My first glimpse of E. O. Wilson came in July, in the late afternoon, when the light fades and dies with alarming speed in Mozambique. He had emerged from his cabin within Gorongosa National Park, one of southern Africa’s great, historic game reserves, just as the nightly winter chill was bestirring itself, and across an expanse of garden, he appeared almost spectral: tall, gaunt, white-haired, and possessed of a strange gait—slow and deliberate, yet almost woozy in the faint swerve described by each long-legged stride.

Wilson’s head was cocked sharply downward as he walked, as if he suffered a neck condition. (Later he would tell me this habit grew from a lifetime of scanning the ground for insect life.) In his right hand, he carried a flowing white net, like what Vladimir Nabokov might have used to pursue butterflies by Lake Geneva. Without fanfare, just before dark, on the first evening of his first visit to Africa below the Sahara, he had begun his first bug-collecting expedition.

If one had to give E. O. Wilson a single label, evolutionary biologist would be as good as any. Sociobiologist, lifelong naturalist, prolific author, committed educator, and high-profile public intellectual might all also serve. But amidst his astonishing range and volume of intellectual output, Wilson’s reputation, and most of his big ideas, have been founded primarily on his study of ants, most famously his discoveries involving ant communication and the social organization of ant communities. As I caught up with him, intending to introduce myself, he stooped down low toward the garden’s dirt path to pick one up, pronouncing its scientific name with the raw delight of a boy hobbyist, and exclaiming, “I think I’ll keep that one. Let me go get a vial and some alcohol to put it in.”

Many more collecting forays would follow over the next two weeks, most of them more concerted than this. But other motives had also lured Wilson, age 82, so far from his home in Lexington, Massachusetts. It is hard to order such things with any precision, so varied and intertwined are Wilson’s interests, but the principal attractions, he told me, involved the chance to explore a rare and imperiled African ecosystem—one largely cut off from scientific study until late last year—and to play an advisory role in its conservation. What made this park, at the southern extremity of Africa’s Great Rift Valley, of particular interest to him was the chance to revisit a field that he helped invent—biogeography, and specifically the special ecology and biodiversity of islands.

Gorongosa’s heavily wooded mountain of the same name was effectively incorporated into the park, by national decree, only last December. It is home to the only largely intact rain forest in all of Mozambique, a semitropical country roughly the size of Texas and Oklahoma. Solitary and broad-shouldered, the mountain rises more than 6,000 feet above the surrounding plains, providing a local climate unlike any other for hundreds of miles around it. It draws its water from the warm, moist winds that blow in from the nearby Indian Ocean, kissing its cool upper flanks and sustaining a unique ecosystem of rare orchids, mountain cypress, and rich bird life like the green-headed oriole, along with any number of other species yet to be identified.

For many years, the religious taboos of local residents kept the mountain from being opened to scientists and tourists, and also offered some measure of environmental protection. Nonetheless, a helicopter ride I recently took revealed the mountain to be under steady attack by locals setting fires to clear fields for farming and to smoke out wild edibles, from bushmeat to insect delicacies. Time and again, Wilson has come back to the subject of ecological hot spots like this in his writing. More than half of the planet’s plant and animal species live in tropical rain forests, which occupy a mere 6 percent of the world’s land surface—territory roughly the size of the lower 48 American states. Across these unique havens of biodiversity, Wilson has estimated that an area equivalent to half the state of Florida is being destroyed each year.

Wilson described Mount Gorongosa’s rain forest to me as “an island in a sea of grasslands,” and said that “biologists should be straining to get there,” to study it and to save it, just as they would some new reef system discovered in an underexplored part of the Pacific. Of the need to thoroughly survey places like Gorongosa, he wrote in his 1984 book, Biophilia: “No process being addressed by modern science is more complicated or, in my opinion, more important.”

