by Sam Kean
Nikita Zimov, who met us at the airport, had foreseen these difficulties. Thanks to his lobbying, the soldiers agreed to let Slater through with only 30 minutes of questioning at the local military base. The soldiers wanted to know whether he had ever been to Syria and, more to the point, whether he was an American spy. “It is good to be a big man in a small town,” Nikita told us as we left the base.
Nikita runs the Northeast Science Station, an Arctic research outpost near Cherskiy, which supports a range of science projects along the Kolyma River, including Pleistocene Park. The station and the park are both funded with a mix of grants from the European Union and America’s National Science Foundation. Nikita’s family makes the 2,500-mile journey from Novosibirsk to the station every May. In the months that follow, they are joined by a rotating group of more than 60 scientists from around the world. When the sky darkens in the fall, the scientists depart, followed by Nikita’s family and finally Nikita himself, who hands the keys to a small team of winter rangers.
We arrived at the station just before dinner. It was a modest place, consisting of 11 hacked-together structures, a mix of laboratories and houses overlooking a tributary of the Kolyma. Station life revolved around a central building topped by a giant satellite dish that once beamed propaganda to this remote region of the Soviet empire.
I’d barely stepped through the door that first night when Nikita offered me a beer. “Americans love IPAs,” he said, handing me a 32-ounce bottle. He led us into the station’s dining hall, a warmly lit, cavernous room directly underneath the satellite dish. During dinner, one of the scientists told me that the Northeast Science Station ranks second among Arctic outposts as a place to do research, behind only Toolik Field Station in Alaska. Nikita later confided that he felt quite competitive with Toolik. Being far less remote, the Alaskan station offers scientists considerable amenities, including seamless delivery from Amazon Prime. But Toolik provides no alcohol, so Nikita balances its advantages by stocking his station with Russian beer and crystal-blue bottles of Siberian vodka, shipped into Cherskiy at a heavy cost. The drinks are often consumed late at night in a roomy riverside sauna, under a sky streaked pink by the midnight sun.
Nikita is the life of the station. He is at every meal, and any travel, by land or water, must be coordinated through him. His father is harder to find. One night, I caught Sergey alone in the dining room, having a late dinner. Squat and barrel-chested, he was sitting at a long table, his thick, gray rope of a ponytail hanging past his tailbone. His beard was a white Brillo Pad streaked with yellow. He chain-smoked all through the meal, drinking vodka, telling stories, and arguing about Russo-American relations. He kept insisting, loudly and in his limited English, that Donald Trump would be elected president in a few months. (Nikita would later tell me that Sergey has considered himself something of a prophet ever since he predicted the fall of the Soviet Union.) Late in the night, he finally mellowed when he turned to his favorite subjects, the deep past and far future of humankind. Since effectively handing the station over to his son, Sergey seems to have embraced a new role. He has become the station’s resident philosopher.
Nikita would probably think philosopher too generous. “My dad likes to lie on the sofa and do science while I do all the work,” he told me the next day. We were descending into an ice cave in Pleistocene Park. Step by cautious step, we made our way down a pair of rickety ladders that dropped 80 feet through the permafrost to the cave’s bottom. Each time our boots found the next rung, we came eye to eye with a more ancient stratum of chilled soil. Even in the Arctic summer, temperatures in the underground network of chambers were below freezing, and the walls were coated with white ice crystals. I felt like we were wandering around in a geode.
Not every wall sparkled with fractals of white frost. Some were windows of clear ice, revealing mud that was 10,000, 20,000, even 30,000 years old. The ancient soil was rich with tiny bone fragments from horses, bison, and mammoths, large animals that would have needed a prolific, cold-resistant food source to survive the Ice Age Arctic. Nikita knelt and scratched at one of the frozen panels with his fingernail. Columns of exhaled steam floated up through the white beam of his headlamp. “See this?” he said. I leaned in, training my lamp on his thumb and forefinger. Between them, he held a thread of vegetable matter so tiny and pale that an errant breath might have reduced it to powder. It was a 30,000-year-old root that had once been attached to a bright-green blade of grass.
