Wild at heart

Oh victorious cow! In its bid for world domination this cunning ungulate has succeeded in training a great army of apes to do its bidding. These slavish primates, so reliant on the gifts of the udder, first killed off the cows’ predators, such as wolves and bears, and even exterminated those other large herbivores, mastodons and mammoths, that once offered competition for the best grasslands. Now the apes are clearing the world’s ancient forests and turning them over to pasture where their bovine masters might graze. They act as if mesmerised by those big wet eyes.

In return for these services a certain sacrifice is made: some cows must be willing to die for the good of their kin. This is the price of power over the primates, who have become addicted to the meat and milk the cows provide. Thanks to this blood pact, the world cattle population has risen to well over a billion, and their dominion is rapidly spreading. But for those pesky vegetarians, their victory would be secure.

So might the relationship between humans and cows look were it not for our tendency to put ourselves at the centre of every story. Where biologists come across relationships like the one between us and our cattle elsewhere in nature, they describe them as “mutualist”, meaning that through their mutual interaction both species benefit. So we provide protection and pasture for cows in return for milk and meat, just as some species of ants provide protection and pasture for aphids in return for the sweet liquid they secrete.

Much as we like to see ourselves as standing above the rest of creation, an increasing amount of research is demonstrating that it is just such interactions that have made us what we are. To understand both our past and our present we must look to these other species – not just cows but also lions, worms, mushrooms and even microbes. As all four of the books under review contend, we need nature in order to be fully human.

This thesis is plausible – indeed important. We are not and never have been set apart from the web of life around us: “No species is an island,” as the biologist Rob Dunn puts it in The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Our Evolution. Even in our modern high-tech urban environments we remain entirely dependent upon these other organisms. “If cows went extinct tomorrow,” writes Dunn, “millions of humans would die.” Our dependence on a few varieties of the grass plant (wheat, rice and maize) is even more striking: if these disappeared, the great majority of humans would quickly starve.

For most of our evolutionary past, however, such relationships were both more varied and more immediate. Our bodies and brains have been fine-tuned over millennia to respond to thousands of species of trees, roots, birds, predators and bugs. The savannah, not the shopping mall, is our natural habitat. The central role of these other creatures in our evolutionary history is the subject of Pat Shipman’s The Animal Connection: A New Perspective on What Makes Us Human. An anthropologist specialising in our early ancestors, she begins with the simple observation that wherever in the world one finds people, there are always animals being milked, walked, herded or watched.

Take dogs, for example, of which there are now hundreds of millions worldwide, keeping us company everywhere from New York apartments to the plateau of Tibet. Shipman believes they were domesticated from wolves more than 30,000 years ago as they “helped hunters find or track prey and protected their home territory and their social group (which included humans)”. It is well understood how we have shaped these wolves: our ancestors would have favoured those that were friendly and useful to humans, so eventually creating the domestic dog of today. But less well studied is how this relationship changed us. Shipman argues that those humans who showed the right skills and sensitivity to manage wolves outlived and out-bred those who tried to go it alone; the result is a world of dog-lovers. Domestication runs two ways.

In her relaxed and balanced style, Shipman makes the case that the more animal-savvy of our ancestors consistently outperformed their rivals from the very dawn of humanity, when we tentatively came down from the trees. She claims that three giant leaps in human development were all about this animal connection: our mastery of stone tools (to kill or cut up these animals); our development of language and eventually writing (to communicate information about animal habits and habitats); and our domestication of other species. Together these laid the foundation for modern societies.

This is a bold hypothesis, and among the evidence she presents is also a great deal of speculation. But there are at least some cases where the results of these connections are clear – such as our alliance with the cow. DNA profiles suggest that 10,000 years ago, the vast majority of humans were lactose intolerant – genetically incapable of digesting milk beyond infancy. Yet in Europe and those areas colonised by Europeans, 95 per cent of the population now can (and do) happily consume dairy products into their dotage. So in these cow-rearing lands, humans with the ability to digest milk spread at the expense of their fussier cousins. In effect, just as we have bred cows for high milk yield, so they have “bred” us to digest this milk (and therefore to have a reason to care for them). And if we have evolved lactose tolerance through our interaction with the bovine, it is not crazy to think we might also have evolved a fondness for dogs, or a predilection for observing the behaviour of predators.

Even if the role of animals is only a fraction of the story, it offers an important and oft-neglected perspective on human development. In The Wild Life of Our Bodies, Rob Dunn extends that perspective beyond the farmyard to a host of other critters. It is not only our familiar furry friends whose company we have evolved to need, he argues, but even parasitic worms and bacteria. In this respect, our success in eliminating such organisms over the past century is not the unalloyed blessing it might seem. Our bodies have had no time to catch up with this unprecedented isolation – 100 years of hygiene is nothing compared with our aeons evolving in the wild. As a consequence, believes Dunn, we are malfunctioning.

