Transcript
Dan Flores (0:01)
Humans belonging to Clovis and Folsom cultures entered an America teeming with a remarkable diversity of Africa like creatures, but confronted.
Steve Rinella (0:11)
An extinction crisis that was possibly precipitated by their own arrival. I'm Dan Flores, and this is the.
Dan Flores (0:18)
American west.
Steve Rinella (0:21)
Brought to you by Velvet Buck. Still in barrel, Velvet Buck arrives this summer, just in time for the season that calls us home. A portion of every bottle supports backcountry hunters and anglers to protect public lands, waters and wildlife. Enjoy responsibly. Clovisia the Beautiful we hardly know our actual beginnings in America. Even Even the stories are set in places we recognize the characters of our deep time. History can be alien to the point of fantasy. But while it may sound unlikely in the 2000s, there's no place quite like downtown Los Angeles for acquiring some sense of how the human story began on the continent. Rancho La Brea Tar Pits, just off Wilshire Boulevard in the heart of a sprawling Pacific coast city, is today the most accessible place in the country for picturing in the mind's eye the wild new world migrating humans found when they first saw America. True enough, there's a sense of time travel shock, having your lift drop you in the middle of swirling, honking LA traffic, only to stand face to face minutes later with Colombian mammoths fatally mired in tar, trumpeting their despair. Even if the mammoths are robots and their forlorn cries don't drown out the traffic, they and La Brea and the Page Museum still work a kind of magic. 20,000 years drops away if you let it, because La Brea preserves tangible remnants of a world at the far ends of the earth for ancestors of ours whose migrations had begun in Africa. The Page Museum is a working laboratory of paleontology where visitors can watch scientists labor over the site's latest discoveries. Many of those are the remains of scavenger predators once lured by the cries of snagged mammoths or the scent of decomposing horses, camels or ground sloths trapped by surface tar near what was once a water source in a dry landscape. The skulls and tusks of the elephants extracted from La Brea are impressive, but anyone who tours the museum has to admit the most stunning display is the wall, the backlit in yellow of hundreds of dire wolf skulls, the strapping canids indigenous to America but memorably revived as fictional Westeros fauna in Game of Thrones left the most remains here of any species. 1800 individuals, the fossils of hundreds of coyotes a brawnier version than our modern animal make up the third most common species here. But in second place are those ultimate ambush predators of the Pleistocene. The western subspecies of sabertooths. Heavily built cats with a fearsome snake like jaw gape and enormous fangs. The replica skull of a saber tooth from La Brea sits a few feet away as I write this. Its rapier sharp canines capable of tearing open a sloth or mammoth calf. Gleaming in rich afternoon light. Each fang measures a full 8 inches from gumline to tip. The vast assemblages of hypercarnivore bones at La Brea join the skeletal remains of mega mammoths and mastodons, giant bison, pronghorns, llamas, California turkeys and many more. The predator list is lengthier than just wolves, coyotes and saber tooths as well as the cats whose remains have come out of the tar, include American cheetahs, steppe lions and giant jaguars. Immense hyperactive, short faced bears, twice the weight of a grizzly died in the asphalt. So did the enormous Miriam's Pterotorn, A Pleistocene bird of prey with a 10 and a half foot wingspan. The remains span indigenous creatures spawned by continental evolution and migrants from Asia, some ancient to America, some recent arrivals. The mammals and birds may seem alien or vaguely African, but in fact this bestiary was purely classically American. The America of the Pleistocene. The Rancho La Brea victims that left their bones and skulls encased in tar were once representatives of one of the grand ecologies of planet Earth. This was a different America than most of us conjure when we imagined the continent Europeans found 500 years ago. But this La Brea world wasn't like the pre Chicxulub age of the dinosaurs absent of humans either. Late in the Pleistocene, our human forebears joined American ecologies as the newest predator. Here these first Americans lived their lives among La Brea creatures and created the first coast to coast human societies in American history. Their presence began to leave the continent and this rich aggregate of impressive animals forever changed. The first time we became aware that humans were actually in America during the Pleistocene was barely a hundred years ago. And the place that happened was along the New Mexico Colorado border. In the days following