Wilson’s first book, The Theory of Island Biogeography, published in 1967, became one of the most influential works in ecological studies. It offered a formula that mathematically predicts a geometric reduction in the biodiversity of a given habitat as the size of the habitat shrinks. Part of Wilson’s work at Gorongosa involved launching a survey of life on the mountain, and also seeking to understand the special dynamics of a park that is small by the standards of its continent, but that nonetheless may contain thousands of species never before discovered, many of them unique to this lonely peak.

Throughout Wilson’s stay here, a team of filmmakers, whose presence attested to a different purpose, trailed him from day to day. Together, Wilson and the filmmakers have selected the park as one of the backdrops for an online, interactive digital textbook called Life on Earth that the Harvard professor emeritus hopes will revolutionize the teaching of biology in secondary schools worldwide.

For all of his projects here, Wilson has a benefactor whose enthusiasm runs as deep as his pockets: Greg Carr, a boyish 51-year-old who grew up in Idaho Falls and made a fortune in the 1980s and ’90s by developing corporate voice-mail systems. Since then, Carr has undertaken a variety of philanthropic activities, including the endowment of a human-rights center at Harvard that bears his name. But in recent years he has made the rehabilitation of Gorongosa Park his personal mission. Since he assumed joint operational control of the park in 2004, in partnership with the Mozambique government, Carr has spent, by his own estimate, perhaps $25 million on the park.

In its heyday in the early 1970s, the park, with its savannas and floodplains, provided one of the richest nature- and game-viewing experiences anywhere in Africa, due particularly to the abundance of its so-called charismatic animals—lions, cheetahs, leopards, elephants, wildebeests, zebras, and more. Back then, it was said that one day spent in Gorongosa was equivalent to three in South Africa’s larger and more famous Kruger National Park. In 1977, however, a rebel movement named Renamo launched a civil war from headquarters in Gorongosa, and things went calamitously downhill.

Nearly a million Mozambicans died as a result of the war, and five times that many people were displaced. “Basically every day, there was fighting in this area, and soldiers slaughtered the animals for food, while ordinary people hunted them because it was impossible to farm,” said Domingos João Muala, a Mozambican park worker and ethnologist. This led to the wholesale elimination of both large grazing mammals and their predators, although I chanced on a pride of lions, rare within the park today, on one cold morning as we emerged from a Land Rover by the ruins of an old park lodge fittingly known as the Lion House.

Mozambique’s civil war came to a negotiated end in 1992, and multiparty elections followed two years later. Rehabilitation work on the park began in 1994, including the hiring of staff and the reopening of roads. Poaching has been gradually suppressed but remains a problem even now. Carr’s ambition is to restore as much of the original ecosystem as possible, all the way up to the apex predators, like cheetahs, four of which his foundation recently acquired for release onto park plains already teeming again with antelope, warthog, and baboon.

Wilson’s faith in the power of conservation movements to restore and preserve places like Gorongosa waxed and waned during the week I spent with him. He talked about the impact of China’s burgeoning appetite for natural resources from Africa, and worried about Africa’s booming population, which is projected to go from roughly 1 billion today to twice that by mid-century. And he offered a dark caution about global warming and the unpredictable impact it will have on many ecosystems, no matter how carefully we try to protect them.

Yet these moments of pessimism gradually came to be overshadowed by an abiding optimism, which seemed to grow stronger as he articulated what he saw as a workable vision of this region’s future. “When I flew in by helicopter, one of the things that impressed me the most was the agriculture,” he said. “Those people are really using the poorest methods to eke out a living, and very little technology. Well, it wouldn’t take all that much to change this. With the introduction of fertilizers and better irrigation and more machinery, the yields could go up pretty quickly, and so would people’s incomes. And with that, what you would see is people moving to cities, and new cities forming, which is the way to relieve pressure on the land. It should be noted that presently, Africa is the world’s fastest-urbanizing continent.”