As evidence he points to the diseases of modernity: “diabetes; autism; allergies; many anxiety disorders; autoimmune diseases; preeclampsia; tooth, jaw, and vision problems; and even heart disease”. The anxiety disorders he puts down to the removal of the original objects of our angst: big scary predators. Many of the other problems he believes are the result of an immune system which is out of kilter as it has evolved to live with a menagerie of now absent invaders.

Some people are, therefore, taking the matter into their own hands. One American asthma sufferer, for example, read that parasitic worms prevented the overreactions of the immune system that might be behind his condition. So he took a flight to Cameroon and wandered the latrines barefoot until he felt “the itch of worms crawling through his thin, once-affluent skin”. Apparently cured of asthma, he now runs a worm-therapy clinic in Mexico.

Though such stories are striking, some of Dunn’s prose is as wild as the subject matter – as if he thought he must compensate for the dryness of much scientific text with hyperbole and histrionics. He need not have – when the subject matter is allowed to speak for itself, it is fascinating. His conclusion, though, goes beyond the science to speculate on how we might re-wild our lives. First, we have to be a little less squeamish about the bugs and worms with which we have long shared our homes and even bodies. Second, we need to bring wild spaces into our towns and cities, with rooftop gardens, high-rise farms, greenery in every spare space and even the re­introduction of large predators such as wolves and bears.

It is for just such projects as these that Richard Louv, author of The Nature Principle: Human Restoration and the End of Nature-Deficit Disorder has long been campaigning. His previous book, Last Child in the Woods (2005), struck a chord with many people when he argued that our children are suffering from what he calls “nature-deficit disorder”. The Nature Principle extends the idea to grown-ups and tells us what to do about it.

Louv draws on research showing that even small-scale exposure to nature – a view of trees, a walk in the park – can make a difference to our physical and psychological well-being. He believes this insight is now catching on, and that soon doctors “will prescribe green exercise and other nature experiences”, while “developers and urban planners will create homes, neighbourhoods, suburbs and cities that are nature-inclusive”. In the meantime, we can all do our bit by planting a butterfly-friendly shrub or organising local walking groups.

Unlike Shipman’s and Dunn’s books, The Nature Principle does not pursue a grand theory. Rather it resembles a naturalist’s field book: a collection of anecdotes, evidence and personal stories that Louv has collected in his years of writing and campaigning. For a book about nature, it suffers from serious overcrowding, as endless characters come and go. But the cumulative effect is inspiring: Louv’s is not a counsel of despair but a gentle exhortation to get out and make the world a little bit greener.

This is simple but sensible advice now that we spend ever more time in front of screens. Yet perhaps even our technology can help bring us some of the benefits of nature. This is something the psychologist Peter Kahn has long been exploring in his research, clearly and passionately documented in Technological Nature: Adaptation and the Future of Human Life. He has, for example, measured the benefits of a window overlooking trees versus the same scene shown on a large plasma screen; the way people interact with a real dog compared with their responses to a robot dog; and even the effects of gardening by computer-steered remote control.

Like the other authors mentioned, Kahn is convinced by the evidence showing that experiencing nature is good for us. What he wanted to know is whether that goodness can be reproduced, given that we are now surrounded by computer screens, smartphones and other artefacts of the silicon age. His results are unequivocal: digital nature is better than nothing but not as good as the real thing. He therefore concludes that “if we employed technological nature only as a bonus on top of our interactions with actual nature, then we would be in good shape. Unfortunately, we keep degrading and destroying actual nature, and we are becoming increasingly impoverished for it.”

If Shipman and Dunn are right in proclaiming the importance of other species in every step of our evolution, then we should not be surprised that those of us surrounded by concrete and glass suffer from Louv’s nature-deficit disorder, nor, as Kahn concludes, that the digital version is a poor substitute. Although they represent quite different disciplines, they come to the same conclusion: that our bodies are crying out for the wild. So put some boots on and go outside. The cows are waiting.

Stephen Cave is a writer and philosopher based in Berlin. His book, ‘Immortality’, is published next year by Random House

The Animal Connection: A New Perspective on What Makes Us Human, by Pat Shipman, Norton, RRP£17.99, 336 pages

The Wild Life of Our Bodies: Predators, Parasites, and Partners That Shape Our Evolution, by Rob Dunn, HarperCollins, RRP£16.99, 304 pages

The Nature Principle: Human Restoration and the End of Nature-Deficit Disorder, by Richard Louv, Algonquin Books, RRP$24.95, 320 pages

Technological Nature: Adaptation and the Future of Human Life, by Peter H Kahn, MIT Press, RRP£17.95, 240 pages

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