For the vast majority of the Earth’s 4.5 billion spins around the sun, its exposed, rocky surfaces lay barren. Plants changed that. Born in the seas like us, they knocked against the planet’s shores for eons. They army-crawled onto the continents, anchored themselves down, and began testing new body plans, performing, in the process, a series of vast experiments on the Earth’s surface. They pushed whole forests of woody stems into the sky to stretch their light-drinking leaves closer to the sun. They learned how to lure pollinators by unfurling perfumed blooms in every color of the rainbow. And nearly 70 million years ago, they began testing a new form that crept out from the shadowy edges of the forest and began spreading a green carpet of solar panel across the Earth.
For tens of millions of years, grasses waged a global land war against forests. According to some scientists, they succeeded by making themselves easy to eat. Unlike other plants, many grasses don’t expend energy on poisons, or thorns, or other herbivore-deterring technologies. By allowing themselves to be eaten, they partner with their own grazers to enhance their ecosystem’s nutrient flows.
Temperate-zone biomes can’t match the lightning-fast bio-cycling of the tropics, where every leaf that falls to the steamy jungle floor is set upon by microbial swarms that dissolve its constituent parts. In a pine forest, a fallen branch might keep its nutrients locked behind bark and needle for years. But grasslands are able to keep nutrients moving relatively quickly, because grasses so easily find their way into the hot, wet stomachs of large herbivores, which are even more microbe-rich than the soil of the tropics. A grazing herbivore returns nutrients to the soil within a day or two, its thick, paste-like dung acting as a fertilizer to help the bitten blades of grass regrow from below. The blades sprout as if from everlasting ribbon dispensers, and they grow faster than any other plant group on Earth. Some bamboo grasses shoot out of the ground at a rate of several feet a day.
Grasses became the base layer for some of the Earth’s richest ecosystems. They helped make giants out of the small, burrowing mammals that survived the asteroid that killed off the dinosaurs some 66 million years ago. And they did it in some of the world’s driest regions, such as the sunbaked plains of the Serengeti, where more than 1 million wildebeests still roam. Or the northern reaches of Eurasia during the most-severe stretches of the Pleistocene.
The root between Nikita’s thumb and forefinger was one foot soldier among trillions that fought in an ecological revolution that human beings would come to join. We descended, after all, from tree-dwellers. Our nearest primate relatives, chimpanzees, bonobos, and gorillas, are still in the forest. Not human beings. We left Africa’s woodlands and wandered into the alien ecology of its grassland savannas, as though sensing their raw fertility. Today, our diets—and those of the animals we domesticated—are still dominated by grasses, especially those we have engineered into mutant strains: rice, wheat, corn, and sugarcane.
“Ask any kid ‘Where do animals live?’ and they will tell you ‘The forest,’” Nikita told me. “That’s what people think of when they think about nature. They think of birds singing in a forest. They should think of the grassland.”
Nikita and I climbed out of the ice cave and headed for the park’s grassland. We had to cross a muddy drainage channel that he had bulldozed to empty a nearby lake, so that grass seeds from the park’s existing fields could drift on the wind and fall onto the newly revealed soil. Fresh tufts of grass were already erupting out of the mud. Nikita does most of his violent gardening with a forest-mowing transporter on
tank treads that stands more than 10 feet tall. He calls it the “mama mammoth.”
When I first laid eyes on Pleistocene Park, I wondered whether it was the grassland views that first lured humans out of the woods. In the treeless plains, an upright biped can see almost into eternity. Cool Arctic winds rushed across the open landscape, fluttering its long ground layer of grasses. On the horizon, I made out a herd of large, gray-and-white animals. Their features came into focus as we hiked closer, especially after one broke into a run. They were horses, like those that sprinted across the plains of Eurasia and the Americas during the Pleistocene, their hooves hammering the ground, compressing the snow so that other grazers could reach cold mouthfuls of grass and survive the winter.
