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It’s easy to become perplexed when contemplating the megafauna extinctions. Paul Martin described the process in North America as a blitzkrieg, an ecological catastrophe that was largely accomplished in a mere thousand years or so — far faster than the earlier extinction spasms in the Old World.
Obviously, the North American spasm was only lightning fast in an evolutionary timeframe. From the perspective of living humans, a thousand years is quite a while. I expect that some of my readers are younger than 200. A much earlier spasm in Africa took place over hundreds of thousands of years. These hominin ancestors were apparently still cadets in their ability to hunt slightly too hard.
All animals pay careful attention to the here and now, in the immediate vicinity. Few, if any, think about tomorrow or next year. Wild ecosystems, and the weather, exist in a state of constant change. It’s impossible to predict what living conditions will be like a year from now, or in two months. What game will be plentiful? What will be scarce?
Small isolated bands of people were living in a vast wilderness, unaware of current conditions in every surrounding hill and valley. There was no way they could accurately monitor the populations of game animals. When hunting was bad, they couldn’t know why. Was the herd declining, or had they wandered elsewhere to visit relatives? An ecosystem is not an enclosed laboratory where everything can be precisely measured and controlled. Hunting is a game of chance.
Anthropologists have reported that some hunter-gatherer cultures, who survived into recent times, understood the risks of overhunting. They developed rituals and taboos for avoiding it. Richard Nelson wrote that when deer numbers declined, the Koyukon people stopped hunting them for several years, and ate other critters instead. Also, when game was abundant, they would stop hunting in a portion of their domain, creating a refuge where game could get a break from hunting, and recharge their numbers. Sometimes mindful efforts at conservation worked well. Sometimes folks starved. Humans were not in full control.
Two important factors in megafauna extinctions were shifting baseline syndrome, and the low reproductive rates of large game animals. Shifting baseline syndrome describes the fact that our conception of “normal” is continuously changing. Kids in school today can’t imagine a world without smart phones, video games, and access to unlimited sources of entertainment. When I was born in 1952, there were five billion fewer humans on Earth. In my childhood, the only glowing screen was a small black and white TV with four boring channels that shut down out at 11:00 P.M. In those days, we kids regularly played together outdoors all the time, and communicated by actually speaking to each other, face to face.
“Normal” in 1960 was far different from normal in 1990, or 2020. My perception of normal fishing is far more modest than my father’s, my grandfather’s, and so on. Each generation experiences fewer and smaller fish, yet each considers the reality they experience to be the normal state. Pleistocene hunters did not know how abundant game was in their grandfather’s days, or 500 years earlier. Nobody probably noticed if the number of mammoths was gradually declining.
Fernando Fernandez concluded that the primary factor in megafauna extinctions was the fact that the jumbo-sized walking meatballs that hunters eagerly desired did not reproduce like bunnies or cockroaches. Killing them just slightly above their fertility rate could wipe them out over the passage of centuries. It wasn’t so much about the intensity of the hunting as the fragility of the hunted. Over a thousand years, and many generations of hunters, extinctions may have been essentially invisible.
Elizabeth Kolbert noted that modern elephants do not reach sexual maturity until their late teens, each pregnancy takes 22 months, and there are never twins. Because they reproduce so slowly, mammoths could have been driven to extinction by nothing more than modest levels of hunting. Doug Peacock estimated that taking only 4 or 5 percent of a slow breeding species could put them on a gradual path to extinction. Peter Ward estimated that if hunters had regularly taken just two percent of the mammoths each year, the extinction process would have taken 400 years — too slow for each generation of hunters to notice. Hunting alone could have wiped them out.
Kolbert wondered how Neanderthals had lived in Europe for more than 100,000 years without causing weird disturbances. She suspected that if humans had never arrived, the good old days of abundant megafauna would have never ended. Prior to the arrival of skilled teams of human hunters, jumbo size provided a survival advantage. Megafauna thrived in Eurasia and the Americas 50,000 years ago, before trouble rumbled in — at which point being huge and slow became a serious vulnerability. Kolbert was not sure if there was ever a time when humans lived in ecological harmony.
