Sapiens

How Sapiens Rose to Power and Caused the First Extinctions

Millions of years ago, humans were insignificant animals, living in the shadows of larger predators and making no more impact than a jellyfish or a gorilla. For most of our history, we shared the planet with many sibling species. While our ancestors, Homo sapiens, evolved in Africa, other humans like the Neanderthals adapted to the cold of Europe, and on the island of Flores, a dwarf species evolved to survive on limited resources. For a long time, at least six different human species walked the earth at once.

All human species shared a defining trait: an exceptionally large brain. This was a risky evolutionary bet, as a big brain is a massive drain on energy. Like a government diverting money from defense to education, we diverted energy from biceps to neurons. A chimpanzee cannot win an argument with a human, but it can easily rip a person apart. Standing upright also changed our destiny. It freed our hands for tool use but narrowed the birth canal, meaning human babies had to be born "prematurely." This long period of infant dependency forced our ancestors to develop deep social ties to survive, making us uniquely flexible and teachable.

For a long time, our place in the food chain was firmly in the middle. We were scavengers who specialized in extracting marrow from bones after the lions and hyenas had finished. This history as an underdog still haunts us; because we jumped to the top so quickly, we are full of fears and anxieties that make us more dangerous than predators who evolved their dominance over millions of years. The mastery of fire was the tool that finally broke the limits of our biology. It gave us a weapon, a way to transform our environment, and, most importantly, a way to cook. By pre-digesting food with fire, we could eat more calories with less effort, allowing our intestines to shrink and our brains to grow even larger.

About 70,000 years ago, our species left Africa and encountered these other human groups. Within a relatively short time, all our siblings vanished. Whether we interbred with them or simply out-competed and slaughtered them, we became the sole survivors of the human family. This expansion was not limited to the Old World. Roughly 45,000 years ago, Sapiens in Indonesia developed the first seafaring societies, building boats to cross hundreds of miles of open water to reach Australia.

This arrival was a turning point in the history of life on Earth. Within a few thousand years, nearly all of Australia’s giant animals vanished—two-ton wombats, flightless birds twice the size of ostriches, and marsupial lions simply disappeared. While some point to climate change, these giants had survived millions of years of weather shifts, only to die out exactly when humans arrived. The pattern repeated itself as humans pushed into the Americas about 16,000 years ago. After inventing thermal clothing to survive the Arctic, Sapiens staged a biological blitzkrieg once the glaciers melted. In just two thousand years, they reached the tip of South America, leaving a trail of extinct mammoths, mastodons, and eight-ton ground sloths in their wake.

Long before we invented the wheel or iron tools, we were already ecological serial killers. We often imagine our ancestors living in harmony with nature, but the archaeological record tells a darker story. The large, slow-breeding animals that had never learned to fear humans were the first to go. We are not just a recent threat to the environment; we have been the deadliest species in the annals of biology for tens of thousands of years.