Like America’s mustangs, Pleistocene Park’s horses come from a line that was once domesticated. But it was hard to imagine these horses being tamed. They moved toward us with a boldness you don’t often see in pens and barns. Nikita is not a man who flinches easily, but he backpedaled quickly when the horses feinted in our direction. He stooped and gathered a bouquet of grass and extended it tentatively. The horses snorted at the offer. They stared at us, dignified and curious, the mystery of animal consciousness beaming out from the black sheen of their eyes. At one point, four lined up in profile, like the famous quartet of gray horses painted by torchlight on the ceiling of Chauvet Cave, in France, some 30,000 years ago.
We walked west through the fields, to where a lone bison was grazing. When seen without a herd, a bison loses some of its glamour as a pure symbol of the wild. But even a single hungry specimen is an ecological force to be reckoned with. This one would eat through acres of grass by the time the year was out. In the warmer months, bison expend some of their awesome muscular energy on the destruction of trees. They shoulder into stout trunks, rubbing them raw and exposing them to the elements. It was easy to envision huge herds of these animals clearing the steppes of Eurasia and North America during the Pleistocene. This one had trampled several of the park’s saplings, reducing them to broken, leafless nubs. Nikita and I worried that the bison would trample us, too, when, upon hearing us inch closer, he reared up his mighty, horned head, stilled his swishing tail, and stared, as though contemplating a charge.
We stayed low and headed away to higher ground to see a musk ox, a grazer whose entire being, inside and out, seems to have been carved by the Pleistocene. A musk ox’s stomach contains exotic microbiota that are corrosive enough to process tundra scrub. Its dense layers of fur provide a buffer that allows it to graze in perfect comfort under the dark, aurora-filled sky of the Arctic winter, untroubled by skin-peeling, 70-below winds.
Nikita wants to bring hordes of musk oxen to Pleistocene Park. He acquired this one on a dicey boat ride hundreds of miles north into the ice-strewn Arctic Ocean. He would have brought back several others, too, but a pair of polar bears made off with them. Admiring the animal’s shiny, multicolored coat, I asked Nikita whether he worried about poachers, especially with a depressed mining town nearby. He told me that hunters from Cherskiy routinely hunt moose, reindeer, and bear in the surrounding forests, “but they don’t hunt animals in the park.”
“Why?” I asked.
“Personal relationships,” he said. “When the leader of the local mafia died, I gave the opening remarks at his funeral.”
Filling Pleistocene Park with giant herbivores is a difficult task because there are so few left. When modern humans walked out of Africa, some 70,000 years ago, we shared this planet with more than 30 land-mammal species that weighed more than a ton. Of those animals, only elephants, hippos, rhinos, and giraffes remain. These African megafauna may have survived contact with human beings because they evolved alongside us over millions of years—long enough for natural selection to bake in the instincts required to share a habitat with the most dangerous predator nature has yet manufactured.
The giant animals that lived on other continents had no such luxury. When we first wandered into their midst, they may have misjudged us as small, harmless creatures. But by the time humans arrived in southern Europe, we’d figured out how to fan out across grasslands in small, fleet-footed groups. And we were carrying deadly projectiles that could be thrown from beyond the intimate range of an animal’s claws or fangs.
Most ecosystems have checks against runaway predation. Population dynamics usually ensure that apex predators are rare. When Africa’s grazing populations dip too low, for instance, lions go hungry and their numbers plummet. The same is true of sharks in the oceans. But when human beings’ favorite prey thins out, we can easily switch to plant foods. This omnivorous resilience may explain a mystery that has vexed fossil hunters for more than a century, as they have slowly unearthed evidence of an extraordinary die-off of large animals all over the world, right at the end of the Pleistocene.
Some scientists think that extreme climate change was the culprit: the global melt transformed land-based biomes, and lumbering megafauna were slow to adapt. But this theory has weaknesses. Many of the vanished species had already survived millions of years of fluctuations between cold and warmth. And with a climate-caused extinction event, you’d expect the effects to be distributed across size and phylum. But small animals mostly survived the end of the Pleistocene. The species that died in high numbers were mammals with huge stores of meat in their flanks—precisely the sort you’d expect spear-wielding humans to hunt.
