This is not quite a transcript, but it is more of a summary of the audio. Substack provides transcripts of the audios that are not too bad. Also, you can turn on closed captions while listening to it by using Google’s Chrome browser and turning on Live Captioning (under “Settings” and “Accessibility”). You can also select any part of the transcript and Substack will play that sound clip. I am continually amazed at how these kinds of technologies are progressing. This is decidedly a less formal way of presenting my work, and we will see if people find it helpful.
Two trends began soon after the first stone tools were crafted: the brains of those bipedal apes began growing and animals vulnerable to those stone tools began going extinct. Giant tortoises were among the first casualties. Armor is a great defensive strategy until something defeats the armor, and giant tortoises had no defense to rock-wielding apes. Beginning more than two million years ago, wherever rock-wielding apes or humans appeared, giant tortoises quickly went extinct. They had a global distribution before the arrival of rock-wielding apes, and they live in only two places on Earth today, which were among the last islands that humans “discovered.”
That trend of growing brains continued before culminating with the arrival of Homo erectus on the evolutionary scene in Africa, currently dated at 2.1 million years ago. In my studies of paleology over the past generation, a constant has been new evidence that pushed back the dates of evolutionary events and dates in the development of human-line societies. Early Homo erecti had brains twice the size of chimps and they were anatomically developed for sleeping on the ground, which was a first for a primate.
Darwin thought that the two greatest inventions of humanity were the control of fire and language. Over the past generation, scientists have argued that both may have been invented two million years ago by Homo erectus. There is some evidence for those ideas, but the controversy will outlive me. What is not disputed is that about 1.8-to-1.7 million years ago, a new kind of stone tool appeared, which Homo erectus invented. At about the same time, Africa’s megafauna began going extinct, and the primary casualties belonged to the elephant family. Homo erectus became apex predators then, and the extinction of Earth’s large animals began to accelerate. Mammoths evolved to graze the new grasslands several million years ago in Africa, but went extinct in Africa during that mid-Pleistocene extinction. They continued to thrive in non-African grasslands, until humans arrived. Those Acheulean hand axes were made for more than 1.5 million years, as humanity’s most enduring tool, along with fire.
The brains of Homo erectus kept growing. In anthropology there are “splitter” and “lumper” schools. Splitters see many human species in the fossil record while lumpers only see a few. The debates over the control of fire have been lively, and Richard Wrangham ignited a controversy by arguing that cooking was a key evolutionary event for the human line, and that the control of fire might be millions of years old. Even though those hand axes were made for more than 1.5 million years, there is evidence that technology kept progressing, and what is called the Middle Stone Age began about 500,000 years ago. Homo Heidelbergensis was its inventor, and that species is argued to have been the direct ancestor of Neanderthals, Homo sapiens, and perhaps Denisovans.
The first migration of the human line from Africa is thought to have happened nearly two million years ago, and although the fossil and artifact record is sparse, it is increasingly accepted that the human line lived across Africa and Eurasia ever since, with many migrations that crisscrossed the continents. The advancing and retreating Eurasian ice sheets definitely had profound impacts on Eurasia and human evolution, which scientists continue to investigate.
Today, the oldest fossils of what have been called Homo sapiens are about 300,000 years old, from Africa. But they did not have the globular skulls of today’s humans, and there is great controversy over when humans became what is called behaviorally modern. To revisit those key dates that keep getting pushed back, when Jane Goodall began her chimp studies in the 1960s, it was generally accepted that only humans used tools. But when chimps were observed using and even making tools, it began an ongoing process of redefining what humans are and what intelligence is. Chimps are far more intelligent than previously presumed. The great apes all readily learn sign language and have performed feats of memory and intelligence that surprised and even shocked scientists. Neanderthals were long seen as dim-witted brutes, but today they are accepted to have been highly capable, and the artifacts and practices that separated Homo sapiens from Neanderthals have been winnowed down quite a bit. Neanderthals were talented cooks, made art, and had other qualities that have led to quite an academic niche that extols their abilities.
Exactly how Homo sapiens became behaviorally modern and prevailed over all other human species is a subject of enduring controversy and mystery. My guess is that Homo sapiens reached a population density, likely in Africa, that allowed for a hyper-social acceleration of cultural learning. That led to what we call behavioral modernity, which was reflected in advanced technologies, art which even today looks modern, and likely a mastery of language that no other humans achieved. That is just my guess, and the controversy will outlive me. But in my studies, with my generalist approach, I saw three basic trends in the human journey that allowed us to dominate Earth like no other species ever did:
1. Our ever increasing levels of energy consumption;
2. Increasing intelligence, both individually and collectively;
3. The rise of tools, which continually became more sophisticated.
Those factors have defined the human journey and likely always will. On energy, I built on the work of Earl Cook and others to create this table on humanity’s energy practices over what I have called the Epochs of the human journey. The time from those stone tools of 3.3 million years ago to the arrival of behaviorally modern humans less than 100,000 years ago I call the First Epoch, in which apes became humans.
