Mangroving: Discovering the Greatest Wilderness

The Greatest Wilderness on Earth

The DNA in you is a coded description of ancient worlds in which your ancestors lived.
DNA is the wisdom out of the old days, and I mean very old days indeed.
     – Richard Dawkins

What is it that makes humans so unique? More than any other animal, we are curious: constantly playing, driven to explore. We are visual: our eyes perceive depth, see in full color, recognize patterns and orient us in space. We are tactile: we grasp the world, and create it anew, with our agile hands. We are social: we live in groups; we need each other, and we love to talk to each other. And we are intellectual: we split the world into categories and understand the connections between them. How did we become such exceptional animals? My hypothesis is that these abilities originated long before we ever walked upright on the ground. They evolved as adaptations in our pre-human ancestors – primates who lived in the trees – precisely because trees are such an exceptionally complex environment to live in.

We humans have walked upright on two legs for the past six million years. Before that, and for at least ten times as long – sixty million years – our primate ancestors spent their lives in trees; a challenging habitat. They climbed and swung through a three-dimensional maze of branches, high above the earth, judging the distance between each handhold and the next. They grew curious, and became the tinkerers of the animal kingdom, the better to exploit the diversity of the forest. They learned to remember where and when the fruit became ripe from year to year. Their fingers became nimble enough to peel the thorns off of edible plants, to catch insects and frogs, and to steal bird eggs. They wove leafy branches into nests to sleep in at night. They lived in troops where they knew every member, and called back and forth through the treetops to communicate with each other. It was the demands of living in forests that forced our ancestors to evolve that great agility of body and mind – which we have inherited from them. We didn’t start becoming exceptional only when we began to walk upright on the savannah, but long before, and I believe it was our long apprenticeship in the trees that ultimately made possible what it is to be human.

What led me to this hypothesis in the first place wasn’t my interest in science or nature. It was a recurring dream I had when I was ten years old. I dreamt that my living room at home had turned into a swamp. When I stepped onto the carpet, it gave way under my feet like a layer of damp leaves over mud. Tall trees stood here and there in the murky light, with long vines hanging down. I climbed onto a root and swung up into the branches like an ape, leaping from branch to branch, the skin of my palms gripping the rough bark. I felt the taste of a primal knowledge. I felt completely free.

That sense of freedom is intoxicating for me. I’ve always felt like a captive animal in my culture, trapped in clothes, shoes, chairs, rooms. Our cities are built exactly to fit us, which, paradoxically, makes them almost too comfortable to live in. There’s no rocky ground to navigate, no branches to stoop under, no flowing water to cross. When you walk along the paved streets, your brain and your senses don’t have enough to grab on to; the landscape is too predictable, lacking the roughness of texture that you find in nature. The word wilderness has many contradictory meanings, and is loaded with outdated perceptions, but it means something straightforward to me: a natural environment so complex that it engages your body and mind in navigating the obstacles, making you move more freely and fluidly than you could on the ground. This is the story of my journey to find the greatest wilderness on earth.

Around the same time as my dream, I became fascinated with the study of human evolution. The books on my bedroom shelf were filled with pictures of chimpanzees in African forests, fossil hominid skulls, and family diagrams of ancestors who have gone extinct. It all conjured up a remote past when we were more animal than human – when we lived not on the ground, like most mammals, but in the trees, up in the sky. The strangeness of it gripped my imagination, and over the years the different threads came together: wondering how our ancestors had evolved, and wanting to climb in trees myself.

Somewhere I read about mangrove forests – a swamp ecosystem that resembles a jungle gym – and I recognized them as the forest in my dream. (As it happens, our primate ancestors evolved in high-canopy rainforest, not mangroves. However, mangroves are a good approximation, and, with their engaging complexity, an excellent fit for my definition of wilderness). But as the years passed I had only brief, tantalizing encounters with them: doing graduate research in Mexico, leading a kayaking trip in Florida, replanting mangrove seedlings in Brazil. I wanted to get to know the mangroves with my own hands, and find out why they mean so much to me.