a flood in the dry Cimarron River. An African American cowboy named George McJunkin was riding through grassy parkland a few hundred yards below the rim rock of a miles long mesa that extended eastward from the Rocky Mountains, checking for ranch fence lines damaged by the flood. Suddenly McJunkin's horse braced its hooves furrowing into foot deep mud at the edge of a ragged scar floodwaters had cut into the slope below the mesa. McJunkin leaned out of his saddle to peer into a fresh chasm sliced into the brown shale. What he saw changed the story of America forever. On a similar rainy August day in 2018, some 35 of us are stepping through the lush grass of that same slope as it angles up towards the rim rock of Johnson Mesa. We're following David Eck, a New Mexico State lands archaeologist with a long ponytail halfway down his back, who is leading us towards the very spot where George McJunkin's horse had pulled up 110 years before. The topography is now a grassy, shallow drain called Wild Horse Arroyo. And as we crowd around its edges, it seems somehow too commonplace to be the scene of one of the continent's most significant historical finds. Nonetheless, this in the flesh is the legendary Folsom archaeological site. What McJunkin had done about where we now stood talking was to spot in the flood gashed arroyo bones of an immense size. They turned out to be from a herd of Bison antiquus, an extinct form of giant bison. But the bones themselves weren't the piece de resistance. At the time, the sciences of ethnology and archaeology in the United States were firm that American Indians had arrived in North America only a couple thousand years prior to the coming of Europeans. In 1926, the Black Cowboy's plea to have a scientist look at his bone pit reached Jesse Figgins, director of the Colorado Museum of Natural History in Denver. Something of an amateur himself, Figgins was mostly interested in fossil bison that might make exhibits in his museum. His team began an excavation of the site in May of 1926 and quickly began finding the skeletal remains of bison of a monstrous size. That was exciting enough. But in their second season of work, on August 29, 1927, Figgins crew troweled up Big History paydirt as David Eck was gesturing to the dimensions of this near century old dig. In the pocket of my light Patagonia jacket, my fingers closed over an object that I could fit into my palm. In shape it was oblate, think a flattened football, but with an end bitten off. Beneath my fingers, I could feel an irregular surface made so by labor intensive flaking to create a pointed blade that dwindled to a remarkably thin base. The delicacy of that base was a result of matching flutes skillfully popped from the flint on both sides. In that first summer of digging, Figginson's paleontologists had unearthed two of these points in the loose dirt of the site. Eventually, the Denver team would find eight of these stunning fluted points scattered amongst the bones. But it wasn't just the bones and not the points that made Folsom what American Museum of Natural History scientist Henry Fairfield Osborne labeled the greatest event in American discoveries. When the second season crew at Folsom flicked the dirt from the ribs of an extinct bison, they were greeted by the sight of one of these fluted points embedded to 2/3 its length in the bone. The bar for proof that humans were part of the American Pleistocene had always been an extinct animal, preserving evidence that as a living creature, it had been killed by human technology. Now, outside the tiny burg of Folsom, New Mexico, that bar was hurdled. America too had an antiquity. How much of an antiquity was still in question? Because radiocarbon dating was yet three decades in the future, Figgins claimed the site was 400,000 years old. Eventually, archaeology and paleontology would agree that on an October day, a band of three dozen humans had driven into a box canyon, killed and butchered 32 giant bison of the species Bison antiquus in the spot where I was now standing. And they had done this 12,450 years ago. No one knows now what these ancient bison hunters call themselves or their weapons. Their beautiful fluted points were likely attached to darts thrown by at addles or spear throwers. But not knowing much about these early Americans didn't prevent the scientists from naming both the points and the people Folsom after the nearby town. Yet Folsom wasn't the book of genesis for America's human history. Six years after the Folsom discovery, there was another dramatic revelation. Out on the featureless sweeps of the southern Great Plains, an ordinary gravel excavation near a tiny farming town named Clovis exposed the bones of long extinct American elephants. A remarkable 28 of them. Science and the reading public knew that America had harbored various kinds of giant elephants in the