Why do we take so much time to invent civilization? Modern Homo sapiens it evolved for the first time approximately 250,000 to 350,000 years ago. But the first steps towards civilization, the harvest and then the domestication of crop plants, began only about 10,000 years ago, and the first civilizations appeared 6,400 years ago.
For 95 percent of the history of our species, we do not cultivate, we create large settlements or complex political hierarchies. We lived in small nomadic bands, hunting and gathering. Then something changed.
We pass from the life of hunter-gatherers to the harvest of plants, then to the cultivation and, finally, to the cities. Surprisingly, this transition occurred only after the ice age megafauna disappeared: mammoths, lazy land giants, giant deer and horses. The reasons why humans began to cultivate are still unclear, but the disappearance of the animals on which we depend for food may have forced our culture to evolve.
The first humans were intelligent enough to cultivate. All modern human groups have similar levels of intelligence, suggesting that our cognitive abilities evolved before these populations separated about 300,000 years ago, and then changed shortly thereafter. If our ancestors didn’t grow plants, it’s not that they weren’t smart enough. Something in the environment prevented them, or they simply did not need it.
Global warming at the end of the last glacial period, 11,700 years ago, probably facilitated agriculture. Warmer temperatures, longer growing seasons, higher rainfall and long-term climatic stability made more areas suitable for cultivation. But it is unlikely that agriculture has been impossible everywhere. And the Earth saw many of these warming events 11,700, 125,000, 200,000 and 325,000 years ago, but previous warming events did not stimulate experiments in agriculture. Climate change may not have been the only driver.
Human migration probably also contributed. When our species expanded from southern Africa throughout the African continent, to Asia, Europe and then the Americas, we found new environments and new food plants. But people occupied these parts of the world long before agriculture began. The domestication of plants delayed human migration for tens of millennia.
If opportunities to invent agriculture already existed, then the late invention of agriculture suggests that our ancestors did not need or wanted to cultivate.
Agriculture has significant disadvantages compared to food. Agriculture requires more effort and offers less free time and a lower diet. If the hunters are hungry in the morning, they can have food in the fire at night. Agriculture requires hard work today to produce food months later, or nothing at all. It requires storage and management of temporary food surpluses to feed people throughout the year.
A hunter who has a bad day can hunt again tomorrow or look for richer hunting areas elsewhere, but the farmers, tied to the ground, are at the mercy of nature’s unpredictability. Rains that arrive too soon or too late, droughts, frost, pests or lobsters can cause crop loss and hunger.
Agriculture also has military disadvantages. The hunter-gatherers are mobile and can travel long distances to attack or retreat. The constant practice with spears and bows made them mortal fighters. Farmers are rooted in their fields, their schedules dictated by the seasons. They are predictable stable targets, whose food reserves tempt the hungry outside.
And having evolved into the lifestyle, humans simply loved being nomadic hunters. Comanche Indians fought to the death to preserve their hunting lifestyle. The Bushmen of Kalahari in South Africa continue to resist becoming farmers and shepherds. Surprisingly, when Polynesian farmers encountered the abundant non-flying birds of New Zealand, they largely abandoned agriculture, creating the Maori culture of moa hunters.
However, something changed. For 10,000 years onwards, humans repeatedly abandoned the hunter-gatherer lifestyle for agriculture. It may be that after the extinction of mammoths and other megafaunas from the Pleistocene era, and excessive hunting of the surviving game, the hunter-gatherer lifestyle became less viable, pushing people to harvest and then grow plants. Perhaps civilization was not born of an impulse towards progress, but of disaster, since the ecological catastrophe forced people to abandon their traditional lifestyles.
When humans left Africa to colonize new lands, large animals disappeared everywhere we stepped. In Europe and Asia, megafauna such as woolly rhinos, mammoths and Irish elk disappeared about 40,000 to 10,000 years ago. In Australia, giant kangaroos and wombats disappeared 46,000 years ago. In North America, horses, camels, giant armadillos, mammoths and sloths decreased and disappeared 15,000 to 11,500 years ago, followed by extinctions in South America 14,000 to 8,000 years ago. After people spread to the Caribbean Islands, Madagascar, New Zealand and Oceania, their megafauna also disappeared. Megafaunal extinctions inevitably followed humans.
The big game harvest like horses, camels and elephants produces a better yield than the small game hunt like rabbits. But large animals such as elephants reproduce slowly and have little offspring compared to small animals such as rabbits, which makes them vulnerable to overexploitation. And so, in all the places we went to, our human ingenuity, hunting with spear throwers, grazing animals with fire, stamping them on the cliffs, meant that we harvested large animals faster than their numbers could replenish. It could be said that it was the first sustainability crisis.
Since the ancient way of life was no longer viable, humans would have been forced to innovate, focusing more and more on harvesting and then growing plants to survive. This allowed human populations to expand. Eating plants instead of meat is a more efficient use of land, so agriculture can help more people in the same area as hunting. People could settle permanently, build settlements and then civilizations.
The archaeological and fossil records tell us that our ancestors could have followed agriculture, but they only did so after they had few alternatives. We would probably have continued to hunt horses and mammoths forever, but we were too good at it and we had probably eliminated our own food supply.
Agriculture and civilization may have been invented not because they were an improvement over our ancestral lifestyle, but because we had no other choice. Agriculture was a desperate attempt to fix things when we took more than the ecosystem could sustain. If so, we abandon the life of the ice age hunters to create the modern world, not with foresight and intention, but by accident, due to an ecological catastrophe that we created thousands of years ago.
This article is republished from The Conversation by Nick Longrich, senior lecturer in Paleontology and Evolutionary Biology, University of Bath, under a Creative Commons license. Read the original article.