For the past few years, I’ve been taking trips to Mexico to climb in mangroves. We camp on the beach, paddle down the river and string up a high-tension tent floor1 between the tree trunks. The tent floor is essential, because the point of mangroving is not just to climb, but also to be able to rest in this radically different environment. When you are lying down on the tent floor, like a chimpanzee in his tree nest, what you see around you looks like high-canopy rainforest, except right at ground level. Branches everywhere sprout from the trunks and stretch upward, supporting a roof of leaves overhead through which the sun shines green. Below, roots sprout from the trunks and arc downward, diving into the water and the mud beneath. You are surrounded not by walls, ceiling or floor, but by living branches, swaying gently with the movement of wind and water; everywhere permeable, everywhere alive, endless, and inviting.

You step onto a root, grab a branch and pull yourself up, hand over hand, into the canopy. The space around you is crisscrossed with branches in every direction – like the thicket of thoughts that fills your mind. It can be a difficult art to pick your way from one to the next.

After a while, you feel a shift. Your brain calms down, and your body finds its own way: hands reaching from branch to branch, feet hooking onto roots, your whole weight is borne from above as your limbs maneuver through space. You learn what a rock climber knows: that your foot can grasp, that your elbow can grip. But rocks are all surface; this is a living network that you explore from the inside. And as climbing becomes play, you feel the joy of swinging through the trees, in the kind of place that was once our home.

So, our relationship to trees is complex and meaningful, but it’s a history that we’ve left far behind; why should we care about it? I think this ancient history is still deeply significant for us today. The forest is the place where our curiosity and creativity began to evolve, precisely as adaptations for navigating the intricacy of that environment. Sixty million years spent living in the trees built into the primates an exceptionally strong urge to explore, which they exercise by playing throughout a childhood that is the longest found in any mammal. We humans elongate our childhood even further; as children we remain dependent for longer, and engage in play that is more intense and all-engrossing, than that of any other primate. And, uniquely, we continue doing this throughout our whole lives. Even as adults, we explore and experiment by making music, painting pictures, playing sports and telling stories, turning our childish play into our brilliance as a species. The capacities that ultimately led to all this complexity began to evolve long before we did; they were required of our ancestors to survive in their forest home. Those sixty million years in the trees were a kind of apprenticeship – the childhood of humanity. Just as our forgotten infancy, our profound dependence on mother and father, has largely shaped us as adults, so our forgotten infancy in the trees has helped make us the humans we have become. Not yet able to alter the world with fire, digging-sticks and arrowheads, we were, in those ancient beginnings, most dependent on the fruits of the forest. And in our utter dependence, we formed an intimate connection with the home that cradled and sheltered us, naked, in its branches.

Even living in cities, we know it’s true that we ultimately depend upon the natural environment to keep us alive. But climbing in trees makes us face that truth in the original sense of the word “depend”: to hang down. Hanging from living tree branches is a vivid illustration of what it means to depend on nature. You and I, with our flexible shoulder joints, grasping hands and good visual depth perception, are still well-adapted to climb in trees. And when we do, we rediscover a talent most of us never knew we had: how to depend on nature with nothing intervening in between.

I set out to find the greatest wilderness on earth. What has my search turned up? The greatest wilderness is not a tropical rainforest, or vast desert, or thundering waterfall. And, perhaps in seeming contradiction to what I’ve been saying here, neither is it a mangrove forest. Climbing in mangroves is a way for us to explore the greatest wilderness on earth, which actually exists inside our bodies and our minds: the hidden boundary in all of us between human and animal.

This needs to be understood correctly. I don’t mean it poetically, or to evoke some sort of spiritual truth, but rather as a precise definition. We humans still carry in each cell, alongside the genes that make us human, much older genes that encode skills for tree-living; adaptations for traversing a canopy of branches; ancient memories of our forest home. Those instructions remain in us from a time long before we walked on the ground as civilized humans full of rational purpose; when we foraged in the trees as wild animals full of intuitive energy. That ancestral primate nature at our core, that wilderness buried within ourselves, is the one that I believe we most crucially need to discover. We humans will continue to explore, and might even succeed, one day, in walking on other planets, without ever coming closer to a deeply felt understanding of our kinship with life on this planet. We are distant relatives of starfish, closer still to giraffes and whales; but we are very close cousins of the primates – who still know how it feels to inhabit the very same forest we once shared with them. The complexity of that forest mirrors the complexity of the wildness within, which is the greatest wilderness on earth.

Postscript: my goal with the Mangroving Project is to guide people in climbing and give them a deep understanding of our evolutionary history. I’ve led three trips to the mangroves in Mexico and plan to lead more. If you’d like to join me on the next trip, check out the website:, or contact me at to learn the details.

The Mangroving Project