will go if we continue with business as usual. As I hope I have convinced you by now, business as usual for the past hundred thousand years has meant that we kill off what we can, farm what best suits our taste buds, and then accidentally favor the sneaky species that survive despite our best intentions. With newer tools, what we can kill grows more diverse and smaller. So too the sneaky go from being rats, to rats and antibiotic-resistant bacteria. This has created our modern urban situation, one in which the only species that are most abundant are those that persist despite us (rats, pigeons, drug-resistant bacteria, drug-resistant roaches, and bedbugs). In old cities, the biggest areas of wild nature are uncleaned alleys and the waste piles of a variety of sorts, where a kind of wildness reigns. In other words, the species present around us are there for reasons other than our active planning. The species we manage because we like them live far away. Business as usual will push the crops to more remote places and the remaining life out of cities. This has already happened in some new cities in China, Brazil, and elsewhere.

  It is sometimes suggested that what we need to do in cities is to restore “nature.” A body of literature and theory often referred to as “biophilia” posits that we have an innate fondness for nature, and so restoring nature to our lives makes us happier and healthier. I disagree for what might seem to be (but is not) a subtle reason. Namely, by any reasonable definition, the species that have filled in around us in cities are nature. The species that live on our bodies are also nature, as are both smallpox and toucans. What is missing from our lives is not nature, but instead a kind of nature that most benefits us. By that same token, the life we love to have in our neighborhoods and daily lives (bio = life, philia = to love) is not all life, but the life that benefits us in some way. When tigers chased us, we had no innate love for them. When diseases killed our families, we had no love for them either. And so what we need in our cities and suburbs as we move forward is not simply “more nature.” More rats would be more nature, as would more roaches and mosquito-vectored diseases. No, what we need are more of some aspects of nature, its richness and variety and, more pointedly, its benefits.

  When we think about benefits, we cannot think simply about what our eyes tell us. The species that benefit us in the future may well include worms, ants, and our gut microbes. They may include, in other words, a much more burgeoning ark of life than we tend to consider when we plan parks and gardens. In our guts, we may really need to give ourselves worms. That we hesitate at this point is largely a function of what our eyes tell us, not of clinical results. We do not yet understand the way worms work as a treatment, but neither do we understand the ways in which most of our modern medicines work. Ask a researcher how Ritalin or pain medication works. In most cases, no one knows. We just know that when taken, a symptom or even a disease goes away. So it is, for now, with the worms.

  Inside our guts, we may be able to manage for specific bacterial species. We may be able to take probiotics that help the bacteria that benefit us, and disfavor those that would do us harm (or disfavor, in any case, the conditions under which such microbes tend to do us harm). As of now, the evidence for the benefits of one particular probiotic over another is ambiguous. Time will provide more nuance. Intellectually, it seems likely that when the composition of our gut fauna comes to deviate from that of a healthy gut, w
e ought to be able to manage the species of our guts in order to make ourselves healthy. Practically speaking, we are not there yet. In the meantime, the IgA antibodies and our appendix go on fighting the good fight to keep things working as they long have worked.

  In our brains, we still feel as though predators lurk nearby. Fear drums our hearts. It raises our levels of stress. This fear seems to be at the root of some of our psychological ill health. We cannot reintroduce predators into our brains in the way we add worms back into our guts. Instead, what we have tended to do is medicate ourselves. We have taken antianxiety pills by the billions. Such pills may have negative effects, but in the short run they tell the brain in essence that “the cougar is not there,” and so the brain rests.

  In addition to giving ourselves worms and probiotics, we might manage the living world around us to be richer and more diverse with the kinds of interactions we once had. We can bring, if not wilderness, wildness back into our lives. Of course, maybe I am just caught up in Despommier’s chase. Maybe he is talking about organic mangos for Whole Foods, not wheat for the masses. Maybe, one might say, at least until Despommier started talking to the mayor of Newark. Sometimes when one chases windmills, one catches them and finds that they can produce most of the energy for a city of people. So too sometimes when one chases a wild building filled with oats, it actually comes to be built.