deep past. But unlike 19th century Mastodon finds in the east, this time the skeletons were intermixed with large 5 to 6 inch long projectile points and tools of an unknown and apparently even more ancient population than the Folsom people. We now know that even these elephant hunters were not the first. What has very recently produced certain evidence for even more ancient arrivals in America, likely in boats following shorelines out of Asia, are human footprints. To be precise, 61 footprints, left primarily by children or adolescents in the soft mud of a lake shore some 23,000 years before the area became New Mexico's White Sands National Park. That blockbuster find by a Park employee in 2019 ultimately drew a team of researchers from the U.S. church Geological Survey to date. The seeds of a species of grass crushed by the footprints. Their dating indicates a time frame at the height of the glacial maximum when it would have been impossible to come overland to America. The human footprints aren't the only tracks researchers are finding. There are also mammoth tracks and prints of dire wolves and giant ground sloths. In one fascinating interaction with the tracks appear to show that a young woman carrying a child on her hip, who she occasionally put down, walked a stretch of lakeshore and returned by the same path, which in the interval, both a mammoth and a ground sloth crossed. The mammoth paid no obvious attention, but the sloth reacted, rearing on its hind legs and what may have been alarm. So far as we now know, only a scant few intrepid souls came to America this early. They remind me of Viking visitors to America a thousand years ago. Their numbers must have been small, with much of America still empty of humans. So 10,000 years later, the elephant hunters we now call Clovis made up the first human culture to spread across all the Americas. An overland arrival that became a rapidly advancing wave 13,000 years ago. The rapidity of their spread suggesting that they encountered few, if any other human cultures along the way. Clovis people occupied every American state from Alaska to Florida for more than three centuries, until a mature United States spread coast to coast. In fact, Clovis stood as the sole human culture that once draped across our entire country. So for three centuries, a very long time ago, America was Clovisia the Beautiful. We are still struggling to understand them. They left no oral or written histories of their monarchs or any defining events. We have no sense of their gods or the philosophies they believed in or what language or family of languages they spoke. We know a great deal about their tools, and we're developing a sense of them from their bones and more recently, from their genetics. But starting 13,050 years ago, and lasting until 12,750 years ago, the Clovisians placed their stamp on the country and its animals and changed the continent. Their name comes from the place where we first became aware of their existence. An ancient arroyo on the outskirts of the small town of Clovis, New Mexico, on the windswept southern high plains. Getting in close to wild creatures holds a fascination that resonates because it taps ancient imperatives still within us. The relationship between prey and their predators involves learning curves, and each side is very good at the algorithm. But prey do have to learn numerous examples from around the world testify that upon initially encountering humans, many wild creatures did not associate us with a threat. There is a term of art for this biological first contact. Wild animals had to learn to be afraid of us. Many died standing and looking, never absorbing the lesson. Finding naive animals that were easy for human hunters was a powerful motive for our species migrations around the world. But just who were these Clovis people who left so many sites across America? More than 20 excavated ones so far, including some 70 butchered elephants. One recent theory that briefly achieved traction in places like National Geographic came from the Smithsonian's Dennis Stanford, who believed that the direct ancestors of the Clovis people reached America 18,000 years ago from Europe. To say that the scientific community scoffed at Stanford's across Atlantic ice claims barely does justice to the profound skepticism that followed it. While Paleolithic hunters in Europe and America did pursue similar megafauna and flint points crafted by Western Europe's Solutrean culture superficially resembled Clovis points, Other researchers dismissed Stanford's claims that the two groups were the same people. Linguistic and genetic conclusions have since refuted Stanford's argument. Once scientists were able to analyze genomic evidence from archaeological sites, they quickly confirmed a trail of genetic kinship stretching from Siberia rather than Europe into the Americas. We now suspect that the people who ultimately swept into America first spent several thousand years on the Bering land bridge itself, Itself the so called Beringian standstill, apparently awaiting more favorable conditions to move southward. That long pause in Beringia may have produced humanity's first domestication of another animal engaged in their own return to America. 