In many of his writings, Wilson places hope in arguments that range from the ethical (humankind will ultimately awaken to its responsibility to the Earth), to the genetic (our evolutionary background has conditioned us to yearn for such things as unspoiled savannas and wilderness), and finally to a kind of naturalist’s spiritualism. “For the naturalist, every entrance into a wild environment rekindles an excitement that is childlike in spontaneity, [and] often tinged with apprehension,” he wrote in his 2002 book, The Future of Life. Every such experience, he continued, reminds us of “the way life ought to be lived, all the time.”

Over dinner on Wilson’s first night at Gorongosa, Carr asked whether the park stood any chance of still retaining all the species it now contains when his young niece reaches her 90s. Wilson’s answer was an exuberant “Yes!” Eventually, the conversation between the biologist and the billionaire turned to the possibility of dramatically expanding the park to create a protected corridor all the way to the Indian Ocean. It was an idea whose logic flows directly from the precepts of island biogeography, which show a dramatic correlation between the size of a habitat and both its diversity and its sustainability. “I see no reason why not,” Wilson enthused. “By all means, you should do it!”

Conversations like these might give the impression that Wilson—one of the most driven and prolific biologists of his generation—has mellowed and is shifting now to a quieter, more retiring, if not truly retired, phase of life, settling into the easy-fitting robes of scientific eminence and mostly lending endorsements and encouragement to the good works of others. And his bug collecting could easily be misinterpreted as a mere enthusiasm, a nostalgic return to the field. But Wilson had rebuked me in our very first encounter, after he had picked up the ant for close inspection, pointedly declaring that he was interested in “more than ants,” and his travel here, like almost everything he does, is bound up with ideas and themes that he has doggedly pursued for decades. (Even in his recently published first novel, the best-selling Anthill, his 24th book, readers schooled in evolutionary science cannot miss the play of long-gestating Wilsonian theories, and linkages to his latest work.)

Indeed, while we sat in camp chairs talking about conservation and ants and countless other subjects, a dispute was raging among evolutionary biologists half a world away, one of the most hotly contested in that field in years—and Wilson was at its center. Christopher X J. Jensen, a Pratt Institute biologist who has blogged about the conflict, described it as a “scientific gang fight.” Its outcome could have big implications for how we understand ourselves and our motivations—and particularly the complex interplay of selfish and altruistic behavior in human nature.

This is hardly the first scientific controversy surrounding Wilson. An even bigger fight erupted around him in the 1970s, as he laid out his ideas on sociobiology in three landmark books, The Insect Societies, Sociobiology, and On Human Nature. At issue throughout were his claims that our genes not only are responsible for our biological form, but help shape our instincts, including our social nature and many other individual traits.

These contentions drew fierce criticism from all across the social sciences, and from prominent specialists in evolution such as Wilson’s late Harvard colleague, Stephen Jay Gould, who helped lead the charge against him.

Wilson defined sociobiology for me as “the systematic study of the biological basis of all forms of social behavior in all organisms.” Gould savagely mocked both Wilson’s ideas and his supposed hubris in a 1986 essay titled “Cardboard Darwinism,” in The New York Review of Books, for seeking “to achieve the greatest reform in human thinking about human nature since Freud,” and Wilson still clearly bears a grudge.

“I believe Gould was a charlatan,” he told me. “I believe that he was … seeking reputation and credibility as a scientist and writer, and he did it consistently by distorting what other scientists were saying and devising arguments based upon that distortion.” It is easy to imagine Wilson privately resenting Gould for another reason, as well—namely, for choosing Freud as a point of comparison rather than his own idol, Darwin, whom he calls “the greatest man in the world.”

“Darwin is the one who changed everything, our self-conception; greater than Copernicus,” Wilson told me. “This guy is irritatingly correct, time and time again, even when he has limited evidence.” In Darwin’s mold, the thrust of Wilson’s life work has been aimed at changing humankind’s self-conception. Indeed it can be difficult, from today’s vantage point, to see what much of the fuss of the 1970s was about, so thoroughly has the Wilsonian idea that our genes shape our nature penetrated the mainstream.

