On a spring day in 2017, along the edge of an ancient lake bed in what is now White Sands National Park in southern New Mexico, the paleontologist Matthew Bennett was following the fossilized tracks of a ground sloth—a bulky Ice Age animal that could weigh more than a ton and whose long, curved claws likely forced it to waddle on the sides of its feet. As Bennett uncovered the crescent-shaped tracks in the sediment, he happened upon one print even stranger than the rest. He told the press that the oval bump in its center made it resemble a “Klingon Bird-of-Prey in negative relief.”

Bennett and his colleagues soon realized they were looking at not one print but two that overlapped. Made in close succession more than 11,000 years ago, the larger belonged to a sloth; the smaller belonged, unmistakably, to a human. More overlapping tracks suggested that a group of adults and children had deliberately stepped into the sloth prints and followed the animal until it turned to face them, dragging its knuckles along the ground as it reared up to its full eight-foot height. In another part of the lake bed, the research team documented a set of similarly aged human prints left by a teenager or young adult who carried a child on one hip while hurrying through territory crisscrossed by sloths and mammoths.

North and South America were the last temperate continents reached by early humans, but humans have nevertheless lived here for a very long time: in 2021 scientists studying another set of fossilized human footprints in the White Sands lake bed published an analysis of the surrounding seed layers that suggested the footprints were about 23,000 years old. The more recent sets of near-simultaneous sloth and human footprints are among the oldest known records of human interactions with other species in North America, and the stories they suggest are familiar: then as now, humans and their fellow animals reacted to one another with curiosity, recklessness, and fear, coexisting in relationships often touched by violence.

In his latest book, Wild New World, the historian Dan Flores follows these fraught interactions from prehistory to the present day, seeking what he calls the “particular American story” of humans and animals in North America. Flores is an emeritus professor at the University of Montana and the author of ten previous books, including Coyote America and American Serengeti (both published in 2016). He describes Wild New World as a work of “big history”—a term coined in 1991 by the historian David Christian, who wrote:

We cannot fully understand the past few millennia without understanding the far longer period of time in which all members of our own species lived as gatherers and hunters, and without understanding the changes that led to the emergence of the earliest agrarian communities and the first urban civilizations.

Flores begins his big history with the Chicxulub asteroid. When it crashed into the Gulf of Mexico 66 million years ago, he writes, “the impact wiped clean the hard drive of evolutionary life all over the planet, but particularly in America.” Chicxulub obliterated most of the dinosaurs (save the ancestors of today’s birds) and almost all North American plant life; with scarce exceptions, it reduced the planet’s animal life to small reptiles, amphibians, and an assemblage of rat-sized, ground-dwelling mammals that were lucky or resourceful enough to survive. These mammals, able to reproduce quickly, began to fill the ecological niches that the asteroid emptied.

Fewer than a million years after Chicxulub hit, some North American mammals were as large as modern-day wolves. Within 10 million years, the earliest horses appeared, followed by prototypical beavers, camels, pronghorn, seals, and sea otters. Some 17 million years ago, during the Miocene, the first mastodons crossed the Bering Land Bridge from Asia to North America, as did the forerunners of elk and deer; toward the end of the Miocene, the rich grasslands of the Great Plains drew sheep, goats, and—belatedly, considering their current all-American reputations—mammoths and bison. This tasty bestiary, in turn, attracted bears and large cats; the famous saber-tooths began to feast on North American grazers about 2.5 million years ago. Meanwhile, our own genus was only beginning to emerge in Africa, and did not seriously set forth from its continent of origin for another two million–plus years.

This story has been told before, but Flores is a skilled raconteur, and he memorably evokes the rich, weird assortment of species that inhabited North America long before any of our direct ancestors. The bustling prairies and forests of what Flores calls “Clovisia the Beautiful” are exhilarating to contemplate—especially given that we know Flores’s tale must end with Homo sapiens giving the Chicxulub asteroid a run for its ecocidal money in the twenty-first century.

The first signs of humans in the North American fossil record are scant and scattered: those footprints in New Mexico, the remains of a mastodon kill in Florida, traces of a mastodon roast in Virginia. But 16,000 years ago, when the retreat of the Pleistocene ice sheets reopened a land route between present-day Alaska and the continental United States, humans began moving rapidly from Asia through Beringia and across North America, establishing a civilization that extended from Alaska to Florida and produced distinctive tools and weaponry for at least three hundred years. While earlier humans likely had little impact on the continent’s plant and animal species, the Clovis people—named for the site in eastern New Mexico where a teenage archaeology enthusiast encountered its projectile points in 1929—had the numbers, and the tools, to leave a far more lasting mark.


