42 pages • 1 hour read
Yuval Noah HarariUnstoppable Us, Volume 1: How Humans Took Over the World
Nonfiction | Book | Middle Grade | Published in 2022A modern alternative to SparkNotes and CliffsNotes, SuperSummary offers high-quality Study Guides with detailed chapter summaries and analysis of major themes, characters, and more.
Chapter 4Chapter Summaries & Analyses
Chapter 4 Summary: “Where Did All the Animals Go?”
When Sapiens migrated out of Africa 70,000 years ago, they went on foot. They developed rafts and canoes once they reached Asia’s coast and were able to populate the whole planet. About 50,000 years ago, they landed in Australia, which was full of megafauna, like a kangaroo that weighed more than 400 pounds and was six feet tall; giant snakes and koalas; and large, flightless birds called genyoris. All these animals became extinct after humans arrived in Australia because Sapiens cooperated in hunting them and unknowingly depleted their populations over time. These animals, which had never seen humans before, did not know to fear them. Humans’ ability to make fire worked to their advantage because they could burn down a densely forested area full of animals and then trap them. Humans similarly depleted the megafauna population on the American continents.
Humans migrated from Siberia to North America on foot due to low sea levels, and they cooperated in large groups to survive the freezing northern winters by developing needles and sewing furs together to make warm clothing that could withstand the elements: “If ancient Sapiens hadn’t invented needles, they probably couldn’t have reached America” (158). These humans rapidly adapted to new climates and environments as they spread out, learning all they could about local plants, topography, and animals: “[A]nd then they invented new tricks, developed new tools, and adapted to the new conditions” (160). They worked together to hunt large game through various strategies, causing their extinction. Smaller game survived because these animals could hide more easily from humans who were also less interested in hunting them because they provided less food. Larger animals were fewer in number and reproduced more slowly and could not survive their encounters with humans.
These animals’ extinction happened slowly but had a dramatic effect on the environment and impacted other animal populations. For instance, the Artic had a greater variety of animals and vegetation in the ancient past. This diversity was because “mammoths acted like snowplows” (170). The tusks they dragged along the land uncovered grass, which the mammoths consumed but which also fed other animals. The land was bare of grass by the springtime, when the climate warmed and new vegetation grew, which acted as another food source for regional animals. This cycle of survival and reproduction broke down when mammoths went extinct because they were not there to clear the snow from the grass. Scientists have found evidence of similar phenomena the world over. Only remote locations, like the Galapagos Islands, did not witness this human impact until modern times. Harari writes, “Perhaps if we all understood just how many animals we’ve already driven to extinction, we’d do more to protect those that still survive” (173).
Ancient humans were unaware of the devastating impact they had on animal populations, an excuse that modern humans don’t have. However, we still possess the ability to tell stories and cooperate. Harari conveys that readers can use these skills to advocate for issues that matter to them, like Kenneth Gorman, who successfully raised awareness about saving whales from extinction in the late 1960s. Humans in the past transformed the world, and so can today’s people.
Chapter 4 Analysis
Harari’s final chapter explores Sapiens’ impact on the world, past and present. It shows that Sapiens’ migrations to virtually every part of the globe had profound long-term consequences of which they were unaware. The Impact of Cooperation on Historical Developments includes negative effects from which modern societies must learn.
Human Evolution and Adaptability led our ancestors to develop methods of migration beyond walking on foot; they invented rafts and canoes to reach lands like Australia and other Pacific islands, for example. Their curiosity encouraged them to go further and further into the ocean:
[A] group of people must have decided to take the risk and sail into the unknown to see for themselves. They loaded as much food and water as they could onto the rafts and into the canoes and started rowing […] Until they finally reach Australia. That was about 50,000 years ago (148).
Many of these lands were untouched by humanity but populated by prehistoric megafauna. Australia, for instance, was teeming with large animals, like the ground sloth, giant birds, huge kangaroos, and 16-foot-long snakes. Humanity’s impact on the environment was minimal until this time. However, once they reached Australia, Sapiens “became the most dangerous animal in the world—the rulers of planet Earth” (149). Our ancestors’ skills of cooperation and fire production were devastating for Australia’s megafauna. Humans unknowingly hunted these large animals to extinction. A large animal might have been able to defend itself against a single human but stood little chance of survival when Sapiens cooperated to hunt them. The Australian megafauna also had no innate fear of humans because they had never encountered them before; Sapiens thus also had the advantageous ability to take them by surprise when hunting. Humans also caused large animals, like the wooly mammoths, to become extinct in the Americas for similar reasons. The Impact of Cooperation on Historical Developments is apparent here, too, because of its impact on the landscape. Extinct mammoths no longer cleared frozen tundra to expose a grassy food source. Smaller animals that depended on this ecosystem for survival died, and the land changed since it was no longer cleared for other plants to grow in the spring. Harari, however, notes that our ancient predecessors did not have bad intentions; they were simply very skilled hunters and unaware of the consequences of their actions.
At this point, the book enters the final stage of its argument. Unlike ancient mankind, modern humans are not ignorant of our effect on the world. We understand our behavior impacts the planet and thus, Harari emphasizes, have an obligation to do something about it. He encourages his young readers to be changemakers and not let their age prevent them from advocating for causes that matter to them. The Power of Storytelling and Human Ingenuity provides opportunities for us to make changes. Harari provides examples in earlier chapters of instances in which humans changed the stories in which they believed. We can do the same now. Kenneth Gormly is an example of a kid who was able to shift narratives about whaling in the 1960s. His advocacy helped lead to change: “[G]overnments around the world eventually passed laws and signed agreements to stop whaling. The blue whale was saved, at least for a while” (178-79). Harari shows that humans can accomplish great things because of our “superpower.” His final chapter ends on a hopeful note and with a call to action, emphasizing the book’s message that humans have a responsibility in correlation to their power in the world.
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