This reality is illustrated, among countless possible examples, in Francis Fukuyama’s most recent book, The Origins of Political Order: From Prehuman Times to the French Revolution. Rejecting the views of classic political philosophers like Hobbes, Locke, and Rousseau that primitive humankind started out as a collection of scattered, unorganized individuals, Fukuyama writes: “Human sociability is not a historical or cultural acquisition, but something hardwired into human nature.” Nowhere is Wilson, who pioneered this view, even mentioned.

The current controversy results from another bid by Wilson to overturn conventional scientific wisdom. For more than four decades, evolutionary biology has been dominated by a school of thought known as “kin selection,” which postulates that some species arrive at cooperative behavior and a complex division of labor as a matter of reproductive strategy among close relatives. In other words, self-sacrifice and other forms of altruism are really driven by what might be described as a coolly selfish calculation: cooperation among related individuals favors the reproduction of kin and hence the propagation of shared genes. This notion was established in a famous mathematical rule laid out by W. D. Hamilton in 1964, Rb>c, which means that genetic benefits (b) realized by helping a relative (R) pass on his or her genes must be greater than the cost (c) of assisting that relative in order for the behavior to be favored by natural selection.

Wilson believes that this whole theory has been a wrong turn, intellectually, and that this bedrock concept, with major implications for understanding our own nature, is overdue for radical revision.

The furor erupted with the publication, in the scientific journal Nature in August 2010, of an article written by Wilson and two co-authors, Martin A. Nowak and Corina E. Tarnita, both of Harvard. Titled “The Evolution of Eusociality,” it amounted to a frontal challenge to a key concept of kin-selection theory, called “inclusive fitness.” Among other things, inclusive fitness says that species like ants have become highly social, and that the sisters that make up the overwhelming bulk of any colony cede the right to reproduce to the queen, because of the extraordinarily high degree of genetic relatedness between the sisters, which surpasses even that between mother and daughter.

Ants and humans are among the very few “eusocial” animals—the most highly social creatures in the history of life on Earth, capable of building complex societies in which individuals specialize in various activities and sometimes act altruistically. Darwin himself, in his most influential book, The Origin of Species, recognized the vexing question of why female ants would sacrifice the right to reproduce rather than seek to pass along their own genes as the greatest challenge to his theory of evolution. Now, employing advanced mathematics involving evolutionary game theory and population genetics, the authors of the controversial Nature article have shaken up the evolutionary-biology establishment by rejecting kin selection, and claiming that the close genetic similarity of sister ants is not mathematically necessary to explain their “eusociality”—and, indeed, is not the cause of it.

The mathematical heavy lifting comes from Nowak and Tarnita, showing, in the words of Nowak, that “simple versions of Hamilton’s rule … are almost always wrong,” and that recent efforts to create more-generalized versions of the rule are of no help in explaining evolution. But the proposed new interpretation of what causes ants and a few other species to become highly social, to the point of intricate specialization and even self-sacrifice, or altruism, is classic Wilson. “The causative agent,” the authors wrote, “is the advantage of a defensible nest.” Eusocial creatures are driven to cooperate not by their relatedness, in other words, but by the advantages that accrue to any group from the division of labor. As natural circumstance forced individuals to interact, certain cooperative traits became advantageous, and proliferated, in a handful of cases.

In support of their attack on kin selection, the authors invoke the rarity of eusociality across the animal kingdom, even among species in which the genetic similarity of kin is extremely high. Among species that use clonal reproduction, for example, only one major group, the gall-making aphids, are known to be eusocial. What’s more, eusocial behavior can occur—even among insects—in the absence of kinship. One example is the propensity of certain solitary bees to behave like eusocial bees when they are forced to live together in the laboratory. “The coerced partners proceed variously to divide labor in foraging, tunneling, guarding.”