Pita Kelekna wrote that large herds of wild horses were once common in the river valleys of western and central Europe. By about 8,000 years ago, they were nearly eliminated by overhunting in most of the continent, except in a few small pockets. Several writers concluded that domestication probably spared horses from extinction. Folks learned that horses were more valuable for transportation, and as beasts of burden. There were many other delicious critters to feast on.
The Australian extinctions probably occurred between 50,000 and 40,000 years ago, following the arrival of humans. Tim Flannery described how ecosystems went through a number of substantial changes, as the early Aborigines learned how to survive in an unusual land, via trial and error. He believes that they finally learned how to live in relative balance by around 12,000 years ago.
Australia was blessed with having ancient worn-out soils, and a bipolar climate. Severe droughts could last years, which might suddenly end with terrific deluges. Thus, Australia was a lousy location for the emergence of agriculture and civilization. Aborigines retained a Stone Age way of life until 1788, when British colonists arrived, and attempted to transplant an English way of life to a land for which it was not ideal.
Humans arrived in New Zealand between 800 and 1,000 years ago, and by 400 years ago the moas were extinct. Moas were ostrich-like birds that could grow to 10 feet (3 m) tall, and weigh 550 pounds (250 kg). Many collections of moa bones have been found, some containing the remains of up to 90,000 birds. Evidence suggests that a third of the meat was tossed away to rot. Obviously, the birds were super-abundant and super-easy to kill.
In the global eco-catastrophe that we are experiencing today, Australasia did not historically play a leading role. The planet-thrashing juggernaut, which was born in Africa, gained a lot of strength and momentum when humans migrated into snow country, where a challenging climate inspired a surge in techno innovation.
In Europe, the era of megafauna extinctions corresponded to the arrival of human colonists. Most of the extinctions occurred in two spasms — from 45,000 to 20,000 years ago in the warmer south, and from 14,000 to 9,000 years ago in the cooler north. The process was much faster than the earlier extinctions in Africa. Two million years ago in Africa, our pre-human ancestors were smaller, and still learning the basics of big game hunting. The humans who later colonized Europe were bigger, stronger, and better equipped for hunting.
Paul Martin had an intriguing notion. In the tropics of Africa and Asia, the warm climate favored the existence of infectious diseases and parasites that tropical primates were vulnerable to, like sleeping sickness and malaria. Maybe these pathogens limited the size of hominin populations, thereby boosting the survival of large game. In the cooler climate of Europe, the pathogens that could harm humans were fewer in number or less virulent. In snow country, maybe healthier humans lived longer and hunted more.
Below is a sampler of some of the species that blinked out in Europe. Most had been around for more than a million years, and had survived multiple ice ages. This list is far from complete, and highly oversimplified. These species had survived for a very long time, but their luck ran out following the arrival of humans.
Irish “elk” were actually a species of large deer (not elk). They existed for several million years, including 400,000 years in Europe. The last ones died 7,700 years ago in the Ural Mountains. They lived throughout Europe, east to Siberia and China, and south to northern Africa.
Straight-tusked elephants were in Europe by around 780,000 years ago, and vanished 30,000 years ago.
Cave hyenas were gone by 13,000 years ago, after 3.5 million years. They dined primarily on horses, steppe wisent, and woolly rhinoceros. Large hyenas could weigh up to 225 pounds (102 kg). They inhabited northern Africa, the Middle East, and much of Europe, and Asia.
Cave bears emerged about 1.2 million years ago, and vanished 29,500 years ago. They ranged from Britain and Spain, east across much of Europe, and into Russia and Iran.
European cave lions were quite similar to the lions still alive in Africa. The two lines diverged about 1.9 million years ago, and the European cats went extinct 13,000 years ago. They ranged in a wide belt from Spain and southern England, to Siberia, Alaska, and the Yukon.