Climate change may have played a supporting role in these extinctions, but as our inventory of fossils has grown, it has strengthened the case for extermination by human rampage. Most telling is the timeline. Between 40,000 and 60,000 years ago, during an ocean-lowering glaciation, a small group of humans set out on a sea voyage from Southeast Asia. In only a few thousand years, they skittered across Indonesia and the Philippines, until they reached Papua New Guinea and Australia, where they found giant kangaroos, lizards twice as long as Komodo dragons, and furry, hippo-sized wombats that kept their young in huge abdominal pouches. Estimating extinction dates is tricky, but most of these species seem to have vanished shortly thereafter.
It took at least another 20,000 years for human beings to trek over the Bering land bridge to the Americas, and a few thousand more to make it down to the southern tip. The journey seems to have taken the form of an extended hunting spree. Before humans arrived, the Americas were home to mammoths, bear-sized beavers, car-sized armadillos, giant camels, and a bison species twice as large as those that graze the plains today. The smaller, surviving bison is now the largest living land animal in the Americas, and it barely escaped extermination: the invasion of gun-toting Europeans reduced its numbers from more than 30 million to fewer than 2,000.
The pattern that pairs human arrival with megafaunal extinction is clearest in the far-flung islands that no human visited until relatively recently. The large animals of Hawaii, Madagascar, and New Zealand disappeared during the past 2,000 years, usually within centuries of human arrival. This pattern even extends to ocean ecosystems. As soon as industrial shipbuilding allowed large groups of humans to establish a permanent presence on the seas, we began hunting marine megafauna for meat and lamp oil. Less than a century later, North Atlantic gray whales were gone, along with 95 percent of North Atlantic humpbacks. Not since the asteroid struck have large animals found it so difficult to survive on planet Earth.
In nature, no event happens in isolation. A landscape that loses its giants becomes something else. Nikita and I walked all the way to the edge of Pleistocene Park, to the border between the grassy plains and the forest, where a line of upstart saplings was shooting out of the ground. Trees like these had sprung out of the soils of the northern hemisphere for ages, but until recently, many were trampled or snapped in half by the mighty, tusked force of the woolly mammoth.
It was only 3 million years ago that elephants left Africa and swept across southern Eurasia. By the time they crossed the land bridge to the Americas, they’d grown a coat of fur. Some of them would have waded into the shallow pa
sses between islands, using their trunks as snorkels. In the deserts south of Alaska, they would have used those same trunks to make mental scent maps of water resources, which were probably sharper in resolution than a bloodhound’s.
The mammoth family assumed new forms in new habitats, growing long fur in northern climes and shrinking to pygmies on Californian islands where food was scarce. But mammoths were always a keystone species on account of their prodigious grazing, their well-digging, and the singular joy they seemed to derive from knocking down trees. A version of this behavior is on display today in South Africa’s Kruger National Park, one of the only places on Earth where elephants live in high densities. As the population has recovered, the park’s woodlands have thinned, just as they did millions of years ago, when elephants helped engineer the African savannas that made humans into humans.
I have often wondered whether the human who first encountered a mammoth retained some cultural memory of its African cousin, in song or story. In the cave paintings that constitute our clearest glimpse into the prehistoric mind, mammoths loom large. In a single French cave, more than 150 are rendered in black outline, their tusks curving just so. In the midst of the transition from caves to constructed homes, some humans lived inside mammoths: 15,000 years ago, early architects built tents from the animals’ bones and tusks.
Whatever wonderment human beings felt upon sighting their first mammoth, it was eventually superseded by more-practical concerns. After all, a single cold-preserved carcass could feed a tribe for a few weeks. It took less than 50 millennia for humans to help kill off the mammoths of Eurasia and North America. Most were dead by the end of the Ice Age. A few survived into historical times, on remote Arctic Ocean outposts like St. Paul Island, a lonely dot of land in the center of the Bering Sea where mammoths lived until about 3600 B.C. A final group of survivors slowly wasted away on Wrangel Island, just north of Pleistocene Park. Mammoth genomes tell us they were already inbreeding when the end came, around 2000 B.C. No one knows how the last mammoth died, but we do know that humans made landfall on Wrangel Island around the same time.