The authors conclude that a very small number of species simply seem to be genetically “spring-loaded,” or “strongly predisposed” to the development of eusociality in conditions where natural selection favors it. The article then ropes humans into the picture in its last and most provocative sentence: “We have not addressed the evolution of human social behavior here, but parallels with the scenarios of animal eusocial evolution exist, and they are, we believe, well worth examining.” Until now, the conventional wisdom on the social evolution of humans has focused on the growth and development of the brain, not on the existence of a social gene or set of such genes that may have spring-loaded humans for civilization—or for altruism. Yet Wilson and his co-authors imply that such genes very likely exist.

The outcry from the evolutionary-theory establishment, including luminaries in the field ranging from Richard Dawkins to Robert Trivers, was exceptionally fierce, including unusually personal attacks. One of several critical letters to the editor published by Nature was signed by 137 scientists. Another letter called the authors’ findings “largely irrelevant.”

Elsewhere, commentators objected that Nature should never have published the article, and only did so because Wilson’s name was attached to it. Some claimed that the authors had not fully understood or had willfully misrepresented kin-selection theory. One commentator even wrote off Wilson for his “senescence.” On his blog, Jerry A. Coyne, a leading figure in the field and a professor in the department of ecology and evolution at the University of Chicago, voiced pity for Tarnita, a Romanian theoretical mathematician who works at Harvard’s Program for Evolutionary Dynamics. Calling the paper “dreck,” he said that it “will always cast a shadow over her career.”

“Nowak et al.,” as the authors are called in the Nature back-and-forth, have firmly held their ground. “Inclusive fitness theory,” they wrote in their published response, “is neither useful nor necessary to explain the evolution of eusociality or other phenomena.” In an e-mail to me, Tarnita wrote about the criticisms directed at her:

Coming from a mathematics background and having contributed a mathematical argument to this discussion, I am not one to be impressed by such statements, unless they are supported by an actual mathematical refutation of my arguments. So far there has been none.

In collaborating with Nowak and Tarnita, Wilson was in effect reprising a tactic that led to his first major theoretical triumph, with island biogeography—joining forces with talented mathematicians. In that instance, in the early 1960s, he teamed up with the late Robert H. MacArthur, whose work on population growth and competition, Wilson says, made him the most important ecologist of his generation.

“Nothing is more attractive to me than a muddled domain awaiting its first theory,” Wilson wrote in Biophilia:

I feel most at home with a jumble of glittering data and the feeling that they might be fitted together for the first time into some new pattern. This inclination made me especially compatible with mathematicians. I became fascinated with the way they think, why they should be so much better at quantitative reasoning than I, what difference it made in the end, why I should be the one so often to suggest moving in a particular direction, but then even more frequently not be able to do so, and finally how different everything looked after a little progress had been made.

Wilson told me the new proposed evolutionary model pulls the field “out of the fever swamp of kin selection,” and he confidently predicted a coming paradigm shift that would promote genetic research to identify the “trigger” genes that have enabled a tiny number of cases, such as the ant family, to achieve complex forms of cooperation. His next book, The Social Conquest of Earth, expands on his theories—and takes up the question left dangling at the end of the Nature article. “It starts with posing the questions that I call the most fundamental of philosophy and religion,” he said. “Where did we come from, what are we, and where are we going?”

Wilson explained the book, which will be released in April, during an animated two-hour discussion on a day that he’d previously set aside for rest. Earlier that morning, he had turned up in his usual baggy, sagging khaki pants and installed himself at a table outside the Gorongosa camp restaurant, slumping silently into a flimsy plastic chair. Soon he could be seen jotting ideas in his small, neat hand, on a yellow legal pad. Once in a while he would tear off a sheet, number it, fold it carefully, and put it in the side pocket of the same blue-striped sport coat he wore every day.