While today’s humans are far less than 1% as violent and aggressive as chimps are, the human journey has not been a pleasant one. As I have written, half of all offspring died, from preindustrial humans going all the way back to gorillas. A significant fraction of those deaths was from killing them. Infanticide is practiced by dozens of primate species, and during the human journey, infanticide was also performed by the parents. For instance, and I don’t know if it is still true today, but until recently, if a hunter-gatherer woman gave birth to twins, she got to pick which one to kill, as she could not afford to carry around two infants. In the hunter-gatherer phase of the human journey, anthropologists have estimated that anywhere between 10% and 50% of children were killed. It was mainly because their societies could not afford to feed them. My guess is that it also happened the First Epoch, but it could come from rivals instead of parents. Neanderthal skeletons have been noted for their many broken bones, like rodeo riders. Those breaks are thought to be from trying to kill megafauna in close quarters, but I doubt that it was all from that.
Genetic evidence supports the idea that around 60,000-to-70,000 years ago, a migration of behaviorally modern humans from Africa, of maybe only a few thousand people, was the migration that conquered Earth. I call that conquest the Second Epoch of the human journey. Wherever humans arrived in that migration, two primary events happened: the extinction of the megafauna and the extinction of all other human species. In my past generation of study, I found a disturbing trend among scientists who romanticized the human past and deflected nearly all responsibility from our species to those extinctions. I have called it the Homo sapiens bias. On one hand, it is understandable, as defending their in-groups goes back to the beginning of social animals. But it was sobering to see how many scientists could not escape that trap. It was a dogma among anthropologists until only the past generation that preliterate humans largely lived in peace. Nothing could be further from the truth. Another comforting myth embraced by far too many scientists is that the members of that migration from Africa had little or nothing to do with the extinction of the world’s megafauna. There have been cadres of scientists and scholars who attribute the megafauna extinctions to climate change, bolide events, and other nonsense.
I could provide many examples of the megafauna extinctions, but one should suffice. As I wrote earlier, when Africa collided with Eurasia, the biggest African winner was the elephant family. They quickly spread throughout Eurasia, and some became huge, such as twice as large as today’s African elephants. They made it to North America by 16 million years ago, and as soon as they could get to South America, three million years ago, they migrated there too. Adults had no effective predators, they were intelligent, with prehensile trunks, and they were opportunistic feeders that soon became “keystone” species, as they shaped and maintained the biomes that fed them. Five different kinds (genera) lived the length of and breadth of Americans when humans invaded less than 20,000 years ago. By 10,000 years ago, the elephant family was completely extinct in the Americas, and I have had to suffer through reading numerous papers and books that presented arguments and evidence that humans had little or nothing to do with it. Some of the defenses were truly ludicrous. As Ed Herman and Noam Chomsky wrote about journalists, the fact that the media serves up Big Lies daily is not a conspiracy so much as it is the structural constraints on the profession, and the vast majority of journalists actually believe what they write. I think that the same goes for those humanity-defending scientists. Even Noam blurbed one of those books that argued for a peaceful human past.
While those defenses of humanity may be understandable and can even be seen as courageous defenses of their in-groups, such scholarship helps obscure just how far humanity has come.
There was no conservation consciousness among those hunter-gatherers. They would hunt the last member of a species to death with pride. It has even happened in recent history. As Azar Gat wrote in his masterpiece, the first-contact accounts of Europeans with isolated indigenous people recorded highly violent and warlike societies, from Australia to the Pacific Northwest to the New Guinea Highlands. The skeletal evidence starkly confirms the ethnographic accounts. About a third of the women’s and a quarter of the men’s skeletons discovered in Australia from the pre-contact days had fractured skulls from interpersonal violence (as well as “parry fractures” of their arms, as they tried to defend themselves). The men generally got broken skulls from quarrels within their societies, while women got it from beatings administered by their husbands.
The favorite and most lethal method of hunter-gatherer warfare was just like what chimps do: the raid. Hunter-gatherers did it at night and at dawn, and they would slaughter the entire encampment, except for the women that they took back with them, for obvious reasons. About a quarter of hunter-gatherer men died violently. For the New Guinea Highlanders who farmed in complete isolation for thousands of years, about a third of their societies went extinct each century from warfare. Rousseau lost that fictional debate with Hobbes. Humans had nasty, brutish, and short lives, pretty much until the Industrial Revolution.
It has been estimated that hunter-gatherers killed one billion large animals during that phase of the human journey. Nearly all of that slaughter happened while Earth was in a cold period, with continental ice sheets in the Norther Hemisphere, which melted off about every 100,000 years, for several thousand years of “summer” before the ice sheets came back. It has been that way for the past million years. Earth would likely be about to grow back those ice sheets if not for the greenhouse gases, carbon dioxide chief among them, which humans have vented to the atmosphere, particularly in the past two centuries of burning hydrocarbon fuels.
Here I am, on the eve of agriculture, and already four pages in. I’ll split these Epoch posts into two and save the domestication and industrial revolutions for the next post.
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