European hippopotamus ranged across Europe, from Spain to Britain to Greece. They emerged 1.8 million years ago, and went extinct 24,000 years ago.
Woolly Mammoths emerged 400,000 years ago in Eurasia, and went extinct in Europe 10,000 years ago.
Woolly rhinoceroses were living on the Tibetan Plateau 3.6 million years ago. They were common throughout Europe and northern Asia, from Spain to China. They survived until 10,000 years ago.
Paul Martin created much controversy with his theory that many of the extinctions in North America took place within a thousand years. Among his critics were Native Americans, who were offended by the implication that their ancient ancestors foolishly hunted too hard. For them, Martin’s ideas had the stinky aroma of racism. The dating of the fossil specimens found so far does not rubbish his theory. He did acknowledge that the extinctions seem to have ended about 12,000 years ago, but by this time, all the remaining large species had probably learned, the hard way, that primates were dangerous predators.
In an attempt to sidestep accusations of racism, a number of experts have tried to shift the primary blame to climate change, but that theory does not hold up as well to scrutiny. Efforts to place the blame on epidemic animal diseases have yet to discover supporting evidence. In the last 50,000 years, there is a clear pattern that megafauna extinctions routinely followed the arrival of humans into new continents — not the ups and downs of glaciation cycles.
As humans crossed into North America from Siberia, hunting began in northwest Canada, and spread south and east like a wild fire. Peter Ward wrote that within one to two thousand years, at least 33 genera (50 species) of large mammals went extinct — far more than in the preceding three million years, which included numerous glaciation cycles. Many of those that disappeared had lived in America for tens of millions of years.
To put the North American extinctions in context, let’s take a peek at some of the evidence.
Elephant family species immigrated into America from 1 to 15 million years ago. There were at least seven varieties (mammoths, mastodons, etc.). They survived until 12,000 years ago.
Horses originated in North America about 4 million years ago, and later spread into South America, Asia, Europe, and Africa. They were extinct in North and South America by 8,000 years ago. The Equus genus includes horses, asses, and zebras.
Saber-tooth cats emerged in Africa 12 million years ago. Some types could grow up to 620 pounds (280 kg). They have been found in North America, South America, Eurasia, and Africa. They went extinct in Africa 1.4 million years ago. In North America they vanished 10,000 years ago.
Scimitar-tooth cats emerged in Africa about 4 million years ago. They vanished from Africa 1.5 million years ago, from Eurasia about 28,000 years ago, and from America about 12,000 years ago.
American lions originated in Africa over a million years ago, and migrated into North America, as far south as Central America. They went extinct around 11,300 years ago.
Camels originated in North America maybe 40 million years ago. By 2 to 5 million years ago, some had crossed into Asia, and spread into Africa. In North America, they went extinct 10,000 years ago. They still survive in the Old World.
Short-faced bears were among the largest land dwelling mammalian carnivores on Earth, and they were abundant in California. The species emerged about 1.8 million years ago, and went extinct about 11,000 years ago.
Giant armadillos were mammals that originated in South America 5.3 million years ago, migrated into North America, and went extinct about 12,000 years ago.
Ground sloths could grow as large as elephants. They emerged in North and South America about 4.9 million years ago, and went extinct 11,000 years ago.
Giant beavers were the largest North American rodent. They emerged about 2.6 million years ago, and went extinct about 11,700 years ago.
Tapirs could grow up to 4.6 feet (1.4 m) long, and weigh up to 496 pounds (225 kg). They emerged 20 to 30 million years ago in North America, and went extinct about 11,000 years ago in America. In China, some survived until 4,000 years ago.
Woodland musk ox could grow to 934 pounds (423 kg). They lived from Alaska to California, and east to New Jersey. They emerged about 2 million years ago, and went extinct about 11,000 years ago.
Dire wolves lived in North and South America from 125,000 to 9,440 years ago. The average wolf weighed about 150 pounds (68 kg). Their prey included camels, bison, mastodons, ground sloths, and horses.