Later he told me that he’s done all of his writing that way, relying on Kathleen M. Horton, the assistant who has worked with him for 45 years, to enter material into a computer and help edit his writing. “Most people are now aware that the digital age is upon us,” he said, with a twinkle in his left eye, the other sightless from a boyhood accident. “It has left me behind. I haven’t had time to learn iPhones and tablets, or even how to run a computer properly, but it’s arrived.”

Wilson told me he’d worked for a decade on the ideas he presents in Social Conquest, drawing on the primary literature in a wide variety of fields to refine his views. These ranged, he said, from molecular genetics and ecology to anthropology and cognitive science. In the book, he proposes a theory to answer what he calls “the great unsolved problem of biology,” namely how roughly two dozen known examples in the history of life—humans, wasps, termites, platypodid ambrosia beetles, bathyergid mole rats, gall-making aphids, one type of snapping shrimp, and others—made the breakthrough to life in highly social, complex societies. Eusocial species, Wilson noted, are by far “the most successful species in the history of life.” Humankind, of course, has thoroughly transformed the environment, achieving a unique dominion. And ants, by some measures, are more successful still. (If you were to weigh all the animals on the planet, you would find that the mass of ants exceeds that of all other insects combined, and also that of all terrestrial nonhuman vertebrates.)

“Wow, the butterflies are out,” Wilson interjected mid-sentence, as a pretty, modestly sized, yellow-and-black creature floated dizzily around his chair.

Wilson announced that his new book may be his last. It is not limited to the discussion of evolutionary biology, but ranges provocatively through the humanities, as well. Summarizing parts of it for me, Wilson was particularly unsparing of organized religion, likening the Book of Revelation, for example, to the ranting of “a paranoid schizophrenic who was allowed to write down everything that came to him.” Toward philosophy, he was only slightly kinder. Generation after generation of students have suffered trying to “puzzle out” what great thinkers like Socrates, Plato, and Descartes had to say on the great questions of man’s nature, Wilson said, but this was of little use, because philosophy has been based on “failed models of the brain.”

Answers to the fundamental mysteries of human nature can only be found elsewhere, Wilson told me—in science, and most particularly in genetics and evolution.

Wilson had begun this particular conversation promising to answer the question of what caused the shift from the genus Australopithecus to Homo and led to the line that ultimately became human. But now he asked, “Can we have lunch before I tell you?,” clearly enjoying playing up the drama.

His theory draws upon many of the most prominent views of how humans emerged. These range from our evolution of the ability to run long distances to our development of the earliest weapons, which involved the improvement of hand-eye coordination. Dramatic climate change in Africa over the course of a few tens of thousands of years also may have forced Australopithecus and Homo to adapt rapidly. And over roughly the same span, humans became cooperative hunters and serious meat eaters, vastly enriching our diet and favoring the development of more-robust brains.

By themselves, Wilson says, none of these theories is satisfying. Taken together, though, all of these factors pushed our immediate prehuman ancestors toward what he called a huge pre-adaptive step: the formation of the earliest communities around fixed camps.

“When humans started having a camp—and we know that Homo erectus had campsites—then we know they were heading somewhere,” he told me. “They were a group progressively provisioned, sending out some individuals to hunt and some individuals to stay back and guard the valuable campsite. They were no longer just wandering through territory, emitting calls. They were on long-term campsites, maybe changing from time to time, but they had come together. They began to read intentions in each other’s behavior, what each other are doing. They started to learn social connections more solidly.”

Wilson’s “campsite” theory, of course, connects us directly back to the species described in the Nature article, and helps him lump humans together with the handful of other known species to have made it across what he calls the evolutionary “bottleneck” toward highly structured social life. “The humans become consistent with all the others,” he said, and the evolutionary steps were likely similar—beginning with the formation of groups within a freely mixing population, followed by the accumulation of pre-adaptations that make eusociality more likely, such as the invention of campsites. Finally comes the rise to prevalence of eusocial alleles—one of two or more alternative forms of a gene that arise by mutation, and are found at the same place on a chromosome—which promote novel behaviors (like communal child care) or suppress old, asocial traits. Now it is up to geneticists, he adds, to “determine how many genes are involved in crossing the eusociality threshold, and to go find those genes.”