Radiocarbon dates suggest that by the end of the Pleistocene, 11,700 years ago, more than three dozen genera of large mammals had gone extinct in North America. Exactly how lethal the Clovisians were is the subject of an extended, and still animated, debate. Flores comes down firmly in favor of the Pleistocene overkill hypothesis, proposed by the geoscientist Paul Martin in the 1960s, in which the Clovisians and their near contemporaries, as they spread across the continent, slaughtered so many unsuspecting large mammals in such a short time that only a few species—including pronghorn, caribou, and bison—survived, in much-diminished numbers. The leading alternative explanation is that this multispecies die-off was driven by climate changes such as the warming at the end of the Pleistocene.

Although Flores acknowledges that “plenty of mysteries remain,” he is dismissive of challenges to the overkill hypothesis, attributing their persistence to an “instinctive rejection of humanity’s ability to alter the planet.” During his lifetime, Martin did face criticism, some of it vitriolic, from scholars who doubted that indigenous Americans—or any early humans, for that matter—were capable of such widespread and irreparable damage. This skepticism, however, was and is more substantive than Flores suggests. Though there is some direct fossil evidence of large-scale Pleistocene hunting by humans, it is far from conclusive, and critics point out that the extinctions, which included birds and reptiles as well as large mammals, may have happened more gradually than Martin surmised. For now, at least, the arguments for both the overkill hypothesis and its alternatives rest heavily on inferences.

One 2018 assessment of expert attitudes toward the overkill hypothesis found that archaeologists are in general unpersuaded by the fossil evidence and tend to see human hunting as only one of several reasons for the Pleistocene die-off. In contrast, ecologists—whose studies of modern species declines and extinctions make them eyewitnesses to humanity’s ability to alter the planet—largely accept the overkill hypothesis, casting it as a distant mirror of modern societies’ awful appetites. Having written about ecological issues for a long time, I find myself inclined toward the latter camp, and toward Flores’s suggestion that the Clovis era was “the moment when the human hand seized the rudder of continental evolution.” But it’s worth asking whether this view is also influenced by instinct.

For most of North America’s flora and fauna, the approximately 10,000 years between the Pleistocene die-off and the arrival of Columbus appear to have been relatively peaceful. Species such as the new, smaller bison expanded to fill empty niches, allowing many indigenous American cultures to continue hunting and gathering instead of resorting to agriculture like their counterparts in Europe and Asia. While some North American societies migrated seasonally with their animal quarries, others stayed in place, building lasting structures such as the massive earthen mounds along rivers in the South and Midwest. Initially erected by hunter-gatherers and inherited by later agricultural societies, these mounds apparently served religious purposes.

Native cultures developed—and continue to develop—elaborate artistic and religious traditions, many centered on the complex connections between humans and other species. Flores cites the work of Rosalyn LaPier, whose book Invisible Reality: Storytellers, Storytakers, and the Supernatural World of the Blackfeet (2017) offers an unusually detailed account of one indigenous American belief system during the nineteenth and early twentieth centuries. In Blackfeet cosmology the “Below World,” where humans reside, is one of three separate but interconnected worlds, each of which contains both visible and invisible, or supernatural, elements. Animals are believed to live in all three worlds, and human alliances with supernatural animals are traditionally seen as a means of survival in unpredictable surroundings. LaPier, recounting stories told by elders around the turn of the twentieth century, observes a common theme:

The Blackfeet believed that they had a distinct relationship with the natural world that was both practical and divine. Based on their ancient experiences they had control and say in the final outcome of their lives.

Flores emphasizes that all human societies, in the Americas and elsewhere, had lasting effects on their ecosystems. That indigenous societies used traditional taboos to restrict the hunting of certain species, such as the passenger pigeon, to particular seasons or locations suggests that harmony between people and other animals, if it existed in North America, was not a default state but the product of deliberate effort.


Yet Flores makes clear that when Europeans arrived on American shores, they began to destroy at an entirely different magnitude. Diseases such as smallpox and measles, never encountered by Native immune systems, quickly took a horrifying toll on indigenous communities. This population crash was followed by a postpandemic boom in wildlife numbers, leading many observers to conclude that sixteenth- and seventeenth-century North America was a sort of Eden—a pernicious assumption that persists in various forms even today.