25,000 years ago, Gray wolves were abundant in Beringia. Since human hunters only ate the fattest parts of the animals they killed, they had leftover lean portions they were willing to share. Some of the wolves had a mutation that made them hypersocial, and puppies with that gene may have been able to bond with humans. There probably also were wolf puppies, known today as gifted word learning animals capable of picking up human language. By the time the two species got to America, humans and their tamed wolves had formed a partnership for the rest of history. Or so goes one theory about dog domestication. Clovis genetics are best represented by a male toddler from a 12,800-year-old burial in Montana. He's known as the Anzik Child, and he's from a site not far from today's Bozeman. The Clovis child was buried with a large cache of artifacts that included eight Clovis points Painted in red ochre after he played an epic role in reconstructing a history of two continents. In 2014, the Anzik Boy was reburied by local tribes in Montana's Shields river, near where he had lain for nearly 13,000 years. While we have no surviving mammoth or mastodon populations to study, we do know a good deal about Asian elephant natural history. And if this closest living relative of mammoths offers clues, America's ancient elephants would have been highly intelligent creatures, Especially acute in what biologists called situational intelligence. Their trunks were elephant analogs to our opposable thumbs, with as many as 150,000 muscle subunits as ecological chemicals. Keystone creatures whose activity shaped landscapes, Mammoths and mastodons foraged in ways that likely transformed American vegetation, the way modern elephants do in Africa. They traveled their huge ranges with an unusually powerful geographic memory. As a recent study of a woolly mammoth's lifetime movements through Alaska 17,000 years ago, reconstructed by analyzing strontium isotope ratios of that reference geography in its tusks, now indicate, all elephants are what biologists refer to as K species, meaning they do not come into sexual maturity until they're 15 years old or older, a state brought on by periodic must. The pachyderm version of sexual heat, from insemination to giving birth, probably took two years, A generational turnover low enough to make population recovery difficult in the face of a new threat. And by the time humans were entering America, mammoths, mastodons, and other archaic elephant species were already suffering from a background rate of extinctions that had been going on for 75,000 years. But as the Rancho La Brea, Folsom and Clovis sites show, elephants and big cats and many other remarkable creatures still occupied the ground where we now commute and go to sleep in our suburbs. Only they all disappeared quite suddenly and mysteriously, long, long ago. That disappearance is one of the most profound ecological and aesthetic events of continental history. As Darwin's ally in the breakthrough to understanding natural selection and evolution, Alfred Russel Wallace wrote, In fact, we present day Americans live in a zoological impoverished world from which all the hugest and fiercest and strangest forms have recently disappeared. Wallace was using recently in a big history sense, all those hugest, fiercest and strangest animals vanished from America between about 30, 13,000 and 9,000 years ago. In fact, we lost 30 genera and 40 species, all of them our very largest creatures, right down to our present moment. These ancient losses make up the most dramatic extinction event since humans have been in North America. But science has never grouped the so called Pleistocene extinctions with the five great planetary extinctions of Earth history. It's different from all of those which were global extinguished life on both land and in the oceans and showed no size bias in the creatures they marked for disappearance. The Pleistocene losses didn't happen in oceans in Africa or in southern Asia. They devastated life on Earth only in Eurasia, North America, South America and Australia. Something very odd seemed to be unfolding in specific parts of the planet during the late Pleistocene. But there is a common thread. Those were all places where human predators out of Africa seeking out large animals to hunt were arriving for the first time. The Pleistocene extinctions, in other words, looked very much like the first, first act of the Anthropocene, the beginnings of what we now call the sixth extinction.