But the story does not end here. In his new book, Wilson posits that two rival forces drive human behavior: group selection and what he calls “individual selection”—competition at the level of the individual to pass along one’s genes—with both operating simultaneously. “Group selection,” he said, “brings about virtue, and—this is an oversimplification, but—individual selection, which is competing with it, creates sin. That, in a nutshell, is an explanation of the human condition.

“Our quarrelsomeness, our intense concentration on groups and on rivalries, down to the last junior-soccer-league game, the whole thing falls into place, in my opinion. Theories of kin selection didn’t do the job at all, but now I think we are close to making sense out of what human beings do and why they can’t settle down.”

By settling down, Wilson said, he meant establishing a lasting peace with each other and learning to live in a sustainable balance with the environment. If Wilson’s new paradigm holds up—“and it will,” he insisted in an e-mail exchange several weeks after visiting Gorongosa—its impact on the social sciences could be as great as its importance for biology, advancing human self-understanding in ways typically associated with the great philosophers he criticized.

“Within groups, the selfish are more likely to succeed,” Wilson told me in a telephone conversation. “But in competition between groups, groups of altruists are more likely to succeed. In addition, it is clear that groups of humans proselytize other groups and accept them as allies, and that that tendency is much favored by group selection.” Taking in newcomers and forming alliances had become a fundamental human trait, he added, because “it is a good way to win.”

Kin-selection theory would explain nepotism, but not the more complex rivalries and alliances that we see throughout human history. If Wilson is right, the human impulse toward racism and tribalism could come to be seen as a reflection of our genetic nature as much as anything else—but so could the human capacity for altruism, and for coalition- and alliance-building. These latter possibilities may help explain Wilson’s abiding optimism—about the environment and many other matters. If these traits are indeed deeply written into our genetic codes, we might hope that we can find ways to emphasize and reinforce them, to build problem-solving coalitions that can endure, and to identify with progressively larger and more-inclusive groups over time.

Once the book comes out, Wilson said, he expects parts of the biological mainstream to howl on cue. He is just as certain, though, that there will be many converts. “I am going to get fuselaged—you know, bombarded,” he said, laughing. “I don’t care, though, because I feel so secure about the theory and interpretation.”

In Gorongosa, Wilson’s study of complex social behavior was centered on the termite, an insect that seemed to obsess him at times during his stay. Termites are unrelated to ants; rather, they are distant cousins of cockroaches. As such, their reproductive strategy is entirely dissimilar to that of ants. But like ants, they are on the shortlist of eusocial animals. For Wilson, how such different creatures ended up creating highly structured societies, replete with castes and the complex division of labor, remains a source of fascination and ongoing study.

Nonetheless, during much of his stay, termite research was crowded out by the broader conservation effort that had brought him here, and by the Life on Earth project—and indeed, the two often ran together, as film crews shadowed him, recording material for the textbook.

One morning, I traveled with him to Mount Gorongosa for an event billed as a “bio blitz,” which combined a classic natural-history specimen-gathering exercise, textbook-filming, and an educational opportunity for the scores of village children who were enlisted in the effort. Normally events like these bring together a diverse team of biologists, but Wilson, who was seated at a table in a makeshift shelter beside a clear stream and just above a waterfall, was on his own this time, and clearly relished being the center of the action.

“You will be seen by other students in many places,” he explained through a translator, as video crews filmed. “Because we wish to help science, we wish to know what is all around here, what species exist here. It is good for your education to see how studies in science can be done, how you can do studies in science.”