Tens of thousands of years before the initial encounters between Europeans and Americans, their respective ancestors parted ways in Africa, with one group traveling north to Europe and the other moving east through Asia and, eventually, across Beringia to North America. During those many centuries of separation, Flores writes, their cultures diverged. In Native American cultures, free-roaming animals remained essential to human diets and economies, and were often regarded as close kin.

In contrast, as wildlife populations dwindled across Eurasia, European societies became primarily agricultural, domesticating animals instead of hunting them. European “invisible realities” were reserved for humans, and in the Aristotelian Great Chain of Being, a hierarchical view of life that dominated European thought, humans ranked just below the angels; all other species followed, ordered by their relative utility to humans. Large predators capable of preying on livestock were considered worse than useless, and Europeans saw wolves as particularly malevolent—an antipathy that later had disastrous effects on North American ecosystems.

Flores does not mention that the Great Chain of Being also provided the rationale for modern racism. The Portuguese began to import slave labor from West Africa in the 1400s, and as other European nations followed, the trade in enslaved people for agricultural and domestic labor expanded into Central Africa and across the Atlantic. European church, state, and popular support for the systematic enslavement of Africans relied at least in part on the belief that people with darker skin were inherently inferior, and by the eighteenth century European intellectuals had revised the Great Chain of Being to include a ranking of human races, unsurprisingly placing their own at the top. When the Swedish naturalist Carl Linnaeus first proposed the species classification system that underpins today’s scientific nomenclature, he divided humanity by skin color into four types, with Europeans at the head of his supposedly natural order. This hierarchy, too, accompanied Europeans to North America, with terrible consequences for untold numbers of human beings and the rest of life on the continent.

Native American knowledge of flora and fauna, accumulated over thousands of years, was decimated by European disease and persecution, and only a handful of European-descended Americans recognized the value of the surviving expertise. Some appreciated the immense diversity of North American plant and animal species, most of them new to European eyes, and Flores profiles several eighteenth- and nineteenth-century naturalists, both famous and obscure, whose work drew attention to its richness, among them William Bartram and the artist Mark Catesby. These discerning observers were, however, exceptions.

Flores notes that while even Adam Smith had argued that self-interest, the fuel of the capitalist engine, was properly leavened by empathy, this caveat was lost on his adherents. Many also dismissed the familial and largely nonhierarchical relationship between humans and other animals suggested by Charles Darwin’s theory of evolution by natural selection. Instead, they contorted Darwin’s ideas about individual competition into “scientific” justifications for social inequalities—and the unrestrained killing of other species. Flores neatly characterizes this thinking. “Even if we were more like animals than we’d thought,” he writes, “animals hadn’t invented guns. We had.”

In the nineteenth century these dubious ideas served as the foundation for an unprecedented—and hideously destructive—national and international market in North American wildlife. Birds were shot and sold by the thousands to satisfy the demand for both meat and feathers; commercial buffalo hunters, who were predominantly white but included some Native Americans, all but exterminated the plains bison as they raced to supply Europeans and urban North Americans with buffalo robes. Some of these hunters, writes Flores, may have genuinely believed that these animal populations were inexhaustible, but plenty understood the likely consequences of their actions. Decades after the slaughter, a hunter named Frank Meyer reflected on the origins of “buffalo fever”: “Maybe we were just a greedy lot who wanted to get ours and to hell with posterity, the buffalo, and anyone else…. I think maybe that is the way it was.”

Importantly, hunters benefited not only from market demand but from government subsidies; state and later federal support for the wholesale killing of wolves and other carnivores extended well into the twentieth century. Few voices opposed this massacre until the Progressive Era, when the extinction or near-extinction of many famous species—among them the bison and the passenger pigeon—combined with a growing awareness of the manifold cruelties of unregulated markets to birth the modern conservation movement.

Wild New World succeeds in establishing a powerful, and credible, narrative of life and death in North America. By extending the history of the continent to the distant time when humans were, at best, bit players in its marvelous ecosystems, Flores reminds us that modern North Americans—despite various and strenuous efforts to ignore our ecological dependence—still walk in the footsteps of our fellow animals.

In their search for a unifying narrative—or, even more ambitiously, what David Christian has described as a secular “origin story” or “creation myth”—practitioners of big history sometimes treat possibilities as certainties. While Flores largely maintains the distinction, he is insufficiently skeptical of both the Pleistocene overkill hypothesis and the biophilia hypothesis, E.O. Wilson’s beguiling but essentially unfalsifiable suggestion that humans have an “innate tendency to focus on life and lifelike processes.” Flores presents biophilia as fact, calling it “a piercing love affair with the other life-forms that surround us on the planet.”

Just as the overkill hypothesis is not necessary to understand that humans have long inflicted heedless cruelty on other species, the biophilia hypothesis is not necessary to understand that humans can treat other species with respect, care, and self-interested foresight. Flores might have strengthened his case for the latter capability by devoting more space to the indigenous-led conservation efforts now underway across the continent, including the campaign to more fully restore bison to the Great Plains. The leaders of these efforts, wary of the enduring stereotype of the “ecological Indian,” generally avoid claims to any innate capacity for protecting other species; they are instead motivated and informed by ancestral experience, cultural traditions, and concern for the ecosystems that support us all.

Any account that begins with the impact of the Chicxulub asteroid and extends to the impact of 1960s Disney nature documentaries, as Flores’s does, must sacrifice some complexities. The broad strokes of Wild New World are usefully complemented by The Market in Birds, in which the historian Andrea Smalley—author of Wild by Nature: North American Animals Confront Colonization (2017)—builds on the extensive unpublished research of the wildlife biologist Henry Reeves, who died in 2013, to complicate a short, crucial chapter in North America’s multispecies epic. As Flores describes, the excesses of the nineteenth-century trade in North American wildlife, particularly its toll on bison and birds, led to public outrage and, eventually, the passage of far-reaching protective legislation.

The usual story is that wealthy sportsmen—appalled by the profligacy of hunters who routinely killed hundreds of birds in a single day to sell as food, ornaments, or specimens for collectors—led the call for restrictions, demanding that Congress protect the animals they both admired and loved to hunt. While this is not untrue, Smalley and Reeves show that the distinction between sportsmen and market hunters was essentially constructed by elite recreational hunters—among them Theodore Roosevelt—as a means of capturing the moral high ground. “Over the course of the late nineteenth and early twentieth centuries,” they write, “the market hunter’s pursuit of profit became an ever-brighter line separating legitimate from illegitimate wildlife killing.”

Drawing on The Shadow of a Gun (1904), the out-of-print memoir of an Illinois market hunter named Henry Clay Merritt, among other primary sources, Smalley and Reeves reveal the fascinating (if often dismaying) variety of motivations, methods, and technologies of the short-lived profession of North American market hunting, including a seven-barreled “armada” that was attached to a skiff and used to shoot down several birds at once. They also show that some market hunters expressed at least as much concern about wildlife as their recreational counterparts. Merritt conceded that his profession was destructive but argued, not without reason, that the accelerating destruction of wetlands by agriculture and development posed a more pressing threat to the wildlife of his home landscape—“this wonderful region,” he wrote, “where the hen cackled on every plain, the quail whistled on every hill…and the ducks swarmed in thousands in every conceivable bayou.”

Though the vilification of market hunters led to legislation that, by 1920, had ended the trade in wild birds, it also helped establish the conservation movement’s reputation for elitism, a reputation—and, to some extent, a reality—that remains a political vulnerability. Consider, for instance, the claims by the timber industry in the 1980s that protecting the northern spotted owl in the Pacific Northwest would lead to economic ruin for both companies and communities: while the claims were highly exaggerated, the longstanding perception that conservation was a special interest of the privileged rather than a universal responsibility primed many working-class people to believe that conservationists were out to destroy their jobs. Similar assumptions prop up today’s manufactured outrage over climate legislation and the regulation of gas stoves.

While sportsmen worked to distinguish themselves from those who hunted for a living, Smalley and Reeves write, they glorified experiences in which wildlife and their habitats functioned as commodities. The authors are perhaps too eager to equate the impact of recreational hunting—and outdoor recreation in general—with the commercial wildlife trade’s enormous body count, but the shared attitudes are undeniable. Even today, conservation organizations routinely present other species as irreplaceable objects, forgetting or ignoring that they are also fellow members of our ecosystems—or, as many traditions far older than the market would put it, kin. “Before we can think about how to prevent wildness from disappearing under the weight of the market,” Smalley and Reeves conclude, “we need to escape the vortex of commerce ourselves.”