Ziploc-style bags were passed out, and Wilson told the children, who sat on the ground before him, to collect all the “creatures, little animals, insects, spiders” they could find, and bring them to him for identification. With that, the children, let loose on the mountainside, threw themselves into the task with abandon, tromping through the stream, seizing bugs in the tall grass, and pursuing other creatures up the hillsides.

As the bagged bugs, lizards, scorpions, and other creatures they brought forth began to pile high, Wilson became almost giddy, seemingly reliving the thrills of his Alabama childhood, when his avid specimen-hunting fostered a growing fascination with nature, and eventually a love of science. For minutes at a time, the white-haired scientist resembled nothing so much as a grandmaster smiting a score of enthusiastic challengers at a speed-chess exhibition, as he quickly named each animal brought to him:

“And here we have—very good—a lycaenid butterfly. Probably that’s a new species, but I’m not going to keep it. Who got that butterfly? … What is this? Wait a minute, where is my magnifying glass, I’ll tell you. Oh yeah, that one I know. I know the genus. That one is a Tetragnatha. … Now the ants … This is an important one. Can you be sure to get that one? All right, wait a minute. I want that one. It’s different. That’s a reduviid, an assassin bug … That’s a—wait a minute, it’ll come to me. This is a coccinellid.”

This medley, one of many, concluded with Wilson saying: “Wow, this is the way to make a real collection, if you are an entomologist. Get a bunch of kids around. No, seriously.”

Later, in a quieter moment, I asked Wilson how he managed to name so many of the creatures, particularly ones far outside his specialty, and on a continent he’s never visited before. He told me that he’d prepped intensively for the experience for two months, consulting both reference books and experts, committing the descriptions of thousands of species to memory. Silently, I recalled a critic’s recent characterization of him as senescent.

A few days earlier, Wilson, remarkably, had taken his very first helicopter ride, a shuttle run that brought him from the nearby port city of Beira to the park’s immense floodplain, dotted by riverine pools thick with caucusing hippos and crocodiles, and finally to a close view of the mountain itself. “Mount Gorongosa!” he exclaimed to me later. “It has always loomed in my imagination as this dark, brooding mountain, but boy, is it magnificent; so bright, so full of life!”

With that, I asked Wilson what made this place so special for him. “Every place is special,” he answered. “But this is—even among all the varieties of natural history that you can get in parks around the world—this one stands out because of its tragic history. The destruction that is being healed, largely through the efforts of one man, this Greg Carr, showing what can be done.”

After a few days here, Wilson amended his vow not to write more books, saying he would like to return next year to work on a book about Gorongosa and its mountain, tentatively titled Gorongosa: The Park as a Window on Eternity. In lieu of producing any more big, theoretical works, though, Wilson tells me, he longs to spend more of his time traveling. Soon, he said, he plans to go to Yosemite National Park to study a rare ant, and late this year he is planning a seven-week expedition in New Caledonia and Vanuatu. He wants to relive his exploits as a 25-year-old naturalist, when he explored the region as part of a 10-year stint of fieldwork during which he worked out the classification of hundreds of species of ants throughout the Pacific region and elsewhere. “These are the things I want to do—travel, visit the places I’ve wanted to go,” he says.

In such a full life, I asked him how he made sense of his own achievements. “How successful you are depends on a small number of qualities and activities, and one of them is luck,” he answered, laughing. Then the man who had told me, a few days earlier, that he was interested in more than ants confided that he was lucky to have settled on them at a young age.

“For every organism, there exists a problem, for the solution of which that organism is ideally suited,” Wilson said. We had been talking over lunch for about two hours, and Wilson had barely touched his food. He paused for a moment, taking a bite of chicken. “A lot of my work was done with pheromones; then came island biogeography, because I could collect enough ants in a short enough period of time to get an idea of the nature of fauna on different islands.” Only then “came the question, ‘What are the driving forces of evolution?’” He put down his fork, and gave a slight smile. “Ants are always there, and this has given me an edge,” he said. “I’ve ridden ants the whole way.”

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